Added shadow variables

src/context.rs

@@ -6,7 +6,10 @@ use std::collections::HashMap;
 pub struct Context {
 	history: Vec<Expression>,
 	variables: HashMap<String, Expression>,
-	functions: HashMap<String, (Vec<String>, Expression)>
+	functions: HashMap<String, (Vec<String>, Expression)>,
+
+	// Shadow variables, for function evaluation.
+	shadow: HashMap<String, Option<Expression>>
 }
 
 // General functions
@@ -16,6 +19,7 @@ impl Context {
 			history: Vec::new(),
 			variables: HashMap::new(),
 			functions: HashMap::new(),
+			shadow: HashMap::new(),
 		}
 	}
 
@@ -42,14 +46,22 @@ impl Context {
 		} else { return Err(()); }
 	}
 
+	// Returns None if this is a "floating" variable
 	pub fn get_variable(&self, s: &String) -> Option<Expression> {
+		if self.shadow.contains_key(s) {
+			return self.shadow.get(s).unwrap().clone();
+		}
+
 		let v: Option<&Expression>;
 		if s == "ans" {
 			v = self.history.last();
 		} else {
 			v = self.variables.get(s);
 		}
-		if v.is_some() { Some(v.unwrap().clone()) } else { None }
+
+		if v.is_some() {
+			return Some(v.unwrap().clone());
+		} else { panic!() }
 	}
 
 	pub fn valid_varible(&self, s: &str) -> bool {
@@ -72,13 +84,25 @@ impl Context {
 	}
 
 	pub fn is_varible(&self, s: &str) -> bool {
-		return self.valid_varible(s) && self.variables.contains_key(s);
+		return self.valid_varible(s) && (
+			self.variables.contains_key(s) ||
+			self.shadow.contains_key(s)
+		);
 	}
 
 	pub fn get_variables(&self) -> &HashMap<String, Expression> {
 		return &self.variables
 	}
 
+	pub fn add_shadow(&mut self, s: String, v: Option<Expression>) {
+		if !self.valid_varible(&s) { panic!() }
+		self.shadow.insert(s, v);
+	}
+
+	pub fn clear_shadow(&mut self) {
+		self.shadow = HashMap::new();
+	}
+
 }
 
 

src/entry/unix/unix.rs

@@ -40,7 +40,7 @@ fn do_expression(
 	// Evaluate expression
 	#[cfg(debug_assertions)]
 	RawTerminal::suspend_raw_mode(&stdout).unwrap();
-	let g_evaluated = evaluate::evaluate(&g, context, false)?;
+	let g_evaluated = evaluate::evaluate(&g, context)?;
 	#[cfg(debug_assertions)]
 	RawTerminal::activate_raw_mode(&stdout).unwrap();
 

src/evaluate/evaluate.rs

@@ -10,8 +10,7 @@ use super::function::eval_function;
 
 pub fn evaluate(
 	t: &Expression,
-	context: &mut Context,
-	allow_incomplete: bool
+	context: &mut Context
 ) -> Result<
 	Expression,
 	(LineLocation, DaisyError)
@@ -52,19 +51,17 @@ pub fn evaluate(
 			let new = match g {
 				Expression::Quantity(_, _) => None,
 				Expression::Tuple(_, _) => None,
-				Expression::Constant(_, c) => { Some(evaluate(&c.value(), context, false).unwrap()) },
+				Expression::Constant(_, c) => { Some(evaluate(&c.value(), context).unwrap()) },
 				Expression::Variable(l, s) => {
 					// Don't move up, re-evaluate
 					// This makes variables containing floating variables work properly
 					// (For example, try x = a + 2, a = 2, x. x should evaluate to 4.)
 					move_up = false;
-					let v = context.get_variable(&s);
+					if !context.is_varible(&s) {
+						return Err((*l, DaisyError::Undefined(s.clone())));
+					}
 
-					// Error if variable is undefined.
-					// Comment this to allow floating varables.
-					if v.is_none() { return Err((*l, DaisyError::Undefined(s.clone()))); }
-
-					v
+					context.get_variable(&s)
 				},
 				Expression::Operator(_, Operator::Function(_), _) => { Some(eval_function(g)?) },
 				Expression::Operator(_, _, _) => { eval_operator(g, context)? },
@@ -80,13 +77,13 @@ pub fn evaluate(
 				*g = new;
 			} else {
 
-				if !allow_incomplete {
+				/*
 				if let Expression::Quantity(_, _) = g {}
 				else {
 					let l = g.get_linelocation();
 					return Err((l, DaisyError::EvaluationError))
 				}
-				}
+				*/
 
 				// Always move up if we couldn't evaluate this node.
 				move_up = true;

src/parser/token.rs

@@ -78,15 +78,13 @@ impl Token {
 			},
 
 			Token::Word(l, s) => {
-
 				let c = Constant::from_string(&s);
 				if c.is_some() { return Ok(Expression::Constant(l, c.unwrap())); }
 
 				let c = Unit::from_string(&s);
 				if c.is_some() { return Ok(Expression::Quantity(l, c.unwrap())); }
 
-				let c = context.get_variable(&s);
-				if c.is_some() { return Ok(Expression::Variable(l, s)); }
+				if context.is_varible(&s) { return Ok(Expression::Variable(l, s)); }
 				return Ok(Expression::Variable(l, s));
 			}
 

src/tests.rs

@@ -10,7 +10,7 @@ fn eval_to_str(s: &str) -> Result<String, ()> {
 	};
 	//let out_str = g.print();
 
-	return match evaluate(&g, &mut Context::new(), false) {
+	return match evaluate(&g, &mut Context::new()) {
 		Ok(x) => Ok(x.to_string_outer()),
 		Err(_) => Err(())
 	};