feat: Add first input builtin

compiler/Makefile

@@ -11,7 +11,7 @@ MAKE     = make
 
 PLUGINS  =
 BUILTINS = obj/builtins/builtins.o obj/builtins/numbers.o \
-           obj/builtins/print.o
+           obj/builtins/io.o
 OBJS     = obj/lex.yy.o obj/y.tab.o obj/codegen.o obj/codegen_expr.o \
            obj/codegen_stat.o obj/ast.o obj/band.o obj/plugins.o obj/scope.o \
            $(PLUGINS) $(BUILTINS) obj/main.o

compiler/src/builtins/builtins.c

@@ -4,15 +4,19 @@
 
 #define decl(n) region_t* n(FILE*, scope_t*, size_t, region_t**)
 
-decl(to_str);
 decl(print);
+decl(read_char);
+
+decl(to_str);
 
 static struct builtin_list_item {
     const char* name;
     builtin_t function;
 } builtins[] = {
-    {"to_str", to_str},
     {"print", print},
+    {"read_char", read_char},
+
+    {"to_str", to_str},
 };
 
 builtin_t find_builtin(const char* name) {

compiler/src/builtins/io.c

@@ -36,3 +36,14 @@ extern region_t* print(FILE* out, scope_t* scope, size_t argc, region_t** argv)
     region_t* result = scope_add_tmp(scope, 1);
     return result;
 }
+
+extern region_t* read_char(FILE* out, scope_t* scope, size_t argc, region_t** argv) {
+    if (argc != 0) {
+        panic("read_char() doesn't accept arguments");
+    }
+
+    region_t* result = scope_add_tmp(scope, 1);
+    move_to(result); input();
+
+    return result;
+}

compiler/src/parser.y

@@ -164,7 +164,11 @@ builtincall: ID OPENING_BRACKETS argumentlist CLOSING_BRACKETS
     }
 ;
 
-argumentlist: expr
+argumentlist: /* empty */
+                {
+                    $$ = builtin_call_expression_new();
+                }
+            | expr
                 {
                     $$ = builtin_call_expression_new();
                     builtin_call_expression_add_argument($$, $1);

compiler/test/cases/019-read-char.in

@@ -0,0 +1 @@
+print(read_char());

compiler/test/cases/019-read-char.out

@@ -0,0 +1 @@
+,.