feat: add floats

src/backend/cranelift.rs

@@ -158,6 +158,8 @@ impl CraneliftBackend {
             Ty::I16 | Ty::U16 => types::I16,
             Ty::I32 | Ty::U32 => types::I32,
             Ty::I64 | Ty::U64 => types::I64,
+            Ty::F32 => types::F32,
+            Ty::F64 => types::F64,
             Ty::Bool => types::I8, // Booleans are represented as 8-bit integers
             _ => unimplemented!("Unsupported type for Cranelift lowering: {:?}", ty),
         }
@@ -221,6 +223,7 @@ impl<'a> FunctionTranslator<'a> {
         match op {
             Operand::Copy(local_id) => self.locals[local_id.0].ty.clone(),
             Operand::Constant(ConstantValue::Integer(_, ty)) => ty.clone(),
+            Operand::Constant(ConstantValue::Float(_, ty)) => ty.clone(),
             Operand::Constant(ConstantValue::Boolean(_)) => Ty::Bool,
         }
     }
@@ -235,6 +238,11 @@ impl<'a> FunctionTranslator<'a> {
                 let cl_ty = CraneliftBackend::lower_type(ty);
                 self.builder.ins().iconst(cl_ty, *val as i64)
             }
+            Operand::Constant(ConstantValue::Float(val, ty)) => match ty {
+                Ty::F32 => self.builder.ins().f32const(*val as f32),
+                Ty::F64 => self.builder.ins().f64const(*val),
+                _ => unreachable!(),
+            },
             Operand::Constant(ConstantValue::Boolean(val)) => self
                 .builder
                 .ins()
@@ -247,10 +255,17 @@ impl<'a> FunctionTranslator<'a> {
             Rvalue::Use(op) => self.translate_operand(op),
             Rvalue::UnaryOp(op, inner) => {
                 let inner_val = self.translate_operand(inner);
-                match op {
-                    UnaryOp::Neg => self.builder.ins().ineg(inner_val),
-                    UnaryOp::Not => {
                 let ty = self.get_operand_type(inner);
+
+                match op {
+                    UnaryOp::Neg => {
+                        if ty.is_float() {
+                            self.builder.ins().fneg(inner_val)
+                        } else {
+                            self.builder.ins().ineg(inner_val)
+                        }
+                    }
+                    UnaryOp::Not => {
                         let cl_ty = CraneliftBackend::lower_type(&ty);
                         let zero = self.builder.ins().iconst(cl_ty, 0);
                         self.builder
@@ -265,36 +280,82 @@ impl<'a> FunctionTranslator<'a> {
 
                 let ty = self.get_operand_type(lhs);
                 let is_signed = matches!(ty, Ty::I8 | Ty::I16 | Ty::I32 | Ty::I64);
+                let is_float = ty.is_float();
 
                 match op {
-                    BinaryOp::Add => self.builder.ins().iadd(lhs_val, rhs_val),
+                    BinaryOp::Add => {
-                    BinaryOp::Sub => self.builder.ins().isub(lhs_val, rhs_val),
+                        if is_float {
-                    BinaryOp::Mul => self.builder.ins().imul(lhs_val, rhs_val),
+                            self.builder.ins().fadd(lhs_val, rhs_val)
+                        } else {
+                            self.builder.ins().iadd(lhs_val, rhs_val)
+                        }
+                    }
+                    BinaryOp::Sub => {
+                        if is_float {
+                            self.builder.ins().fsub(lhs_val, rhs_val)
+                        } else {
+                            self.builder.ins().isub(lhs_val, rhs_val)
+                        }
+                    }
+                    BinaryOp::Mul => {
+                        if is_float {
+                            self.builder.ins().fmul(lhs_val, rhs_val)
+                        } else {
+                            self.builder.ins().imul(lhs_val, rhs_val)
+                        }
+                    }
                     BinaryOp::Div => {
-                        if is_signed {
+                        if is_float {
+                            self.builder.ins().fdiv(lhs_val, rhs_val)
+                        } else if is_signed {
                             self.builder.ins().sdiv(lhs_val, rhs_val)
                         } else {
                             self.builder.ins().udiv(lhs_val, rhs_val)
                         }
                     }
                     BinaryOp::Rem => {
-                        if is_signed {
+                        if is_float {
+                            unimplemented!("float remainder is not natively supported in Cranelift")
+                        } else if is_signed {
                             self.builder.ins().srem(lhs_val, rhs_val)
                         } else {
                             self.builder.ins().urem(lhs_val, rhs_val)
                         }
                     }
                     BinaryOp::Eq => {
+                        if is_float {
+                            self.builder
+                                .ins()
+                                .fcmp(ir::condcodes::FloatCC::Equal, lhs_val, rhs_val)
+                        } else {
                             self.builder
                                 .ins()
                                 .icmp(ir::condcodes::IntCC::Equal, lhs_val, rhs_val)
                         }
+                    }
                     BinaryOp::Neq => {
-                        self.builder
+                        if is_float {
-                            .ins()
+                            self.builder.ins().fcmp(
-                            .icmp(ir::condcodes::IntCC::NotEqual, lhs_val, rhs_val)
+                                ir::condcodes::FloatCC::NotEqual,
+                                lhs_val,
+                                rhs_val,
+                            )
+                        } else {
+                            self.builder.ins().icmp(
+                                ir::condcodes::IntCC::NotEqual,
+                                lhs_val,
+                                rhs_val,
+                            )
+                        }
                     }
                     BinaryOp::Lt => {
+                        if is_float {
+                            self.builder.ins().fcmp(
+                                ir::condcodes::FloatCC::LessThan,
+                                lhs_val,
+                                rhs_val,
+                            )
+                        } else {
                             let cc = if is_signed {
                                 ir::condcodes::IntCC::SignedLessThan
                             } else {
@@ -302,7 +363,15 @@ impl<'a> FunctionTranslator<'a> {
                             };
                             self.builder.ins().icmp(cc, lhs_val, rhs_val)
                         }
+                    }
                     BinaryOp::Le => {
+                        if is_float {
+                            self.builder.ins().fcmp(
+                                ir::condcodes::FloatCC::LessThanOrEqual,
+                                lhs_val,
+                                rhs_val,
+                            )
+                        } else {
                             let cc = if is_signed {
                                 ir::condcodes::IntCC::SignedLessThanOrEqual
                             } else {
@@ -310,7 +379,15 @@ impl<'a> FunctionTranslator<'a> {
                             };
                             self.builder.ins().icmp(cc, lhs_val, rhs_val)
                         }
+                    }
                     BinaryOp::Gt => {
+                        if is_float {
+                            self.builder.ins().fcmp(
+                                ir::condcodes::FloatCC::GreaterThan,
+                                lhs_val,
+                                rhs_val,
+                            )
+                        } else {
                             let cc = if is_signed {
                                 ir::condcodes::IntCC::SignedGreaterThan
                             } else {
@@ -318,7 +395,15 @@ impl<'a> FunctionTranslator<'a> {
                             };
                             self.builder.ins().icmp(cc, lhs_val, rhs_val)
                         }
+                    }
                     BinaryOp::Ge => {
+                        if is_float {
+                            self.builder.ins().fcmp(
+                                ir::condcodes::FloatCC::GreaterThanOrEqual,
+                                lhs_val,
+                                rhs_val,
+                            )
+                        } else {
                             let cc = if is_signed {
                                 ir::condcodes::IntCC::SignedGreaterThanOrEqual
                             } else {
@@ -331,3 +416,4 @@ impl<'a> FunctionTranslator<'a> {
             }
         }
     }
+}

src/frontend/ast.rs

@@ -34,18 +34,18 @@ pub type TypedStmtKind = StmtKind<Typed>;
 pub type TypedExpr = Expr<Typed>;
 pub type TypedExprKind = ExprKind<Typed>;
 
-#[derive(Debug, PartialEq, Eq)]
+#[derive(Debug, PartialEq)]
 pub struct Module<P: Phase = Untyped> {
     pub decls: Vec<Decl<P>>,
 }
 
-#[derive(Debug, PartialEq, Eq)]
+#[derive(Debug, PartialEq)]
 pub struct Decl<P: Phase = Untyped> {
     pub kind: DeclKind<P>,
     pub span: Span,
 }
 
-#[derive(Debug, PartialEq, Eq)]
+#[derive(Debug, PartialEq)]
 pub enum DeclKind<P: Phase = Untyped> {
     Function {
         name: String,
@@ -79,16 +79,18 @@ pub enum TypeKind {
     U16,
     U32,
     U64,
+    F32,
+    F64,
     Bool,
 }
 
-#[derive(Debug, PartialEq, Eq)]
+#[derive(Debug, PartialEq)]
 pub struct Stmt<P: Phase = Untyped> {
     pub kind: StmtKind<P>,
     pub span: Span,
 }
 
-#[derive(Debug, PartialEq, Eq)]
+#[derive(Debug, PartialEq)]
 pub enum StmtKind<P: Phase = Untyped> {
     Compound {
         inner: Vec<Stmt<P>>,
@@ -118,14 +120,14 @@ pub enum StmtKind<P: Phase = Untyped> {
     Continue,
 }
 
-#[derive(Debug, PartialEq, Eq)]
+#[derive(Debug, PartialEq)]
 pub struct Expr<P: Phase = Untyped> {
     pub kind: ExprKind<P>,
     pub ty: P::ExprType,
     pub span: Span,
 }
 
-#[derive(Debug, PartialEq, Eq)]
+#[derive(Debug, PartialEq)]
 pub enum ExprKind<P: Phase = Untyped> {
     Identifier {
         name: String,
@@ -133,6 +135,9 @@ pub enum ExprKind<P: Phase = Untyped> {
     Integer {
         value: u64,
     },
+    Float {
+        value: f64,
+    },
     Boolean {
         value: bool,
     },

src/frontend/lexer.rs

@@ -80,6 +80,8 @@ impl<'src> Lexer<'src> {
             "u16" => TokenKind::U16,
             "u32" => TokenKind::U32,
             "u64" => TokenKind::U64,
+            "f32" => TokenKind::F32,
+            "f64" => TokenKind::F64,
             "bool" => TokenKind::Bool,
 
             "true" | "false" => TokenKind::BooleanLit,
@@ -108,6 +110,43 @@ impl<'src> Lexer<'src> {
 
         self.advance_while(|ch| ch.is_digit(radix));
 
+        // Handle floating point literals (fraction and optional exponent)
+        if radix == 10 {
+            let mut is_float = false;
+
+            if self.peek() == Some('.') {
+                let mut chars = self.source[self.cursor..].chars();
+                chars.next(); // consume '.'
+                if chars.next().is_some_and(|ch| ch.is_ascii_digit()) {
+                    self.advance(); // consume '.'
+                    self.advance_while(|ch| ch.is_ascii_digit());
+                    is_float = true;
+                }
+            }
+
+            if matches!(self.peek(), Some('e' | 'E')) {
+                let mut chars = self.source[self.cursor..].chars();
+                chars.next(); // consume 'e'
+                let next_char = chars.next();
+
+                if next_char.is_some_and(|ch| ch.is_ascii_digit())
+                    || (matches!(next_char, Some('+' | '-'))
+                        && chars.next().is_some_and(|ch| ch.is_ascii_digit()))
+                {
+                    self.advance(); // consume 'e'
+                    if matches!(self.peek(), Some('+' | '-')) {
+                        self.advance(); // consume sign
+                    }
+                    self.advance_while(|ch| ch.is_ascii_digit());
+                    is_float = true;
+                }
+            }
+
+            if is_float {
+                return TokenKind::FloatLit;
+            }
+        }
+
         TokenKind::IntegerLit
     }
 
@@ -240,6 +279,20 @@ mod test {
         )
     }
 
+    #[test]
+    fn float_literals() {
+        assert_eq!(
+            tokenize("3.14 0.001 42.0 1e5 2.5e-3"),
+            vec![
+                Token::new(TokenKind::FloatLit, "3.14", Span::new(0, 4)),
+                Token::new(TokenKind::FloatLit, "0.001", Span::new(5, 10)),
+                Token::new(TokenKind::FloatLit, "42.0", Span::new(11, 15)),
+                Token::new(TokenKind::FloatLit, "1e5", Span::new(16, 19)),
+                Token::new(TokenKind::FloatLit, "2.5e-3", Span::new(20, 26)),
+            ]
+        );
+    }
+
     #[test]
     fn boolean_literals() {
         assert_eq!(
@@ -254,7 +307,7 @@ mod test {
     #[test]
     fn types() {
         assert_eq!(
-            tokenize("i8 i16 i32 i64 u8 u16 u32 u64 bool"),
+            tokenize("i8 i16 i32 i64 u8 u16 u32 u64 f32 f64 bool"),
             vec![
                 Token::new(TokenKind::I8, "i8", Span::new(0, 2)),
                 Token::new(TokenKind::I16, "i16", Span::new(3, 6)),
@@ -264,7 +317,9 @@ mod test {
                 Token::new(TokenKind::U16, "u16", Span::new(18, 21)),
                 Token::new(TokenKind::U32, "u32", Span::new(22, 25)),
                 Token::new(TokenKind::U64, "u64", Span::new(26, 29)),
-                Token::new(TokenKind::Bool, "bool", Span::new(30, 34)),
+                Token::new(TokenKind::F32, "f32", Span::new(30, 33)),
+                Token::new(TokenKind::F64, "f64", Span::new(34, 37)),
+                Token::new(TokenKind::Bool, "bool", Span::new(38, 42)),
             ]
         )
     }

src/frontend/parser.rs

@@ -223,6 +223,7 @@ impl<'src> Parser<'src> {
     /// ```ebnf
     /// type = "i8" | "i16" | "i32" | "i64"
     ///      | "u8" | "u16" | "u32" | "u64"
+    ///      | "f32" | "f64"
     ///      | "bool" ;
     /// ```
     pub fn parse_type(&mut self) -> ParseResult<Type> {
@@ -261,6 +262,14 @@ impl<'src> Parser<'src> {
                 self.advance();
                 TypeKind::U64
             }
+            TokenKind::F32 => {
+                self.advance();
+                TypeKind::F32
+            }
+            TokenKind::F64 => {
+                self.advance();
+                TypeKind::F64
+            }
             TokenKind::Bool => {
                 self.advance();
                 TypeKind::Bool
@@ -617,6 +626,17 @@ impl<'src> Parser<'src> {
                 })
             }
 
+            TokenKind::FloatLit => {
+                let token = self.advance().unwrap();
+                let value = token.text.parse().unwrap();
+
+                Ok(Expr {
+                    kind: ExprKind::Float { value },
+                    ty: (),
+                    span: token.span,
+                })
+            }
+
             TokenKind::BooleanLit => {
                 let token = self.advance().unwrap();
 
@@ -706,8 +726,8 @@ mod test {
         token::Span,
     };
 
-    #[derive(Debug, PartialEq, Eq)]
+    #[derive(Debug, PartialEq)]
-    enum TestResult<T: Debug + Eq + PartialEq> {
+    enum TestResult<T: Debug + PartialEq> {
         Success(T),
         Recovered(T, Vec<ParseError>),
         Error(Vec<ParseError>),
@@ -715,7 +735,7 @@ mod test {
 
     use TestResult::*;
 
-    fn parse<'src, T: Debug + Eq + PartialEq>(
+    fn parse<'src, T: Debug + PartialEq>(
         source: &'src str,
         method: impl Fn(&mut Parser<'src>) -> ParseResult<T>,
     ) -> TestResult<T> {
@@ -775,6 +795,18 @@ mod test {
         );
     }
 
+    #[test]
+    fn float_literals() {
+        assert_eq!(
+            parse("3.14;", Parser::parse_expr),
+            Success(Expr {
+                kind: ExprKind::Float { value: 3.14 },
+                ty: (),
+                span: Span::new(0, 4)
+            })
+        );
+    }
+
     #[test]
     fn boolean_literals() {
         assert_eq!(
@@ -969,6 +1001,29 @@ mod test {
         );
     }
 
+    #[test]
+    fn let_stmt_float() {
+        assert_eq!(
+            parse("let a: f32 = 3.14;", Parser::parse_stmt),
+            Success(Stmt {
+                kind: StmtKind::Let {
+                    name: "a".to_string(),
+                    name_span: Span::new(4, 5),
+                    ty: Some(Type {
+                        kind: TypeKind::F32,
+                        span: Span::new(7, 10),
+                    }),
+                    initializer: Some(Expr {
+                        kind: ExprKind::Float { value: 3.14 },
+                        ty: (),
+                        span: Span::new(13, 17),
+                    }),
+                },
+                span: Span::new(0, 18)
+            })
+        );
+    }
+
     #[test]
     fn while_stmt() {
         assert_eq!(

src/frontend/sema.rs

@@ -35,6 +35,8 @@ pub enum Ty {
     U16,
     U32,
     U64,
+    F32,
+    F64,
     Bool,
     Unit,
     Var(usize),
@@ -49,6 +51,16 @@ impl Ty {
             Ty::I8 | Ty::I16 | Ty::I32 | Ty::I64 | Ty::U8 | Ty::U16 | Ty::U32 | Ty::U64
         )
     }
+
+    /// Returns `true` if the type is a fundamental floating point type.
+    pub fn is_float(&self) -> bool {
+        matches!(self, Ty::F32 | Ty::F64)
+    }
+
+    /// Returns `true` if the type is numeric (integer or float).
+    pub fn is_numeric(&self) -> bool {
+        self.is_integer() || self.is_float()
+    }
 }
 
 impl From<&TypeKind> for Ty {
@@ -62,6 +74,8 @@ impl From<&TypeKind> for Ty {
             TypeKind::U16 => Ty::U16,
             TypeKind::U32 => Ty::U32,
             TypeKind::U64 => Ty::U64,
+            TypeKind::F32 => Ty::F32,
+            TypeKind::F64 => Ty::F64,
             TypeKind::Bool => Ty::Bool,
         }
     }
@@ -77,7 +91,8 @@ pub struct Sema {
     errors: Vec<SemanticError>,
     deferred_unary_neg: Vec<(Span, Ty, Ty, Option<u64>)>,
     deferred_binary: Vec<(Span, Ty)>,
-    deferred_literals: Vec<(Span, Ty)>,
+    deferred_int_literals: Vec<(Span, Ty)>,
+    deferred_float_literals: Vec<(Span, Ty)>,
     loop_depth: usize,
 }
 
@@ -91,7 +106,8 @@ impl Sema {
             errors: Vec::new(),
             deferred_unary_neg: Vec::new(),
             deferred_binary: Vec::new(),
-            deferred_literals: Vec::new(),
+            deferred_int_literals: Vec::new(),
+            deferred_float_literals: Vec::new(),
             loop_depth: 0,
         }
     }
@@ -469,7 +485,7 @@ impl Sema {
 
             ExprKind::Integer { value } => {
                 let ty = self.new_var();
-                self.deferred_literals.push((expr.span, ty.clone()));
+                self.deferred_int_literals.push((expr.span, ty.clone()));
 
                 TypedExpr {
                     kind: TypedExprKind::Integer { value: *value },
@@ -478,6 +494,17 @@ impl Sema {
                 }
             }
 
+            ExprKind::Float { value } => {
+                let ty = self.new_var();
+                self.deferred_float_literals.push((expr.span, ty.clone()));
+
+                TypedExpr {
+                    kind: TypedExprKind::Float { value: *value },
+                    ty,
+                    span: expr.span,
+                }
+            }
+
             ExprKind::Boolean { value } => TypedExpr {
                 kind: TypedExprKind::Boolean { value: *value },
                 ty: Ty::Bool,
@@ -685,6 +712,7 @@ impl Sema {
         let kind = match expr.kind {
             TypedExprKind::Identifier { name } => TypedExprKind::Identifier { name },
             TypedExprKind::Integer { value } => TypedExprKind::Integer { value },
+            TypedExprKind::Float { value } => TypedExprKind::Float { value },
             TypedExprKind::Boolean { value } => TypedExprKind::Boolean { value },
 
             TypedExprKind::Unary { op, expr } => TypedExprKind::Unary {
@@ -715,7 +743,7 @@ impl Sema {
             let result_resolved = self.apply_subst(&result_ty);
 
             let inner_final = if let Ty::Var(_) = inner_resolved {
-                if result_resolved.is_integer() {
+                if result_resolved.is_numeric() {
                     let _ = self.unify(&inner_resolved, &result_resolved);
                     result_resolved.clone()
                 } else {
@@ -733,7 +761,7 @@ impl Sema {
             // If the value is known at compile time, we can avoid promoting to a larger size
             // as long as the exact value fits within the signed equivalent of the same size.
             let promoted_ty = match inner_final {
-                Ty::I8 | Ty::I16 | Ty::I32 | Ty::I64 => Ok(inner_final),
+                Ty::I8 | Ty::I16 | Ty::I32 | Ty::I64 | Ty::F32 | Ty::F64 => Ok(inner_final),
 
                 Ty::U8 => Ok(if known_value.is_some_and(|v| v <= i8::MAX as u64) {
                     Ty::I8
@@ -762,7 +790,7 @@ impl Sema {
                         Err("cannot promote u64 to a larger signed type")
                     }
                 }
-                _ => Err("unary minus only works on integer types"),
+                _ => Err("unary minus only works on numeric types"),
             };
 
             match promoted_ty {
@@ -788,15 +816,15 @@ impl Sema {
                 resolved
             };
 
-            if !final_ty.is_integer() {
+            if !final_ty.is_numeric() {
                 self.errors.push(SemanticError::new(
-                    "binary operators only work on integer types",
+                    "binary operators only work on numeric types",
                     span,
                 ));
             }
         }
 
-        for (span, ty) in std::mem::take(&mut self.deferred_literals) {
+        for (span, ty) in std::mem::take(&mut self.deferred_int_literals) {
             let resolved = self.apply_subst(&ty);
 
             let final_ty = if let Ty::Var(_) = resolved {
@@ -814,6 +842,23 @@ impl Sema {
                 ));
             }
         }
+
+        for (span, ty) in std::mem::take(&mut self.deferred_float_literals) {
+            let resolved = self.apply_subst(&ty);
+
+            let final_ty = if let Ty::Var(_) = resolved {
+                let default = Ty::F32;
+                let _ = self.unify(&resolved, &default);
+                default
+            } else {
+                resolved
+            };
+
+            if !final_ty.is_float() {
+                self.errors
+                    .push(SemanticError::new("expected float type for literal", span));
+            }
+        }
     }
 }
 
@@ -867,6 +912,48 @@ mod test {
         assert!(errors[0].message.contains("undeclared identifier `x`"));
     }
 
+    #[test]
+    fn valid_float_ops() {
+        let src = "fn test(a: f32, b: f32) -> f32 { return a + b - a * b / a; }";
+        assert!(analyze(src).is_ok());
+    }
+
+    #[test]
+    fn valid_float_comparison() {
+        let src = "fn test(a: f64, b: f64) -> bool { return a <= b; }";
+        assert!(analyze(src).is_ok());
+    }
+
+    #[test]
+    fn valid_float_unary_neg() {
+        let src = "fn test(a: f64) -> f64 { return -a; }";
+        assert!(analyze(src).is_ok());
+    }
+
+    #[test]
+    fn float_type_mismatch() {
+        let src = "fn test(a: f32, b: i32) -> f32 { return a + b; }";
+        let errors = analyze(src).unwrap_err();
+        assert!(errors.iter().any(|e| e.message.contains("type mismatch")));
+    }
+
+    #[test]
+    fn float_literal_inference() {
+        let src = "fn test() { let a = 3.14; }";
+        assert!(analyze(src).is_ok());
+    }
+
+    #[test]
+    fn float_literal_invalid_type() {
+        let src = "fn test() { let a: i32 = 3.14; }";
+        let errors = analyze(src).unwrap_err();
+        assert!(
+            errors
+                .iter()
+                .any(|e| e.message.contains("expected float type for literal"))
+        );
+    }
+
     #[test]
     fn binary_op_non_integer() {
         let src = "fn bad_bin() -> bool { return true + false; }";
@@ -874,7 +961,7 @@ mod test {
 
         assert!(errors.iter().any(|e| {
             e.message
-                .contains("binary operators only work on integer types")
+                .contains("binary operators only work on numeric types")
         }));
     }
 
@@ -898,7 +985,7 @@ mod test {
 
         assert!(errors.iter().any(|e| {
             e.message
-                .contains("unary minus only works on integer types")
+                .contains("unary minus only works on numeric types")
         }));
     }
 
@@ -921,16 +1008,6 @@ mod test {
         assert!(analyze(src).is_ok());
     }
 
-    #[test]
-    fn invalid_comparison() {
-        let src = "fn test(a: bool, b: bool) -> bool { return a == b; }";
-        let errors = analyze(src).unwrap_err();
-        assert!(errors.iter().any(|e| {
-            e.message
-                .contains("binary operators only work on integer types")
-        }));
-    }
-
     #[test]
     fn valid_if() {
         let src = "fn test() { if true { return; } }";

src/frontend/token.rs

@@ -53,6 +53,7 @@ pub enum TokenKind {
     Identifier,
     IntegerLit,
     BooleanLit,
+    FloatLit,
 
     // Keywords
     Fn,
@@ -73,6 +74,8 @@ pub enum TokenKind {
     U16,
     U32,
     U64,
+    F32,
+    F64,
     Bool,
 
     // Operators
@@ -115,6 +118,7 @@ impl Display for TokenKind {
             TokenKind::Identifier => "an identifier",
             TokenKind::IntegerLit => "an integer",
             TokenKind::BooleanLit => "a boolean",
+            TokenKind::FloatLit => "a float",
             TokenKind::Fn => "`fn`",
             TokenKind::If => "`if`",
             TokenKind::Else => "`else`",
@@ -131,6 +135,8 @@ impl Display for TokenKind {
             TokenKind::U16 => "`u16`",
             TokenKind::U32 => "`u32`",
             TokenKind::U64 => "`u64`",
+            TokenKind::F32 => "`f32`",
+            TokenKind::F64 => "`f64`",
             TokenKind::Bool => "`bool`",
             TokenKind::Plus => "`+`",
             TokenKind::Minus => "`-`",

src/middle/builder.rs

@@ -343,6 +343,9 @@ impl FuncBuilder {
             TypedExprKind::Integer { value } => {
                 Operand::Constant(ConstantValue::Integer(*value, expr.ty.clone()))
             }
+            TypedExprKind::Float { value } => {
+                Operand::Constant(ConstantValue::Float(*value, expr.ty.clone()))
+            }
             TypedExprKind::Boolean { value } => Operand::Constant(ConstantValue::Boolean(*value)),
             TypedExprKind::Unary { op, expr: inner } => {
                 let inner_op = self.lower_expr(inner);

src/middle/fold.rs

@@ -94,6 +94,7 @@ fn evaluate_unary(op: UnaryOp, val: &ConstantValue) -> Option<ConstantValue> {
         (UnaryOp::Neg, ConstantValue::Integer(v, ty)) => {
             Some(ConstantValue::Integer(v.wrapping_neg(), ty.clone()))
         }
+        (UnaryOp::Neg, ConstantValue::Float(v, ty)) => Some(ConstantValue::Float(-v, ty.clone())),
         (UnaryOp::Not, ConstantValue::Boolean(b)) => Some(ConstantValue::Boolean(!b)),
         _ => None,
     }
@@ -165,6 +166,20 @@ fn evaluate_binary(
             _ => None,
         },
 
+        (ConstantValue::Float(l, ty), ConstantValue::Float(r, _)) => match op {
+            BinaryOp::Add => Some(ConstantValue::Float(l + r, ty.clone())),
+            BinaryOp::Sub => Some(ConstantValue::Float(l - r, ty.clone())),
+            BinaryOp::Mul => Some(ConstantValue::Float(l * r, ty.clone())),
+            BinaryOp::Div => Some(ConstantValue::Float(l / r, ty.clone())),
+            BinaryOp::Rem => Some(ConstantValue::Float(l % r, ty.clone())),
+            BinaryOp::Eq => Some(ConstantValue::Boolean(l == r)),
+            BinaryOp::Neq => Some(ConstantValue::Boolean(l != r)),
+            BinaryOp::Lt => Some(ConstantValue::Boolean(l < r)),
+            BinaryOp::Le => Some(ConstantValue::Boolean(l <= r)),
+            BinaryOp::Gt => Some(ConstantValue::Boolean(l > r)),
+            BinaryOp::Ge => Some(ConstantValue::Boolean(l >= r)),
+        },
+
         _ => None,
     }
 }

src/middle/mir.rs

@@ -72,6 +72,7 @@ pub enum Operand {
 #[derive(Debug, Clone)]
 pub enum ConstantValue {
     Integer(u64, Ty),
+    Float(f64, Ty),
     Boolean(bool),
 }
 

tests/float_comparisons.test

@@ -0,0 +1,24 @@
+[code]
+fn is_less_f64(x: f64, y: f64) -> bool {
+    return x < y;
+}
+
+fn is_greater_eq_f32(x: f32, y: f32) -> bool {
+    return x >= y;
+}
+
+[harness]
+#include <stdbool.h>
+
+extern bool is_less_f64(double x, double y);
+extern bool is_greater_eq_f32(float x, float y);
+
+int main() {
+    if (!is_less_f64(3.14, 5.0)) return 1;
+    if (is_less_f64(5.0, 3.14)) return 2;
+    if (!is_greater_eq_f32(2.5f, 2.5f)) return 3;
+    return 0;
+}
+
+[expected_return_code]
+0

tests/float_f32_arithmetic.test

@@ -0,0 +1,20 @@
+[code]
+fn test_f32(x: f32, y: f32) -> f32 {
+    let z: f32 = 1.5;
+    // (4.0 + 2.0) * 1.5 - (4.0 / 2.0) = 6.0 * 1.5 - 2.0 = 9.0 - 2.0 = 7.0
+    return (x + y) * z - (x / y);
+}
+
+[harness]
+extern float test_f32(float x, float y);
+
+int main() {
+    float result = test_f32(4.0f, 2.0f);
+    if (result == 7.0f) {
+        return 0;
+    }
+    return 1;
+}
+
+[expected_return_code]
+0

tests/float_f64_arithmetic.test

@@ -0,0 +1,20 @@
+[code]
+fn test_f64(x: f64, y: f64) -> f64 {
+    let z: f64 = 2.5;
+    // (7.0 - 2.0) / 2.5 + (7.0 * 2.0) = 5.0 / 2.5 + 14.0 = 2.0 + 14.0 = 16.0
+    return (x - y) / z + (x * y);
+}
+
+[harness]
+extern double test_f64(double x, double y);
+
+int main() {
+    double result = test_f64(7.0, 2.0);
+    if (result == 16.0) {
+        return 0;
+    }
+    return 1;
+}
+
+[expected_return_code]
+0

tests/float_parsing.test

@@ -0,0 +1,17 @@
+[code]
+fn test_exponents() -> f64 {
+    let a: f64 = 1e3;
+    let b: f64 = 2.5e-1;
+    return a * b; // 1000.0 * 0.25 = 250.0
+}
+
+[harness]
+extern double test_exponents();
+
+int main() {
+    if (test_exponents() == 250.0) return 0;
+    return 1;
+}
+
+[expected_return_code]
+0

tests/float_unary.test

@@ -0,0 +1,21 @@
+[code]
+fn negate_f32(x: f32) -> f32 {
+    return -x;
+}
+
+fn negate_f64(x: f64) -> f64 {
+    return -x;
+}
+
+[harness]
+extern float negate_f32(float x);
+extern double negate_f64(double x);
+
+int main() {
+    if (negate_f32(3.5f) != -3.5f) return 1;
+    if (negate_f64(-4.2) != 4.2) return 2;
+    return 0;
+}
+
+[expected_return_code]
+0