gaming

[

@@ -0,0 +1,5 @@
+x :i32 = 3;
+y := fn(a: i32, b, c) x = 3;
+while true {
+    print("hello");
+}

src/parser/cursor/mod.rs

@@ -1,3 +1,5 @@
+use std::borrow::Borrow;
+
 use crate::io::{CompilerMsg, Span, Spanned};
 
 mod lit;
@@ -35,8 +37,8 @@ impl<'a> Cursor<'a> {
         })
     }
 
-    pub fn next_if(&mut self, token: &Token) -> bool {
+    pub fn next_if(&mut self, token: impl Borrow<Token>) -> bool {
-        if self.peek().is_some_and(|t| t == token) {
+        if self.peek().is_some_and(|t| t == token.borrow()) {
             self.next();
             true
         } else {
@@ -52,11 +54,6 @@ impl<'a> Cursor<'a> {
         self.next().ok_or_else(CompilerMsg::unexpected_eof)
     }
 
-    pub fn expect_peek(&self) -> Result<&Token, CompilerMsg> {
-        self.peek().ok_or_else(CompilerMsg::unexpected_eof)
-        // Ok(self.peek().unwrap())
-    }
-
     pub fn expect(&mut self, token: Token) -> Result<Token, CompilerMsg> {
         let next = self.expect_next()?;
         if next == token {
@@ -87,7 +84,7 @@ impl CompilerMsg {
     pub fn unexpected_token(token: &Token, span: Span, expected: &str) -> Self {
         Self {
             spans: vec![span],
-            msg: format!("Unexpected token '{}'; expected {expected}", token),
+            msg: format!("Unexpected token '{}', expected {expected}", token),
         }
     }
 

src/parser/node/parse.rs

@@ -1,3 +1,5 @@
+use std::ops::Index;
+
 use crate::{
     io::{CompilerMsg, Span},
     parser::{
@@ -25,10 +27,17 @@ impl<'a> ParseCtx<'a> {
         }
     }
 
-    pub fn parse<P: Parsable>(&mut self) -> Result<Id<P>, CompilerMsg> {
+    pub fn parse<N: Parsable>(&mut self) -> Result<Id<N>, CompilerMsg> {
+        self.parse_with(N::parse)
+    }
+
+    pub fn parse_with<N: Node>(
+        &mut self,
+        f: impl FnOnce(&mut Self) -> Result<N, CompilerMsg>,
+    ) -> Result<Id<N>, CompilerMsg> {
         let old_start = self.start;
         self.start = self.cursor.peek_start();
-        let res = P::parse(self).map(|r| self.push(r));
+        let res = f(self).map(|r| self.push(r));
         self.start = old_start;
         res
     }
@@ -92,3 +101,11 @@ impl<'a> std::ops::DerefMut for ParseCtx<'a> {
         &mut self.cursor
     }
 }
+
+impl<N: Node> Index<Id<N>> for ParseCtx<'_> {
+    type Output = N;
+
+    fn index(&self, index: Id<N>) -> &Self::Output {
+        &self.nodes[index]
+    }
+}

src/parser/nodes/body.rs

@@ -8,25 +8,19 @@ pub struct Body {
 impl Parsable for Body {
     fn parse(ctx: &mut ParseCtx) -> Result<Self, CompilerMsg> {
         let mut exprs = Vec::new();
-        let mut final_semicolon = false;
+        fn at_end(ctx: &mut ParseCtx) -> bool {
-        match ctx.peek() {
+            ctx.peek().is_none_or(|t| *t == Token::CloseCurly)
-            None | Some(Token::CloseCurly) => {
-                return Ok(Self {
-                    exprs,
-                    final_semicolon,
-                });
         }
-            _ => (),
+        let final_semicolon = loop {
+            if at_end(ctx) {
+                break true;
             }
             exprs.push(ctx.parse()?);
-        while ctx.next_if(&Token::Semicolon) {
+            if at_end(ctx) {
-            final_semicolon = true;
+                break false;
-            if ctx.peek().is_none_or(|t| *t == Token::CloseCurly) {
-                break;
-            }
-            exprs.push(ctx.parse()?);
-            final_semicolon = false;
             }
+            ctx.expect(Token::Semicolon)?;
+        };
         Ok(Self {
             exprs,
             final_semicolon,

src/parser/nodes/expr.rs

@@ -37,22 +37,22 @@ pub enum Expr {
 
 impl Parsable for Expr {
     fn parse(ctx: &mut ParseCtx) -> Result<Self, CompilerMsg> {
-        let mut res = Self::parse_unit(ctx)?;
+        let mut res = Self::unit(ctx)?;
         while let Some(next) = ctx.peek() {
             res = match next {
                 Token::Equal => {
                     let target = ctx.push_adv(res);
-                    let val = Self::push_unit(ctx)?;
+                    let val = ctx.parse_with(Self::unit)?;
                     Expr::Assign { target, val }
                 }
                 Token::Colon => {
                     let target = ctx.push_adv(res);
                     let mut ty = None;
-                    if !ctx.next_if(&Token::Equal) {
+                    if !ctx.next_if(Token::Equal) {
                         ty = Some(ctx.parse()?);
                         ctx.expect(Token::Equal)?;
                     }
-                    let val = Self::push_unit(ctx)?;
+                    let val = ctx.parse_with(Self::unit)?;
                     Expr::Define { target, ty, val }
                 }
                 Token::OpenParen => {
@@ -68,11 +68,7 @@ impl Parsable for Expr {
 }
 
 impl Expr {
-    fn push_unit(ctx: &mut ParseCtx) -> Result<Id<Self>, CompilerMsg> {
+    fn unit(ctx: &mut ParseCtx) -> Result<Self, CompilerMsg> {
-        let res = Self::parse_unit(ctx)?;
-        Ok(ctx.push(res))
-    }
-    fn parse_unit(ctx: &mut ParseCtx) -> Result<Self, CompilerMsg> {
         Ok(match ctx.expect_next()? {
             Token::Dash => Self::Negate(ctx.parse()?),
             Token::Ident(s) => Self::Ident(ctx.ident(s)),
@@ -80,12 +76,12 @@ impl Expr {
             Token::Fn => Self::Fn(ctx.parse()?),
             Token::If => {
                 let cond = ctx.parse()?;
-                let body = ctx.parse()?;
+                let body = cond_body(cond, ctx)?;
                 Self::If { cond, body }
             }
             Token::While => {
                 let cond = ctx.parse()?;
-                let body = ctx.parse()?;
+                let body = cond_body(cond, ctx)?;
                 Self::While { cond, body }
             }
             Token::Loop => {
@@ -93,7 +89,7 @@ impl Expr {
                 Self::Loop { body }
             }
             Token::OpenParen => {
-                if ctx.next_if(&Token::CloseParen) {
+                if ctx.next_if(Token::CloseParen) {
                     Self::Lit(ctx.push(Lit::Unit))
                 } else {
                     let inner = ctx.parse()?;
@@ -109,6 +105,25 @@ impl Expr {
             other => return ctx.unexpected(&other, "an expression"),
         })
     }
+
+    pub fn is_group(&self) -> bool {
+        matches!(self, Expr::Group(_))
+    }
+
+    pub fn block(ctx: &mut ParseCtx) -> Result<Expr, CompilerMsg> {
+        ctx.expect(Token::OpenCurly)?;
+        let id = ctx.parse()?;
+        ctx.expect(Token::CloseCurly)?;
+        Ok(Expr::Block(id))
+    }
+}
+
+fn cond_body(cond: Id<Expr>, ctx: &mut ParseCtx) -> Result<Id<Expr>, CompilerMsg> {
+    if ctx[cond].is_group() {
+        ctx.parse()
+    } else {
+        ctx.parse_with(Expr::block)
+    }
 }
 
 impl FmtNode for Expr {

src/parser/nodes/func.rs

@@ -1,7 +1,8 @@
 use super::*;
 
 pub struct Func {
-    args: Vec<Id<Ident>>,
+    args: Vec<Id<Param>>,
+    ret: Option<Id<Type>>,
     body: Id<Expr>,
 }
 
@@ -9,21 +10,33 @@ impl Parsable for Func {
     fn parse(ctx: &mut ParseCtx) -> Result<Self, CompilerMsg> {
         ctx.expect(Token::OpenParen)?;
         let args = ctx.list(Token::Comma, Token::CloseParen)?;
-        let body = ctx.parse()?;
+        let mut ret = None;
-        Ok(Self { args, body })
+        if ctx.next_if(Token::Arrow) {
+            ret = Some(ctx.parse()?);
+        }
+        let body = if ret.is_some() {
+            ctx.parse_with(Expr::block)
+        } else {
+            ctx.parse()
+        }?;
+        Ok(Self { args, ret, body })
     }
 }
 
 impl FmtNode for Func {
     fn fmt(&self, f: &mut std::fmt::Formatter, ctx: DisplayCtx) -> std::fmt::Result {
-        write!(f, "(")?;
+        write!(f, "fn(")?;
         if let Some((last, rest)) = self.args.split_last() {
             for arg in rest {
                 write!(f, "{}, ", arg.dsp(ctx))?;
             }
             write!(f, "{}", last.dsp(ctx))?;
         }
-        write!(f, ") {}", self.body.dsp(ctx))?;
+        write!(f, ") ")?;
+        if let Some(ret) = self.ret {
+            write!(f, "-> {} ", ret.dsp(ctx))?;
+        }
+        self.body.fmt(f, ctx)?;
         Ok(())
     }
 }

src/parser/nodes/mod.rs

@@ -2,11 +2,13 @@ mod body;
 mod expr;
 mod func;
 mod ident;
+mod param;
 mod ty;
 pub use body::*;
 pub use expr::*;
 pub use func::*;
 pub use ident::*;
+pub use param::*;
 pub use ty::*;
 
 use super::{DisplayCtx, FmtNode, Id, Lit, Node, NodeVec, Parsable, ParseCtx, Token};
@@ -19,6 +21,7 @@ def_nodes! {
     lits: Lit,
     types: Type,
     funcs: Func,
+    params: Param,
 }
 
 macro_rules! def_nodes {

src/parser/nodes/param.rs

@@ -0,0 +1,27 @@
+use super::*;
+
+pub struct Param {
+    name: Id<Ident>,
+    ty: Option<Id<Type>>,
+}
+
+impl Parsable for Param {
+    fn parse(ctx: &mut ParseCtx) -> Result<Self, CompilerMsg> {
+        let name = ctx.parse()?;
+        let mut ty = None;
+        if ctx.next_if(Token::Colon) {
+            ty = Some(ctx.parse()?);
+        }
+        Ok(Self { name, ty })
+    }
+}
+
+impl FmtNode for Param {
+    fn fmt(&self, f: &mut std::fmt::Formatter, ctx: DisplayCtx) -> std::fmt::Result {
+        self.name.fmt(f, ctx)?;
+        if let Some(ty) = self.ty {
+            write!(f, ": {}", ty.dsp(ctx))?;
+        }
+        Ok(())
+    }
+}

test/main.lang

@@ -1,6 +1,7 @@
 x :i32 = 3;
-y := fn(a, b, c) {};
+while true {
-while Some(a) := b {
     print("hello");
-   f(x, y, z)
+    print(x);
-}
+};
+
+y := fn(x: i32) -> i32 {x};