Basic functionality achieved

src/executor.rs

@@ -6,11 +6,15 @@ pub struct LispState {
 	table: HashMap<String, LispValue>,
 }
 
+fn add_function<T: Into<String> + Clone>(table: &mut HashMap<String, LispValue>, name: T, func: fn(Vec<LispValue>) -> Vec<LispValue>) {
+	table.insert(name.clone().into(), LispValue::RustFunction(name.into(), func));
+}
+
 impl LispState {
 	pub fn new() -> LispState {
 		let mut table = HashMap::new();
 
-		table.insert(String::from("print"), LispValue::RustFunction(String::from("print"), |x| {
+		add_function(&mut table, "print", |x| {
 			let mut strings = Vec::new();
 			for val in x {
 				strings.push(val.to_string());
@@ -19,24 +23,66 @@ impl LispState {
 			let str = strings.join(" ");
 			println!("{}", str);
 
-			LispValue::Nil
-		}));
+			vec![LispValue::Nil]
+		});
+
+		add_function(&mut table, "add", |x| {
+			if x.len() != 2 {
+				return vec![LispValue::Nil]
+			}
+
+			if let (LispValue::Integer(lhs), LispValue::Integer(rhs)) = (&x[0], &x[1]) {
+				return vec![LispValue::Integer(lhs + rhs)];
+			} else if let (LispValue::String(lhs), LispValue::String(rhs)) = (&x[0], &x[1]) {
+				return vec![LispValue::String(lhs.to_owned() + rhs)];
+			} else {
+				return vec![LispValue::Nil];
+			}
+		});
 
 		LispState {
 			table
 		}
 	}
 
-	pub fn execute(&self, instructions: Vec<OpCode>) {
-		for op in instructions {
-			match op {
-				OpCode::Call(func, args) => {
-					let f = self.table.get(&func).unwrap();
+	fn do_call(&self, opcode: &OpCode) -> Vec<LispValue> {
+		if let OpCode::Call(func, args) = opcode {
+			let f = self.table.get(func).unwrap();
+
+			let mut args: Vec<LispValue> = args.clone();
+			for i in 0..args.len() {
+				let arg = &args[i];
+				if let LispValue::Eval(OpCode::Exp(opcodes)) = arg {
+					if opcodes.len() < 1 {
+						args[i] = LispValue::Nil;
+						continue;
+					}
+
+					let call_opcode = opcodes.last().unwrap();
+					let mut res = self.do_call(call_opcode);
+					args.remove(i);
+					for j in 0..res.len() {
+						args.insert(i + j, res.remove(0));
+					}
+				}
+			}
 			if let LispValue::RustFunction(_, f) = f {
-						f(args);
+				return f(args.to_vec());
 			} else {
 				todo!();
 			}
+
+		} else {
+			panic!("Bad OpCode: expected OpCode::Call")
+		}
+	}
+
+	pub fn execute(&self, instructions: Vec<OpCode>) {
+		println!("{:?}", instructions);
+		for op in instructions {
+			match op {
+				OpCode::Call(func, args) => {
+					self.do_call(&OpCode::Call(func, args));
 				},
 				OpCode::Exp(ins) =>  {
 					self.execute(ins);

src/main.rs

@@ -17,7 +17,6 @@ fn main() {
 			Vec::new()
 		}
 	};
-	println!("{:?}", tokens);
 	let instructions = parse(tokens);
 
 	let state = LispState::new();

src/parser.rs

@@ -2,12 +2,15 @@ use std::fmt;
 
 use crate::Token;
 
+#[derive(Debug, Clone)]
 pub enum LispValue {
 	Nil,
 	String(String),
+	Integer(i32),
 	LispFunction(String, Vec<OpCode>),
-	RustFunction(String, fn(Vec<LispValue>) -> LispValue),
-	Exp(OpCode)
+	RustFunction(String, fn(Vec<LispValue>) -> Vec<LispValue>),
+	Ref(String),
+	Eval(OpCode)
 }
 
 impl fmt::Display for LispValue {
@@ -17,6 +20,8 @@ impl fmt::Display for LispValue {
 			LispValue::String(str) => write!(f, "{}", str),
 			LispValue::LispFunction(name, _) => write!(f, "<'{}': Lisp Function>", name),
 			LispValue::RustFunction(name, _) => write!(f, "<'{}': Rust Function>", name),
+			LispValue::Integer(num) => write!(f, "{}", num),
+			LispValue::Ref(name) => write!(f, "<'{}': Reference>", name),
 			_ => todo!()
 		}
 	}
@@ -34,6 +39,13 @@ impl From<String> for LispValue {
 	}
 }
 
+impl From<i32> for LispValue {
+	fn from(value: i32) -> Self {
+		LispValue::Integer(value)
+	}
+}
+
+#[derive(Debug, Clone)]
 pub enum OpCode {
 	Call(String, Vec<LispValue>),
 	Exp(Vec<OpCode>)
@@ -44,7 +56,7 @@ fn read_exp(open_paren_idx: usize, tokens: &Vec<Token>) -> Option<(Vec<Token>, u
 	let mut tkns = Vec::new();
 	let mut depth = 0;
 
-	for i in open_paren_idx..tokens.len() - 1 {
+	for i in open_paren_idx..tokens.len() {
 		match &tokens[i] {
 			Token::OpenParen => {
 				if depth != 0 {
@@ -56,6 +68,8 @@ fn read_exp(open_paren_idx: usize, tokens: &Vec<Token>) -> Option<(Vec<Token>, u
 				depth -= 1;
 				if depth == 0 {
 					return Some((tkns, i));
+				} else {
+					tkns.push(Token::CloseParen)
 				}
 			}
 			token => {
@@ -68,15 +82,51 @@ fn read_exp(open_paren_idx: usize, tokens: &Vec<Token>) -> Option<(Vec<Token>, u
 }
 
 fn parse_exp(tokens: Vec<Token>) -> Vec<OpCode> {
-	todo!()
+	let mut opcodes = Vec::new();
+	
+	if tokens.len() < 1 {
+		return opcodes;
+	}
+
+	if let Token::Identifier(name) = &tokens[0] {
+		let mut args = Vec::new();
+		
+		let mut i = 1;
+		while i < tokens.len() {
+			let tkn = &tokens[i];
+			match tkn {
+				Token::OpenParen => {
+					let (tkns, close_paren_idx) = read_exp(i, &tokens).unwrap();
+					args.push(LispValue::Eval(OpCode::Exp(parse_exp(tkns))));
+					i = close_paren_idx;
+				},
+				Token::Identifier(name) => {
+					args.push(LispValue::Ref(name.to_owned()));
+				},
+				Token::Integer(num) => {
+					args.push(LispValue::Integer(*num));
+				},
+				Token::String(str) => {
+					args.push(LispValue::String(str.to_owned()));
+				}
+				Token::CloseParen => {
+					panic!("Unexpected closing parenthesis");
+				},
+				_ => todo!()
+			}
+
+			i += 1;
+		}
+
+		opcodes.push(OpCode::Call(name.to_owned(), args))
+	}
+
+	opcodes
 }
 
 pub fn parse(tokens: Vec<Token>) -> Vec<OpCode> {
 	let mut opcodes = Vec::new();
 	
-	let mut current_depth = 0;
-	let mut seeking = false;
-	
 	let mut i = 0;
 	while i < tokens.len() {
 		match &tokens[i] {
@@ -86,13 +136,13 @@ pub fn parse(tokens: Vec<Token>) -> Vec<OpCode> {
 				i = close_paren_idx;
 			}
 			tkn => {
+				// TODO: Include more error data
 				panic!("Unexpected token {:?}", tkn);
 			}
 		}
 		i += 1;
 	}
 
-
 	// opcodes.push(OpCode::Call("print".to_string(), vec![
 	// 	LispValue::from("Hello, World!")
 	// ]));

src/test.lisp

@@ -1,10 +1,5 @@
 ; This is a comment
 
-(print "Hello, World") ; OpCode::Call("print", {"Hello, World"})
+(print "Hello, World")
 
 (print (add 1 2))
-;	OpCode::Call("print", {
-;		OpCode::Exp({
-;			OpCode::Call("add", 1, 2)
-;		})
-;	})

src/tokenizer.rs

@@ -154,8 +154,10 @@ impl Tokenizer {
 						self.storage.push(c);
 						continue;
 
+
 					// Allow numbers to also start with _ for fun
 					// ______100_0__: 1,000
+					
 					// TODO: delete this when I expand identifiers to include more symbols
 					} else if c.is_numeric() || c == '_' {
 						self.reading_num = true;