float literals

src/codegen_x86_64.rs

@@ -148,6 +148,12 @@ _builtin_cvttsd2si:
     cvttsd2si rax, xmm0
     ret
 
+section .text._builtin_f64_to_float
+_builtin_f64_to_float:
+    cvtsd2ss xmm0, xmm0
+    movd eax, xmm0
+    ret
+
 section .text._builtin_syscall
 _builtin_syscall:
     mov rax, rdi
@@ -603,6 +609,13 @@ _builtin_environ:
                 TokenType::IntLiteral => {
                     emit!(&mut self.output, "    mov rax, {}", token.lexeme);
                 }
+                TokenType::FloatLiteral => {
+                    emit!(
+                        &mut self.output,
+                        "    mov rax, __float64__({})",
+                        token.lexeme
+                    );
+                }
                 TokenType::CharLiteral => {
                     emit!(
                         &mut self.output,
@@ -639,8 +652,13 @@ _builtin_environ:
                 self.compile_expr(env, right)?;
                 match op.token_type {
                     TokenType::Minus => {
+                        if self.expr_types[&right.id] == "f64" {
+                            emit!(&mut self.output, "    mov rbx, 0x8000000000000000");
+                            emit!(&mut self.output, "    xor rax, rbx");
+                        } else {
                             emit!(&mut self.output, "    neg rax");
                         }
+                    }
                     TokenType::Bang => {
                         emit!(&mut self.output, "    test rax, rax");
                         emit!(&mut self.output, "    sete al");

src/parser.rs

@@ -675,6 +675,7 @@ impl Parser {
     fn primary(&mut self) -> Result<Expr, ZernError> {
         if self.match_token(&[
             TokenType::IntLiteral,
+            TokenType::FloatLiteral,
             TokenType::CharLiteral,
             TokenType::StringLiteral,
             TokenType::True,

src/symbol_table.rs

@@ -53,6 +53,10 @@ impl SymbolTable {
                 ),
                 ("_builtin_cvtsi2sd".into(), FnType::new("f64", vec!["i64"])),
                 ("_builtin_cvttsd2si".into(), FnType::new("i64", vec!["f64"])),
+                (
+                    "_builtin_f64_to_float".into(),
+                    FnType::new("i64", vec!["f64"]),
+                ),
                 ("_builtin_syscall".into(), FnType::new_variadic("i64")),
                 ("_builtin_environ".into(), FnType::new("ptr", vec![])),
                 ("_var_arg".into(), FnType::new("any", vec!["i64"])),

src/tokenizer.rs

@@ -39,6 +39,7 @@ pub enum TokenType {
     StringLiteral,
     CharLiteral,
     IntLiteral,
+    FloatLiteral,
     True,
     False,
 
@@ -338,6 +339,8 @@ impl Tokenizer {
     }
 
     fn scan_number(&mut self) -> Result<(), ZernError> {
+        let mut is_float = false;
+
         if self.match_char('x') {
             while self.peek().is_ascii_hexdigit() {
                 self.advance();
@@ -350,10 +353,24 @@ impl Tokenizer {
             while self.peek().is_ascii_digit() {
                 self.advance();
             }
+            if self.current + 1 < self.source.len()
+                && self.peek() == '.'
+                && self.source[self.current + 1] != '.'
+            {
+                is_float = true;
+                self.advance();
+                while self.peek().is_ascii_digit() {
+                    self.advance();
+                }
+            }
         }
 
+        if is_float {
+            self.add_token(TokenType::FloatLiteral)
+        } else {
             self.add_token(TokenType::IntLiteral)
         }
+    }
 
     fn scan_identifier(&mut self) -> Result<(), ZernError> {
         while self.peek().is_alphanumeric() || self.peek() == '_' || self.peek() == '.' {

src/typechecker.rs

@@ -429,6 +429,7 @@ impl<'a> TypeChecker<'a> {
             ExprKind::Grouping(expr) => self.typecheck_expr(env, expr),
             ExprKind::Literal(token) => match token.token_type {
                 TokenType::IntLiteral => Ok("i64".into()),
+                TokenType::FloatLiteral => Ok("f64".into()),
                 TokenType::CharLiteral => Ok("u8".into()),
                 TokenType::StringLiteral => Ok("str".into()),
                 TokenType::True => Ok("bool".into()),
@@ -439,8 +440,8 @@ impl<'a> TypeChecker<'a> {
                 let right_type = self.typecheck_expr(env, right)?;
                 match op.token_type {
                     TokenType::Minus => {
-                        expect_type!(right_type, "i64", op.loc);
+                        expect_types!(right_type, ["f64", "i64"], op.loc);
-                        Ok("i64".into())
+                        Ok(right_type)
                     }
                     TokenType::Bang => {
                         expect_types!(right_type, ["bool", "i64", "ptr", "u8"], op.loc);