From 426c4c005ea227b6953945c8bacb92575f5e392d Mon Sep 17 00:00:00 2001
From: ghostly_zsh <pokeball.181818@gmail.com>
Date: Thu, 15 Aug 2024 15:53:16 -0500
Subject: [PATCH] basic break and continue but it doesn't quite work

---
 kabel/src/codegen.rs         | 46 ++++++++++++++++++++++++++++++++++++
 kabel/src/main.rs            |  5 ++--
 kabel/src/name_resolution.rs |  2 ++
 3 files changed, 50 insertions(+), 3 deletions(-)

diff --git a/kabel/src/codegen.rs b/kabel/src/codegen.rs
index 057ffd4cf342e96ea8d98d23893a41b05e90ec32..222dc7bb633041e6601d5d2534ae1fba75d25618 100644
--- a/kabel/src/codegen.rs
+++ b/kabel/src/codegen.rs
@@ -3,6 +3,8 @@ use crate::{ast::{ASTType, BinOp, Lit, Name, UnOp, AST}, codegen_binary, codegen
 pub struct Codegen {
     pub vm: VM,
     pub scopes: Vec<usize>, // number of variables declared in the scope
+    break_stack: Vec<Vec<usize>>,
+    continue_stack: Vec<Vec<usize>>,
 }
 
 impl Codegen {
@@ -11,6 +13,8 @@ impl Codegen {
             vm: VM::new(Vec::new(), Vec::new(),
                 Vec::new(), text),
             scopes: vec![0],
+            break_stack: Vec::new(),
+            continue_stack: Vec::new(),
         }
     }
     pub fn visit(&mut self, ast: AST) {
@@ -24,6 +28,12 @@ impl Codegen {
             While(condition, block) => {
                 self.visit_while(*condition, *block);
             }
+            Break => {
+                self.visit_break(&ast);
+            }
+            Continue => {
+                self.visit_continue(&ast);
+            }
             If(condition, block, else_expr) => {
                 self.visit_if(*condition, *block, *else_expr);
             }
@@ -56,6 +66,9 @@ impl Codegen {
         }
     }
     pub fn visit_while(&mut self, condition: AST, block: AST) {
+        self.break_stack.push(Vec::new());
+        self.continue_stack.push(Vec::new());
+
         let end_jmp = self.vm.chunk.len();
         self.visit(condition.clone());
         self.vm.chunk.push(OpCode::JNE.into());
@@ -79,6 +92,39 @@ impl Codegen {
             self.vm.lines.last_mut().unwrap().1 += 3;
         }
         self.patch_jump(start_jmp_loc);
+
+        let breaks = self.break_stack.pop().expect("break stack empty on pop");
+        for loc in breaks {
+            self.patch_jump(loc);
+        }
+        let continues = self.continue_stack.pop().expect("continue stack empty on pop");
+        for loc in continues {
+            let jump = loc - end_jmp - 2;
+            self.vm.chunk[loc] = ((jump >> 8) & 0xFF) as u8;
+            self.vm.chunk[loc + 1] = (jump & 0xFF) as u8;
+        }
+    }
+    pub fn visit_break(&mut self, ast: &AST) {
+        self.vm.chunk.push(OpCode::JMP.into());
+        self.vm.chunk.push(0xFF);
+        self.vm.chunk.push(0xFF);
+        if self.vm.lines.last().unwrap().0 != ast.end_line {
+            self.vm.lines.push((ast.end_line, 3));
+        } else {
+            self.vm.lines.last_mut().unwrap().1 += 3;
+        }
+        self.break_stack.last_mut().expect("break not in a loop").push(self.vm.chunk.len()-2);
+    }
+    pub fn visit_continue(&mut self, ast: &AST) {
+        self.vm.chunk.push(OpCode::JMP_UP.into());
+        self.vm.chunk.push(0xFF);
+        self.vm.chunk.push(0xFF);
+        if self.vm.lines.last().unwrap().0 != ast.end_line {
+            self.vm.lines.push((ast.end_line, 3));
+        } else {
+            self.vm.lines.last_mut().unwrap().1 += 3;
+        }
+        self.continue_stack.last_mut().expect("continue not in a loop").push(self.vm.chunk.len()-2);
     }
     pub fn visit_if(&mut self, condition: AST, block: AST, else_expr: Option<AST>) {
         self.visit(condition.clone());
diff --git a/kabel/src/main.rs b/kabel/src/main.rs
index 7dbe4058ef88fb1545efcf072e7003485229ccd2..ca5ecc15529cee374297d9d509a8942d959cd00b 100644
--- a/kabel/src/main.rs
+++ b/kabel/src/main.rs
@@ -12,10 +12,9 @@ fn main() {
     let program =
 "
 for(var i = 0; i < 5; i++) {
-    var j = 0;
     print i;
-    print j;
-    j++;
+    continue;
+    print i;
 }
 ".to_string();
 
diff --git a/kabel/src/name_resolution.rs b/kabel/src/name_resolution.rs
index ca90f0b537a4ef1888782e3ac575e5ded5291f93..fdacaad4c285977917d60719d71da4444005da16 100644
--- a/kabel/src/name_resolution.rs
+++ b/kabel/src/name_resolution.rs
@@ -64,6 +64,8 @@ impl Resolver {
                 let block = self.visit(*block);
                 ast_from_ast!(While(Box::new(condition), Box::new(block)), ast, ast)
             }
+            Break => { ast_from_ast!(Break, ast, ast) }
+            Continue => { ast_from_ast!(Continue, ast, ast) }
             For(expr1, expr2, expr3, block) => {
                 let mut n_expr1 = None;
                 let mut n_expr2 = None;