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detailed parser error reporting [wip - 1 example]

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This commit is contained in:
Roland Conybeare 2025-07-19 21:09:57 -05:00
commit 65a83cd77c
19 changed files with 256 additions and 84 deletions
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43
xo-reader/src/reader/reader.cpp
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@ -43,7 +43,7 @@ namespace xo {
/* each loop iterations reads one token */
/* read one token from input */
auto [tk, used_span, error] = this->tokenizer_.scan2(input, eof);
auto [tk, used_span, error1] = this->tokenizer_.scan2(input, eof);
log && log(xtag("consumed", used_span));
log && log(xtag("input.pre", input));
@ -53,45 +53,60 @@ namespace xo {
if (tk.is_valid()) {
/* forward just-read token to parser */
auto expr = this->parser_.include_token(tk);
auto parser_result = this->parser_.include_token(tk);
if (expr) {
if (parser_result.is_expression()) {
log && log(xtag("outcome", "victory!"),
xtag("expr", expr));
xtag("expr", parser_result.result_expr()));
/* token completes an expression -> victory */
return reader_result(expr, expr_span, parser_.stack_size(), reader_error());
return reader_result(parser_result.result_expr(),
expr_span, parser_.stack_size(), reader_error());
} else if (parser_result.is_error()) {
/* 1. parser detected error.
* 2. tokenizer_.input_state() refers to position just after offending token
* 3. error_pos here is 0 because error detected at token boundary
*/
reader_error error2(parser_result.error_src_function(),
parser_result.error_description(),
tokenizer_.input_state().rewind(tk.text().size()),
0 /*error_pos*/);
std::cout << "parser error pre-report:" << std::endl;
error2.report(std::cout);
return reader_result(nullptr, expr_span, parser_.stack_size(), error2);
} else {
/* token did not complete an expression
* (e.g. token for '[')
*
* input span may conotain more tokens -> iterate
* input span may contain more tokens -> iterate
*/
}
} else {
if (error.is_error()) {
if (error1.is_error()) {
/* tokenizer detected an error */
std::cout << "tokenizer error pre-report:" << std::endl;
error.report(std::cout);
error1.report(std::cout);
return reader_result(nullptr, expr_span, parser_.stack_size(),
reader_error(error.src_function(),
error.error_description(),
error.input_state(),
error.error_pos()));
reader_error(error1.src_function(),
error1.error_description(),
error1.input_state(),
error1.error_pos()));
} else {
/* control should not come here */
assert(input.empty());
}
/* ono more tokens in input */
/* need more tokens in input */
break;
}
}
/* control here: either
/* control here: eithero
* 1. input.empty (perhaps ate some whitespace, ok)
* 2. missing or incomplete token (ok unless eof)
*/