Added unit fromstring

src/parser/mod.rs

@@ -12,7 +12,8 @@ use crate::parser::groupify::groupify;
 use crate::parser::treeify::treeify;
 use crate::parser::find_subs::find_subs;
 
-use crate::quantity::{Quantity, BaseUnit};
+use crate::quantity::Quantity;
+use crate::quantity::Unit;
 
 use crate::tokens::Token;
 
@@ -89,28 +90,35 @@ impl PreToken {
 			},
 
 			PreToken::PreWord(l, s) => {
-				return Ok(match &s[..] {
+				let c = match &s[..] {
 					// Mathematical constants
 					// 100 digits of each.
-					"π"|"pi" => { Token::Constant(Quantity::new_float_from_string("3.141592653589793238462643383279502884197169399375105820974944592307816406286208998628034825342117067").unwrap(), String::from("π")) },
-					"e" => { Token::Constant(Quantity::new_float_from_string("2.718281828459045235360287471352662497757247093699959574966967627724076630353547594571382178525166427").unwrap(), String::from("e")) },
-					"phi"|"φ" => { Token::Constant(Quantity::new_float_from_string("1.618033988749894848204586834365638117720309179805762862135448622705260462818902449707207204189391137").unwrap(), String::from("φ")) },
+					"π"|"pi" => { Some(Token::Constant(Quantity::new_float_from_string(
+						"3.141592653589793238462643383279502884197169399375105820974944592307816406286208998628034825342117067"
+					).unwrap(), String::from("π")))},
 
-					// Units
-					"m" => {
-						let mut u = Quantity::new_rational(1f64).unwrap();
-						u.add_unit(BaseUnit::Meter, 1f64);
-						Token::Number(u)
-					},
+					"e" => { Some(Token::Constant(Quantity::new_float_from_string(
+						"2.718281828459045235360287471352662497757247093699959574966967627724076630353547594571382178525166427"
+					).unwrap(), String::from("e"))) },
 
-					"s" => {
-						let mut u = Quantity::new_rational(1f64).unwrap();
-						u.add_unit(BaseUnit::Second, 1f64);
-						Token::Number(u)
-					}
+					"phi"|"φ" => { Some(Token::Constant(Quantity::new_float_from_string(
+						"1.618033988749894848204586834365638117720309179805762862135448622705260462818902449707207204189391137"
+					).unwrap(), String::from("φ"))) },
 
-					_ => { return Err((l, ParserError::Undefined(s))); }
-				});
+					_ => { None }
+				};
+
+				if c.is_some() { return Ok(c.unwrap()); }
+
+				let c = Unit::from_string(&s);
+
+				if c.is_some() {
+					let mut q = Quantity::new_rational(1f64).unwrap();
+					q.set_unit(c.unwrap());
+					return Ok(Token::Number(q));
+				}
+
+				return Err((l, ParserError::Undefined(s)));
 			}
 
 			PreToken::Container(v) => { return Ok(v); }

src/quantity/unit.rs

@@ -95,6 +95,22 @@ impl Unit {
 		return u;
 	}
 
+	pub fn from_string(s: &str) -> Option<Unit> {
+		let b = match s {
+			"m" => BaseUnit::Meter,
+			"s" => BaseUnit::Second,
+			"kg" => BaseUnit::Kilogram,
+			"a" => BaseUnit::Ampere,
+			"k" => BaseUnit::Kelvin,
+			"mol" => BaseUnit::Mole,
+			"c" => BaseUnit::Candela,
+			_ => { return None; }
+		};
+
+		let mut u = Unit::new();
+		u.insert(b, 1f64);
+		return Some(u);
+	}
 }