If statement expression

semantic/src/scope.rs

@@ -82,8 +82,7 @@ impl LocalScope {
         }
     }
 
-    pub fn with_block(self: &Arc<Self>, block: &mut parser::ast::Block) {
-        for statement in &mut block.0 {
+    pub fn with_statement(self: &Arc<Self>, statement: &mut Statement) {
         match statement {
             Statement::Block(b) => self.clone().with_block(b),
             Statement::VarDecl { name, init, .. } => {
@@ -103,9 +102,25 @@ impl LocalScope {
             Statement::Expression(e) => {
                 self.get_type_from_expr(e);
             }
+            Statement::If {
+                condition,
+                then_branch,
+                else_branch,
+            } => {
+                self.get_type_from_expr(condition);
+                self.clone().with_statement(then_branch);
+                if let Some(else_branch) = else_branch {
+                    self.clone().with_statement(else_branch);
+                }
+            }
             _ => {}
         }
     }
+
+    pub fn with_block(self: &Arc<Self>, block: &mut parser::ast::Block) {
+        for statement in &mut block.0 {
+            self.with_statement(statement);
+        }
     }
 
     pub fn walk_postfixes(
@@ -137,6 +152,24 @@ impl LocalScope {
                     }
                     _ => unimplemented!(),
                 },
+                Postfix::Binary(op, right) => match op {
+                    parser::ast::BinaryOp::Equal
+                    | parser::ast::BinaryOp::NotEqual
+                    | parser::ast::BinaryOp::GreaterThan
+                    | parser::ast::BinaryOp::LessThan
+                    | parser::ast::BinaryOp::GreaterThanOrEqual
+                    | parser::ast::BinaryOp::LessThanOrEqual => {
+                        self.get_type_from_expr(right)?;
+                        current_type = Arc::new(TypeRef::Name("bool".to_string()));
+                    }
+                    parser::ast::BinaryOp::Plus
+                    | parser::ast::BinaryOp::Minus
+                    | parser::ast::BinaryOp::Multiply
+                    | parser::ast::BinaryOp::Divide
+                    | parser::ast::BinaryOp::Modulo => {
+                        self.get_type_from_expr(right)?;
+                    }
+                },
                 _ => unimplemented!(),
             }
         }

test/src/main.ms

@@ -3,5 +3,20 @@ package main;
 import "fmt";
 
 function main() {
+    doSomething();
+    let a = doSomethingElse();
+
+    if (a + 1 == 67 + 1) {
+        fmt.println(a);
+    }
+}
+
+function doSomething() {
     fmt.println("hello");
 }
+
+function doSomethingElse(): int {
+    fmt.println("world");
+
+    return 67;
+}