Revert "Change function declaration syntax"

This reverts commit b21c781a64.

examples/hello_world.sb

@@ -1,4 +1,3 @@
-main :: () {
-    return "Hello World"
+fn main(n) {
+    n * 2;
 }
-

src/lexer/mod.rs

@@ -53,8 +53,6 @@ pub enum TokenKind {
     Slash,
     /// ":"
     Colon,
-    /// "::"
-    DoubleColon,
     /// ";"
     SemiColon,
     /// "!"
@@ -107,6 +105,7 @@ pub enum Keyword {
     If,
     Else,
     Return,
+    Function,
     Boolean,
     Unknown,
 }
@@ -185,13 +184,7 @@ impl Cursor<'_> {
                 }
                 _ => Assign,
             },
-            ':' => match self.first() {
-                ':' => {
-                    self.bump();
-                    DoubleColon
-                }
-                _ => Colon,
-            },
+            ':' => Colon,
             ';' => SemiColon,
             ',' => Comma,
             '<' => match self.first() {
@@ -290,6 +283,7 @@ impl Cursor<'_> {
         match original {
             c if c == "if" => Keyword::If,
             c if c == "else" => Keyword::Else,
+            c if c == "fn" => Keyword::Function,
             c if c == "true" || c == "false" => Keyword::Boolean,
             c if c == "let" => Keyword::Let,
             c if c == "return" => Keyword::Return,

src/lexer/tests.rs

@@ -160,46 +160,18 @@ mod tests {
 
     #[test]
     fn test_functions() {
-        let mut tokens = tokenize("fib :: () {}").into_iter();
-
-        assert_eq!(
-            tokens.nth(0).unwrap(),
-            Token {
-                len: 3,
-                kind: TokenKind::Identifier("fib".into()),
-                raw: "fib".to_owned(),
-                pos: Position {
-                    raw: 2,
-                    line: 1,
-                    offset: 2
-                }
-            }
-        );
-
-        assert_eq!(
-            tokens.nth(0).unwrap(),
-            Token {
-                len: 1,
-                kind: TokenKind::Whitespace,
-                raw: " ".to_owned(),
-                pos: Position {
-                    raw: 3,
-                    line: 1,
-                    offset: 3
-                }
-            }
-        );
+        let mut tokens = tokenize("fn fib() {}").into_iter();
 
         assert_eq!(
             tokens.nth(0).unwrap(),
             Token {
                 len: 2,
-                kind: TokenKind::DoubleColon,
-                raw: "::".to_owned(),
+                kind: TokenKind::Keyword(Keyword::Function),
+                raw: "fn".to_owned(),
                 pos: Position {
-                    raw: 5,
+                    raw: 1,
                     line: 1,
-                    offset: 5
+                    offset: 1
                 }
             }
         );
@@ -209,7 +181,7 @@ mod tests {
     fn test_comments() {
         let mut tokens = tokenize(
             "// foo
-fib :: () {}
+fn fib() {}
         ",
         )
         .into_iter()
@@ -233,30 +205,16 @@ fib :: () {}
             }
         );
 
-        assert_eq!(
-            tokens.nth(0).unwrap(),
-            Token {
-                len: 3,
-                kind: TokenKind::Identifier("fib".into()),
-                raw: "fib".to_owned(),
-                pos: Position {
-                    raw: 9,
-                    line: 2,
-                    offset: 3
-                }
-            }
-        );
-
         assert_eq!(
             tokens.nth(0).unwrap(),
             Token {
                 len: 2,
-                kind: TokenKind::DoubleColon,
-                raw: "::".to_owned(),
+                kind: TokenKind::Keyword(Keyword::Function),
+                raw: "fn".to_owned(),
                 pos: Position {
-                    raw: 12,
+                    raw: 8,
                     line: 2,
-                    offset: 6
+                    offset: 2
                 }
             }
         );

src/parser/mod.rs

@@ -48,8 +48,6 @@ impl Parser {
             self.peeked.pop()
         };
 
-        dbg!(&item);
-
         self.current = item.to_owned();
         item
     }
@@ -151,8 +149,9 @@ impl Parser {
     }
 
     fn parse_function(&mut self) -> Result<Function, String> {
+        self.match_keyword(Keyword::Function)?;
         let name = self.match_identifier()?;
-        self.match_token(TokenKind::DoubleColon)?;
+
         self.match_token(TokenKind::BraceOpen)?;
 
         let arguments: Vec<Variable> = match self.peek() {

src/parser/tests.rs

@@ -3,7 +3,7 @@ use crate::parser::*;
 
 #[test]
 fn test_parse_empty_function() {
-    let raw = "main :: () {}";
+    let raw = "fn main() {}";
     let tokens = tokenize(raw);
     let tree = parse(tokens, Some(raw.to_string()));
     assert!(tree.is_ok())
@@ -12,7 +12,7 @@ fn test_parse_empty_function() {
 #[test]
 fn test_parse_function_with_return() {
     let raw = "
-    main :: () {
+    fn main() {
         return 1
     }
     ";
@@ -24,7 +24,7 @@ fn test_parse_function_with_return() {
 #[test]
 fn test_parse_redundant_semicolon() {
     let raw = "
-    main :: () {
+    fn main() {
         return 1;
     }
     ";
@@ -46,12 +46,12 @@ fn test_parse_no_function_context() {
 #[test]
 fn test_parse_multiple_functions() {
     let raw = "
-    foo :: () {
+    fn foo() {
         let x = 2
         return x
     }
 
-    bar :: () {
+    fn bar() {
         let y = 5
         return y
     }
@@ -64,7 +64,7 @@ fn test_parse_multiple_functions() {
 #[test]
 fn test_parse_variable_declaration() {
     let raw = "
-    main :: () {
+    fn main() {
         let x = 1
         return x
     }
@@ -77,7 +77,7 @@ fn test_parse_variable_declaration() {
 #[test]
 fn test_parse_function_with_args() {
     let raw = "
-    main :: (foo) {
+    fn main(foo) {
         return foo
     }
     ";
@@ -89,11 +89,11 @@ fn test_parse_function_with_args() {
 #[test]
 fn test_parse_function_call() {
     let raw = "
-    main :: (foo) {
+    fn main(foo) {
         foo()
     }
 
-    foo :: () {
+    fn foo() {
         foo(2)
     }
     ";
@@ -105,11 +105,11 @@ fn test_parse_function_call() {
 #[test]
 fn test_parse_return_function_call() {
     let raw = "
-    main :: () {
+    fn main() {
         return fib(2)
     }
 
-    fib :: () {
+    fn fib() {
         return fib(2)
     }
     ";
@@ -121,11 +121,11 @@ fn test_parse_return_function_call() {
 #[test]
 fn test_parse_function_call_multiple_arguments() {
     let raw = "
-    main :: () {
+    fn main() {
         fib(1, 2, 3)
     }
 
-    fib :: () {
+    fn fib() {
         return 2
     }
     ";
@@ -137,11 +137,11 @@ fn test_parse_function_call_multiple_arguments() {
 #[test]
 fn test_parse_nexted_function_call() {
     let raw = "
-    main :: () {
+    fn main() {
         fib(fib(2), 2)
     }
 
-    fib :: (n) {
+    fn fib(n) {
         return 2
     }
     ";
@@ -153,7 +153,7 @@ fn test_parse_nexted_function_call() {
 #[test]
 fn test_parse_basic_ops() {
     let raw = "
-    main :: () {
+    fn main() {
         return 2 * 5
     }
     ";
@@ -165,7 +165,7 @@ fn test_parse_basic_ops() {
 #[test]
 fn test_parse_compound_ops() {
     let raw = "
-    main :: () {
+    fn main() {
         2 * 5 / 3
     }
     ";
@@ -177,7 +177,7 @@ fn test_parse_compound_ops() {
 #[test]
 fn test_parse_compound_ops_with_function_call() {
     let raw = "
-    main :: () {
+    fn main() {
         return 2 * fib(1) / 3
     }
     ";
@@ -189,7 +189,7 @@ fn test_parse_compound_ops_with_function_call() {
 #[test]
 fn test_parse_compound_ops_with_strings() {
     let raw = "
-    main :: () {
+    fn main() {
         return 2 * \"Hello\"
     }
     ";
@@ -201,7 +201,7 @@ fn test_parse_compound_ops_with_strings() {
 #[test]
 fn test_parse_compound_ops_with_identifier() {
     let raw = "
-    main :: (n) {
+    fn main(n) {
         return 2 * n
     }
     ";
@@ -214,7 +214,7 @@ fn test_parse_compound_ops_with_identifier() {
 #[ignore]
 fn test_parse_compound_ops_with_identifier_first() {
     let raw = "
-    main :: (n) {
+    fn main(n) {
         return n * 2
     }
     ";
@@ -226,7 +226,7 @@ fn test_parse_compound_ops_with_identifier_first() {
 #[test]
 fn test_parse_compound_ops_return() {
     let raw = "
-    main :: (n) {
+    fn main(n) {
         return 2 * n
     }
     ";
@@ -238,7 +238,7 @@ fn test_parse_compound_ops_return() {
 #[test]
 fn test_parse_basic_conditional() {
     let raw = "
-    main :: (n) {
+    fn main(n) {
         if n {
             return n
         }
@@ -252,7 +252,7 @@ fn test_parse_basic_conditional() {
 #[test]
 fn test_parse_basic_conditional_with_multiple_statements() {
     let raw = "
-    main :: (n) {
+    fn main(n) {
         if n {
             let x = 2 * n
             return x