propane/spec/test_parse_inner_nested.d

65 lines
2.0 KiB
D

import testparser;
import testutils;
/* Grammar: see test_parse_inner_nested.c. */
size_t mylexfn(p_context_t * context, p_token_info_t * out_token_info)
{
size_t result = p_lex(context, out_token_info);
if (result != P_SUCCESS)
{
return result;
}
if (out_token_info.token == TOKEN_lparen)
{
/* Nested parse of the parenthesized sub-expression, stopping at the
* closing ')' follow token. This re-enters the parser while the outer
* parse is suspended in this lex callback. */
p_token_t[] follow_tokens = [TOKEN_rparen];
size_t inner_result = p_parse_inner_Start(context, follow_tokens);
if (inner_result != P_SUCCESS)
{
return inner_result;
}
int value = p_result_Start(context);
/* p_parse_inner rewound the input so that ')' was not consumed; consume
* it now. */
p_token_info_t rparen_info;
size_t rparen_result = p_lex(context, &rparen_info);
assert(rparen_result == P_SUCCESS);
assert(rparen_info.token == TOKEN_rparen);
/* Replace the '(' token with a synthesized num carrying the nested
* parse result. */
out_token_info.token = TOKEN_num;
out_token_info.pvalue.v_default = value;
}
return P_SUCCESS;
}
int eval(string input)
{
p_context_t * context = p_context_new(input);
assert(p_parse(context) == P_SUCCESS);
int value = p_result(context);
p_context_delete(context);
return value;
}
int main()
{
return 0;
}
unittest
{
/* No parentheses: plain outer parse. */
assert_eq(5, eval("2 + 3"));
/* A single group evaluated by the nested parse. */
assert_eq(3, eval("(1 + 2)"));
/* A group in the middle of an outer expression. */
assert_eq(14, eval("2 + (3 + 4) + 5"));
/* Nested groups: the nested parse re-enters itself. */
assert_eq(37, eval("2 + (10 + (20 + 5))"));
assert_eq(15, eval("(1 + 2) + (3 + (4 + 5))"));
}