From b9712dacfbe3c6d1495e2e1362e7622fc2d42590 Mon Sep 17 00:00:00 2001
From: janis <janis@nirgendwo.xyz>
Date: Sun, 2 Nov 2025 00:30:00 +0100
Subject: [PATCH] fix ast gen with nested binary ops

---
 lang/src/ast.asm  | 54 +++++++++++++++++------------------------------
 lang/tests/ast.rs |  5 +++++
 2 files changed, 24 insertions(+), 35 deletions(-)

diff --git a/lang/src/ast.asm b/lang/src/ast.asm
index 31bf739..f14f7a4 100644
--- a/lang/src/ast.asm
+++ b/lang/src/ast.asm
@@ -4,11 +4,11 @@ default rel
 %include "src/ast.inc"
 
 section .rdata
-    PRECEDENCE_ADD equ 90
-    PRECEDENCE_SUB equ 90
-    PRECEDENCE_MUL equ 100
-    PRECEDENCE_DIV equ 100
-    PRECEDENCE_REM equ 100
+    PRECEDENCE_ADD dw 90
+    PRECEDENCE_SUB dw 90
+    PRECEDENCE_MUL dw 100
+    PRECEDENCE_DIV dw 100
+    PRECEDENCE_REM dw 100
 
 section .text
 extern vec_init_with
@@ -28,6 +28,7 @@ extern tokeniser_init
 extern find_lexeme
 extern peek_lexeme
 extern expect_token
+extern skip_token
 extern unwrap_token
 extern peek_expect_token
 
@@ -400,6 +401,7 @@ parse_primary_expr:
 parse_binary_expr:
     push rbp
     mov rbp, rsp
+    push rbx
 
     ; size: 24, align: 8
     ; start-structs
@@ -438,40 +440,19 @@ parse_binary_expr:
     lea rdi, [rsp + 32]         ; lexeme
     call peek_lexeme
     mov rax, [rsp + 32]
+    mov byte [rsp + 16], al     ; operator
+    mov bx, -1
     cmp al, TOKEN_PLUS
-    je .add
+    cmove bx, word [rel PRECEDENCE_ADD]
     cmp al, TOKEN_MINUS
-    je .sub
+    cmove bx, word [rel PRECEDENCE_SUB]
     cmp al, TOKEN_STAR
-    je .mul
+    cmove bx, word [rel PRECEDENCE_MUL]
     cmp al, TOKEN_SLASH
-    je .div
-    jmp .done
-
-.add:
-    mov dil, TOKEN_PLUS
-    call unwrap_token
-    mov byte [rsp + 16], TOKEN_PLUS
-    mov byte [rsp + 18], PRECEDENCE_ADD
-    jmp .right
-.sub:
-    mov dil, TOKEN_MINUS
-    call unwrap_token
-    mov byte [rsp + 16], TOKEN_MINUS
-    mov byte [rsp + 18], PRECEDENCE_SUB
-    jmp .right
-.mul:
-    mov dil, TOKEN_STAR
-    call unwrap_token
-    mov byte [rsp + 16], TOKEN_STAR
-    mov byte [rsp + 18], PRECEDENCE_MUL
-    jmp .right
-.div:
-    mov dil, TOKEN_SLASH
-    call unwrap_token
-    mov byte [rsp + 16], TOKEN_SLASH
-    mov byte [rsp + 18], PRECEDENCE_DIV
-    jmp .right
+    cmove bx, word [rel PRECEDENCE_DIV]
+    cmp bx, -1
+    je .done
+    mov byte [rsp + 18], bl
 
 .right:
     mov dil, [rsp + 17]
@@ -479,6 +460,8 @@ parse_binary_expr:
     cmp al, dil                 ; our_precedence <= upper_precedence
     jle .done
 
+    call skip_token             ; consume operator
+
     mov rdi, [rsp]         ; Ast
     mov sil, [rsp + 18]
     call parse_binary_expr
@@ -529,6 +512,7 @@ parse_binary_expr:
     mov rax, [rsp + 8]          ; left
     movzx rdx, byte [rsp + 19]  ; left_placeness
     add rsp, 64
+    pop rbx
     pop rbp
     ret
 
diff --git a/lang/tests/ast.rs b/lang/tests/ast.rs
index 29c0603..469aa54 100644
--- a/lang/tests/ast.rs
+++ b/lang/tests/ast.rs
@@ -60,6 +60,11 @@ fn main() {
         };
     }
 
+    print_ast(
+        b"fn main() -> void { return 1 * 2 + 3 * 4; }",
+        |ast| unsafe { parse_func(ast) },
+    );
+
     print_ast(b"3 + 4", |ast| unsafe { parse_expr(ast) });
     print_ast(b"fn main() -> void { return 1 + 2; }", |ast| unsafe {
         parse_func(ast)