From a0811a84e381d64069834d5c0097669d66f4b627 Mon Sep 17 00:00:00 2001
From: Shagun Agrawal <agrawalshagun07@gmail.com>
Date: Sat, 10 Aug 2024 11:27:28 +0530
Subject: Add parsing and tacky generation for binary operators

Fix grammar to handle left associativity

Update parser for binary operators

Update tacky generation for binary operators
---
 src/cljcc/parser.clj | 46 +++++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 41 insertions(+), 5 deletions(-)

(limited to 'src/cljcc/parser.clj')

diff --git a/src/cljcc/parser.clj b/src/cljcc/parser.clj
index 8852d91..bee6d32 100644
--- a/src/cljcc/parser.clj
+++ b/src/cljcc/parser.clj
@@ -1,6 +1,7 @@
 (ns cljcc.parser
   (:require
-   [instaparse.core :as insta]))
+   [instaparse.core :as insta]
+   [clojure.pprint :as pp]))
 
 (def whitespace
   (insta/parser
@@ -14,11 +15,32 @@
     function = #'int\\b' identifier <'('> #'void\\b' <')'> <'{'> statement <'}'>
     statement = #'return\\b' exp <';'>
     exp = exp-prime
-    <exp-prime> = constant | unop-exp | <'('> exp-prime <')'>
+    <exp-prime> = <'('> exp-prime <')'> | unop-exp | constant-exp
     unop-exp = unop exp
     unop = #'-' | #'~'
     identifier = #'[a-zA-Z_]\\w*\\b'
-    constant = #'[0-9]+\\b'
+    constant-exp = #'[0-9]+\\b'
+    keyword = #'int\\b' | #'return\\b' | #'void\\b'"
+   :auto-whitespace whitespace))
+
+(def binop-parser
+  (insta/parser
+   "<program> = function+
+    function = #'int\\b' identifier <'('> #'void\\b' <')'> <'{'> statement <'}'>
+    statement = #'return\\b' exp <';'>
+    exp = exp-prime
+    <exp-prime> = mul-div-mod | add-exp | sub-exp
+    add-exp = exp-prime <'+'> mul-div-mod
+    sub-exp = exp-prime <'-'> mul-div-mod
+    <mul-div-mod> = term | mul-exp | div-exp | mod-exp
+    mul-exp = mul-div-mod <'*'> term
+    div-exp = mul-div-mod <'/'> term
+    mod-exp = mul-div-mod <'%'> term
+    <term> = constant-exp | unary-exp | <'('> exp-prime <')'>
+    unary-exp = unary-operator term
+    unary-operator = #'-' | #'~'
+    identifier = #'[a-zA-Z_]\\w*\\b'
+    constant-exp = #'[0-9]+\\b'
     keyword = #'int\\b' | #'return\\b' | #'void\\b'"
    :auto-whitespace whitespace))
 
@@ -26,7 +48,7 @@
   (not (insta/failure? result)))
 
 (defn parse [source]
-  (c-parser source))
+  (binop-parser source))
 
 (comment
 
@@ -41,6 +63,20 @@
    return -(((((10)))));
    }")
 
-  (parse "int main(void) {
+  (pp/pprint (parse "int main(void) {
    return -(((((10)))));
    }"))
+
+  (pp/pprint
+   (binop-parser
+    "int main(void) {
+    return -1 * 2 - ~3 * -(-4 + 5);
+     }"))
+
+  (pp/pprint
+   (binop-parser
+    "int main(void) {
+       return -2;
+     }"))
+
+  ())
-- 
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