core: Add support for '#ifdef' directive

Signed-off-by: Ian Moffett <ian@mirocom.org>

core/parser.c

@@ -158,6 +158,69 @@ parse_define(struct rifle_state *state, struct token *tok)
     return 0;
 }
 
+/*
+ * Skip to an '#endif' token
+ *
+ * @state: Compiler state
+ * @tok:   Last token
+ *
+ * Returns zero on success
+ */
+static int
+parse_skip_to_endif(struct rifle_state *state, struct token *tok)
+{
+    if (state == NULL || tok == NULL) {
+        return -1;
+    }
+
+    while (tok->type != TT_ENDIF) {
+        if (parse_scan(state, tok) < 0) {
+            ueof(state);
+            return -1;
+        }
+    }
+
+    return 0;
+}
+
+/*
+ * Parse an '#ifdef' preprocessing directive
+ *
+ * @state: Compiler state
+ * @tok:   Last token
+ *
+ * Returns zero on success
+ */
+static int
+parse_ifdef(struct rifle_state *state, struct token *tok)
+{
+    struct symbol *symbol;
+
+    if (state == NULL || tok == NULL) {
+        return -1;
+    }
+
+    if (tok->type != TT_IFDEF) {
+        return -1;
+    }
+
+    /* EXPECT <IDENT> */
+    if (parse_expect(state, TT_IDENT, tok) < 0) {
+        return -1;
+    }
+
+    symbol = symbol_from_name(
+        &state->symtab,
+        tok->s
+    );
+
+    if (symbol == NULL) {
+        parse_skip_to_endif(state, tok);
+    }
+
+    return 0;
+}
+
 /*
  * Handle the preprocessing stage
  *
@@ -175,6 +238,14 @@ parse_preprocess(struct rifle_state *state)
                 return -1;
             }
 
+            break;
+        case TT_IFDEF:
+            if (parse_ifdef(state, &tok) < 0) {
+                return -1;
+            }
+
+            break;
+        case TT_ENDIF:
             break;
         default:
             tokbuf_push(&state->tokbuf, &tok);
@@ -185,6 +256,18 @@ parse_preprocess(struct rifle_state *state)
     return 0;
 }
 
+static int
+parse_begin(struct rifle_state *state)
+{
+    struct token tok;
+
+    while (parse_scan(state, &tok) == 0) {
+        printf("got token %s\n", tokstr(&tok));
+    }
+
+    return 0;
+}
+
 int
 parser_parse(struct rifle_state *state)
 {
@@ -199,6 +282,13 @@ parser_parse(struct rifle_state *state)
             return -1;
         }
 
+        break;
+    case 1:
+        /* Parse loop */
+        if (parse_begin(state) < 0) {
+            return -1;
+        }
+
         break;
     }
 

core/rifle.c

@@ -39,9 +39,11 @@ compile(const char *in_path)
         return -1;
     }
 
-    if (parser_parse(&state) < 0) {
-        rifle_state_destroy(&state);
-        return -1;
+    for (int i = 0; i < 2; ++i) {
+        if (parser_parse(&state) < 0) {
+            rifle_state_destroy(&state);
+            return -1;
+        }
     }
 
     rifle_state_destroy(&state);