use const for function declaration, comma separated args

example/ex.hyc

@@ -1,4 +1,4 @@
-let foo: int = 1;
+let foo: string = 1;
 
 fun bar (baz: int) -> int = baz + 1;
 fun qux (quux: int) -> int = do
@@ -6,4 +6,7 @@ fun qux (quux: int) -> int = do
     bar(corge);
 end;
 
+fun add (lhs: int, rhs: int) -> int = lhs + rhs;
+print(add(34, 35));
+
 print(qux(5));

src/back/js.rs

@@ -46,7 +46,7 @@ fn gen_ir(ir: &IR) -> String {
             };
 
             format!(
-                "function {}({}) {{ {} }}",
+                "const {} = ({}) => {{ {} }};",
                 name,
                 args,
                 body

src/front/parse.rs

@@ -12,7 +12,7 @@ pub enum Token {
     Delimiter(char),
     Semicolon,
     Assign, Colon,
-    Comma,
+    Comma, Dot,
     ReturnHint,
 
     // Keywords
@@ -46,6 +46,7 @@ pub fn lexer() -> impl Parser<char, Vec<(Token, Span)>, Error = Simple<char>> {
         just(':').to(Token::Colon),
         just(',').to(Token::Comma),
         just("->").to(Token::ReturnHint), 
+        just(".").to(Token::Dot),
     ));
 
     let operator = choice((
@@ -152,9 +153,8 @@ fn expr_parser() -> impl Parser<Token, Expr, Error = Simple<Token>> + Clone {
 
     let expr = recursive(|expr| {
         let args = expr.clone()
-            .repeated()
-            .or_not()
-            .map(|item| item.unwrap_or_else(Vec::new));
+            .separated_by(just(Token::Comma))
+            .allow_trailing();
 
         let atom = literal
             .or(ident.map(Expr::Ident))
@@ -177,7 +177,7 @@ fn expr_parser() -> impl Parser<Token, Expr, Error = Simple<Token>> + Clone {
                     args,
                 }
             });
-        
+
         let unary =  choice((
                 just(Token::Operator("-".to_string())).to("-"),
                 just(Token::Operator("!".to_string())).to("!")))
@@ -263,7 +263,8 @@ fn expr_parser() -> impl Parser<Token, Expr, Error = Simple<Token>> + Clone {
                 (ident
                     .then_ignore(just(Token::Colon))
                     .then(ident))
-                .repeated()
+                .separated_by(just(Token::Comma))
+                .allow_trailing()
             )
             .then_ignore(just(Token::Delimiter(')')))
             .then_ignore(just(Token::ReturnHint))

src/main.rs

@@ -25,6 +25,7 @@ use middle::ir;
 /// Contains code generator.
 pub mod back;
 
+/// Utility functions.
 pub mod util;
 use crate::util::log;
 

src/middle/ir.rs

@@ -1,27 +1,13 @@
-use core::fmt;
-
 use crate::front::parse::Expr;
 
 #[derive(Debug, Clone)]
 pub enum TypeHint {
     Int,
-    Float, Double,
+    Float,
     Bool,
     String,
 }
 
-impl fmt::Display for TypeHint {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        match self {
-            TypeHint::Int => write!(f, "int"),
-            TypeHint::Float => write!(f, "float"),
-            TypeHint::Double => write!(f, "double"),
-            TypeHint::Bool => write!(f, "bool"),
-            TypeHint::String => write!(f, "char*"),
-        }
-    }
-}
-
 #[derive(Debug, Clone)]
 pub enum Value {
     Int(i64),