One step closer to functions

src/executor.rs

@@ -1,12 +1,14 @@
 use std::{collections::HashMap, fmt};
 
+use crate::PreLispValue;
+
 #[cfg(test)]
 mod tests {
-    use crate::{parse, LispState, LispValue, Tokenizer, TokenizerError};
+    use crate::{parse, LispState, LispValue, Tokenizer};
 
     use super::add_function;
 
-	fn get_exec_result(source: &str) -> Result<Vec<LispValue>, TokenizerError> {
+	fn get_exec_result(source: &str) -> Result<Vec<LispValue>, Box<dyn std::error::Error>> {
 		let mut state = LispState::new();
 
 		state.table.insert(String::from("output"), LispValue::List(vec![], false));
@@ -15,13 +17,13 @@ mod tests {
 				v.push(LispValue::List(args, false))
 			}
 
-			vec![LispValue::Nil]
+			Ok(vec![LispValue::Nil])
 		});
 
 		let mut tokenizer = Tokenizer::new(String::from(source));
 		let instructions = parse(tokenizer.tokenize()?);
 
-		state.execute(instructions);
+		state.execute(instructions)?;
 
 		let mut out = Vec::new();
 		if let LispValue::List(outerlist, _) = &state.table["output"] {
@@ -38,7 +40,7 @@ mod tests {
 	}
 
 	#[test]
-	fn test_hello_world() -> Result<(), TokenizerError> {
+	fn test_hello_world() -> Result<(), Box<dyn std::error::Error>> {
 		assert_eq!(
 			vec![
 				LispValue::String(String::from("Hello, World!"))
@@ -51,7 +53,7 @@ mod tests {
 	}
 
 	#[test]
-	fn test_math() -> Result<(), TokenizerError> {
+	fn test_math() -> Result<(), Box<dyn std::error::Error>> {
 		assert_eq!(
 			vec![
 				LispValue::Float(16.05)
@@ -72,16 +74,26 @@ mod tests {
 	}
 }
 
-use crate::PreLispValue;
-
 pub struct LispState {
 	table: HashMap<String, LispValue>,
 }
 
-fn add_function<T: Into<String> + Clone>(table: &mut HashMap<String, LispValue>, name: T, func: fn(&mut LispState, Vec<LispValue>) -> Vec<LispValue>) {
+
-	table.insert(name.clone().into(), LispValue::RustFunction(name.into(), func));
+#[derive(Debug)]
+pub struct RuntimeError {
+	message: String,
 }
 
+impl fmt::Display for RuntimeError {
+	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+		write!(f, "Runtime Error: {}", self.message)
+	}
+}
+
+impl std::error::Error for RuntimeError {}
+
+type RustFunctionType = fn(&mut LispState, Vec<LispValue>) -> Result<Vec<LispValue>, RuntimeError>;
+
 #[derive(Debug, Clone, PartialEq)]
 pub enum LispValue {
 	Nil,
@@ -89,8 +101,9 @@ pub enum LispValue {
 	Integer(i32),
 	Float(f32),
 	List(Vec<LispValue>, bool),
-	LispFunction(String, Vec<LispValue>),
+	LispFunction(String, Vec<String>, Vec<LispValue>),
-	RustFunction(String, fn(&mut LispState, Vec<LispValue>) -> Vec<LispValue>),
+	RustFunction(String, RustFunctionType),
+	Var(String)
 }
 
 impl fmt::Display for LispValue {
@@ -99,7 +112,7 @@ impl fmt::Display for LispValue {
 		match self {
 			LispValue::Nil => write!(f, "nil"),
 			LispValue::String(str) => write!(f, "\"{}\"", str),
-			LispValue::LispFunction(name, _) => write!(f, "<function {}>", name),
+			LispValue::LispFunction(name, _, _) => write!(f, "<function {}>", name),
 			LispValue::RustFunction(name, _) => write!(f, "<function {}>", name),
 			LispValue::Integer(num) => write!(f, "{}", num),
 			LispValue::Float(num) => write!(f, "{}", num),
@@ -123,6 +136,19 @@ impl fmt::Display for LispValue {
 	}
 }
 
+fn get_type(v: &LispValue) -> String {
+	match v {
+		LispValue::Nil => String::from("nil"),
+		LispValue::Integer(_) => String::from("int"),
+		LispValue::Float(_) => String::from("float"),
+		LispValue::String(_) => String::from("string"),
+		LispValue::List(_, _) => String::from("list"),
+		LispValue::LispFunction(_, _, _) => String::from("function"),
+		LispValue::RustFunction(_, _) => String::from("function"),
+		LispValue::Var(_) => String::from("symbol")
+	}
+}
+
 impl From<&str> for LispValue {
 	fn from(value: &str) -> Self {
 		LispValue::String(value.to_string())
@@ -143,6 +169,15 @@ impl From<f32> for LispValue {
 		LispValue::Float(value)
 	}
 }
+impl From<Vec<LispValue>> for LispValue {
+	fn from(value: Vec<LispValue>) -> Self {
+		LispValue::List(value, false)
+	}
+}
+
+fn add_function<T: Into<String> + Clone>(table: &mut HashMap<String, LispValue>, name: T, func: RustFunctionType) {
+	table.insert(name.clone().into(), LispValue::RustFunction(name.into(), func));
+}
 
 impl LispState {
 	pub fn new() -> LispState {
@@ -157,7 +192,7 @@ impl LispState {
 			let str = strings.join(" ");
 			println!("{}", str);
 
-			vec![LispValue::Nil]
+			Ok(vec![LispValue::Nil])
 		});
 
 		add_function(&mut table, "concat", |_, args| {
@@ -167,14 +202,14 @@ impl LispState {
 			}
 
 			let str = strings.concat();
-			vec![LispValue::String(str)]
+			Ok(vec![LispValue::String(str)])
 		});
 
 		add_function(&mut table, "add", |_, args| {
 			if args.len() < 1 {
-				return vec![LispValue::Nil]
+				return Ok(vec![LispValue::Nil])
 			} else if args.len() == 1 {
-				return vec![args[0].clone()];
+				return Ok(vec![args[0].clone()]);
 			}
 
 			let mut t = "int";
@@ -182,7 +217,9 @@ impl LispState {
 				match v {
 					LispValue::Float(_) => t = "float",
 					LispValue::Integer(_) => (),
-					_ => return vec![LispValue::Nil]
+					_ => return Err(RuntimeError {
+						message: format!("Invalid argument to 'add' (expected float or int, got {}", get_type(v))
+					})
 				}
 			}
 
@@ -196,7 +233,7 @@ impl LispState {
 							unreachable!()
 						}
 					}
-					return vec![LispValue::Integer(sum)];
+					return Ok(vec![LispValue::Integer(sum)]);
 				},
 				"float" => {
 					let mut sum = 0.0 as f32;
@@ -209,7 +246,7 @@ impl LispState {
 							unreachable!()
 						}
 					}
-					return vec![LispValue::Float(sum)];
+					return Ok(vec![LispValue::Float(sum)]);
 				},
 				_ => unreachable!()
 			}
@@ -217,9 +254,9 @@ impl LispState {
 
 		add_function(&mut table, "sub", |_, args| {
 			if args.len() < 1 {
-				return vec![LispValue::Nil]
+				return Ok(vec![LispValue::Nil]);
 			} else if args.len() == 1 {
-				return vec![args[0].clone()];
+				return Ok(vec![args[0].clone()]);
 			}
 
 			let mut t = "int";
@@ -227,7 +264,9 @@ impl LispState {
 				match v {
 					LispValue::Float(_) => t = "float",
 					LispValue::Integer(_) => (),
-					_ => return vec![LispValue::Nil]
+					_ => return Err(RuntimeError {
+						message: format!("Invalid argument to 'sub' (expected float or int, got {}", get_type(v))
+					})
 				}
 			}
 
@@ -242,7 +281,7 @@ impl LispState {
 								unreachable!()
 							}
 						}
-						return vec![LispValue::Integer(sum)];
+						return Ok(vec![LispValue::Integer(sum)]);
 					} else {
 						unreachable!()
 					}
@@ -259,7 +298,7 @@ impl LispState {
 								unreachable!()
 							}
 						}
-						return vec![LispValue::Float(sum)];
+						return Ok(vec![LispValue::Float(sum)]);
 					} else if let LispValue::Integer(n) = args[0] {
 						let mut sum = n as f32;
 						for i in 1..args.len() {
@@ -271,7 +310,7 @@ impl LispState {
 								unreachable!()
 							}
 						}
-						return vec![LispValue::Float(sum)];
+						return Ok(vec![LispValue::Float(sum)]);
 					} {
 						unreachable!()
 					}
@@ -282,9 +321,9 @@ impl LispState {
 
 		add_function(&mut table, "mul", |_, args| {
 			if args.len() < 1 {
-				return vec![LispValue::Nil]
+				return Ok(vec![LispValue::Nil]);
 			} else if args.len() == 1 {
-				return vec![args[0].clone()];
+				return Ok(vec![args[0].clone()]);
 			}
 
 			let mut t = "int";
@@ -292,7 +331,9 @@ impl LispState {
 				match v {
 					LispValue::Float(_) => t = "float",
 					LispValue::Integer(_) => (),
-					_ => return vec![LispValue::Nil]
+					_ => return Err(RuntimeError {
+						message: format!("Invalid argument to 'mul' (expected float or int, got {}", get_type(v))
+					})
 				}
 			}
 
@@ -307,7 +348,7 @@ impl LispState {
 								unreachable!()
 							}
 						}
-						return vec![LispValue::Integer(sum)];
+						return Ok(vec![LispValue::Integer(sum)]);
 					} else {
 						unreachable!()
 					}
@@ -324,7 +365,7 @@ impl LispState {
 								unreachable!()
 							}
 						}
-						return vec![LispValue::Float(product)];
+						return Ok(vec![LispValue::Float(product)]);
 					} else if let LispValue::Integer(n) = args[0] {
 						let mut product = n as f32;
 						for i in 1..args.len() {
@@ -336,7 +377,7 @@ impl LispState {
 								unreachable!()
 							}
 						}
-						return vec![LispValue::Float(product)];
+						return Ok(vec![LispValue::Float(product)]);
 					} {
 						unreachable!()
 					}
@@ -347,9 +388,9 @@ impl LispState {
 
 		add_function(&mut table, "div", |_, args| {
 			if args.len() < 1 {
-				return vec![LispValue::Nil]
+				return Ok(vec![LispValue::Nil]);
 			} else if args.len() == 1 {
-				return vec![args[0].clone()];
+				return Ok(vec![args[0].clone()]);
 			}
 
 			let mut t = "int";
@@ -357,7 +398,9 @@ impl LispState {
 				match v {
 					LispValue::Float(_) => t = "float",
 					LispValue::Integer(_) => (),
-					_ => return vec![LispValue::Nil]
+					_ => return Err(RuntimeError {
+						message: format!("Invalid argument to 'div' (expected float or int, got {}", get_type(v))
+					})
 				}
 			}
 
@@ -372,7 +415,7 @@ impl LispState {
 								unreachable!()
 							}
 						}
-						return vec![LispValue::Integer(sum)];
+						return Ok(vec![LispValue::Integer(sum)]);
 					} else {
 						unreachable!()
 					}
@@ -389,7 +432,7 @@ impl LispState {
 								unreachable!()
 							}
 						}
-						return vec![LispValue::Float(product)];
+						return Ok(vec![LispValue::Float(product)]);
 					} else if let LispValue::Integer(n) = args[0] {
 						let mut product = n as f32;
 						for i in 1..args.len() {
@@ -401,7 +444,7 @@ impl LispState {
 								unreachable!()
 							}
 						}
-						return vec![LispValue::Float(product)];
+						return Ok(vec![LispValue::Float(product)]);
 					} {
 						unreachable!()
 					}
@@ -427,11 +470,11 @@ impl LispState {
 				PreLispValue::List(list, quoted) => {
 					LispValue::List(Self::handle_prevalues(self, list), quoted)
 				},
-				PreLispValue::LispFunction(name, instructions) => {
+				PreLispValue::LispFunction(name, arg_names, instructions) => {
-					LispValue::LispFunction(name, Self::handle_prevalues(self, instructions))
+					LispValue::LispFunction(name, arg_names, Self::handle_prevalues(self, instructions))
 				},
 				PreLispValue::Var(name) => {
-					self.table.get(&name).unwrap_or(&LispValue::Nil).to_owned()
+					LispValue::Var(name)
 				}
 			})
 		}
@@ -439,50 +482,98 @@ impl LispState {
 		out
 	}
 
-	fn eval_list(&mut self, list: &Vec<LispValue>, quoted: bool) -> (Vec<LispValue>, bool) {
+	fn eval_list(&mut self, env: &mut HashMap<String, LispValue>, list: &Vec<LispValue>, quoted: bool) -> Result<(Vec<LispValue>, bool), RuntimeError> {
 		if list.len() < 1 {
-			return (vec![LispValue::List(Vec::new(), quoted)], false);
+			return Ok((vec![LispValue::List(Vec::new(), quoted)], false));
 		}
 
 		let list = &mut list.clone();
 
 		for i in 0..list.len() {
+			if let LispValue::Var(name) = &list[i] {
+				list[i] = env.get(name).unwrap_or_else(|| self.table.get(name).unwrap_or(&LispValue::Nil)).to_owned();
+			}
 			if let LispValue::List(elements, quoted) = &list[i] {
-				let (elems, astuple) = self.eval_list(elements, *quoted);
+				if let Ok((elems, astuple)) = self.eval_list(env, elements, *quoted) {
-				if astuple {
+					if astuple {
-					list[i] = elems.get(0).unwrap_or(&LispValue::Nil).to_owned();
+						list[i] = elems.get(0).unwrap_or(&LispValue::Nil).to_owned();
-					for j in 1..elems.len() {
+						for j in 1..elems.len() {
-						list.insert(i, elems[j].to_owned());
+							list.insert(i, elems[j].to_owned());
+						}
+					} else {
+						list[i] = LispValue::List(elems, *quoted);
 					}
-				} else {
-					list[i] = LispValue::List(elems, *quoted);
 				}
 			}
 		}
 
 		if quoted {
-			return (list.to_vec(), false);
+			return Ok((list.to_vec(), false));
 		}
 
 		if let LispValue::RustFunction(_name, f) = &list[0] {
-			(f(self, list[1..].to_vec()), true)
+			Ok((f(self, list[1..].to_vec())?, true))
-		} else if let LispValue::LispFunction(_name, _) = &list[0] {
+		} else if let LispValue::LispFunction(_name, _, _) = &list[0] {
-			(self.call_lisp_func(&list[0], list[1..].to_vec()), true)
+			Ok((self.call_lisp_func(env, &list[0], list[1..].to_vec())?, true))
 		} else {
-			(list.to_vec(), false)
+			Ok((list.to_vec(), false))
 		}
 	}
 
-	fn call_lisp_func(&mut self, f: &LispValue, args: Vec<LispValue>) -> Vec<LispValue> {
+	fn call_lisp_func(&mut self, env: &mut HashMap<String, LispValue>, f: &LispValue, args: Vec<LispValue>) -> Result<Vec<LispValue>, RuntimeError> {
-		todo!("Calling lisp function {} with args {:?}", f, args)
+		let (arg_names, instructions) = match f {
-	}
+			LispValue::LispFunction(_, arg_names, i) => {
+				(arg_names, i)
+			},
+			_ => return Err(RuntimeError {
+				message: format!("Invalid argument to call_lisp_func (expected function, got {})", get_type(f))
+			})
+		};
 
-	pub fn execute(&mut self, instructions: Vec<PreLispValue>) {
+		for i in 0..arg_names.len() {
-		let instructions = Self::handle_prevalues(self, instructions);
+			env.insert(arg_names[i].to_owned(), args.get(i).unwrap_or(&LispValue::Nil).to_owned());
-		for val in instructions {
+		}
-			if let LispValue::List(elements, quoted) = val {
+
-				self.eval_list(&elements, quoted);
+		let mut out = Vec::new();
+		for l in instructions {
+			if let LispValue::List(elements, quoted) = l {
+				let (values, astuple) = self.eval_list(env, &elements, *quoted)?;
+				if values.len() > 0 && values[0] != LispValue::Nil {
+					if astuple {
+						for v in values {
+							out.push(v);
+						}
+					} else {
+						out.push(values.into());
+					}
+				}
 			}
 		}
+		Ok(out)
+	}
+
+	pub fn execute(&mut self, instructions: Vec<PreLispValue>) -> Result<Vec<LispValue>, RuntimeError> {
+		let instructions = Self::handle_prevalues(self, instructions);
+		
+		let mut outs = Vec::new();
+
+		let mut env = HashMap::new();
+
+		for val in instructions {
+			if let LispValue::List(elements, quoted) = val {
+				let (vals, astuple) = self.eval_list(&mut env, &elements, quoted)?;
+				if astuple {
+					for val in vals {
+						outs.push(val);
+					}
+				} else {
+					outs.push(vals.into())
+				}
+			} else {
+				outs.push(val);
+			}
+		}
+
+		Ok(outs)
 	}
 }

src/parser.rs

@@ -93,7 +93,7 @@ pub enum PreLispValue {
 	Integer(i32),
 	Float(f32),
 	List(Vec<PreLispValue>, bool), // Values, Quoted
-	LispFunction(String, Vec<PreLispValue>),
+	LispFunction(String, Vec<String>, Vec<PreLispValue>),
 }
 
 impl fmt::Display for PreLispValue {
@@ -101,7 +101,7 @@ impl fmt::Display for PreLispValue {
 		match self {
 			PreLispValue::Nil => write!(f, "nil"),
 			PreLispValue::String(str) => write!(f, "{}", str),
-			PreLispValue::LispFunction(name, _) => write!(f, "<'{}': Lisp Function>", name),
+			PreLispValue::LispFunction(name, _, _) => write!(f, "<'{}': Lisp Function>", name),
 			PreLispValue::Integer(num) => write!(f, "{}", num),
 			PreLispValue::Float(num) => write!(f, "{}", num),
 			_ => todo!()

src/tokenizer.rs

@@ -118,6 +118,8 @@ impl fmt::Display for TokenizerError {
 	}
 }
 
+impl std::error::Error for TokenizerError {}
+
 pub struct Tokenizer {
 	code: String,
 	line: u64,