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xo-parser: prep: semicolon expr separator, prep for infix ops

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This commit is contained in:
Roland Conybeare 2024-08-06 23:09:05 -04:00
commit 37268113fb
6 changed files with 409 additions and 60 deletions
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15
src/reader/reader.cpp
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@ -17,6 +17,9 @@ namespace xo {
reader_result
reader::read_expr(const span_type & input_arg, bool eof)
{
constexpr bool c_debug_flag = true;
scope log(XO_DEBUG(c_debug_flag));
span_type input = input_arg;
/* input text-span consumed by this call.
@ -32,7 +35,13 @@ namespace xo {
const auto & tk = sr.first;
const span_type & used_span = sr.second;
log && log(xtag("used_span", used_span));
log && log(xtag("input.pre", input));
input = input.after_prefix(used_span);
log && log(xtag("expr_span.pre", expr_span));
expr_span += used_span;
if (tk.is_valid()) {
@ -40,6 +49,9 @@ namespace xo {
auto expr = this->parser_.include_token(tk);
if (expr) {
log && log(xtag("outcome", "victory!"),
xtag("expr", expr));
/* token completes an expression -> victory */
return reader_result(expr, expr_span);
} else {
@ -48,7 +60,6 @@ namespace xo {
*
* input span may contain more tokens -> iterate
*/
input = input.after_prefix(used_span);
}
} else {
assert(input.empty());
@ -76,6 +87,8 @@ namespace xo {
}
}
log && log(xtag("outcome", "noop"));
return reader_result(nullptr, expr_span);
}