Functions!!!

No scoping yet though

src/executor.rs

@@ -4,7 +4,7 @@ use crate::PreLispValue;
 
 #[cfg(test)]
 mod tests {
-    use crate::{parse, LispState, LispValue, Tokenizer};
+    use crate::{Parser, LispState, LispValue, Tokenizer};
 
     use super::add_function;
 
@@ -21,7 +21,8 @@ mod tests {
 		});
 
 		let mut tokenizer = Tokenizer::new(String::from(source));
-		let instructions = parse(tokenizer.tokenize()?);
+		let mut parser = Parser::new(tokenizer.tokenize()?);
+		let instructions = parser.parse();
 
 		state.execute(instructions)?;
 
@@ -136,6 +137,34 @@ impl fmt::Display for LispValue {
 	}
 }
 
+fn lisp_display(v: LispValue) -> String {
+	#[allow(unreachable_patterns)]
+	match v {
+		LispValue::Nil => String::from("nil"),
+		LispValue::String(str) => str,
+		LispValue::LispFunction(name, _, _) => format!("<function {}>", name),
+		LispValue::RustFunction(name, _) => format!("<function {}>", name),
+		LispValue::Integer(num) => num.to_string(),
+		LispValue::Float(num) => num.to_string(),
+		LispValue::List(elems, quoted) => {
+			let mut strs = Vec::new();
+
+			for e in elems {
+				strs.push(e.to_string());
+			}
+
+			if quoted {
+				format!("'({})", strs.join(" "))
+			} else {
+				format!("({})", strs.join(" "))
+			}
+		},
+		val => {
+			format!("{}", val)
+		}
+	}
+}
+
 fn get_type(v: &LispValue) -> String {
 	match v {
 		LispValue::Nil => String::from("nil"),
@@ -183,10 +212,32 @@ impl LispState {
 	pub fn new() -> LispState {
 		let mut table = HashMap::new();
 
+		add_function(&mut table, "echo", |_, args| {
+			return Ok(args);
+		});
+
+		add_function(&mut table, "set", |state, args| {
+			if args.len() != 2 {
+				return Err(RuntimeError {
+					message: format!("Bad arguments to set (expected 2, got {})", args.len())
+				})
+			}
+
+			if let LispValue::String(name) = &args[0] {
+				state.table.insert(name.to_owned(), args[1].clone());
+			} else {
+				return Err(RuntimeError {
+					message: format!("Bad argument 1 to set (expected string, got {})", get_type(&args[0]))
+				})
+			}
+
+			Ok(vec![args[1].clone()])
+		});
+
 		add_function(&mut table, "print", |_, args| {
 			let mut strings = Vec::new();
 			for val in args {
-				strings.push(val.to_string());
+				strings.push(lisp_display(val));
 			}
 
 			let str = strings.join(" ");
@@ -198,7 +249,7 @@ impl LispState {
 		add_function(&mut table, "concat", |_, args| {
 			let mut strings = Vec::new();
 			for val in args {
-				strings.push(val.to_string());
+				strings.push(lisp_display(val));
 			}
 
 			let str = strings.concat();

src/main.rs

@@ -7,16 +7,17 @@ use parser::*;
 mod executor;
 use executor::*;
 
-fn main() -> Result<(), TokenizerError> {
+fn main() -> Result<(), Box<dyn std::error::Error>> {
     let source = std::fs::read_to_string("src/test.lisp").unwrap();
 
     let mut tokenizer = Tokenizer::new(source);
 	let tokens = tokenizer.tokenize()?;
-	let instructions = parse(tokens);
+	let mut parser = Parser::new(tokens);
+	let instructions = parser.parse();
 
 	let mut state = LispState::new();
 
-	state.execute(instructions);
+	state.execute(instructions)?;
 
 	Ok(())
 }

src/parser.rs

@@ -1,13 +1,14 @@
-use std::fmt;
+use std::{collections::HashMap, fmt};
 
 #[cfg(test)]
 mod tests {
-    use crate::{parse, PreLispValue, Tokenizer, TokenizerError};
+    use crate::{Parser, PreLispValue, Tokenizer, TokenizerError};
 
 	fn quick_parse(source: &str) -> Result<Vec<PreLispValue>, TokenizerError> {
 		let mut tokenizer = Tokenizer::new(String::from(source));
 		let tokens = tokenizer.tokenize()?;
-		Ok(parse(tokens))
+		let mut parser = Parser::new(tokens);
+		Ok(parser.parse())
 	}
 
 	fn var(name: &str) -> PreLispValue {
@@ -218,24 +219,148 @@ fn parse_exp(tokens: Vec<Token>, quoted: bool) -> PreLispValue {
 	PreLispValue::List(values, quoted)
 }
 
-pub fn parse(tokens: Vec<Token>) -> Vec<PreLispValue> {
-	let mut values = Vec::new();
+pub struct Parser {
+	tokens: Vec<Token>,
+	macros: HashMap<String, fn(Vec<PreLispValue>) -> Vec<PreLispValue>>,
+}
 
-	let mut i = 0;
-	while i < tokens.len() {
-		match &tokens[i] {
-			Token::OpenParen => {
-				let (tkns, close_paren_idx) = read_exp(i, &tokens).unwrap();
-				values.push(parse_exp(tkns, false));
-				i = close_paren_idx;
+fn add_macro(
+	macros: &mut HashMap<String, fn(Vec<PreLispValue>) -> Vec<PreLispValue>>,
+	name: impl Into<String>,
+	mac: fn(Vec<PreLispValue>) -> Vec<PreLispValue>) {
+
+		macros.insert(name.into(), mac);
+}
+
+impl Parser {
+	pub fn new(tokens: Vec<Token>) -> Parser {
+		let mut macros = HashMap::new();
+
+		add_macro(&mut macros, "set", |x| {
+			if x.len() != 3 ||
+			(
+				!matches!(x[1], PreLispValue::Var(_)) &&
+				!matches!(x[1], PreLispValue::String(_))
+			) {
+				return x;
 			}
-			tkn => {
-				// TODO: Include more error data
-				panic!("Unexpected token {:?}", tkn);
+
+			let mut list = x.clone();
+
+			if let PreLispValue::Var(name) = &list[1] {
+				list[1] = PreLispValue::String(name.to_owned())
 			}
+
+			list
+		});
+
+		add_macro(&mut macros, "fn", |x| {
+			if x.len() < 3 || x.len() > 4 {
+				return x;
+			}
+
+			let mut name: String = String::new();
+			let mut args: &Vec<PreLispValue> = &Vec::new();
+			let mut list: &Vec<PreLispValue> = &Vec::new();
+
+			if x.len() == 3 {
+				if 
+					!matches!(x[1], PreLispValue::List(_, _)) ||
+					!matches!(x[2], PreLispValue::List(_, _))
+				{
+					return x;
+				}
+				name = String::from("Anonymous");
+				if let PreLispValue::List(l, _) = &x[1] {
+					args = l;
+				}
+				if let PreLispValue::List(l, _) = &x[2] {
+					list = l;
+				}
+			} else if x.len() == 4 {
+				if
+					!matches!(x[1], PreLispValue::Var(_)) ||
+					!matches!(x[2], PreLispValue::List(_, _)) ||
+					!matches!(x[3], PreLispValue::List(_, _))
+				{
+					return x;
+				}
+				if let PreLispValue::Var(n) = &x[1] {
+					name = n.to_owned();
+				}
+				if let PreLispValue::List(l, _) = &x[2] {
+					args = l;
+				}
+				if let PreLispValue::List(l, _) = &x[3] {
+					list = l;
+				}
+			} else {
+				return x;
+			}
+
+			let mut arg_names = Vec::new();
+			for arg in args {
+				if let PreLispValue::Var(n) = arg {
+					arg_names.push(n.to_owned());
+				}
+			}
+
+			let func = PreLispValue::LispFunction(name.clone(), arg_names, list.to_owned());
+
+			if x.len() == 4 {
+				return vec![PreLispValue::Var(String::from("set")), name.into(), func]
+			}
+
+			return vec![PreLispValue::Var(String::from("echo")), func];
+		});
+
+		Parser {
+			tokens,
+			macros
 		}
-		i += 1;
 	}
 
-	values
+	fn macro_check(&mut self, input: Vec<PreLispValue>, quoted: bool) -> Vec<PreLispValue> {
+		if quoted || input.len() < 1 {
+			return input;
+		}
+
+		let mut output = input.clone();
+
+		for i in 0..output.len() {
+			if let PreLispValue::List(elems, quoted) = &output[i] {
+				output[i] = PreLispValue::List(self.macro_check(elems.to_vec(), *quoted), *quoted);
+			}
+		}
+
+		if let PreLispValue::Var(name) = &output[0] {
+			if self.macros.contains_key(name) {
+				return self.macros.get(name).unwrap()(output);
+			}
+		}
+
+		output
+	}
+
+	pub fn parse(&mut self) -> Vec<PreLispValue> {
+		let mut values = Vec::new();
+	
+		let mut i = 0;
+		while i < self.tokens.len() {
+			match &self.tokens[i] {
+				Token::OpenParen => {
+					let (tkns, close_paren_idx) = read_exp(i, &self.tokens).unwrap();
+					values.push(parse_exp(tkns, false));
+					i = close_paren_idx;
+				}
+				tkn => {
+					// TODO: Include more error data
+					panic!("Unexpected token {:?}", tkn);
+				}
+			}
+			i += 1;
+		}
+	
+		self.macro_check(values, false)
+	}
 }

src/test.lisp

@@ -1 +1,11 @@
-(print '(add 1 2))
+(fn hi (name) (
+	(print (concat "Hello, " name "!"))
+))
+
+(hi "Joe")
+
+(hi (fn(x) (
+	(print x)
+)))
+
+(name "Balls")

src/tokenizer.rs

@@ -180,16 +180,14 @@ impl Tokenizer {
 			}
 
 			if self.reading_identifier {
-				if !char.is_alphabetic() {
+				if char.is_alphabetic() {
+					self.storage.push(char);
+				} else {
 					self.reading_identifier = false;
 
 					tokens.push(Token::Identifier(self.storage.iter().collect()));
 					self.storage.clear();
-					continue;
 				}
-
-				self.storage.push(char);
-				continue;
 			}
 
 			if self.reading_num {
@@ -259,6 +257,9 @@ impl Tokenizer {
 				'\'' => tokens.push(Token::Quote),
 				',' => tokens.push(Token::Unquote),
 				c => {
+					if self.reading_identifier || self.reading_num || self.reading_string {
+						continue;
+					}
 					if c.is_alphabetic() {
 						self.reading_identifier = true;
 						self.storage.clear();