function parameters

src/data.rs

@@ -38,12 +38,20 @@ pub enum Statement {
     Let(String, Expr),
     // Type(String, Type),
     Expr(Expr),
-    Func(String, Type, Block),
+    Func(Func),
     // Break,
     // Continue,
     // Type,
 }
 
+#[derive(Debug, Clone)]
+pub struct Func {
+    pub name: String,
+    pub params: Vec<(String, Type)>,
+    pub ret: Type,
+    pub block: Block
+}
+
 #[derive(Debug, Clone)]
 pub struct Block(pub Vec<Statement>);
 

src/generator.rs

@@ -5,9 +5,9 @@ optimizations
 - write negative numberss directly instead of as positive + sign flip
 */
 
-use crate::Error;
-use crate::data::{Expr, Literal, BinaryOp, PrefixOp, Statement, Pattern, Type, self, Block};
+use crate::data::{self, BinaryOp, Block, Expr, Func, Literal, Pattern, PrefixOp, Statement, Type};
 use crate::parser::Context;
+use crate::Error;
 
 pub struct Generator {
     output: Box<dyn std::io::Write>,
@@ -15,9 +15,7 @@ pub struct Generator {
 
 impl Generator {
     pub fn new(output: Box<dyn std::io::Write>) -> Generator {
-        Generator {
-            output
-        }
+        Generator { output }
     }
 
     fn write_module(&mut self, stmts: &[Statement]) -> Result<(), Error> {
@@ -25,42 +23,56 @@ impl Generator {
         write!(self.output, "(module");
         for stmt in stmts {
             match stmt {
-                Statement::Func(name, ret, block) => {
-                    ctx.locals.insert(name.clone(), ret.clone());
-                },
-                Statement::Let(..) | Statement::Expr(..) => return Err(Error::syn("incorrect top level statement")),
+                Statement::Func(Func { name, ret, params, .. }) => {
+                    ctx.funcs.insert(name.clone(), (params.clone(), ret.clone()));
+                }
+                Statement::Let(..) | Statement::Expr(..) => {
+                    return Err(Error::syn("incorrect top level statement"))
+                }
             };
         }
         for stmt in stmts {
             match stmt {
-                Statement::Func(name, ret, block) => self.write_func(&ctx, name, ret, block)?,
-                Statement::Let(..) | Statement::Expr(..) => return Err(Error::syn("incorrect top level statement")),
+                Statement::Func(func) => self.write_func(&ctx, func)?,
+                Statement::Let(..) | Statement::Expr(..) => {
+                    return Err(Error::syn("incorrect top level statement"))
+                }
             };
         }
         write!(self.output, ")");
         Ok(())
     }
-    
-    fn write_func(&mut self, ctx: &Context, name: &str, ret: &Type, block: &Block) -> Result<(), Error> {
-        write!(self.output, " (func ${name}");
-        if name == "main" {
+
+    fn write_func(&mut self, ctx: &Context, func: &Func) -> Result<(), Error> {
+        write!(self.output, " (func ${}", func.name);
+        if func.name == "main" {
             write!(self.output, " (export \"_start\")");
         }
-        if !ret.is_empty() {
-            write!(self.output, " (result {})", ret.string());
-        }
-        write!(self.output, " (local $match i32)");
-        writeln!(self.output);
 
-        let expr = Expr::Block(block.clone());
+        let expr = Expr::Block(func.block.clone());
         let mut ctx = ctx.clone();
         let mut exprs = Vec::new();
 
-        let inferred = block.infer(&ctx)?;
-        if ret != &inferred {
-            return Err(Error::TypeError(format!("fn should return {ret:?}, but instead returns {inferred:?}")));
+        for (name, ty) in &func.params {
+            ctx.locals.insert(name.clone(), ty.clone());
+            write!(self.output, " (param ${} {})", name, ty.string());
+        }
+
+        if !func.ret.is_empty() {
+            write!(self.output, " (result {})", func.ret.string());
         }
         
+        writeln!(self.output);
+        writeln!(self.output, "(local $match i32)");
+        
+        let inferred = func.block.infer(&ctx)?;
+        if func.ret != inferred {
+            return Err(Error::TypeError(format!(
+                "fn should return {:?}, but instead returns {inferred:?}",
+                func.ret
+            )));
+        }
+
         get_locals(&expr, &mut ctx, &mut exprs);
 
         for (name, _) in &exprs {
@@ -75,9 +87,9 @@ impl Generator {
             gen_expr(expr, &ctx);
             println!("local.set ${name}");
         }
-    
+
         gen_expr(&expr, &ctx);
-        
+
         write!(self.output, ")");
 
         Ok(())
@@ -85,12 +97,6 @@ impl Generator {
 }
 
 pub fn generate(statements: &[Statement]) -> Result<(), Error> {
-    let expr = match &statements[0] {
-        Statement::Expr(expr) => expr.clone(),
-        Statement::Func(name, ty, block) => data::Expr::Block(data::Block(vec![Statement::Func(name.clone(), ty.clone(), block.clone())])),
-        _ => todo!(),
-    };
-    
     let mut gen = Generator::new(Box::new(std::io::stdout()));
     gen.write_module(statements)
 }
@@ -102,9 +108,9 @@ fn gen_expr(expr: &Expr, ctx: &Context) {
             Literal::Float(f) => println!("f64.const {f}"),
             Literal::Boolean(b) => println!("i32.const {}", if *b { 1 } else { 0 }),
             _ => todo!(),
-        }
+        },
         Expr::Variable(name) => {
-            println!("local.get ${name}");            
+            println!("local.get ${name}");
         }
         Expr::Binary(op, a, b) => {
             gen_expr(&a, ctx);
@@ -122,7 +128,7 @@ fn gen_expr(expr: &Expr, ctx: &Context) {
                 BinaryOp::Sub => println!("{ty}.sub"),
                 BinaryOp::Div => println!("{ty}.div_u"), // do i _u or _s?
                 BinaryOp::Mod => println!("{ty}.rem_u"),
-                BinaryOp::Eq  => println!("{ty}.eq"),
+                BinaryOp::Eq => println!("{ty}.eq"),
                 BinaryOp::Neq => println!("{ty}.neq"),
                 BinaryOp::Less => println!("{ty}.lt_u"),
                 BinaryOp::Greater => println!("{ty}.gt_u"),
@@ -138,7 +144,7 @@ fn gen_expr(expr: &Expr, ctx: &Context) {
                 }
                 return;
             }
-            
+
             gen_expr(e, ctx);
             match op {
                 PrefixOp::Minus => {
@@ -158,21 +164,18 @@ fn gen_expr(expr: &Expr, ctx: &Context) {
         }
         // FIXME: awful code until i fix patching up parser and lexer
         Expr::Match(cond, arms) => {
-            println!(";; --- set match variable");
             gen_expr(cond, ctx);
             println!("local.set $match");
-            
-            println!(";; --- generate match");
-            
+
             for (idx, (pat, expr)) in arms.iter().enumerate() {
                 match pat {
                     Pattern::Literal(lit) => match lit {
                         Literal::Integer(int) => println!("i32.const {}", int),
                         Literal::Boolean(b) => println!("i32.const {}", if *b { 1 } else { 0 }),
                         _ => todo!(),
-                    }
+                    },
                 };
-                
+
                 println!("local.get $match");
                 println!("i32.eq");
                 println!("(if (result i32) (then");
@@ -186,7 +189,6 @@ fn gen_expr(expr: &Expr, ctx: &Context) {
                 }
             }
             println!("{}", ")".repeat(arms.len() * 2));
-            println!(";; --- done");
         }
         Expr::Block(b) => {
             for (i, stmt) in b.0.iter().enumerate() {
@@ -197,11 +199,14 @@ fn gen_expr(expr: &Expr, ctx: &Context) {
                             println!("drop");
                         }
                     }
-                    _ => {},
+                    _ => {}
                 }
             }
         }
-        Expr::Call(func, _) => {
+        Expr::Call(func, args) => {
+            for expr in args {
+                gen_expr(expr, ctx);
+            }
             println!("call ${func}");
         }
     };
@@ -218,12 +223,12 @@ fn get_locals(expr: &Expr, ctx: &mut Context, exprs: &mut Vec<(String, Expr)>) {
                         exprs.push((name.clone(), expr.clone()));
                     }
                     Statement::Expr(expr) => get_locals(&expr, ctx, exprs),
-                    Statement::Func(name, ret, ..) => {
+                    Statement::Func(Func { name, ret, .. }) => {
                         ctx.locals.insert(name.clone(), todo!());
-                    },
+                    }
                 }
             }
-        },
+        }
         Expr::Unary(_, expr) => get_locals(&expr, ctx, exprs),
         Expr::Binary(_, a, b) => {
             get_locals(&a, ctx, exprs);

src/main.rs

@@ -39,17 +39,26 @@ fn main() {
     //         }
     //     }
     // ".into());
+    // let mut lexer = lexer::Lexer::new("
+    //     fn main() -> i32 {
+    //         two() * three()
+    //     }
+
+    //     fn two() -> i32 {
+    //         (2 * 2) / 2
+    //     }
+
+    //     fn three() -> i32 {
+    //         10 * 6 / 20
+    //     }
+    // ".into());
     let mut lexer = lexer::Lexer::new("
         fn main() -> i32 {
-            two() * three()
+            add_three(30)
         }
 
-        fn two() -> i32 {
-            (2 * 2) / 2
-        }
-
-        fn three() -> i32 {
-            10 * 6 / 20
+        fn add_three(n: i32) -> i32 {
+            n + 3
         }
     ".into());
 

src/parser.rs

@@ -1,6 +1,6 @@
 use std::collections::HashMap;
 
-use crate::data::{BinaryOp, Block, Expr, Literal, Pattern, PrefixOp, Statement, Type};
+use crate::data::{BinaryOp, Block, Expr, Literal, Pattern, PrefixOp, Statement, Type, Func};
 use crate::lexer::{Token, Symbol};
 use crate::Error;
 
@@ -12,6 +12,7 @@ pub struct Parser {
 #[derive(Debug, Clone)]
 pub struct Context {
     pub locals: HashMap<String, Type>,
+    pub funcs: HashMap<String, (Vec<(String, Type)>, Type)>,
 }
 
 impl Parser {
@@ -60,7 +61,20 @@ impl Parser {
                 self.eat(Token::Fn)?;
                 let name = self.parse_ident()?;
                 self.eat(Token::OpenParan)?;
-                // TODO: parameters
+                let mut params = vec![];
+                while !self.peek_tok().is_some_and(|tok| tok == &Token::CloseParan) {
+                    let name = self.parse_ident()?;
+                    self.eat(Token::Symbol(Symbol::Colon))?;
+                    let ty = self.parse_type()?;
+                    params.push((name, ty));
+                    
+                    if self.peek_tok() == Some(&Token::Symbol(Symbol::Comma)) {
+                        self.eat(Token::Symbol(Symbol::Comma))?;
+                    } else {
+                        break;
+                    }
+                }
+                
                 self.eat(Token::CloseParan)?;
                 let ret = if self.peek_tok().is_some_and(|tok| tok == &Token::Symbol(Symbol::ThinArrow)) {
                     self.eat(Token::Symbol(Symbol::ThinArrow))?;
@@ -71,7 +85,7 @@ impl Parser {
                 self.eat(Token::OpenBrace)?;
                 let block = self.parse_block()?;
                 self.eat(Token::CloseBrace)?;
-                Statement::Func(name, ret, block)
+                Statement::Func(Func { name, params, ret, block })
             }
             _ => Statement::Expr(self.parse_expr(0)?),
         };
@@ -138,9 +152,17 @@ impl Parser {
                 let ident = ident.clone();
                 if self.peek_tok().is_some_and(|t| *t == Token::OpenParan) {
                     self.eat(Token::OpenParan);
-                    // TODO: function parameters
+                    let mut params = vec![];
+                    while !self.peek_tok().is_some_and(|tok| tok == &Token::CloseParan) {
+                        params.push(self.parse_expr(0)?);
+                        if self.peek_tok() == Some(&Token::Symbol(Symbol::Comma)) {
+                            self.eat(Token::Symbol(Symbol::Comma))?;
+                        } else {
+                            break;
+                        }
+                    }
                     self.eat(Token::CloseParan);
-                    Expr::Call(ident, vec![])
+                    Expr::Call(ident, params)
                 } else {
                     Expr::Variable(ident)
                 }

src/types.rs

@@ -44,8 +44,25 @@ impl Expr {
                 Ok(match_ty)
             }
             Self::Block(block) => block.infer(ctx),
-            Self::Call(name, ..) => match ctx.locals.get(name) {
-                Some(ty) => Ok(ty.clone()),
+            Self::Call(name, args) => match ctx.funcs.get(name) {
+                Some((params, ret)) => {
+                    if args.len() < params.len() {
+                        return Err(Error::ty("missing parameters"));
+                    }
+                    
+                    if args.len() > params.len() {
+                        return Err(Error::ty("too many parameters"));
+                    }
+
+                    for (arg, (name, ty)) in args.iter().zip(params) {
+                        let got = arg.infer(ctx)?;
+                        if got != *ty {
+                            return Err(Error::TypeError(format!("wrong type for {name}: it should've been {ty:?} but you put a {got:?}", )));
+                        }
+                    }
+                    
+                    Ok(ret.clone())
+                }
                 None => Err(Error::ReferenceError(format!(
                     "cannot find variable {name}"
                 ))),
@@ -149,6 +166,7 @@ impl Context {
     pub fn new() -> Context {
         Context {
             locals: HashMap::new(),
+            funcs: HashMap::new(),
         }
     }
 }