From a740c9af25df49524a8a08bdc5de35825c87dec5 Mon Sep 17 00:00:00 2001
From: Hojun Choi <hojuchoi@student.42seoul.kr>
Date: Mon, 2 Sep 2024 19:15:21 +0900
Subject: [PATCH] add arithmetic operators

---
 README.md |  1 +
 bltin.c   |  9 +++++++++
 dat.h     |  3 +++
 eval.c    | 49 +++++++++++++++++++++++++++++++++++++++++++++++++
 obj.c     |  4 ++--
 parser.c  |  2 +-
 6 files changed, 65 insertions(+), 3 deletions(-)
 create mode 100644 README.md

diff --git a/README.md b/README.md
new file mode 100644
index 0000000..a8620eb
--- /dev/null
+++ b/README.md
@@ -0,0 +1 @@
+(define fac (lambda (n) (if ((eq n 0) 1) (1 (* n (fac (+ n -1)))))))
diff --git a/bltin.c b/bltin.c
index 1c504d2..8fec558 100644
--- a/bltin.c
+++ b/bltin.c
@@ -4,6 +4,9 @@
 Object Nil	= (Object){.type=OSYMBOL, .sym="nil"};
 Object Minus= (Object){.type=OBLTIN, .sym="-"};
 Object Plus	= (Object){.type=OBLTIN, .sym="+"};
+Object Mul	= (Object){.type=OBLTIN, .sym="*"};
+Object Div	= (Object){.type=OBLTIN, .sym="/"};
+Object Mod	= (Object){.type=OBLTIN, .sym="%"};
 Object Lambda= (Object){.type=OBLTIN, .sym="lambda"};
 Object Car	= (Object){.type=OBLTIN, .sym="car"};
 Object Cdr	= (Object){.type=OBLTIN, .sym="cdr"};
@@ -15,6 +18,9 @@ Object Eq	= (Object){.type=OBLTIN, .sym="eq"};
 Object If	= (Object){.type=OBLTIN, .sym="if"};
 
 extern Object* fnplus(Object *, Object *);
+extern Object* fnmul(Object *, Object *);
+extern Object* fndiv(Object *, Object *);
+extern Object* fnmod(Object *, Object *);
 extern Object* fnlambda(Object *, Object *);
 extern Object* fndefine(Object *, Object *);
 extern Object* fnsetq(Object *, Object *);
@@ -37,6 +43,9 @@ bltinlookup(Object *obj)
 	}bltins[] = {
 		{&Lambda , fnlambda},
 		{&Plus , fnplus},
+		{&Mul , fnmul},
+		{&Mod , fnmod},
+		{&Div , fndiv},
 		{&Define ,fndefine},
 		{&Setq ,fnsetq},
 		{&Quote ,fnquote},
diff --git a/dat.h b/dat.h
index cd201f4..ed12710 100644
--- a/dat.h
+++ b/dat.h
@@ -84,6 +84,9 @@ extern GC *gc;
 extern Object Nil;
 extern Object Minus;
 extern Object Plus;
+extern Object Mul;
+extern Object Div;
+extern Object Mod;
 extern Object Lambda;
 extern Object Car;
 extern Object Cdr;
diff --git a/eval.c b/eval.c
index ec6bdf3..6ca7241 100644
--- a/eval.c
+++ b/eval.c
@@ -160,6 +160,55 @@ fnplus(Object *env, Object *list)
     }
 }
 
+Object*
+fnmul(Object *env, Object *list)
+{
+    Object *p=evallist(env, list);
+    if(p->car->type != OINT)
+        error("* take only [INT]");
+	long sum = p->car->num;
+    for(p=p->cdr;p!=&Nil; p=p->cdr){
+		if(p->car->type != OINT)
+			error("* take only [INT]");
+		sum *= p->car->num;
+	}
+	return newint(gc, sum);
+}
+
+Object*
+fndiv(Object *env, Object *list)
+{
+    Object *p=evallist(env, list);
+    if(p->car->type != OINT)
+        error("/ take only [INT]");
+	long sum = p->car->num;
+    for(p=p->cdr;p!=&Nil; p=p->cdr){
+		if(p->car->type != OINT)
+			error("/ take only [INT]");
+        if(p->car->num == 0)
+            error("Can't div zero");
+		sum /= p->car->num;
+	}
+	return newint(gc, sum);
+}
+
+Object*
+fnmod(Object *env, Object *list)
+{
+    Object *p=evallist(env, list);
+    if(p->car->type != OINT)
+        error("%% take only [INT]");
+	long sum = p->car->num;
+    for(p=p->cdr;p!=&Nil; p=p->cdr){
+		if(p->car->type != OINT)
+			error("%% take only [INT]");
+        if(p->car->num == 0)
+            error("Can't mod zero");
+		sum %= p->car->num;
+	}
+	return newint(gc, sum);
+}
+
 long
 eq(Object *env, Object *a, Object *b)
 {
diff --git a/obj.c b/obj.c
index 631d42c..8017c27 100644
--- a/obj.c
+++ b/obj.c
@@ -51,8 +51,8 @@ Object*
 newsymbol(GC *gc, char *str, int len)
 {
 	static Object *syms[] = {
-		&Nil,  &Minus, &Plus, &Lambda, &Car, &Cdr, &Quote, &Cons,
-        &Define, &Setq, &Eq, &If,
+		&Nil,  &Minus, &Plus, &Mul, &Mod, &Div,
+        &Lambda, &Car, &Cdr, &Quote, &Cons, &Define, &Setq, &Eq, &If,
 	};
 	for(int i = 0; i < sizeof(syms)/sizeof(syms[0]); ++i){
 		Object *c = syms[i];
diff --git a/parser.c b/parser.c
index d3b543d..badedaf 100644
--- a/parser.c
+++ b/parser.c
@@ -6,7 +6,7 @@
 
 #define SYMBOL_LEN 64
 
-const char symbolchars[] = "*-=+<>'";
+const char symbolchars[] = "*/%-=+<>'";
 
 static Object* lparlist(void);
 static Object* list(void);