Add p_set_position()

spec/test_set_position.d

@@ -0,0 +1,66 @@
+import testparser;
+import std.stdio;
+import testutils;
+
+int main()
+{
+    return 0;
+}
+
+unittest
+{
+    /* See test_set_position.c for details. */
+
+    /* Baseline: without p_set_position(), positions start at (1, 1). */
+    {
+        string input = "ab";
+        p_context_t * context = p_context_new(input);
+        p_position_t pos = p_position(context);
+        assert(pos.row == 1);
+        assert(pos.col == 1);
+        p_token_info_t token_info;
+        assert(p_lex(context, &token_info) == P_SUCCESS);
+        assert(token_info.token == TOKEN_a);
+        assert(token_info.position.row == 1);
+        assert(token_info.position.col == 1);
+    }
+
+    /* p_set_position() overrides the initial position. */
+    {
+        string input = "ab";
+        p_context_t * context = p_context_new(input);
+        p_set_position(context, p_position_t(5u, 20u));
+        p_position_t pos = p_position(context);
+        assert(pos.row == 5);
+        assert(pos.col == 20);
+        p_token_info_t token_info;
+        assert(p_lex(context, &token_info) == P_SUCCESS);
+        assert(token_info.token == TOKEN_a);
+        assert(token_info.position.row == 5);
+        assert(token_info.position.col == 20);
+        assert(p_lex(context, &token_info) == P_SUCCESS);
+        assert(token_info.token == TOKEN_b);
+        assert(token_info.position.row == 5);
+        assert(token_info.position.col == 21);
+    }
+
+    /* p_set_position() before a full parse still parses successfully. */
+    {
+        string input = "ab";
+        p_context_t * context = p_context_new(input);
+        p_set_position(context, p_position_t(3u, 7u));
+        assert(p_parse_Start(context) == P_SUCCESS);
+    }
+
+    /* p_set_position() before a parse that fails: error position is
+     * relative to the set starting point. */
+    {
+        string input = "aa";
+        p_context_t * context = p_context_new(input);
+        p_set_position(context, p_position_t(10u, 2u));
+        assert(p_parse_Start(context) == P_UNEXPECTED_TOKEN);
+        p_position_t err_pos = p_position(context);
+        assert(err_pos.row == 10);
+        assert(err_pos.col == 3);
+    }
+}