Fixed small function

Added configuration
Cleaned up context args

Cargo.lock

@@ -8,12 +8,6 @@ version = "1.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "d468802bab17cbc0cc575e9b053f41e72aa36bfa6b7f55e3529ffa43161b97fa"
 
-[[package]]
-name = "az"
-version = "1.2.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "7b7e4c2464d97fe331d41de9d5db0def0a96f4d823b8b32a2efd503578988973"
-
 [[package]]
 name = "bitflags"
 version = "1.3.2"
@@ -28,24 +22,14 @@ checksum = "baf1de4339761588bc0619e3cbc0120ee582ebb74b53b4efbf79117bd2da40fd"
 
 [[package]]
 name = "daisycalc"
-version = "1.0.0"
+version = "1.0.1"
 dependencies = [
  "cfg-if",
- "rug",
+ "num",
  "termion",
  "toml",
 ]
 
-[[package]]
-name = "gmp-mpfr-sys"
-version = "1.5.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "5b560063e2ffa8ce9c2ef9bf487f2944a97deca5b8de0b5bcd0ae6437ef8b75f"
-dependencies = [
- "libc",
- "windows-sys",
-]
-
 [[package]]
 name = "hashbrown"
 version = "0.12.3"
@@ -64,9 +48,9 @@ dependencies = [
 
 [[package]]
 name = "libc"
-version = "0.2.140"
+version = "0.2.147"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "99227334921fae1a979cf0bfdfcc6b3e5ce376ef57e16fb6fb3ea2ed6095f80c"
+checksum = "b4668fb0ea861c1df094127ac5f1da3409a82116a4ba74fca2e58ef927159bb3"
 
 [[package]]
 name = "memchr"
@@ -74,6 +58,82 @@ version = "2.5.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "2dffe52ecf27772e601905b7522cb4ef790d2cc203488bbd0e2fe85fcb74566d"
 
+[[package]]
+name = "num"
+version = "0.4.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b05180d69e3da0e530ba2a1dae5110317e49e3b7f3d41be227dc5f92e49ee7af"
+dependencies = [
+ "num-bigint",
+ "num-complex",
+ "num-integer",
+ "num-iter",
+ "num-rational",
+ "num-traits",
+]
+
+[[package]]
+name = "num-bigint"
+version = "0.4.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "608e7659b5c3d7cba262d894801b9ec9d00de989e8a82bd4bef91d08da45cdc0"
+dependencies = [
+ "autocfg",
+ "num-integer",
+ "num-traits",
+]
+
+[[package]]
+name = "num-complex"
+version = "0.4.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1ba157ca0885411de85d6ca030ba7e2a83a28636056c7c699b07c8b6f7383214"
+dependencies = [
+ "num-traits",
+]
+
+[[package]]
+name = "num-integer"
+version = "0.1.45"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "225d3389fb3509a24c93f5c29eb6bde2586b98d9f016636dff58d7c6f7569cd9"
+dependencies = [
+ "autocfg",
+ "num-traits",
+]
+
+[[package]]
+name = "num-iter"
+version = "0.1.43"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7d03e6c028c5dc5cac6e2dec0efda81fc887605bb3d884578bb6d6bf7514e252"
+dependencies = [
+ "autocfg",
+ "num-integer",
+ "num-traits",
+]
+
+[[package]]
+name = "num-rational"
+version = "0.4.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0638a1c9d0a3c0914158145bc76cff373a75a627e6ecbfb71cbe6f453a5a19b0"
+dependencies = [
+ "autocfg",
+ "num-bigint",
+ "num-integer",
+ "num-traits",
+]
+
+[[package]]
+name = "num-traits"
+version = "0.2.16"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f30b0abd723be7e2ffca1272140fac1a2f084c77ec3e123c192b66af1ee9e6c2"
+dependencies = [
+ "autocfg",
+]
+
 [[package]]
 name = "numtoa"
 version = "0.1.0"
@@ -98,17 +158,6 @@ dependencies = [
  "redox_syscall",
 ]
 
-[[package]]
-name = "rug"
-version = "1.19.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "555e8b44763d034526db899c88cd56ccc4486cd38b444c8aa0e79d4e70ae5a34"
-dependencies = [
- "az",
- "gmp-mpfr-sys",
- "libc",
-]
-
 [[package]]
 name = "serde"
 version = "1.0.164"
@@ -170,63 +219,6 @@ dependencies = [
  "winnow",
 ]
 
-[[package]]
-name = "windows-sys"
-version = "0.42.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "5a3e1820f08b8513f676f7ab6c1f99ff312fb97b553d30ff4dd86f9f15728aa7"
-dependencies = [
- "windows_aarch64_gnullvm",
- "windows_aarch64_msvc",
- "windows_i686_gnu",
- "windows_i686_msvc",
- "windows_x86_64_gnu",
- "windows_x86_64_gnullvm",
- "windows_x86_64_msvc",
-]
-
-[[package]]
-name = "windows_aarch64_gnullvm"
-version = "0.42.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "597a5118570b68bc08d8d59125332c54f1ba9d9adeedeef5b99b02ba2b0698f8"
-
-[[package]]
-name = "windows_aarch64_msvc"
-version = "0.42.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e08e8864a60f06ef0d0ff4ba04124db8b0fb3be5776a5cd47641e942e58c4d43"
-
-[[package]]
-name = "windows_i686_gnu"
-version = "0.42.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c61d927d8da41da96a81f029489353e68739737d3beca43145c8afec9a31a84f"
-
-[[package]]
-name = "windows_i686_msvc"
-version = "0.42.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "44d840b6ec649f480a41c8d80f9c65108b92d89345dd94027bfe06ac444d1060"
-
-[[package]]
-name = "windows_x86_64_gnu"
-version = "0.42.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8de912b8b8feb55c064867cf047dda097f92d51efad5b491dfb98f6bbb70cb36"
-
-[[package]]
-name = "windows_x86_64_gnullvm"
-version = "0.42.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "26d41b46a36d453748aedef1486d5c7a85db22e56aff34643984ea85514e94a3"
-
-[[package]]
-name = "windows_x86_64_msvc"
-version = "0.42.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "9aec5da331524158c6d1a4ac0ab1541149c0b9505fde06423b02f5ef0106b9f0"
-
 [[package]]
 name = "winnow"
 version = "0.4.6"

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "daisycalc"
-version = "1.0.0"
+version = "1.0.1"
 edition = "2021"
 build = "buildscript/main.rs"
 license = "GPL-3.0-only"
@@ -28,7 +28,8 @@ cfg-if = "1.0.0"
 
 [target.'cfg(target_family = "unix")'.dependencies]
 termion = "2.0.1"
-rug = "1.19.2"
+num = "0.4.1"
+#astro-float = "0.7.1"
 
 [build-dependencies]
 toml = "0.7.4"

README.md

@@ -5,6 +5,7 @@ A high-precision scientific calculator with support for units, derivatives, and
 Many features are missing, this is still under development.
 
 # 📦 Installation
+ - **Cargo:** `cargo install daisycalc`
  - **Arch:** `yay -S daisy`
  - **Debian:** coming soon
 
@@ -14,7 +15,7 @@ Binary will be in `target/release/daisy`
 
 # 📹 Screenshot
 
-![](https://betalupi.com/static/git/daisy.png)
+![Screenshot](https://github.com/rm-dr/daisy/assets/96270320/cc71887a-0fde-46b2-a13b-96b05098b158)
 
 # 🛠️ Features
  - Open-source

TODO.md

@@ -1,50 +1,40 @@
 ## Version Bump checklist
+ - TODO: build and publish script
  - update Cargo.toml
  - run cargo test
  - commit
- - git tag -a v1.0.0 -m "Version 1.0.0"
  - push
+ - merge
+ - git tag -a v1.0.0 -m "Version 1.0.0" on merge commit
  - cargo publish
  - Update packages
 
 
-
 ## Pre-release
- - Fix linelocation (consistent, what does an operator's linelocation mean?)
  - Tuple operations
  - we don't need vectors as arguments to operators
- - Assignment tests
+ - Fix linelocation when evaluating functions
 
 ## Parser
- - Better error when `sin = 2`
  - Should functions be operators?
  - Binary, hex, octal numbers
 
 
 ## General
+ - Better tests (assignment, many expressions in one context)
  - Optional config file
  - Optional history file
- - daisyrc file
  - Compile to WASM, publish a webapp
- - Options:
-   - disable replacement
-   - disable special characters
-   - 1/ as -1 power toggle
-   - powers as superscripts toggle
  - evaluate straight from command line
- - Auto-push to crates.io
- - Package for debian
-
+ - Package for debian, nix
 
 
 ## Internals
  - Non-recursive treeify
  - Faster factorial function. Maybe use gamma instead?
  - Arbitrary precision float (rug doesn't offer arbitrary exponents)
- - Remove rug dependency (too big, incompatible)
 
 ## Math Features
- - Dice
  - Mean, Median, Min
  - Arbitrary base logarithm
  - Derivatives
@@ -52,21 +42,16 @@
  - Complex numbers
  - acot/acoth functions
  - Sums and products with functional arguments
+ - Add functions: gcd, inverse mod, dice
 
 ## Prompt
+ - Fix terminal color detection
  - Live syntax/output (like firefox js terminal)
- - Syntax highlight input and output
+ - Syntax highlighting
  - fish-style tab completion
  - Numbered expressions, history recall
- - Color configuration
  - Enable/disable unit sets (defaults?)
  - Consistent unit ordering
- - Better linelocation
-   - we shouldn't need to re-print user input on evaluation errors, red arrows should adjust themselves to the prettyprinted string
- - Backend-independent colorful printing
-   - Better colors in error texts
- - Better substitution. Consistent: when ascii, when unicode?
- - Command to list substitutions
 
 ## Units
  - long prefixes (megatonne, etc)

shell.nix

@@ -0,0 +1,11 @@
+let
+ pkgs = import (fetchTarball "https://github.com/NixOS/nixpkgs/archive/f155f0cf4ea43c4e3c8918d2d327d44777b6cad4.tar.gz") {};
+in pkgs.mkShell {
+  buildInputs = with pkgs; [
+    cargo
+    rustc
+    rustfmt
+    m4
+   ];
+}
+

src/command/mod.rs

@@ -44,8 +44,8 @@ fn greeter() -> FormattedText {
 
 #[inline(always)]
 pub fn do_command(
+	context: &mut Context,
 	s: &String,
-	context: &mut Context
 ) -> FormattedText {
 	let args: Vec<&str> = s.split(" ").collect();
 	let first = args[0];
@@ -170,7 +170,7 @@ pub fn do_command(
 
 					t.push(&format!(
 						"  {key}{padding} = [c]{v}[n]\n",
-						v = value.to_string(),
+						v = value.display(context),
 					));
 				}
 			}
@@ -184,7 +184,7 @@ pub fn do_command(
 
 					t.push(&format!(
 						"  {s}{padding} = [c]{v}[n]\n",
-						v = exp.to_string(),
+						v = exp.display(context),
 					));
 				}
 			}
@@ -224,13 +224,13 @@ pub fn do_command(
 			if args.len() != 2 {
 				return FormattedText::new(
 					format!(
-						"[c]{first}[n] [t]takes exactly two arguments.[n]\n\n",
+						"[c]{first}[n] [t]takes exactly one argument.[n]\n\n",
 					)
 				);
 			}
 
 			let v = args[1].to_string();
-			let v = substitute(&v, context);
+			let v = substitute(context, &v);
 			let r = context.delete(&v);
 
 			return match r {

src/context.rs

@@ -3,7 +3,68 @@ use crate::quantity::freeunit_from_string;
 use std::collections::HashMap;
 
 #[derive(Debug)]
+#[derive(Clone)]
+pub struct Config {
+
+	// How to color terminal text.
+	// 0: No colors
+	// 1: ANSI-compatible, 8 colors
+	// 2: Full 256 color and special styles
+	pub term_color_type: u8,
+
+	// Should we accept input and print in unicode?
+	//pub enable_unicode: bool,
+
+	// Should we replace certain strings (like "pi")
+	// with prettier unicode alternatives?
+	//
+	// Automatically disabled if enable_unicode is off.
+	pub enable_substituion: bool,
+
+	// Should we print simple powers
+	// as unicode superscript chars?
+	//
+	// Automatically disables if enable_unicode is off.
+	pub enable_super_powers: bool,
+
+	// Should we write "one-over" fractions
+	// as -1 powers?
+	//
+	// Automatically disabled if enable_super_powers is off.
+	pub enable_one_over_power: bool,
+}
+
+impl Config {
+	pub fn new() -> Config {
+		Config{
+			term_color_type: 2,
+			enable_substituion: true,
+			//enable_unicode: true,
+			enable_super_powers: true,
+			enable_one_over_power: true
+		}
+	}
+
+	pub fn check(&mut self) {
+		//if !self.enable_unicode {
+		//	self.enable_substituion = false;
+		//	self.enable_super_powers = false;
+		//}
+
+		if !self.enable_super_powers {
+			self.enable_one_over_power = false
+		}
+	}
+}
+
+
+
+
+#[derive(Debug)]
+//#[derive(Clone)]
 pub struct Context {
+	pub config: Config,
+
 	history: Vec<Expression>,
 	variables: HashMap<String, Expression>,
 	functions: HashMap<String, (Vec<String>, Expression)>,
@@ -15,11 +76,12 @@ pub struct Context {
 // General functions
 impl Context {
 	pub fn new() -> Context {
-		Context{
+		Context {
+			config: Config::new(),
 			history: Vec::new(),
 			variables: HashMap::new(),
 			functions: HashMap::new(),
-			shadow: HashMap::new(),
+			shadow: HashMap::new()
 		}
 	}
 
@@ -64,6 +126,7 @@ impl Context {
 		} else { panic!() }
 	}
 
+	// Can we define a new variable with this name?
 	pub fn valid_varible(&self, s: &str) -> bool {
 		if {
 			Function::from_string(s).is_some() ||
@@ -83,11 +146,18 @@ impl Context {
 		}
 	}
 
+	// Can we get a value fro mthis variable name?
 	pub fn is_varible(&self, s: &str) -> bool {
-		return self.valid_varible(s) && (
-			self.variables.contains_key(s) ||
-			self.shadow.contains_key(s)
-		);
+		return {
+			(
+				s == "ans" &&
+				self.history.len() != 0
+			) ||
+			(
+				self.valid_varible(s) &&
+				(self.variables.contains_key(s) || self.shadow.contains_key(s))
+			)
+		};
 	}
 
 	pub fn get_variables(&self) -> &HashMap<String, Expression> {

src/entrypoint/unix/promptbuffer.rs

@@ -1,11 +1,12 @@
 use std::collections::VecDeque;
 use std::io::Write;
 use termion::raw::RawTerminal;
-use termion::color;
-use termion::style;
+use crate::formattedtext;
 use crate::parser::substitute_cursor;
 use crate::context::Context;
 
+const PROMPT_STR: &str = "==> ";
+
 #[derive(Debug)]
 pub struct PromptBuffer {
 	// History
@@ -37,70 +38,43 @@ impl PromptBuffer {
 	}
 
 	// Same as write_primpt, but pretends there is no cursor
-	pub fn write_prompt_nocursor(&mut self, stdout: &mut RawTerminal<std::io::Stdout>, context: &Context) -> Result<(), std::io::Error> {
-		// Draw prettyprinted expression
-		let (_, s) = substitute_cursor(&self.get_contents(), self.buffer.chars().count(), context);
-
-		write!(
-			stdout, "\r{}{}==>{}{} {}",
-			style::Bold,
-			color::Fg(color::Blue),
-			color::Fg(color::Reset),
-			style::Reset,
-			s
-		)?;
-
-		// If this string is shorter, clear the remaining old one.
-		if s.chars().count() < self.last_print_len {
-			write!(
-				stdout, "{}{}",
-				" ".repeat(self.last_print_len - s.chars().count()),
-				termion::cursor::Left((self.last_print_len - s.chars().count()) as u16)
-			)?;
+	pub fn write_prompt_nocursor(&mut self, context: &Context, stdout: &mut RawTerminal<std::io::Stdout>) -> Result<(), std::io::Error> {
+		let tmp = self.cursor;
+		self.cursor = 0;
+		let r = self.write_prompt(context, stdout);
+		self.cursor = tmp;
+		return r;
 	}
 
-		self.last_print_len = s.chars().count();
-		stdout.flush()?;
-		return Ok(());
-	}
-
-	pub fn write_prompt(&mut self, stdout: &mut RawTerminal<std::io::Stdout>, context: &Context) -> Result<(), std::io::Error> {
+	pub fn write_prompt(&mut self, context: &Context, stdout: &mut RawTerminal<std::io::Stdout>) -> Result<(), std::io::Error> {
 		let l = self.buffer.chars().count();
 		let i = if l == 0 {0} else {l - self.cursor};
 
 		// Draw prettyprinted expression
-		let (display_cursor, s) = substitute_cursor(&self.get_contents(), i, context);
+		let (display_c, s) = substitute_cursor(context, &self.get_contents(), i);
 	
 		write!(
-			stdout, "\r{}{}==>{}{} {}",
-			style::Bold,
-			color::Fg(color::Blue),
-			color::Fg(color::Reset),
-			style::Reset,
+			stdout, "\r{}{PROMPT_STR}{}{}",
+			formattedtext::format_map('p', context).unwrap(),
+			formattedtext::format_map('n', context).unwrap(),
 			s
 		)?;
 
 		// If this string is shorter, clear the remaining old one.
 		if s.chars().count() < self.last_print_len {
-			write!(
-				stdout, "{}{}",
-				" ".repeat(self.last_print_len - s.chars().count()),
-				termion::cursor::Left((self.last_print_len - s.chars().count()) as u16)
-			)?;
-		}
-
-
-		// Move cursor to correct position
-		if display_cursor != 0 {
 			write!(
 				stdout, "{}",
-				termion::cursor::Left(display_cursor as u16)
+				" ".repeat(self.last_print_len - s.chars().count()),
 			)?;
-			stdout.flush()?;
 		}
-		self.last_print_len = s.chars().count();
+
+		write!(
+			stdout, "\r{}",
+			termion::cursor::Right((display_c + PROMPT_STR.chars().count()) as u16)
+		)?;
 
 		stdout.flush()?;
+		self.last_print_len = s.chars().count();
 
 		return Ok(());
 	}

src/entrypoint/unix/unix.rs

@@ -1,4 +1,3 @@
-use std::io::Write;
 use std::io::stdout;
 use std::io::stdin;
 use std::env;
@@ -6,35 +5,63 @@ use std::env;
 use termion::{
 	event::Key,
 	input::TermRead,
-	raw::IntoRawMode
+	raw::IntoRawMode,
+	color::DetectColors
 };
 
 use super::promptbuffer::PromptBuffer;
 use crate::command;
 use crate::context::Context;
-
+use crate::FormattedText;
 
 #[inline(always)]
 pub fn main() -> Result<(), std::io::Error> {
 	let mut stdout = stdout().into_raw_mode().unwrap();
 	let mut pb: PromptBuffer = PromptBuffer::new(64);
-	let mut context: Context = Context::new();
+	let mut context = Context::new();
+
+	// Set color compatibilty
+	let term_colors = stdout.available_colors().unwrap_or(0);
+	if term_colors >= 256 {
+		context.config.term_color_type = 2;
+	} else if term_colors >= 8 {
+		context.config.term_color_type = 1;
+	} else {
+		context.config.term_color_type = 0;
+	}
+
+	context.config.check();
+
 
 
 	// Handle command-line arguments
 	let args: Vec<String> = env::args().collect();
 	if args.iter().any(|s| s == "--help") {
-		let t = command::do_command(&String::from("help"), &mut context);
-		t.write(&mut stdout)?;
+		let t = command::do_command(&mut context, &String::from("help"));
+		t.write(&context, &mut stdout)?;
 		return Ok(());
 	} else if args.iter().any(|s| s == "--version") {
-		write!(stdout, "Daisy v{}\r\n", env!("CARGO_PKG_VERSION"))?;
+		let t = FormattedText::new(format!(
+			"Daisy v{}\n", env!("CARGO_PKG_VERSION")
+		));
+		t.write(&context, &mut stdout)?;
+		return Ok(());
+	} else if args.iter().any(|s| s == "--debug") {
+		let t = FormattedText::new(format!(
+			concat!(
+				"Daisy v{}\n",
+				"Your terminal supports {} colors.\n"
+			),
+			env!("CARGO_PKG_VERSION"),
+			term_colors
+		));
+		t.write(&context, &mut stdout)?;
 		return Ok(());
 	}
 
 	'outer: loop {
 
-		pb.write_prompt(&mut stdout, &context)?;
+		pb.write_prompt(&mut context, &mut stdout)?;
 
 		let stdin = stdin();
 		for c in stdin.keys() {
@@ -43,19 +70,19 @@ pub fn main() -> Result<(), std::io::Error> {
 					'\n' => {
 						// Print again without cursor, in case we pressed enter
 						// while inside a substitution
-						pb.write_prompt_nocursor(&mut stdout, &context)?;
+						pb.write_prompt_nocursor(&mut context, &mut stdout)?;
 						let in_str = pb.enter();
-						write!(stdout, "\r\n")?;
+						FormattedText::newline(&mut stdout)?;
 						if in_str == "" { break; }
 
 						if in_str.trim() == "quit" {
 							break 'outer;
 						} else {
-							let r = crate::do_string(&in_str, &mut context);
+							let r = crate::do_string(&mut context, &in_str);
 
 							match r {
 								Ok(t) | Err(t) => {
-									t.write(&mut stdout).unwrap();
+									t.write(&context, &mut stdout).unwrap();
 								}
 							}
 						}
@@ -79,10 +106,10 @@ pub fn main() -> Result<(), std::io::Error> {
 				};
 			};
 
-			pb.write_prompt(&mut stdout, &context)?;
+			pb.write_prompt(&mut context, &mut stdout)?;
 		}
 	}
 
-	write!(stdout, "\r\n")?;
+	FormattedText::newline(&mut stdout)?;
 	return Ok(());
 }

src/evaluate/evaluate.rs

@@ -9,8 +9,8 @@ use super::function::eval_function;
 
 
 pub fn evaluate(
-	t: &Expression,
-	context: &mut Context
+	context: &mut Context,
+	t: &Expression
 ) -> Result<
 	Expression,
 	(LineLocation, DaisyError)
@@ -51,7 +51,7 @@ pub fn evaluate(
 			let new = match g {
 				Expression::Quantity(_, _) => None,
 				Expression::Tuple(_, _) => None,
-				Expression::Constant(_, c) => { Some(evaluate(&c.value(), context).unwrap()) },
+				Expression::Constant(_, c) => { Some(evaluate(context, &c.value()).unwrap()) },
 				Expression::Variable(l, s) => {
 					// Don't move up, re-evaluate
 					// This makes variables containing floating variables work properly
@@ -63,8 +63,8 @@ pub fn evaluate(
 
 					context.get_variable(&s)
 				},
-				Expression::Operator(_, Operator::Function(_), _) => { Some(eval_function(g)?) },
-				Expression::Operator(_, _, _) => { eval_operator(g, context)? },
+				Expression::Operator(_, Operator::Function(_), _) => { eval_function(g)? },
+				Expression::Operator(_, _, _) => { eval_operator(context, g)? },
 			};
 
 			if let Some(mut new) = new {

src/evaluate/function.rs

@@ -26,7 +26,7 @@ fn to_radians(q: Quantity) -> Result<Quantity, ()> {
 
 
 
-pub fn eval_function(g: &Expression) -> Result<Expression, (LineLocation, DaisyError)> {
+pub fn eval_function(g: &Expression) -> Result<Option<Expression>, (LineLocation, DaisyError)> {
 
 	let Expression::Operator(loc, Operator::Function(f), args) = g else {unreachable!()};
 
@@ -41,113 +41,112 @@ pub fn eval_function(g: &Expression) -> Result<Expression, (LineLocation, DaisyE
 		))
 	};
 
-	let Expression::Quantity(l, q) = a else {panic!()};
-
+	let Expression::Quantity(l, q) = a else { return Ok(None); };
 
 	match f {
-		Function::NoUnit => { return Ok(Expression::Quantity(*loc + *l, q.without_unit())); }
-		Function::ToBase => { return Ok(Expression::Quantity(*loc + *l, q.convert_to_base())); }
+		Function::NoUnit => { return Ok(Some(Expression::Quantity(*loc + *l, q.without_unit()))); }
+		Function::ToBase => { return Ok(Some(Expression::Quantity(*loc + *l, q.convert_to_base()))); }
 
 
 
 		Function::Abs => {
 			if !q.unitless() { return Err((*loc + *l, DaisyError::IncompatibleUnit));}
-			return Ok(Expression::Quantity(*loc + *l, q.abs()));
+			return Ok(Some(Expression::Quantity(*loc + *l, q.abs())));
 		},
 		Function::Floor => {
 			if !q.unitless() { return Err((*loc + *l, DaisyError::IncompatibleUnit));}
-			return Ok(Expression::Quantity(*loc + *l, q.floor()));
+			return Ok(Some(Expression::Quantity(*loc + *l, q.floor())));
 		},
 		Function::Ceil => {
 			if !q.unitless() { return Err((*loc + *l, DaisyError::IncompatibleUnit));}
-			return Ok(Expression::Quantity(*loc + *l, q.ceil()));
+			return Ok(Some(Expression::Quantity(*loc + *l, q.ceil())));
 		},
 		Function::Round => {
 			if !q.unitless() { return Err((*loc + *l, DaisyError::IncompatibleUnit));}
-			return Ok(Expression::Quantity(*loc + *l, q.round()));
+			return Ok(Some(Expression::Quantity(*loc + *l, q.round())));
 		},
 		Function::NaturalLog => {
 			if !q.unitless() { return Err((*loc + *l, DaisyError::IncompatibleUnit));}
-			return Ok(Expression::Quantity(*loc + *l, q.ln()));
+			return Ok(Some(Expression::Quantity(*loc + *l, q.ln())));
 		},
 		Function::TenLog => {
 			if !q.unitless() { return Err((*loc + *l, DaisyError::IncompatibleUnit));}
-			return Ok(Expression::Quantity(*loc + *l, q.log10()));
+			return Ok(Some(Expression::Quantity(*loc + *l, q.log10())));
 		},
 
 
 
 		Function::Sin => {
 			let Ok(q) = to_radians(q.clone()) else { return Err((*loc + *l, DaisyError::IncompatibleUnit)); };
-			return Ok(Expression::Quantity(*loc + *l, q.sin()));
+			return Ok(Some(Expression::Quantity(*loc + *l, q.sin())));
 		},
 		Function::Cos => {
 			let Ok(q) = to_radians(q.clone()) else { return Err((*loc + *l, DaisyError::IncompatibleUnit)); };
-			return Ok(Expression::Quantity(*loc + *l, q.cos()));
+			return Ok(Some(Expression::Quantity(*loc + *l, q.cos())));
 		},
 		Function::Tan => {
 			let Ok(q) = to_radians(q.clone()) else { return Err((*loc + *l, DaisyError::IncompatibleUnit)); };
-			return Ok(Expression::Quantity(*loc + *l, q.tan()));
+			return Ok(Some(Expression::Quantity(*loc + *l, q.tan())));
 		},
 		Function::Csc => {
 			let Ok(q) = to_radians(q.clone()) else { return Err((*loc + *l, DaisyError::IncompatibleUnit)); };
-			return Ok(Expression::Quantity(*loc + *l, q.csc()));
+			return Ok(Some(Expression::Quantity(*loc + *l, q.csc())));
 		},
 		Function::Sec => {
 			let Ok(q) = to_radians(q.clone()) else { return Err((*loc + *l, DaisyError::IncompatibleUnit)); };
-			return Ok(Expression::Quantity(*loc + *l, q.sec()));
+			return Ok(Some(Expression::Quantity(*loc + *l, q.sec())));
 		},
 		Function::Cot => {
 			let Ok(q) = to_radians(q.clone()) else { return Err((*loc + *l, DaisyError::IncompatibleUnit)); };
-			return Ok(Expression::Quantity(*loc + *l, q.cot()));
+			return Ok(Some(Expression::Quantity(*loc + *l, q.cot())));
 		},
 		Function::Sinh => {
 			let Ok(q) = to_radians(q.clone()) else { return Err((*loc + *l, DaisyError::IncompatibleUnit)); };
-			return Ok(Expression::Quantity(*loc + *l, q.sinh()));
+			return Ok(Some(Expression::Quantity(*loc + *l, q.sinh())));
 		},
 		Function::Cosh => {
 			let Ok(q) = to_radians(q.clone()) else { return Err((*loc + *l, DaisyError::IncompatibleUnit)); };
-			return Ok(Expression::Quantity(*loc + *l, q.cosh()));
+			return Ok(Some(Expression::Quantity(*loc + *l, q.cosh())));
 		},
 		Function::Tanh => {
 			let Ok(q) = to_radians(q.clone()) else { return Err((*loc + *l, DaisyError::IncompatibleUnit)); };
-			return Ok(Expression::Quantity(*loc + *l, q.tanh()));
+			return Ok(Some(Expression::Quantity(*loc + *l, q.tanh())));
 		},
 		Function::Csch => {
 			let Ok(q) = to_radians(q.clone()) else { return Err((*loc + *l, DaisyError::IncompatibleUnit)); };
-			return Ok(Expression::Quantity(*loc + *l, q.csch()));
+			return Ok(Some(Expression::Quantity(*loc + *l, q.csch())));
 		},
 		Function::Sech => {
 			let Ok(q) = to_radians(q.clone()) else { return Err((*loc + *l, DaisyError::IncompatibleUnit)); };
-			return Ok(Expression::Quantity(*loc + *l, q.sech()));
+			return Ok(Some(Expression::Quantity(*loc + *l, q.sech())));
 		},
 		Function::Coth => {
 			let Ok(q) = to_radians(q.clone()) else { return Err((*loc + *l, DaisyError::IncompatibleUnit)); };
-			return Ok(Expression::Quantity(*loc + *l, q.coth()));
+			return Ok(Some(Expression::Quantity(*loc + *l, q.coth())));
 		},
 		Function::Asin => {
 			if !q.unitless() { return Err((*loc + *l, DaisyError::IncompatibleUnit));}
-			return Ok(Expression::Quantity(*loc + *l, q.asin()));
+			return Ok(Some(Expression::Quantity(*loc + *l, q.asin())));
 		},
 		Function::Acos => {
 			if !q.unitless() { return Err((*loc + *l, DaisyError::IncompatibleUnit));}
-			return Ok(Expression::Quantity(*loc + *l, q.acos()));
+			return Ok(Some(Expression::Quantity(*loc + *l, q.acos())));
 		},
 		Function::Atan => {
 			if !q.unitless() { return Err((*loc + *l, DaisyError::IncompatibleUnit));}
-			return Ok(Expression::Quantity(*loc + *l, q.atan()));
+			return Ok(Some(Expression::Quantity(*loc + *l, q.atan())));
 		},
 		Function::Asinh => {
 			if !q.unitless() { return Err((*loc + *l, DaisyError::IncompatibleUnit));}
-			return Ok(Expression::Quantity(*loc + *l, q.asinh()));
+			return Ok(Some(Expression::Quantity(*loc + *l, q.asinh())));
 		},
 		Function::Acosh => {
 			if !q.unitless() { return Err((*loc + *l, DaisyError::IncompatibleUnit));}
-			return Ok(Expression::Quantity(*loc + *l, q.acosh()));
+			return Ok(Some(Expression::Quantity(*loc + *l, q.acosh())));
 		},
 		Function::Atanh => {
 			if !q.unitless() { return Err((*loc + *l, DaisyError::IncompatibleUnit));}
-			return Ok(Expression::Quantity(*loc + *l, q.atanh()));
+			return Ok(Some(Expression::Quantity(*loc + *l, q.atanh())));
 		},
 
 
@@ -160,7 +159,7 @@ pub fn eval_function(g: &Expression) -> Result<Expression, (LineLocation, DaisyE
 			let mut r = q.without_unit();
 			r += Quantity::new_rational(-273.15f64).unwrap();
 
-			return Ok(Expression::Quantity(*loc + *l, r));
+			return Ok(Some(Expression::Quantity(*loc + *l, r)));
 		},
 		Function::ToFahrenheit => {
 			let mut k = Quantity::new_rational(1f64).unwrap();
@@ -172,7 +171,7 @@ pub fn eval_function(g: &Expression) -> Result<Expression, (LineLocation, DaisyE
 			r += Quantity::new_rational(-459.67).unwrap();
 
 
-			return Ok(Expression::Quantity(*loc + *l, r));
+			return Ok(Some(Expression::Quantity(*loc + *l, r)));
 		},
 		Function::FromCelsius => {
 			if !q.unitless() { return Err((*loc + *l, DaisyError::IncompatibleUnit));}
@@ -181,7 +180,7 @@ pub fn eval_function(g: &Expression) -> Result<Expression, (LineLocation, DaisyE
 			r += q.clone();
 			r.insert_unit(FreeUnit::from_whole(WholeUnit::Kelvin), Scalar::new_rational(1f64).unwrap());
 
-			return Ok(Expression::Quantity(*loc + *l, r));
+			return Ok(Some(Expression::Quantity(*loc + *l, r)));
 		},
 		Function::FromFahrenheit => {
 			if !q.unitless() { return Err((*loc + *l, DaisyError::IncompatibleUnit));}
@@ -191,7 +190,7 @@ pub fn eval_function(g: &Expression) -> Result<Expression, (LineLocation, DaisyE
 			r *= Quantity::new_rational_from_frac(5i64, 9i64).unwrap();
 			r.insert_unit(FreeUnit::from_whole(WholeUnit::Kelvin), Scalar::new_rational(1f64).unwrap());
 
-			return Ok(Expression::Quantity(*loc + *l, r));
+			return Ok(Some(Expression::Quantity(*loc + *l, r)));
 		}
 	}
 }

src/evaluate/operator.rs

@@ -7,7 +7,7 @@ use crate::errors::DaisyError;
 use super::evaluate;
 
 
-pub fn eval_operator(g: &Expression, context: &mut Context) -> Result<Option<Expression>, (LineLocation, DaisyError)> {
+pub fn eval_operator(context: &mut Context, g: &Expression) -> Result<Option<Expression>, (LineLocation, DaisyError)> {
 
 	let Expression::Operator(op_loc, op, args) = g else {panic!()};
 
@@ -52,7 +52,7 @@ pub fn eval_operator(g: &Expression, context: &mut Context) -> Result<Option<Exp
 			}
 
 
-			let r = evaluate(&exp, context)?;
+			let r = evaluate(context, &exp)?;
 			context.clear_shadow();
 
 			return Ok(Some(r));
@@ -75,12 +75,26 @@ pub fn eval_operator(g: &Expression, context: &mut Context) -> Result<Option<Exp
 			if let Expression::Quantity(la, a) = a {
 				if let Expression::Quantity(lb, b) = b {
 					if !a.unit.compatible_with(&b.unit) {
+						let a = a.convert_to_base().unit;
+						let b = b.convert_to_base().unit;
+
+						let a_s: String;
+						let b_s: String;
+						if a.unitless() {
+							a_s = String::from("scalar");
+						} else {
+							a_s = a.display(context);
+						}
+
+						if b.unitless() {
+							b_s = String::from("scalar");
+						} else {
+							b_s = b.display(context);
+						}
+
 						return Err((
 							*la + *lb + *op_loc,
-							DaisyError::IncompatibleUnits(
-								a.convert_to_base().unit.to_string(),
-								b.convert_to_base().unit.to_string()
-							)
+							DaisyError::IncompatibleUnits(a_s, b_s)
 						));
 					}
 					return Ok(Some(Expression::Quantity(*la + *lb + *op_loc, a.clone() + b.clone())));
@@ -98,12 +112,24 @@ pub fn eval_operator(g: &Expression, context: &mut Context) -> Result<Option<Exp
 			if let Expression::Quantity(la, a) = a {
 				if let Expression::Quantity(lb, b) = b {
 					if !a.unit.compatible_with(&b.unit) {
+
+						let a_s: String;
+						let b_s: String;
+						if a.unitless() {
+							a_s = String::from("scalar");
+						} else {
+							a_s = a.display(context);
+						}
+
+						if b.unitless() {
+							b_s = String::from("scalar");
+						} else {
+							b_s = b.display(context);
+						}
+
 						return Err((
 							*la + *lb + *op_loc,
-							DaisyError::IncompatibleUnits(
-								a.convert_to_base().unit.to_string(),
-								b.convert_to_base().unit.to_string()
-							)
+							DaisyError::IncompatibleUnits(a_s, b_s)
 						));
 					}
 					return Ok(Some(Expression::Quantity(*la + *lb + *op_loc, a.clone() - b.clone())));
@@ -138,7 +164,8 @@ pub fn eval_operator(g: &Expression, context: &mut Context) -> Result<Option<Exp
 
 			if let Expression::Quantity(la, a) = a {
 				if let Expression::Quantity(lb, b) = b {
-					return Ok(Some(Expression::Quantity(*la + *lb + *op_loc, a.clone() * b.clone())));
+					let o = a.clone() * b.clone();
+					return Ok(Some(Expression::Quantity(*la + *lb + *op_loc, o)));
 				}
 			}
 
@@ -162,6 +189,11 @@ pub fn eval_operator(g: &Expression, context: &mut Context) -> Result<Option<Exp
 					if va.fract() != Quantity::new_rational(0f64).unwrap() { return Err((*la + *lb + *op_loc, DaisyError::BadMath)); }
 					if vb.fract() != Quantity::new_rational(0f64).unwrap() { return Err((*la + *lb + *op_loc, DaisyError::BadMath)); }
 
+
+					let o = va.clone() % vb.clone();
+					if o.is_nan() {return Err((*la + *lb + *op_loc, DaisyError::BadMath));}
+
+
 					return Ok(Some(Expression::Quantity(*la + *lb + *op_loc, va.clone() % vb.clone())));
 				} else { return Ok(None); }
 			} else { return Ok(None); }
@@ -176,12 +208,26 @@ pub fn eval_operator(g: &Expression, context: &mut Context) -> Result<Option<Exp
 				if let Expression::Quantity(lb, vb) = b {
 					let n = va.clone().convert_to(vb.clone());
 					if n.is_none() {
+						let va = va.convert_to_base().unit;
+						let vb = vb.convert_to_base().unit;
+
+						let a_s: String;
+						let b_s: String;
+						if va.unitless() {
+							a_s = String::from("scalar");
+						} else {
+							a_s = a.display(context);
+						}
+
+						if vb.unitless() {
+							b_s = String::from("scalar");
+						} else {
+							b_s = b.display(context);
+						}
+
 						return Err((
 							*la + *lb + *op_loc,
-							DaisyError::IncompatibleUnits(
-								va.convert_to_base().unit.to_string(),
-								vb.convert_to_base().unit.to_string()
-							)
+							DaisyError::IncompatibleUnits(a_s, b_s)
 						));
 					}
 					return Ok(Some(Expression::Quantity(*la + *lb + *op_loc, n.unwrap())));

src/formattedtext.rs

@@ -5,6 +5,7 @@ use termion::style;
 use termion::clear;
 use termion::cursor;
 use std::ops::Add;
+use crate::context::Context;
 
 
 #[derive(Debug)]
@@ -18,8 +19,108 @@ impl ToString for FormattedText {
 }
 
 
-impl FormattedText {
+fn format_map_none(c: char) -> Option<String> {
+	Some(match c {
+		'n'|'i'|'t'|'a'|
+		'e'|'c'|'s'|'r'|
+		'p'
+		=> { "".to_string() },
+		_ => { return None }
+	})
+}
 
+
+fn format_map_ansi(c: char) -> Option<String> {
+	Some(match c {
+		'n' => { // Normal text
+			format!("{}{}", color::Fg(color::Reset), color::Bg(color::Reset))
+		},
+		'i' => { // Normal italic text
+			format!("{}{}", color::Fg(color::Reset), color::Bg(color::Reset))
+		},
+		't' => { // Title text (should be cyan)
+			format!("{}{}", color::Fg(color::AnsiValue(6)), color::Bg(color::Reset))
+		},
+		'a' => { // Colored text (should be pink)
+			format!("{}{}", color::Fg(color::AnsiValue(5)), color::Bg(color::Reset))
+		},
+		'e' => { // Error titles (should be red)
+			format!("{}{}", color::Fg(color::AnsiValue(1)), color::Bg(color::Reset))
+		},
+		'c' => { // Console text (inverted black on white)
+			format!("{}{}", color::Fg(color::AnsiValue(0)), color::Bg(color::AnsiValue(7)))
+		},
+		'p' => { // Input prompt (how ==> is styled) (should be blue)
+			format!("{}{}", color::Fg(color::AnsiValue(4)), color::Bg(color::Reset))
+		},
+		's' => { // Repeat prompt (how => is styled) (should be pink)
+			format!("{}{}", color::Fg(color::AnsiValue(5)), color::Bg(color::Reset))
+		},
+		'r' => { // Result prompt (how = is styled) (should be green)
+			format!("{}{}", color::Fg(color::AnsiValue(2)), color::Bg(color::Reset))
+		},
+
+		_ => { return None }
+	})
+}
+
+
+// style::reset also resets color.
+// Make sure color comes AFTER style reset.
+fn format_map_full(c: char) -> Option<String> {
+	Some(match c {
+		'n' => { // Normal text
+			format!("{}{}", style::Reset, color::Fg(color::Reset))
+		},
+		'i' => { // Normal italic text
+			format!("{}{}", color::Fg(color::Reset), style::Italic)
+		},
+		't' => { // Title text
+			format!("{}{}", color::Fg(color::Magenta), style::Bold)
+		},
+		'a' => { // Colored text
+			format!("{}{}", style::Reset, color::Fg(color::Magenta))
+		},
+		'e' => { // Error titles
+			format!("{}{}", color::Fg(color::Red), style::Bold)
+		},
+		'c' => { // Console text
+			format!("{}{}", color::Fg(color::LightBlack), style::Italic)
+		},
+		'p' => { // Input prompt (how ==> is styled)
+			format!("{}{}", color::Fg(color::Blue), style::Bold)
+		},
+		's' => { // Repeat prompt (how => is styled)
+			format!("{}{}", color::Fg(color::Magenta), style::Bold)
+		},
+		'r' => { // Result prompt (how = is styled)
+			format!("{}{}", color::Fg(color::Green), style::Bold)
+		},
+
+
+		_ => { return None }
+	})
+}
+
+pub fn format_map(c: char, context: &Context) -> Option<String> {
+	match context.config.term_color_type {
+		0 => format_map_none(c),
+		1 => format_map_ansi(c),
+		2 => format_map_full(c),
+		_ => unreachable!("Invalid term_color_type")
+	}
+}
+
+
+impl FormattedText {
+	pub fn newline(stdout: &mut RawTerminal<std::io::Stdout>) -> Result<(), std::io::Error> {
+		write!(stdout, "\n")?;
+		return Ok(());
+	}
+}
+
+
+impl FormattedText {
 	pub fn new(s: String) -> FormattedText {
 		return FormattedText {
 			text: s
@@ -31,7 +132,7 @@ impl FormattedText {
 	}
 
 
-	pub fn write(&self, stdout: &mut RawTerminal<std::io::Stdout>) -> Result<(), std::io::Error> {
+	pub fn write(&self, context: &Context, stdout: &mut RawTerminal<std::io::Stdout>) -> Result<(), std::io::Error> {
 
 		if self.text == "[clear]" {
 			write!(
@@ -58,30 +159,17 @@ impl FormattedText {
 					let b = chars.next().unwrap();
 
 					match (a, b) {
-						('n', ']') => { // Normal text
-							s.push_str(&format!("{}{}", color::Fg(color::Reset), style::Reset));
-						},
-						('i', ']') => { // Normal italic text
-							s.push_str(&format!("{}{}", color::Fg(color::Reset), style::Italic));
-						},
-						('t', ']') => { // Title text
-							s.push_str(&format!("{}{}", color::Fg(color::Magenta), style::Bold));
-						},
-						('a', ']') => { // Colored text
-							s.push_str(&format!("{}{}", color::Fg(color::Magenta), style::Reset));
-						},
-						('e', ']') => { // Error titles
-							s.push_str(&format!("{}{}", color::Fg(color::Red), style::Bold));
-						},
-						('c', ']') => { // Console text
-							s.push_str(&format!("{}{}", color::Fg(color::LightBlack), style::Italic));
-						},
+						(c, ']') => { // Normal text
 
-						('s', ']') => { // Repeat prompt (how => is styled)
-							s.push_str(&format!("{}{}", color::Fg(color::Magenta), style::Bold));
-						},
-						('r', ']') => { // Result prompt (how = is styled)
-							s.push_str(&format!("{}{}", color::Fg(color::Green), style::Bold));
+							let q = format_map(c, context);
+
+							if q.is_some() {
+								s.push_str(&q.unwrap());
+							} else {
+								s.push('[');
+								s.push(a);
+								s.push(b);
+							}
 						},
 
 						_ => {
@@ -96,7 +184,7 @@ impl FormattedText {
 			}
 		}
 
-		write!(stdout, "{}", s)?;
+		write!(stdout, "\r{}", s)?;
 		return Ok(());
 	}
 }

src/main.rs

@@ -26,21 +26,21 @@ fn main() -> Result<(), std::io::Error> {
 
 #[inline(always)]
 pub fn do_string(
-	s: &String,
-	mut context: &mut Context
+	context: &mut Context,
+	s: &String
 ) -> Result<FormattedText, FormattedText> {
 
 	let r: (LineLocation, DaisyError);
 	if command::is_command(s) {
-		return Ok(command::do_command(s, &mut context));
+		return Ok(command::do_command(context, s));
 	} else if s.contains("=") {
-		let x = do_assignment(s, &mut context);
+		let x = do_assignment(context, s);
 		match x {
 			Ok(t) => { return Ok(t) },
 			Err(t) => { r = t }
 		};
 	} else {
-		let x = do_expression(s, &mut context);
+		let x = do_expression(context, s);
 		match x {
 			Ok((t, e)) => { context.push_hist(e); return Ok(t) },
 			Err(t) => { r = t }
@@ -73,25 +73,25 @@ pub fn do_string(
 // Returns a FormattedText with output that should be printed.
 #[inline(always)]
 fn do_expression(
-	s: &String,
-	context: &mut Context
+	context: &mut Context,
+	s: &String
 ) -> Result<(FormattedText, parser::Expression), (LineLocation, DaisyError)> {
 
 	let mut output = FormattedText::new("".to_string());
 
-	let g = parser::parse(&s, context)?;
-	let g_evaluated = evaluate::evaluate(&g, context)?;
+	let g = parser::parse(context, &s)?;
+	let g_evaluated = evaluate::evaluate(context, &g)?;
 
 	// Display parsed string
 	output.push(&format!(
 		" [s]=>[n] {}\n\n",
-		g.to_string()
+		g.display(context)
 	));
 
 	// Display result
 	output.push(&format!(
 		"  [r]=[n] {}\n\n",
-		g_evaluated.to_string_outer(),
+		g_evaluated.display_outer(context),
 	));
 
 	return Ok((output, g_evaluated));
@@ -102,8 +102,8 @@ fn do_expression(
 // Returns a FormattedText with output that should be printed.
 #[inline(always)]
 fn do_assignment(
-	s: &String,
-	context: &mut Context
+	context: &mut Context,
+	s: &String
 ) -> Result<FormattedText, (LineLocation, DaisyError)> {
 
 	let mut output = FormattedText::new("".to_string());
@@ -135,8 +135,8 @@ fn do_assignment(
 			.unwrap_or_else(|| parts[0].len());
 
 
-	let left = substitute(&parts[0].trim().to_string(), &context);
-	let right = substitute(&parts[1].trim().to_string(), &context);
+	let left = substitute(context, &parts[0].trim().to_string());
+	let right = substitute(context, &parts[1].trim().to_string());
 	let is_function = left.contains("(");
 
 	// The order of methods below is a bit odd.
@@ -212,7 +212,7 @@ fn do_assignment(
 		}
 
 		// Parse right hand side
-		let g = parser::parse(&right, context);
+		let g = parser::parse(context, &right);
 		let Ok(g) = g else {
 			let Err((l, e)) = g else { unreachable!() };
 			return Err((
@@ -224,12 +224,12 @@ fn do_assignment(
 		// Display parsed string
 		output.push(&format!(
 			" [s]=>[n] {left} = {}\n\n",
-			g.to_string()
+			g.display(context)
 		));
 
 		// Evaluate expression with shadow variables
 		for a in &args { context.add_shadow(a.to_string(), None);}
-		let g_evaluated = evaluate::evaluate(&g, context);
+		let g_evaluated = evaluate::evaluate(context, &g);
 		context.clear_shadow();
 		let Ok(_g_evaluated) = g_evaluated else {
 			let Err((l, e)) = g_evaluated else { unreachable!() };
@@ -254,7 +254,7 @@ fn do_assignment(
 		}
 
 		// Parse right hand side
-		let g = parser::parse(&right, context);
+		let g = parser::parse(context, &right);
 		let Ok(g) = g else {
 			let Err((l, e)) = g else { unreachable!() };
 			return Err((
@@ -266,11 +266,11 @@ fn do_assignment(
 		// Display parsed string
 		output.push(&format!(
 			" [t]=>[n] {left} = {}\n\n",
-			g.to_string()
+			g.display(context)
 		));
 
 		// Evaluate expression
-		let g_evaluated = evaluate::evaluate(&g, context);
+		let g_evaluated = evaluate::evaluate(context, &g);
 		let Ok(g_evaluated) = g_evaluated else {
 			let Err((l, e)) = g_evaluated else { unreachable!() };
 			return Err((

src/parser/expression/expression.rs

@@ -1,5 +1,6 @@
 use std::collections::VecDeque;
 use crate::quantity::Quantity;
+use crate::context::Context;
 
 use super::Operator;
 use super::Constant;
@@ -10,6 +11,23 @@ use super::super::LineLocation;
 #[derive(Debug)]
 #[derive(Clone)]
 pub enum Expression {
+	// Meaning of `LineLocation`:
+	//
+	// For Variables, Constants, Quantities, Tuples:
+	// If this expression was parsed, LineLocation is what part of the prompt was parsed to get this expression
+	// If this expression is the result of a calculation, LineLocaion is the sum of the LineLocations of
+	//	all expressions used to make it. In other words, it points to the part of the prompt that was evaluated
+	//	to get this new expression.
+	//
+	// For Operators:
+	// Linelocation points to the operator's position in the prompt.
+	// If this is a function, it points to the function name.
+	// If this is `+`, `!`, or etc, it points to that character.
+	// Operator arguments are NOT included in this linelocation.
+	//
+	//
+	// All the above rules are implemented when parsing and evaluating expressions.
+
 	Variable(LineLocation, String),
 	Quantity(LineLocation, Quantity),
 	Constant(LineLocation, Constant),
@@ -17,17 +35,17 @@ pub enum Expression {
 	Tuple(LineLocation, VecDeque<Expression>),
 }
 
-impl ToString for Expression {
-	fn to_string(&self) -> String {
+impl Expression {
+	pub fn display(&self, context: &Context) -> String {
 		match self {
-			Expression::Quantity(_, v) => v.to_string(),
+			Expression::Quantity(_, v) => v.display(context),
 			Expression::Constant(_, c) => c.to_string(),
 			Expression::Variable(_, s) => s.clone(),
-			Expression::Operator(_, o,a) => o.print(a),
+			Expression::Operator(_, o,a) => o.display(context, a),
 			Expression::Tuple(_, v) => {
 				format!("({})",
 					v.iter()
-						.map(|x| x.to_string())
+						.map(|x| x.display(context))
 						.collect::<Vec<String>>()
 						.join(", ")
 				)
@@ -39,16 +57,16 @@ impl ToString for Expression {
 impl Expression {
 	// This is called only when this is the outermost Expression.
 	// This sometimes leads to different--usually more verbose--behavior.
-	pub fn to_string_outer(&self) -> String {
+	pub fn display_outer(&self, context: &Context) -> String {
 		match self {
-			Expression::Quantity(_, v) => v.to_string_outer(),
+			Expression::Quantity(_, v) => v.display_outer(context),
 			Expression::Constant(_, c) => c.to_string(),
 			Expression::Variable(_, s) => s.clone(),
-			Expression::Operator(_, o,a) => o.print(a),
+			Expression::Operator(_, o,a) => o.display(context, a),
 			Expression::Tuple(_, v) => {
 				format!("({})",
 					v.iter()
-						.map(|x| x.to_string())
+						.map(|x| x.display(context))
 						.collect::<Vec<String>>()
 						.join(", ")
 				)

src/parser/expression/operator.rs

@@ -62,7 +62,7 @@ impl Operator {
 	}
 
 	#[inline(always)]
-	pub fn from_string(s: &str, context: &Context) -> Option<Operator> {
+	pub fn from_string(context: &Context, s: &str) -> Option<Operator> {
 
 		let f = Function::from_string(s);
 		if let Some(f) = f {
@@ -128,8 +128,8 @@ impl Operator {
 	}
 
 	#[inline(always)]
-	fn add_parens_to_arg(&self, arg: &Expression) -> String {
-		let mut astr: String = arg.to_string();
+	fn add_parens_to_arg(&self, context: &Context, arg: &Expression) -> String {
+		let mut astr: String = arg.display(context);
 		if let Expression::Operator(_, o,_) = arg {
 			if o.print_map() < self.print_map() {
 				astr = format!("({})", astr);
@@ -139,8 +139,8 @@ impl Operator {
 	}
 
 	#[inline(always)]
-	fn add_parens_to_arg_strict(&self, arg: &Expression) -> String {
-		let mut astr: String = arg.to_string();
+	fn add_parens_to_arg_strict(&self, context: &Context, arg: &Expression) -> String {
+		let mut astr: String = arg.display(context);
 		if let Expression::Operator(_, o,_) = arg {
 			if o.print_map() <= self.print_map() {
 				astr = format!("({})", astr);
@@ -150,56 +150,56 @@ impl Operator {
 	}
 
 
-	pub fn print(&self, args: &VecDeque<Expression>) -> String {
+	pub fn display(&self, context: &Context, args: &VecDeque<Expression>) -> String {
 		match self {
 			Operator::Negative => {
-				return format!("-{}", self.add_parens_to_arg(&args[0]));
+				return format!("-{}", self.add_parens_to_arg(context, &args[0]));
 			},
 
 			Operator::Sqrt => {
 				return format!(
 					"√{}",
-					self.add_parens_to_arg(&args[0]),
+					self.add_parens_to_arg(context, &args[0]),
 				);
 			},
 
 			Operator::ModuloLong => {
 				return format!(
 					"{} mod {}",
-					self.add_parens_to_arg(&args[0]),
-					self.add_parens_to_arg(&args[1])
+					self.add_parens_to_arg(context, &args[0]),
+					self.add_parens_to_arg(context, &args[1])
 				);
 			},
 
 			Operator::DivideLong => {
 				return format!(
 					"{} per {}",
-					self.add_parens_to_arg(&args[0]),
-					self.add_parens_to_arg(&args[1])
+					self.add_parens_to_arg(context, &args[0]),
+					self.add_parens_to_arg(context, &args[1])
 				);
 			},
 
 			Operator::UnitConvert => {
 				return format!(
 					"{} to {}",
-					self.add_parens_to_arg(&args[0]),
-					self.add_parens_to_arg(&args[1])
+					self.add_parens_to_arg(context, &args[0]),
+					self.add_parens_to_arg(context, &args[1])
 				);
 			},
 
 			Operator::Modulo => {
 				return format!(
 					"{} % {}",
-					self.add_parens_to_arg(&args[0]),
-					self.add_parens_to_arg(&args[1])
+					self.add_parens_to_arg(context, &args[0]),
+					self.add_parens_to_arg(context, &args[1])
 				);
 			},
 
 			Operator::Subtract => {
 				return format!(
 					"{} - {}",
-					self.add_parens_to_arg(&args[0]),
-					self.add_parens_to_arg(&args[1])
+					self.add_parens_to_arg(context, &args[0]),
+					self.add_parens_to_arg(context, &args[1])
 				);
 			},
 
@@ -207,10 +207,14 @@ impl Operator {
 
 				let q = &args[1];
 
-				if q.is_unitless_integer() && !q.to_string().contains("e") {
+				if {
+					context.config.enable_super_powers &&
+					q.is_unitless_integer() &&
+					!q.display(context).contains("e")
+				} {
 					// Write integer powers as a superscript
 					let mut b = String::new();
-					for c in q.to_string().chars() {
+					for c in q.display(context).chars() {
 						b.push(match c {
 							'-' => '⁻',
 							'0' => '⁰',
@@ -229,27 +233,27 @@ impl Operator {
 
 					return format!(
 						"{}{}",
-						self.add_parens_to_arg_strict(&args[0]),
+						self.add_parens_to_arg_strict(context, &args[0]),
 						b
 					);
 				} else {
 					return format!(
 						"{}^{}",
-						self.add_parens_to_arg_strict(&args[0]),
-						self.add_parens_to_arg_strict(&args[1])
+						self.add_parens_to_arg_strict(context, &args[0]),
+						self.add_parens_to_arg_strict(context, &args[1])
 					);
 				}
 			},
 
 			Operator::Factorial => {
-				return format!("{}!", self.add_parens_to_arg(&args[0]));
+				return format!("{}!", self.add_parens_to_arg(context, &args[0]));
 			},
 
 			Operator::Add => {
 				return format!(
 					"{} + {}",
-					self.add_parens_to_arg(&args[0]),
-					self.add_parens_to_arg(&args[1])
+					self.add_parens_to_arg(context, &args[0]),
+					self.add_parens_to_arg(context, &args[1])
 				);
 			},
 
@@ -279,26 +283,26 @@ impl Operator {
 					if let Expression::Quantity(_, u) = b {
 						if u.unit.no_space() {
 							return format!("{}{}",
-								self.add_parens_to_arg_strict(a),
-								self.add_parens_to_arg_strict(b)
+								self.add_parens_to_arg_strict(context, a),
+								self.add_parens_to_arg_strict(context, b)
 							);
 						} else {
 							return format!("{} {}",
-								self.add_parens_to_arg_strict(a),
-								self.add_parens_to_arg_strict(b)
+								self.add_parens_to_arg_strict(context, a),
+								self.add_parens_to_arg_strict(context, b)
 							);
 						}
 					} else {
 						return format!("{}{}",
-							self.add_parens_to_arg_strict(a),
-							self.add_parens_to_arg_strict(b)
+							self.add_parens_to_arg_strict(context, a),
+							self.add_parens_to_arg_strict(context, b)
 						);
 					};
 
 				} else {
 					return format!("{} × {}",
-						self.add_parens_to_arg_strict(a),
-						self.add_parens_to_arg_strict(b)
+						self.add_parens_to_arg_strict(context, a),
+						self.add_parens_to_arg_strict(context, b)
 					);
 				}
 			},
@@ -309,25 +313,25 @@ impl Operator {
 
 
 				if let Expression::Quantity(_, q) = a {
-					if q.is_one() {
+					if q.is_one() && context.config.enable_one_over_power {
 						return format!("{}⁻¹",
-							self.add_parens_to_arg_strict(b)
+							self.add_parens_to_arg_strict(context, b)
 						);
 					}
 				}
 
 				return format!("{} ÷ {}",
-					self.add_parens_to_arg_strict(a),
-					self.add_parens_to_arg_strict(b)
+					self.add_parens_to_arg_strict(context, a),
+					self.add_parens_to_arg_strict(context, b)
 				);
 			},
 
 			Operator::Function(s) => {
-				return format!("{}({})", s.to_string(), args[0].to_string());
+				return format!("{}({})", s.to_string(), args[0].display(context));
 			},
 
 			Operator::UserFunction(s) => {
-				return format!("{}({})", s.to_string(), args[0].to_string());
+				return format!("{}({})", s, args[0].display(context));
 			}
 		};
 	}

src/parser/mod.rs

@@ -18,59 +18,79 @@ use crate::context::Context;
 use crate::errors::DaisyError;
 
 pub fn parse(
-	s: &String, context: &Context
+	context: &Context, s: &String
 ) -> Result<Expression, (LineLocation, DaisyError)> {
 
-	let expressions = stage::tokenize(s, context);
-	let (_, expressions) = stage::find_subs(expressions);
-	let g = stage::groupify(expressions, context)?;
-	let g = stage::treeify(g, context)?;
+	let mut expressions = stage::tokenize(context, s);
+	if context.config.enable_substituion {
+		(_, expressions) = stage::find_subs(expressions);
+	}
+	let g = stage::groupify(context, expressions)?;
+	let g = stage::treeify(context, g)?;
 
 	return Ok(g);
 }
 
 pub fn parse_no_context(s: &String) -> Result<Expression, (LineLocation, DaisyError)> {
-	parse(s, &Context::new())
+	parse(&Context::new(), s)
 }
 
-pub fn substitute(s: &String, context: &Context) -> String {
-	let (_, s) = substitute_cursor(s, s.chars().count(), context);
+
+
+// Substitiution replaces certain string with pretty unicode characters.
+// When it is enabled, ALL input strings are substituted. Variable and
+// operator tokens use the replaced string value. Make sure both the
+// original and the replaced strings are handled correctly by the parser.
+pub fn substitute(context: &Context, s: &String) -> String {
+	if !context.config.enable_substituion { return s.clone(); }
+	let (_, s) = substitute_cursor(context, s, s.chars().count());
 	return s;
 }
 
 pub fn substitute_cursor(
+	context: &Context,
 	s: &String, // The string to substitute
-	c: usize,   // Location of the cursor right now
-	context: &Context
+	c: usize    // Location of the cursor right now
 ) -> (
-	usize,  // Location of cursor in substituted string
+	usize,  // New cursor
 	String  // String with substitutions
 ) {
+
+	if !context.config.enable_substituion { return (c, s.clone()); }
 	if s == "" { return (c, s.clone()) }
+	
+	
 	let mut new_s = s.clone();
 
-	let l = s.chars().count();
-	let expressions = stage::tokenize(s, context);
+	let expressions = stage::tokenize(context, s);
 	let (mut subs, _) = stage::find_subs(expressions);
-	let mut new_c = l - c;
+	let mut new_c = c.clone();
 
 	while subs.len() > 0 {
-		let r = subs.pop_back().unwrap();
 		// Apply substitutions in reverse order
+		// r is the current substitution: (linelocation, string)
+		let r = subs.pop_back().unwrap();
 
 		if { // Don't substitute if our cursor is inside the substitution
 			c >= r.0.pos &&
 			c < r.0.pos+r.0.len
 		} { continue; }
 
-		if c < r.0.pos {
-			let ct = r.1.chars().count();
-			if ct >= r.0.len {
-				if new_c >= ct - r.0.len {
-					new_c += ct - r.0.len
-				}
-			} else {
-				new_c -= r.0.len - ct
+		// If this substitution is before our cursor,
+		// we need to adjust our cursor's position.
+		if c > r.0.pos {
+			let c_o = r.0.len; // Old length 
+			let c_n = r.1.chars().count(); // New length
+
+			if c_n > c_o {
+				// Move cursor right by difference
+				new_c += c_n - c_o;
+
+			} else if c_n < c_o {
+				// Move cursor left by difference
+				if new_c >= c_o - c_n {
+					new_c -= c_o - c_n;
+				} else { new_c = 0; }
 			}
 		}
 

src/parser/stage/find_subs.rs

@@ -6,11 +6,69 @@ use super::super::{
 };
 
 
+fn sub_string(s: &str) -> Option<&'static str> {
+	let r = match s {
+
+		/* Only found in operator tokens */
+
+		"*"    => "×",
+		"/"    => "÷",
+		"sqrt" => "√",
+		"rt"   => "√",
+
+
+
+		/* Only found in word tokens */
+
+		// Greek letters
+		"alpha"   => "α",
+		"beta"    => "β",
+		"gamma"   => "γ",
+		"delta"   => "δ",
+		"epsilon" => "ε",
+		"zeta"    => "ζ",
+		"eta"     => "η",
+		"theta"   => "θ",
+		//"iota"    => {Some("ι")}, // looks just like i
+		//"kappa"   => {Some("κ")}, // looks just like k
+		"lambda"  => "λ",
+		"mu"      => "μ",
+		//"nu"      => {Some("ν")}, // looks just like v
+		"xi"      => "ξ",
+		//"omicron" => {Some("ο")}, // looks exactly like o
+		"pi"      => "π",
+		"rho"     => "ρ",
+		"sigma"   => "σ",
+		"tau"     => "τ",
+		//"upsilon" => {Some("υ")}, // looks just like u
+		"phi"     => "φ",
+		"chi"     => "χ",
+		//"psi"     => {Some("ψ")},  Conflict with pound / square inch
+		"omega"   => "ω",
+
+		// Constants
+		"epsilon_zero" => "ε₀",
+		"eps_zero"     => "ε₀",
+		"g_zero"       => "g₀",
+		"mu_zero"      => "μ₀",
+		"h_bar"        => "ℏ",
+
+		// Misc
+		"deg" => "°",
+
+		_ => { return None; }
+	};
+	return Some(r);
+}
+
+
+// Finds substitutions in an array of tokens.
+// Returns new token array and substitution list.
 pub fn find_subs(
 	mut g: VecDeque<Token>,
 ) -> (
-	VecDeque<(LineLocation, String)>,
-	VecDeque<Token>
+	VecDeque<(LineLocation, String)>, // List of substrings to replace (in order)
+	VecDeque<Token> // New token array, with updated strings and linelocations
 ) {
 
 	// Array of replacements
@@ -24,62 +82,19 @@ pub fn find_subs(
 	while g.len() > 0 {
 		let mut t = g.pop_front().unwrap();
 
+
 		let target: Option<&str> = match &mut t {
 			Token::Operator(_, s) => {
-				let target = match &s[..] {
-					"*" => {Some("×")},
-					"/" => {Some("÷")},
-					"sqrt"    => {Some("√")},
-					"rt"      => {Some("√")},
-					_ => {None}
-				};
+				let target = sub_string(s);
 
 				// Update token contents too.
-				// This makes sure that errors also contain the updated text.
+				// This makes errors and printouts use the updated string.
 				if target.is_some() { *s = String::from(target.unwrap()); }
 				target
 			},
 
 			Token::Word(_, s) => {
-				let target = match &s[..] {
-					// Greek letters
-					"alpha"   => {Some("α")},
-					"beta"    => {Some("β")},
-					"gamma"   => {Some("γ")},
-					"delta"   => {Some("δ")},
-					"epsilon" => {Some("ε")},
-					"zeta"    => {Some("ζ")},
-					"eta"     => {Some("η")},
-					"theta"   => {Some("θ")},
-					//"iota"    => {Some("ι")},
-					//"kappa"   => {Some("κ")},
-					"lambda"  => {Some("λ")},
-					"mu"      => {Some("μ")},
-					//"nu"      => {Some("ν")},
-					"xi"      => {Some("ξ")},
-					//"omicron" => {Some("ο")},
-					"pi"      => {Some("π")},
-					"rho"     => {Some("ρ")},
-					"sigma"   => {Some("σ")},
-					"tau"     => {Some("τ")},
-					//"upsilon" => {Some("υ")},
-					"phi"     => {Some("φ")},
-					"chi"     => {Some("χ")},
-					//"psi"     => {Some("ψ")},  Conflict with pound / square inch
-					"omega"   => {Some("ω")},
-
-					// Constants
-					"epsilon_zero" => {Some("ε₀")},
-					"eps_zero"     => {Some("ε₀")},
-					"g_zero"       => {Some("g₀")},
-					"mu_zero"      => {Some("μ₀")},
-					"h_bar"        => {Some("ℏ")},
-
-					// Misc
-					"deg" => {Some("°")}
-					_ => {None}
-				};
-
+				let target = sub_string(s);
 				if target.is_some() { *s = String::from(target.unwrap()); }
 				target
 			},
@@ -88,7 +103,7 @@ pub fn find_subs(
 		};
 
 		if target.is_none() {
-			// Even if nothing changed, we need to update token location
+			// Even if nothing changed, we need to update the new token's linelocation
 			let l = t.get_mut_linelocation();
 			*l = LineLocation{pos: l.pos - offset, len: l.len};
 		} else {

src/parser/stage/groupify.rs

@@ -11,8 +11,8 @@ use crate::context::Context;
 
 
 fn lookback_signs(
-	g: &mut VecDeque<Token>,
-	context: &Context
+	context: &Context,
+	g: &mut VecDeque<Token>
 ) -> Result<(), (LineLocation, DaisyError)> {
 
 	// Convert `-` operators to `neg` operators
@@ -44,7 +44,7 @@ fn lookback_signs(
 				(Token::Operator(_, sa), Token::Operator(l,sb))
 				=> {
 					if {
-						let o = Operator::from_string(sa, context);
+						let o = Operator::from_string(context, sa);
 
 						o.is_some() &&
 						(
@@ -101,11 +101,11 @@ fn lookback_signs(
 
 // Inserts implicit operators
 fn lookback(
-	g: &mut VecDeque<Token>,
-	context: &Context
+	context: &Context,
+	g: &mut VecDeque<Token>
 ) -> Result<(), (LineLocation, DaisyError)> {
 
-	lookback_signs(g, context)?;
+	lookback_signs(context, g)?;
 
 	let mut i: usize = 0;
 	while i < g.len() {
@@ -142,7 +142,7 @@ fn lookback(
 				=> {
 					let la = la.clone();
 					let lb = lb.clone();
-					let o = Operator::from_string(s, context);
+					let o = Operator::from_string(context, s);
 
 					g.insert(i-1, b);
 					if o.is_some() {
@@ -164,7 +164,7 @@ fn lookback(
 				=> {
 					let la = la.clone();
 					let lb = lb.clone();
-					let o = Operator::from_string(s, context);
+					let o = Operator::from_string(context, s);
 
 					g.insert(i-1, b);
 					if o.is_some() {
@@ -196,8 +196,8 @@ fn lookback(
 
 
 pub fn groupify(
-	mut g: VecDeque<Token>,
-	context: &Context
+	context: &Context,
+	mut g: VecDeque<Token>
 ) -> Result<
 	Token,
 	(LineLocation, DaisyError)
@@ -240,7 +240,7 @@ pub fn groupify(
 
 				let (_, mut v) = levels.pop().unwrap();
 				let (_, v_now) = levels.last_mut().unwrap();
-				lookback(&mut v, context)?;
+				lookback(context, &mut v)?;
 
 				let q = is_tuple.pop().unwrap();
 				if q {
@@ -275,7 +275,7 @@ pub fn groupify(
 		let (_, v_now) = levels.last_mut().unwrap();
 
 		if v.len() == 0 { return Err((l, DaisyError::EmptyGroup)) }
-		lookback(&mut v, context)?;
+		lookback(context, &mut v)?;
 
 		let q = is_tuple.pop().unwrap();
 		if q {
@@ -294,7 +294,7 @@ pub fn groupify(
 		return Err((l, DaisyError::BadTuple));
 	}
 
-	lookback(&mut v, context)?;
+	lookback(context, &mut v)?;
 
 	return Ok(Token::Group(
 		LineLocation{pos:0, len:last_linelocation.pos + last_linelocation.len},

src/parser/stage/tokenize.rs

@@ -10,10 +10,10 @@ use super::super::{
 // Called whenever a token is finished.
 #[inline(always)]
 fn push_token(
+	context: &Context,
 	g: &mut VecDeque<Token>,
 	t: Option<Token>,
-	stop_i: usize,
-	context: &Context
+	stop_i: usize
 ) {
 
 	if t.is_none() { return }
@@ -60,7 +60,7 @@ fn push_token(
 
 	// Some operators are written as words.
 	if let Token::Word(l, s) = &t {
-		if Operator::from_string(s, context).is_some() {
+		if Operator::from_string(context, s).is_some() {
 			t = Token::Operator(*l, s.clone());
 		}
 	}
@@ -69,7 +69,7 @@ fn push_token(
 }
 
 /// Turns a string into Tokens. First stage of parsing.
-pub fn tokenize(input: &String, context: &Context) -> VecDeque<Token> {
+pub fn tokenize(context: &Context, input: &String) -> VecDeque<Token> {
 	let mut t: Option<Token> = None; // The current token we're reading
 	let mut g: VecDeque<Token> = VecDeque::with_capacity(32);
 
@@ -88,7 +88,7 @@ pub fn tokenize(input: &String, context: &Context) -> VecDeque<Token> {
 					// If we're not building a number, finalize
 					// previous token and start one.
 					_ => {
-						push_token(&mut g, t, i, context);
+						push_token(context, &mut g, t, i);
 						t = Some(Token::Quantity(LineLocation{pos: i, len: 0}, String::from(c)));
 					}
 				};
@@ -102,7 +102,7 @@ pub fn tokenize(input: &String, context: &Context) -> VecDeque<Token> {
 					Some(Token::Quantity(_, val)) => { val.push(c); },
 
 					_ => {
-						push_token(&mut g, t, i, context);
+						push_token(context, &mut g, t, i);
 						t = Some(Token::Word(LineLocation{pos: i, len: 0}, String::from(c)));
 					}
 				};
@@ -122,7 +122,7 @@ pub fn tokenize(input: &String, context: &Context) -> VecDeque<Token> {
 						} else {
 							// Otherwise, end the number.
 							// We probably have a subtraction.
-							push_token(&mut g, t, i, context);
+							push_token(context, &mut g, t, i);
 							t = Some(Token::Operator(
 								LineLocation{pos: i, len: 1},
 								String::from(c)
@@ -134,7 +134,7 @@ pub fn tokenize(input: &String, context: &Context) -> VecDeque<Token> {
 					// Multi-character operators with - and + are NOT supported!
 					// (for example, we can't use -> for unit conversion)
 					_ => {
-						push_token(&mut g, t, i, context);
+						push_token(context, &mut g, t, i);
 						t = Some(Token::Operator(
 							LineLocation{pos: i, len: 1},
 							String::from(c)
@@ -144,7 +144,7 @@ pub fn tokenize(input: &String, context: &Context) -> VecDeque<Token> {
 			},
 
 			',' => {
-				push_token(&mut g, t, i, context);
+				push_token(context, &mut g, t, i);
 				t = Some(Token::TupleDelim(LineLocation{pos: i, len: 1}));
 			},
 
@@ -157,7 +157,7 @@ pub fn tokenize(input: &String, context: &Context) -> VecDeque<Token> {
 				match &mut t {
 					Some(Token::Operator(_, val)) => { val.push(c); },
 					_ => {
-						push_token(&mut g, t, i, context);
+						push_token(context, &mut g, t, i);
 						t = Some(Token::Operator(LineLocation{pos: i, len: 0}, String::from(c)));
 					}
 				};
@@ -165,17 +165,17 @@ pub fn tokenize(input: &String, context: &Context) -> VecDeque<Token> {
 
 			// Group
 			'(' => {
-				push_token(&mut g, t, i, context);
+				push_token(context, &mut g, t, i);
 				t = Some(Token::GroupStart(LineLocation{pos: i, len: 0}));
 			},
 			')' => {
-				push_token(&mut g, t, i, context);
+				push_token(context, &mut g, t, i);
 				t = Some(Token::GroupEnd(LineLocation{pos: i, len: 0}));
 			},
 
 			// Space. Basic seperator.
 			' ' => {
-				push_token(&mut g, t, i, context);
+				push_token(context, &mut g, t, i);
 				t = None;
 			}
 
@@ -185,7 +185,7 @@ pub fn tokenize(input: &String, context: &Context) -> VecDeque<Token> {
 					Some(Token::Word(_, val)) => { val.push(c); },
 
 					_ => {
-						push_token(&mut g, t, i, context);
+						push_token(context, &mut g, t, i);
 						t = Some(Token::Word(LineLocation{pos: i, len: 0}, String::from(c)));
 					}
 				};
@@ -193,7 +193,7 @@ pub fn tokenize(input: &String, context: &Context) -> VecDeque<Token> {
 		};
 	}
 
-	push_token(&mut g, t, input.chars().count(), context);
+	push_token(context, &mut g, t, input.chars().count());
 
 	return g;
 }

src/parser/stage/treeify.rs

@@ -10,9 +10,9 @@ use super::super::{
 };
 
 fn treeify_binary(
+	context: &Context,
 	i: usize,
-	g_inner: &mut VecDeque<Token>,
-	context: &Context
+	g_inner: &mut VecDeque<Token>
 ) -> Result<bool, (LineLocation, DaisyError)> {
 
 	let this: &Token = &g_inner[i];
@@ -56,7 +56,7 @@ fn treeify_binary(
 
 
 	if let Token::Operator(l, s) = left {
-		let o = Operator::from_string(s, context);
+		let o = Operator::from_string(context, s);
 		if o.is_none() { return Err((*l, DaisyError::Syntax)); } // Bad string
 		let o = o.unwrap();
 
@@ -72,7 +72,7 @@ fn treeify_binary(
 	}
 
 	if let Token::Operator(l, s) = right {
-		let o = Operator::from_string(s, context);
+		let o = Operator::from_string(context, s);
 		if o.is_none() { return Err((*l, DaisyError::Syntax)); } // Bad string
 		let o = o.unwrap();
 
@@ -91,7 +91,7 @@ fn treeify_binary(
 	// This operator
 	let this_op = {
 		let Token::Operator(l, s) = this else {panic!()};
-		let o = Operator::from_string(s, context);
+		let o = Operator::from_string(context, s);
 		if o.is_none() { return Err((*l, DaisyError::Syntax)); } // bad operator string
 		o.unwrap()
 	};
@@ -99,14 +99,14 @@ fn treeify_binary(
 	// The operators contesting our arguments
 	let left_op = if i > 1 {
 		let Token::Operator(l, s) = &g_inner[i-2] else {panic!()};
-		let o = Operator::from_string(s, context);
+		let o = Operator::from_string(context, s);
 		if o.is_none() { return Err((*l, DaisyError::Syntax)); } // Bad operator string
 		Some(o.unwrap())
 	} else { None };
 
 	let right_op = if i < g_inner.len()-2 {
 		let Token::Operator(l, s) = &g_inner[i+2] else {panic!()};
-		let o = Operator::from_string(s, context);
+		let o = Operator::from_string(context, s);
 		if o.is_none() { return Err((*l, DaisyError::Syntax)); } // Bad operator string
 		Some(o.unwrap())
 	} else { None };
@@ -122,20 +122,20 @@ fn treeify_binary(
 		let right_pre = g_inner.remove(i-1).unwrap();
 		let mut left: Expression; let mut right: Expression;
 		if let Token::Group(l, _) = right_pre {
-			right = treeify(right_pre, context)?;
+			right = treeify(context, right_pre)?;
 			right.set_linelocation(&(right.get_linelocation() + l));
 		} else if let Token::Tuple(l, _) = right_pre {
-			right = treeify(right_pre, context)?;
+			right = treeify(context, right_pre)?;
 			right.set_linelocation(&(right.get_linelocation() + l));
 		} else {
 			right = right_pre.to_expression(context)?;
 		}
 
 		if let Token::Group(l, _) = left_pre {
-			left = treeify(left_pre, context)?;
+			left = treeify(context, left_pre)?;
 			left.set_linelocation(&(left.get_linelocation() + l));
 		} else if let Token::Tuple(l, _) = left_pre {
-			left = treeify(left_pre, context)?;
+			left = treeify(context, left_pre)?;
 			left.set_linelocation(&(left.get_linelocation() + l));
 		} else {
 			left = left_pre.to_expression(context)?;
@@ -143,7 +143,7 @@ fn treeify_binary(
 
 		let (l, o) = {
 			let Token::Operator(l, s) = this_pre else {panic!()};
-			let o = Operator::from_string(&s, context);
+			let o = Operator::from_string(context, &s);
 			if o.is_none() { panic!() }
 			(l, o.unwrap())
 		};
@@ -161,10 +161,10 @@ fn treeify_binary(
 }
 
 fn treeify_unary(
+	context: &Context,
 	i: usize,
 	g_inner: &mut VecDeque<Token>,
-	left_associative: bool,
-	context: &Context
+	left_associative: bool
 ) -> Result<bool, (LineLocation, DaisyError)> {
 
 	let this: &Token = &g_inner[i];
@@ -224,7 +224,7 @@ fn treeify_unary(
 		// This operator
 		let this_op = {
 			let Token::Operator(l, s) = this else {panic!()};
-			let o = Operator::from_string(s, context);
+			let o = Operator::from_string(context, s);
 				if o.is_none() { return Err((*l, DaisyError::Syntax)); } // Bad string
 			o.unwrap()
 		};
@@ -233,14 +233,14 @@ fn treeify_unary(
 		let next_op = if left_associative {
 			if i > 1 {
 				let Token::Operator(l, s) = &g_inner[i-2] else {panic!()};
-				let o = Operator::from_string(s, context);
+				let o = Operator::from_string(context, s);
 				if o.is_none() { return Err((*l, DaisyError::Syntax)); } // Bad string
 				Some(o.unwrap())
 			} else { None }
 		} else {
 			if i < g_inner.len()-2 {
 				let Token::Operator(l, s) = &g_inner[i+2] else {panic!()};
-				let o = Operator::from_string(s, context);
+				let o = Operator::from_string(context, s);
 				if o.is_none() { return Err((*l, DaisyError::Syntax)); } // Bad string
 				Some(o.unwrap())
 			} else { None }
@@ -255,10 +255,10 @@ fn treeify_unary(
 				next_pre = g_inner.remove(i).unwrap();
 			}
 			if let Token::Group(l, _) = next_pre {
-				next = treeify(next_pre, context)?;
+				next = treeify(context, next_pre)?;
 				next.set_linelocation(&(next.get_linelocation() + l));
 			} else if let Token::Tuple(l, _) = next_pre {
-				next = treeify(next_pre, context)?;
+				next = treeify(context, next_pre)?;
 				next.set_linelocation(&(next.get_linelocation() + l));
 			} else {
 				next = next_pre.to_expression(context)?;
@@ -267,7 +267,7 @@ fn treeify_unary(
 
 			let (l, o) = {
 				let Token::Operator(l, s) = this_pre else {panic!()};
-				let o = Operator::from_string(&s, context);
+				let o = Operator::from_string(context, &s);
 				if o.is_none() { panic!() }
 				(l, o.unwrap())
 			};
@@ -292,8 +292,8 @@ fn treeify_unary(
 
 
 pub fn treeify(
-	mut g: Token,
-	context: &Context
+	context: &Context,
+	mut g: Token
 ) -> Result<Expression, (LineLocation, DaisyError)> {
 
 	let (l, g_inner): (LineLocation, &mut VecDeque<Token>) = match g {
@@ -301,7 +301,7 @@ pub fn treeify(
 		Token::Tuple(l, parts) => {
 			let mut t: VecDeque<Expression> = VecDeque::new();
 			for p in parts {
-				t.push_back(treeify(p, context)?);
+				t.push_back(treeify(context, p)?);
 			};
 
 			return Ok(Expression::Tuple(l, t));
@@ -332,7 +332,7 @@ pub fn treeify(
 		// If not an operator, move on.
 		let this_op = match &g_inner[i] {
 			Token::Operator(l, s) => {
-				let o = Operator::from_string(&s, context);
+				let o = Operator::from_string(context, &s);
 				if o.is_none() { return Err((*l, DaisyError::Syntax)); }
 				o.unwrap()
 			},
@@ -346,9 +346,9 @@ pub fn treeify(
 			let mut changed = false;
 			if this_op.is_left_associative() {
 				if this_op.is_binary() {
-					changed = treeify_binary(i, g_inner, context)?;
+					changed = treeify_binary(context, i, g_inner)?;
 				} else {
-					changed = treeify_unary(i, g_inner, left_associative, context)?;
+					changed = treeify_unary(context, i, g_inner, left_associative)?;
 				}
 			}
 
@@ -360,9 +360,9 @@ pub fn treeify(
 		} else {
 			if !this_op.is_left_associative() {
 				if this_op.is_binary() {
-					treeify_binary(i, g_inner, context)?;
+					treeify_binary(context, i, g_inner)?;
 				} else {
-					treeify_unary(i, g_inner, left_associative, context)?;
+					treeify_unary(context, i, g_inner, left_associative)?;
 				}
 			}
 			j -= 1
@@ -378,7 +378,7 @@ pub fn treeify(
 		},
 		Token::Tuple(_, _) |
 		Token::Group(_,_) => {
-			treeify(g, context)
+			treeify(context, g)
 		},
 
 

src/quantity/quantity.rs

@@ -7,6 +7,7 @@ use std::ops::{
 };
 use std::cmp::Ordering;
 
+use crate::context::Context;
 use crate::quantity::Unit;
 use crate::quantity::FreeUnit;
 
@@ -21,12 +22,12 @@ pub struct Quantity {
 
 
 
-impl ToString for Quantity {
-	fn to_string(&self) -> String {
+impl Quantity {
+	pub fn display(&self, context: &Context) -> String {
 		let n = self.scalar.to_string();
 		if self.unitless() { return n; }
 
-		let u = self.unit.to_string();
+		let u = self.unit.display(context);
 		if self.is_one() { return u; };
 
 		if self.unit.no_space() {
@@ -38,11 +39,11 @@ impl ToString for Quantity {
 }
 
 impl Quantity {
-	pub fn to_string_outer(&self) -> String {
+	pub fn display_outer(&self, context: &Context) -> String {
 		let n = self.scalar.to_string();
 		if self.unitless() { return n; }
 
-		let u = self.unit.to_string();
+		let u = self.unit.display(context);
 		if self.unit.no_space() {
 			return format!("{n}{u}");
 		} else {

src/quantity/scalar/f64base.rs

@@ -8,6 +8,7 @@ use std::ops::{
 
 use std::cmp::Ordering;
 use super::ScalarBase;
+use super::dec_to_sci;
 
 
 macro_rules! foward {
@@ -25,16 +26,39 @@ pub struct F64Base where {
 }
 
 impl ToString for F64Base {
-	fn to_string(&self) -> String { self.val.to_string() }
+	fn to_string(&self) -> String {
+		// Remove negative sign from string
+		let mut s = self.val.to_string();
+		
+		let neg = s.starts_with("-");
+		if neg { s = String::from(&s[1..]); }
+		
+		// Power of ten
+		let mut p: i64 = {
+			if let Some(x) = s.find(".") {
+				x as i64
+			} else {
+				s.len() as i64
+			}
+		};
+		p -= 1;
+
+		// We no longer need a decimal point in our string.
+		// also, trim off leading zeros and adjust power.
+		let mut s: &str = &s.replace(".", "");
+		s = &s[0..];
+		s = s.trim_end_matches('0');
+		while s.starts_with('0') {
+			s = &s[1..];
+			p -= 1;
+		}
+
+		return dec_to_sci(neg, s.to_string(), p);
+	}
 }
 
 
 impl ScalarBase for F64Base {
-
-	fn from_f64(f: f64) -> Option<F64Base> {
-		return Some(F64Base{ val: f });
-	}
-
 	fn from_string(s: &str) -> Option<F64Base> {
 		let v = s.parse::<f64>();
 		let v = match v {
@@ -51,6 +75,7 @@ impl ScalarBase for F64Base {
 	fn is_one(&self) -> bool {self.val == 1f64}
 	fn is_negative(&self) -> bool { self.val.is_sign_negative() }
 	fn is_positive(&self) -> bool { self.val.is_sign_positive() }
+	fn is_int(&self) -> bool { self.val.floor() == self.val }
 
 	foward!(abs);
 	foward!(floor);
@@ -60,9 +85,11 @@ impl ScalarBase for F64Base {
 	foward!(sin);
 	foward!(cos);
 	foward!(tan);
-	foward!(csc);
-	foward!(sec);
-	foward!(cot);
+
+	fn csc(&self) -> Option<F64Base> { Some(F64Base{ val: 1f64/self.val.sin() }) }
+	fn sec(&self) -> Option<F64Base> { Some(F64Base{ val: 1f64/self.val.cos() }) }
+	fn cot(&self) -> Option<F64Base> { Some(F64Base{ val: 1f64/self.val.tan() }) }
+
 	foward!(asin);
 	foward!(acos);
 	foward!(atan);
@@ -70,9 +97,11 @@ impl ScalarBase for F64Base {
 	foward!(sinh);
 	foward!(cosh);
 	foward!(tanh);
-	foward!(csch);
-	foward!(sech);
-	foward!(coth);
+
+	fn csch(&self) -> Option<F64Base> { Some(F64Base{ val: 1f64/self.val.sinh() }) }
+	fn sech(&self) -> Option<F64Base> { Some(F64Base{ val: 1f64/self.val.cosh() }) }
+	fn coth(&self) -> Option<F64Base> { Some(F64Base{ val: 1f64/self.val.tanh() }) }
+
 	foward!(asinh);
 	foward!(acosh);
 	foward!(atanh);
@@ -161,11 +190,11 @@ impl Rem<F64Base> for F64Base {
 
 	fn rem(self, modulus: F64Base) -> Self::Output {
 		if {
-			(!self.fract().unwrap().is_zero()) ||
-			(!modulus.fract().unwrap().is_zero())
+			(!self.is_int()) ||
+			(!modulus.is_int())
 		} { panic!() }
 
-		F64Base{val : self.val.fract() % modulus.val.fract()}
+		F64Base{val : self.val.round() % modulus.val.round()}
 	}
 }
 

src/quantity/scalar/floatbase.rs

@@ -1,7 +1,7 @@
-use rug::Float;
-use rug::Assign;
-use rug::ops::AssignRound;
-use rug::ops::Pow;
+use bigdecimal::BigDecimal;
+use bigdecimal::Zero;
+use bigdecimal::RoundingMode;
+use std::str::FromStr;
 
 use std::ops::{
 	Add, Sub, Mul, Div,
@@ -14,158 +14,151 @@ use std::ops::{
 use std::cmp::Ordering;
 
 use super::ScalarBase;
-use super::PRINT_LEN;
-use super::FLOAT_PRECISION;
+use super::dec_to_sci;
+
 
 #[derive(Debug)]
 #[derive(Clone)]
 pub struct FloatBase where {
-	pub val: Float
+	pub val: BigDecimal
 }
 
 impl FloatBase {
-	pub fn from<T>(a: T) -> Option<FloatBase> where
-		Float: Assign<T> + AssignRound<T>
-	{
-		let v = Float::with_val(FLOAT_PRECISION, a);
-		return Some(FloatBase{ val: v });
+	pub fn new(s: &str) -> FloatBase {
+		return FloatBase {
+			val: s.parse().unwrap()
+		};
 	}
 }
 
+
 impl ToString for FloatBase {
 	fn to_string(&self) -> String {
-		let (sign, mut string, exp) = self.val.to_sign_string_exp(10, Some(PRINT_LEN));
 
-		// zero, nan, or inf.
-		let sign = if sign {"-"} else {""};
-		if exp.is_none() { return format!("{sign}{string}"); }
-		let exp = exp.unwrap();
-
-		// Remove trailing zeros.
-		// At this point, string is guaranteed to be nonzero.
-		while string.chars().last().unwrap() == '0' {
-			string.remove(string.len() - 1);
+		if self.val.is_nan() {
+			return "NaN".to_string();
+		} else if self.val.is_inf_neg() {
+			return "-Inf".to_string();
+		} else if self.val.is_inf_pos() {
+			return "+Inf".to_string();
 		}
 
-		let exp_u: usize;
 
-		if exp < 0 {
-			exp_u = (-exp).try_into().unwrap()
-		} else {
-			exp_u = exp.try_into().unwrap()
-		}
+		// Already in scientific notation,we just need to trim significant digits.
+		let mut _a = self.val.round(32, astro_float::RoundingMode::Up).to_string();
+		let mut _b = _a.split('e');
 
-		if exp_u >= PRINT_LEN {
-			// Exponential notation
-			let pre = &string[0..1];
-			let post = &string[1..];
+		let mut s = String::from(_b.next().unwrap()); // Decimal
+		let p: i64 = _b.next().unwrap().parse().unwrap(); // Exponent
 
-			format!(
-				"{pre}{}{post}e{}",
-				if post.len() != 0 {"."} else {""},
-				//if exp > 0 {"+"} else {""},
-				exp - 1
-			)
-		} else {
-			if exp <= 0 { // Decimal, needs `0.` and leading zeros
-				format!(
-					"{sign}0.{}{string}",
-					"0".repeat(exp_u)
-				)
-			} else if exp_u < string.len() { // Decimal, needs only `.`
-				format!(
-					"{sign}{}.{}",
-					&string[0..exp_u],
-					&string[exp_u..]
-				)
-			} else { // Integer, needs trailing zeros
-				format!(
-					"{sign}{string}{}",
-					"0".repeat(exp_u - string.len())
-				)
-			}
-		}
+		// Remove negative sign from string
+		let neg = s.starts_with("-");
+		if neg { s = String::from(&s[1..]); }
 
+		// We no longer need a decimal point in our string.
+		// also, trim off leading zeros and adjust power.
+		let mut s: &str = &s.replace(".", "");
+		s = &s[0..];
+		s = s.trim_end_matches('0');
+		s = s.trim_start_matches('0');
+
+		return dec_to_sci(neg, s.to_string(), p);
 	}
 }
 
 
-macro_rules! foward {
-	( $x:ident ) => {
-		fn $x(&self) -> Option<FloatBase> {
-			Some(FloatBase{ val: self.val.clone().$x()})
-		}
-	}
-}
 
 impl ScalarBase for FloatBase {
 
-	fn from_f64(f: f64) -> Option<FloatBase> {
-		let v = Float::with_val(FLOAT_PRECISION, f);
-		return Some(FloatBase{ val: v });
-	}
-
 	fn from_string(s: &str) -> Option<FloatBase> {
-		let v = Float::parse(s);
+		let v = BigDecimal::from_str(s);
 		let v = match v {
 			Ok(x) => x,
 			Err(_) => return None
 		};
 
-		return Some(
-			FloatBase{ val:
-				Float::with_val(FLOAT_PRECISION, v)
-			}
-		);
+		return Some(FloatBase{ val: v });
 	}
 
-	foward!(fract);
+	//foward!(fract);
 
 	fn is_zero(&self) -> bool {self.val.is_zero()}
-	fn is_one(&self) -> bool {self.val == Float::with_val(FLOAT_PRECISION, 1)}
-	fn is_negative(&self) -> bool { self.val.is_sign_negative() }
-	fn is_positive(&self) -> bool { self.val.is_sign_positive() }
+	fn is_one(&self) -> bool {self.val == BigDecimal::from_str("1").unwrap()}
+	fn is_negative(&self) -> bool { self.val.sign() == num::bigint::Sign::Minus }
+	fn is_positive(&self) -> bool { self.val.sign() == num::bigint::Sign::Plus }
 
-	fn is_int(&self) -> bool {
-		self.fract() == FloatBase::from_f64(0f64)
+	fn is_int(&self) -> bool { self.val.is_integer() }
+
+	fn abs(&self) -> Option<FloatBase> { Some(FloatBase{ val: self.val.abs() }) }
+	fn round(&self) -> Option<FloatBase> { Some(FloatBase{ val: self.val.round(0) }) }
+
+	fn floor(&self) -> Option<FloatBase> {
+		let (_, scale) = self.val.as_bigint_and_exponent();
+		Some(FloatBase{ val: self.val.with_scale_round(scale, RoundingMode::Down) })
 	}
 
-	foward!(abs);
-	foward!(floor);
-	foward!(ceil);
-	foward!(round);
-
-	foward!(sin);
-	foward!(cos);
-	foward!(tan);
-	foward!(csc);
-	foward!(sec);
-	foward!(cot);
-	foward!(asin);
-	foward!(acos);
-	foward!(atan);
-
-	foward!(sinh);
-	foward!(cosh);
-	foward!(tanh);
-	foward!(csch);
-	foward!(sech);
-	foward!(coth);
-	foward!(asinh);
-	foward!(acosh);
-	foward!(atanh);
-
-	foward!(exp);
-	foward!(ln);
-	foward!(log10);
-	foward!(log2);
-
-	fn log(&self, base: FloatBase) -> Option<FloatBase> {
-		Some(FloatBase{ val: self.val.clone().log10() } / base.log10().unwrap())
+	fn ceil(&self) -> Option<FloatBase> {
+		let (_, scale) = self.val.as_bigint_and_exponent();
+		Some(FloatBase{ val: self.val.with_scale_round(scale, RoundingMode::Up) })
 	}
 
-	fn pow(&self, base: FloatBase) -> Option<FloatBase> {
-		Some(FloatBase{ val: self.val.clone().pow(base.val)})
+	fn fract(&self) -> Option<FloatBase> { Some(self.clone() - self.floor().unwrap()) }
+
+
+	fn sin(&self) -> Option<FloatBase> {
+		let c0: BigDecimal = "1.276278962".parse().unwrap();
+		let c1: BigDecimal = "-.285261569".parse().unwrap();
+		let c2: BigDecimal = "0.009118016".parse().unwrap();
+		let c3: BigDecimal = "-.000136587".parse().unwrap();
+		let c4: BigDecimal = "0.000001185".parse().unwrap();
+		let c5: BigDecimal = "-.000000007".parse().unwrap();
+		
+
+		// z should be between -0.25 to 0.25 (percent of a full circle)
+		let z: BigDecimal = self.val.clone() / 360f64;
+		let w = BigDecimal::from(4) * z;
+		let x: BigDecimal = 2 * w.clone() * w.clone() - 1;
+
+		let p = (
+			c0 * 1 +
+			c1 * x.clone() +
+			c2 * (2 * x.clone()*x.clone() - 1) +
+			c3 * (4 * x.clone()*x.clone()*x.clone() - 3 * x.clone()) +
+			c4 * (8 * x.clone()*x.clone()*x.clone()*x.clone() - 8 * x.clone()*x.clone() + 1) +
+			c5 * (16 * x.clone()*x.clone()*x.clone()*x.clone()*x.clone() - 20 * x.clone()*x.clone()*x.clone() + 5 * x.clone())
+		) * w;
+
+		return Some(FloatBase{ val: p })
+	}
+	fn cos(&self) -> Option<FloatBase> { Some(FloatBase{ val: "1".parse().unwrap() }) }
+	fn tan(&self) -> Option<FloatBase> { Some(FloatBase{ val: "1".parse().unwrap() }) }
+	fn csc(&self) -> Option<FloatBase> { Some(FloatBase{ val: "1".parse().unwrap() }) }
+	fn sec(&self) -> Option<FloatBase> { Some(FloatBase{ val: "1".parse().unwrap() }) }
+	fn cot(&self) -> Option<FloatBase> { Some(FloatBase{ val: "1".parse().unwrap() }) }
+	fn asin(&self) -> Option<FloatBase> { Some(FloatBase{ val: "1".parse().unwrap() }) }
+	fn acos(&self) -> Option<FloatBase> { Some(FloatBase{ val: "1".parse().unwrap() }) }
+	fn atan(&self) -> Option<FloatBase> { Some(FloatBase{ val: "1".parse().unwrap() }) }
+	fn sinh(&self) -> Option<FloatBase> { Some(FloatBase{ val: "1".parse().unwrap() }) }
+	fn cosh(&self) -> Option<FloatBase> { Some(FloatBase{ val: "1".parse().unwrap() }) }
+	fn tanh(&self) -> Option<FloatBase> { Some(FloatBase{ val: "1".parse().unwrap() }) }
+	fn csch(&self) -> Option<FloatBase> { Some(FloatBase{ val: "1".parse().unwrap() }) }
+	fn sech(&self) -> Option<FloatBase> { Some(FloatBase{ val: "1".parse().unwrap() }) }
+	fn coth(&self) -> Option<FloatBase> { Some(FloatBase{ val: "1".parse().unwrap() }) }
+	fn asinh(&self) -> Option<FloatBase> { Some(FloatBase{ val: "1".parse().unwrap() }) }
+	fn acosh(&self) -> Option<FloatBase> { Some(FloatBase{ val: "1".parse().unwrap() }) }
+	fn atanh(&self) -> Option<FloatBase> { Some(FloatBase{ val: "1".parse().unwrap() }) }
+	fn exp(&self) -> Option<FloatBase> { Some(FloatBase{ val: "1".parse().unwrap() }) }
+	fn ln(&self) -> Option<FloatBase> { Some(FloatBase{ val: "1".parse().unwrap() }) }
+	fn log10(&self) -> Option<FloatBase> { Some(FloatBase{ val: "1".parse().unwrap() }) }
+	fn log2(&self) -> Option<FloatBase> { Some(FloatBase{ val: "1".parse().unwrap() }) }
+
+
+	fn log(&self, _base: FloatBase) -> Option<FloatBase> {
+		Some(FloatBase{ val: "1".parse().unwrap() })
+	}
+
+	fn pow(&self, _base: FloatBase) -> Option<FloatBase> {
+		Some(FloatBase{ val: "1".parse().unwrap() })
 	}
 
 }
@@ -223,7 +216,7 @@ impl Div for FloatBase {
 
 impl DivAssign for FloatBase where {
 	fn div_assign(&mut self, other: Self) {
-		self.val /= other.val;
+		self.val = self.val.clone() / other.val;
 	}
 }
 
@@ -240,11 +233,11 @@ impl Rem<FloatBase> for FloatBase {
 
 	fn rem(self, modulus: FloatBase) -> Self::Output {
 		if {
-			(!self.fract().unwrap().is_zero()) ||
-			(!modulus.fract().unwrap().is_zero())
+			(!self.is_int()) ||
+			(!modulus.is_int())
 		} { panic!() }
 
-		FloatBase{val : self.val.fract() % modulus.val.fract()}
+		FloatBase{val : self.val.round(0) % modulus.val.round(0)}
 	}
 }
 

src/quantity/scalar/mod.rs

@@ -1,10 +1,92 @@
-const FLOAT_PRECISION: u32 = 1024;
-const PRINT_LEN: usize = 5; // How many significant digits we will show in output
+//const FLOAT_PRECISION: u32 = 1024;
+const SHOW_SIG: usize = 5; // How many significant digits we will show in output
+const MAX_LEN: usize = 5; // If a scientific exponent is >= this value, do not use scientific notation.
 
 pub(in self) mod rationalbase;
-pub(in self) mod floatbase;
-//mod f64base;
+
+
+// Pick a float implementation.
+// floatbase is high-precision, f64base is for testing.
+
+//pub(in self) mod floatbase;
+//pub use floatbase::FloatBase;
+
+pub(in self) mod f64base;
+pub use f64base::F64Base as FloatBase;
+
+
 
 mod scalar;
 pub use self::scalar::Scalar;
 pub use self::scalar::ScalarBase;
+
+
+
+// Convert a string to scientific notation,
+// with parameters SHOW_SIG and MAX_LEN.
+//
+// input:
+//  neg: true if negative
+//  s: decimal portion. Must contain only digits and a single decimal point.
+//     zeros must be stripped from both ends.
+//  p: power of ten to multiply by.
+//
+//  So, (-1)^(neg) + (s * 10^p) should give us our number.
+
+#[allow(dead_code)]
+pub(in self) fn dec_to_sci(neg: bool, mut s: String, p: i64) -> String {
+	// Pick significant digits and round
+	if s.len() > SHOW_SIG {
+		let round;
+		if s.len() != SHOW_SIG + 1 {
+			round = s[SHOW_SIG..SHOW_SIG+1].parse().unwrap();
+		} else { round = 0; }
+
+		s = String::from(&s[0..SHOW_SIG]);
+
+		if round >= 5 {
+			let new = s[s.len()-1..s.len()].parse::<u8>().unwrap() + 1u8;
+			if new != 10 {
+				s = format!("{}{new}", &s[0..s.len()-1]);
+			}
+		}
+	}
+
+	s = format!("{s}{}", "0".repeat(SHOW_SIG - s.len()));
+	// at this point, s is guaranteed to have exactly SHOW_SIG digits.
+
+	let neg = if neg {"-"} else {""};
+
+	if (p.abs() as usize) < MAX_LEN {
+		// Print whole decimal
+
+		if p >= 0 {
+			let q = p as usize;
+
+			let first = &s[0..q+1];
+			let mut rest = &s[q+1..];
+			rest = rest.trim_end_matches('0');
+			if rest == "" {
+				return format!("{neg}{first}");
+			} else {
+				return format!("{neg}{first}.{rest}");
+			}
+		} else {
+			let q = p.abs() as usize;
+			let t = format!("0.{}{s}", "0".repeat(q-1));
+			return format!("{neg}{}", t.trim_end_matches('0'));
+		}
+
+	} else {
+		// Print full scientific notation
+
+		let first = &s[0..1];
+		let mut rest = &s[1..];
+		rest = rest.trim_end_matches('0');
+		if rest == "" {
+			return format!("{neg}{first}e{p}");
+		} else {
+			return format!("{neg}{first}.{rest}e{p}");
+		}
+	}
+}

src/quantity/scalar/rationalbase.rs

@@ -1,5 +1,7 @@
-use rug::Rational;
-use rug::Integer;
+use num::rational::BigRational;
+use num::BigInt;
+use num::Num;
+use num::Signed;
 
 use std::ops::{
 	Add, Sub, Mul, Div,
@@ -22,7 +24,7 @@ macro_rules! cant_do {
 #[derive(Debug)]
 #[derive(Clone)]
 pub struct RationalBase where {
-	pub val: Rational
+	pub val: BigRational
 }
 
 impl ToString for RationalBase{
@@ -33,18 +35,12 @@ impl ToString for RationalBase{
 
 impl RationalBase {
 	pub fn from_frac(t: i64, b: i64) -> Option<RationalBase> {
-		let v = Rational::from((t, b));
+		let v = BigRational::new_raw(BigInt::from(t), BigInt::from(b));
 		return Some(RationalBase{ val: v });
 	}
 }
 
 impl ScalarBase for RationalBase {
-	fn from_f64(f: f64) -> Option<RationalBase> {
-		let v = Rational::from_f64(f);
-		if v.is_none() { return None }
-		return Some(RationalBase{ val: v.unwrap() });
-	}
-
 	fn from_string(s: &str) -> Option<RationalBase> {
 		// Scientific notation
 		let mut sci = s.split("e");
@@ -89,7 +85,7 @@ impl ScalarBase for RationalBase {
 
 
 		// From fraction string
-		let r = Rational::from_str_radix(&s, 10);
+		let r = BigRational::from_str_radix(&s, 10);
 		let r = match r {
 			Ok(x) => x,
 			Err(_) => return None
@@ -100,18 +96,13 @@ impl ScalarBase for RationalBase {
 	}
 
 
-	fn fract(&self) -> Option<RationalBase> {
-		Some(RationalBase{val: self.val.clone().fract_floor(Integer::new()).0})
-	}
+	fn fract(&self) -> Option<RationalBase> { Some(RationalBase{val: self.val.fract()}) }
+	fn is_int(&self) -> bool { self.val.is_integer() }
 
-	fn is_int(&self) -> bool {
-		self.fract() == RationalBase::from_f64(0f64)
-	}
-
-	fn is_zero(&self) -> bool {self.val == Rational::from((0,1))}
-	fn is_one(&self) -> bool {self.val == Rational::from((1,1))}
-	fn is_negative(&self) -> bool { self.val.clone().signum() == -1 }
-	fn is_positive(&self) -> bool { self.val.clone().signum() == 1 }
+	fn is_zero(&self) -> bool {self.val == BigRational::from_integer(BigInt::from(0))}
+	fn is_one(&self) -> bool {self.val == BigRational::from_integer(BigInt::from(1))}
+	fn is_negative(&self) -> bool { self.val.is_negative() }
+	fn is_positive(&self) -> bool { self.val.is_positive() }
 
 	fn abs(&self) -> Option<RationalBase> {Some(RationalBase{val: self.val.clone().abs()})}
 	fn floor(&self) -> Option<RationalBase> {Some(RationalBase{val: self.val.clone().floor()})}
@@ -153,9 +144,7 @@ impl Add for RationalBase where {
 	type Output = Self;
 
 	fn add(self, other: Self) -> Self::Output {
-		Self {
-			val: self.val + other.val
-		}
+		Self { val: self.val + other.val }
 	}
 }
 
@@ -169,9 +158,7 @@ impl Sub for RationalBase {
 	type Output = Self;
 
 	fn sub(self, other: Self) -> Self::Output {
-		Self {
-			val: self.val - other.val
-		}
+		Self { val: self.val - other.val }
 	}
 }
 
@@ -185,9 +172,7 @@ impl Mul for RationalBase {
 	type Output = Self;
 
 	fn mul(self, other: Self) -> Self::Output {
-		Self {
-			val: self.val * other.val
-		}
+		Self { val: self.val * other.val }
 	}
 }
 
@@ -201,9 +186,7 @@ impl Div for RationalBase {
 	type Output = Self;
 
 	fn div(self, other: Self) -> Self::Output {
-		Self {
-			val: self.val / other.val
-		}
+		Self { val: self.val / other.val }
 	}
 }
 
@@ -217,9 +200,7 @@ impl Neg for RationalBase where {
 	type Output = Self;
 
 	fn neg(self) -> Self::Output {
-		Self {
-			val: -self.val
-		}
+		Self { val: -self.val }
 	}
 }
 
@@ -228,15 +209,15 @@ impl Rem<RationalBase> for RationalBase {
 
 	fn rem(self, modulus: RationalBase) -> Self::Output {
 		if {
-			*self.val.denom() != 1 ||
-			*modulus.val.denom() != 1
+			*self.val.denom() != BigInt::from(1) ||
+			*modulus.val.denom() != BigInt::from(1)
 		} { panic!() }
 
 		RationalBase{
-			val : Rational::from((
+			val : BigRational::new_raw(
 				self.val.numer() % modulus.val.numer(),
-				1
-			))
+				BigInt::from(1)
+			)
 		}
 	}
 }

src/quantity/scalar/scalar.rs

@@ -7,7 +7,7 @@ use std::ops::{
 };
 use std::cmp::Ordering;
 
-use super::floatbase::FloatBase as FloatBase;
+use super::FloatBase as FloatBase;
 use super::rationalbase::RationalBase;
 
 
@@ -21,7 +21,6 @@ pub trait ScalarBase:
 	PartialEq + PartialOrd
 {
 	// Creation
-	fn from_f64(f: f64) -> Option<Self>;
 	fn from_string(s: &str) -> Option<Self>;
 
 	// Utility
@@ -87,8 +86,8 @@ fn to_float(r: Scalar) -> Scalar {
 	match &r {
 		Scalar::Float {..} => r,
 		Scalar::Rational {v} => wrap_float!(
-			FloatBase::from(v.val.numer()).unwrap() /
-			FloatBase::from(v.val.denom()).unwrap()
+			FloatBase::from_string(&v.val.numer().to_string()).unwrap() /
+			FloatBase::from_string(&v.val.denom().to_string()).unwrap()
 		)
 	}
 }
@@ -105,13 +104,13 @@ impl ToString for Scalar {
 // Creation methods
 impl Scalar {
 	pub fn new_float(f: f64) -> Option<Self> {
-		let v = FloatBase::from_f64(f);
+		let v = FloatBase::from_string(&f.to_string());
 		if v.is_none() { return None; }
 		return Some(wrap_float!(v.unwrap()));
 	}
 
 	pub fn new_rational(f: f64) -> Option<Self> {
-		let r = RationalBase::from_f64(f);
+		let r = RationalBase::from_string(&f.to_string());
 		if r.is_none() { return None; }
 		return Some(wrap_rational!(r.unwrap()));
 	}
@@ -185,8 +184,8 @@ impl Scalar {
 
 	pub fn is_nan(&self) -> bool {
 		match self {
-			Scalar::Float {v} => {v.val.is_nan()},
-			Scalar::Rational {..} => {panic!()}
+			Scalar::Float{ v } => {v.val.is_nan()},
+			Scalar::Rational {..} => {false}
 		}
 	}
 

src/quantity/unit/unit.rs

@@ -4,6 +4,7 @@ use std::ops::{
 	MulAssign, DivAssign
 };
 
+use crate::context::Context;
 use crate::quantity::Scalar;
 use crate::quantity::Quantity;
 use super::FreeUnit;
@@ -16,8 +17,8 @@ pub struct Unit {
 	pub val: HashMap<FreeUnit, Scalar>
 }
 
-impl ToString for Unit {
-	fn to_string(&self) -> String {
+impl Unit {
+	pub fn display(&self, context: &Context) -> String {
 
 		if self.unitless() { return String::new(); };
 
@@ -37,7 +38,11 @@ impl ToString for Unit {
 
 			if *p == Scalar::new_rational(1f64).unwrap() {
 				t.push_str(&format!("{c}·"));
-			} else if p.is_int() && !p.to_string().contains("e"){
+			} else if {
+				context.config.enable_super_powers &&
+				p.is_int() &&
+				!p.to_string().contains("e")
+			} {
 				t.push_str(&c);
 				for c in p.to_string().chars() {
 					t.push( match c {
@@ -74,7 +79,11 @@ impl ToString for Unit {
 			bottom_count += 1;
 			if t.len() != 0 && *p == Scalar::new_rational(-1f64).unwrap() {
 				b.push_str(&format!("{c}·"));
-			} else if p.is_int() && !p.to_string().contains("e") {
+			} else if {
+				context.config.enable_super_powers &&
+				p.is_int() &&
+				!p.to_string().contains("e")
+			} {
 				b.push_str(&c);
 				for c in p.to_string().chars() {
 					if c == '-' && t.len() != 0 { continue; }
@@ -266,7 +275,6 @@ impl Unit {
 		let mut q = Quantity::new_rational(1f64).unwrap();
 		q.set_unit(b);
 		return Some(q);
-
 	}
 }
 

src/tests.rs

@@ -10,8 +10,10 @@ fn eval_to_str(s: &str) -> Result<String, ()> {
 	};
 	//let out_str = g.print();
 
-	return match evaluate(&g, &mut Context::new()) {
-		Ok(x) => Ok(x.to_string_outer()),
+	let mut c = Context::new();
+
+	return match evaluate(&mut c, &g) {
+		Ok(x) => Ok(x.display_outer(&c)),
 		Err(_) => Err(())
 	};
 }
@@ -129,7 +131,7 @@ fn operators() {
 
 	good_expr("125", "5^(+3)");
 	good_expr("125", "+5^3");
-	good_expr("0.2148", "3 ^ (-1.4)");
+	good_expr("0.21479", "3 ^ (-1.4)");
 
 	// Should parse as ((2^3)^4)^5
 	good_expr("1.1529e18", "2^3^4^5");
@@ -160,6 +162,7 @@ fn operators() {
 
 	good_expr("2", "6/3");
 	good_expr("2", "5%3");
+	good_expr("4", "2^5 mod 7");
 	good_expr("8", "5+3");
 	good_expr("64", "4^3");
 	good_expr("64", "4 ^ 3");
@@ -182,6 +185,7 @@ fn operators() {
 	bad_expr("1e5!");
 	bad_expr("0^(-1)");
 	bad_expr("pi!");
+	bad_expr("2.5 mod 8");
 }
 
 #[test]