Coerce eq and string=.

Fix regression in prim_minus

Author: NJdevPro

src/minilisp.c

@@ -674,11 +674,24 @@ static Obj *PRIM_OP(void *root, Obj **env, Obj **list) {            \
 
 // (+ <integer> ...)
 PRIM_ARITHMETIC_OP(prim_plus, +, += )
-PRIM_ARITHMETIC_OP(prim_minus, -, -= )
 PRIM_ARITHMETIC_OP(prim_mult, *, *= )
 PRIM_ARITHMETIC_OP(prim_div , /, /= )
 PRIM_ARITHMETIC_OP(prim_modulo, %, %= )
 
+// (- <integer> ...)
+static Obj *prim_minus(void *root, Obj **env, Obj **list) {
+    Obj *args = eval_list(root, env, list);
+    for (Obj *p = args; p != Nil; p = p->cdr)
+        if (p->car->type != TINT)
+            error("- takes only numbers", (*list)->line_num);
+    if (args->cdr == Nil)
+        return make_int(root, -args->car->value);
+    long long r = args->car->value;
+    for (Obj *p = args->cdr; p != Nil; p = p->cdr)
+        r -= p->car->value;
+    return make_int(root, r);
+}
+
 // (op <integer> <integer>)
 #define PRIM_COMPARISON_OP(PRIM_OP, OP)                             \
 static Obj *PRIM_OP(void *root, Obj **env, Obj **list) {            \
@@ -860,9 +873,17 @@ static Obj *prim_if(void *root, Obj **env, Obj **list) {
 // (eq expr expr)
 static Obj *prim_eq(void *root, Obj **env, Obj **list) {
     if (length(*list) != 2)
-        error("Malformed eq", (*list)->line_num);
+        error("eq takes 2 arguments only", (*list)->line_num);
     Obj *values = eval_list(root, env, list);
-    return values->car == values->cdr->car ? True : Nil;
+    Obj *first = values->car;
+    Obj *second = values->cdr->car;
+    if (first->type == TSTRING){
+        if (second->type == TSTRING)
+            return strcmp(first->name, second->name) == 0 ? True : Nil;
+        else
+            error("The 2 arguments of eq must be of the same type", (*list)->line_num);
+    } 
+    return first == second ? True : Nil;
 }
 
 // String primitives
@@ -931,18 +952,6 @@ static Obj *prim_string_to_symbol(void *root, Obj **env, Obj **list) {
     return intern(root, args->car->name);
 }
 
-// String comparison
-static Obj *prim_string_eq(void *root, Obj **env, Obj **list) {
-    Obj *args = eval_list(root, env, list);
-    if (length(args) != 2)
-        error("string= requires 2 arguments", (*list)->line_num);
-    
-    if (args->car->type != TSTRING || args->cdr->car->type != TSTRING)
-        error("string= arguments must be strings", (*list)->line_num);
-        
-    return strcmp(args->car->name, args->cdr->car->name) == 0 ? True : Nil;
-}
-
 static void add_primitive(void *root, Obj **env, char *name, Primitive *fn) {
     DEFINE2(sym, prim);
     *sym = intern(root, name);
@@ -994,7 +1003,6 @@ static void define_primitives(void *root, Obj **env) {
     add_primitive(root, env, "string-concat", prim_string_concat);
     add_primitive(root, env, "symbol->string", prim_symbol_to_string);
     add_primitive(root, env, "string->symbol", prim_string_to_symbol);
-    add_primitive(root, env, "string=", prim_string_eq);
     add_primitive(root, env, "load", prim_load);
     add_primitive(root, env, "exit", prim_exit);
 }

test.sh

@@ -146,6 +146,8 @@ run eq t "(eq 'foo 'foo)"
 run eq t "(eq + +)"
 run eq '()' "(eq 'foo 'bar)"
 run eq '()' "(eq + 'bar)"
+run eq '()' '(eq "hello" "Hello")'
+run eq t  '(eq "hello" "hello")'
 
 # gensym
 run gensym G__0 '(gensym)'
@@ -165,8 +167,6 @@ run restargs '(3 5 7)' '(defun f (x . y) (cons x y)) (f 3 5 7)'
 run restargs '(3)'    '(defun f (x . y) (cons x y)) (f 3)'
 
 # strings
-run string= '()' '(string= "hello" "Hello")'
-run string= t  '(string= "hello" "hello")'
 run 'symbol->string' 'twelve' "
   (define twelve 12)
   (symbol->string 'twelve)"