Makefile

@@ -20,7 +20,6 @@ OBJS = \
 
 LIBS = \
 	-r lib/lists.scm \
-	-r lib/logic.scm \
 	-r lib/io.scm    \
 	-r lib/type_predicates.scm
 

lib/logic.scm

@@ -1 +0,0 @@
-(define (not x) (if x #false #true))

src/builtins.c

@@ -31,6 +31,8 @@ static struct Object *func_equal_QN(size_t args_count, struct Object **args_arra
 static struct Object *func_number_TO_string(size_t args_count, struct Object **args_array);
 static struct Object *func_string_TO_symbol(size_t args_count, struct Object **args_array);
 static struct Object *func_symbol_TO_string(size_t args_count, struct Object **args_array);
+// Logical operators
+static struct Object *func_not(size_t args_count, struct Object **args_array);
 // Arithmetic operators
 static struct Object *func_EQ(size_t args_count, struct Object **args_array);
 static struct Object *func_PLUS(size_t args_count, struct Object **args_array);
@@ -60,6 +62,8 @@ static struct Object builtins[] = {
     { .type = TYPE_PROCEDURE, .procedure = { "number->string",  func_number_TO_string      } },
     { .type = TYPE_PROCEDURE, .procedure = { "string->symbol",  func_string_TO_symbol      } },
     { .type = TYPE_PROCEDURE, .procedure = { "symbol->string",  func_symbol_TO_string      } },
+    // Logical operators
+    { .type = TYPE_PROCEDURE, .procedure = { "not",             func_not                   } },
     // Arithmetic operators
     { .type = TYPE_PROCEDURE, .procedure = { "=",               func_EQ                    } },
     { .type = TYPE_PROCEDURE, .procedure = { "+",               func_PLUS                  } },
@@ -451,6 +455,18 @@ struct Object *func_symbol_TO_string(
     return Object_new_string(symbol->s);
 }
 
+/*********************
+ * Logical operators *
+ *********************/
+
+struct Object *func_not(
+    const size_t args_count,
+    struct Object **const args_array
+) {
+    assert(args_count == 1);
+    return Object_new_boolean(Object_is_false(args_array[0]));
+}
+
 /************************
  * Arithmetic operators *
  ************************/

src/syntax.c

@@ -89,7 +89,7 @@ struct Object *syntax_if(
     struct Object *const environment
 ) {
     assert(Object_is_pair(args));
-    struct Object *const cond_expr = args->pair.car;
+    struct Object *const cond = args->pair.car;
     struct Object *const then_else_list = args->pair.cdr;
     assert(then_else_list);
     assert(Object_is_pair(then_else_list));
@@ -100,7 +100,7 @@ struct Object *syntax_if(
     struct Object *const else_branch = else_list->pair.car;
     assert(OBJECT_IS_NULL(else_list->pair.cdr));
 
-    if (Object_is_false(eval(cond_expr, environment))) {
+    if (Object_is_false(cond)) {
         return eval(else_branch, environment);
     } else {
         return eval(then_branch, environment);

tests/arcana/builtin.scm

@@ -26,6 +26,8 @@
 (assert-true (procedure? (arcana/builtin 'number->string)))
 (assert-true (procedure? (arcana/builtin 'string->symbol)))
 (assert-true (procedure? (arcana/builtin 'symbol->string)))
+; Logical operators
+(assert-true (procedure? (arcana/builtin 'not)))
 ; Arithmetic operators
 (assert-true (procedure? (arcana/builtin '=)))
 (assert-true (procedure? (arcana/builtin '+)))