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reader reports tokenizer errors through normal return

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This commit is contained in:
Roland Conybeare 2025-07-19 16:47:59 -05:00
commit 781adeb0d3
10 changed files with 149 additions and 20 deletions
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17
include/xo/reader/reader.hpp
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@ -6,6 +6,7 @@
#pragma once
#include "parser.hpp"
#include "reader_error.hpp"
#include "xo/expression/Expression.hpp"
#include "xo/expression/pretty_expression.hpp"
#include "xo/tokenizer/tokenizer.hpp"
@ -19,8 +20,8 @@ namespace xo {
using Expression = xo::ast::Expression;
using span_type = span<const char>;
reader_result(rp<Expression> expr, span_type rem, std::size_t psz)
: expr_{std::move(expr)}, rem_{rem}, parser_stack_size_{psz} {}
reader_result(rp<Expression> expr, span_type rem, std::size_t psz, const reader_error & error)
: expr_{std::move(expr)}, rem_{rem}, parser_stack_size_{psz}, error_{error} {}
/** true if reader parsed a complete expression **/
bool expr_complete() const { return expr_.get(); }
@ -37,6 +38,9 @@ namespace xo {
* will be zero whenever @ref expr_ is non-null
**/
std::size_t parser_stack_size_ = 0;
/** error description, whenever .error_.is_error() is true **/
reader_error error_;
};
/**
@ -53,7 +57,7 @@ namespace xo {
*
* for (auto rem = input; !rem.empty();) {
* // res: (parsed-expr, used)
* auto res = rdr.read_expr(rem, eof);
* auto [expres = rdr.read_expr(rem, eof);
*
* if (res.first) {
* // do something with res.first (parsed expr)
@ -112,6 +116,13 @@ namespace xo {
**/
reader_result read_expr(const span_type & input, bool eof);
/** reset to known starting point after encountering an error.
* - remainder of stashed current line.
* Necesary for well-formatted error reporting.
* - current parsing state
**/
void reset_to_idle_toplevel();
private:
/** tokenizer: text -> tokens **/
tokenizer_type tokenizer_;