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xo-parser: + reader class (tokenizer -> parser pipeline)

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This commit is contained in:
Roland Conybeare 2024-08-06 09:43:32 -04:00
commit 7e311ab0cb
3 changed files with 113 additions and 6 deletions
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41
include/xo/parser/reader.hpp
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@ -6,10 +6,27 @@
#pragma once
#include "parser.hpp"
#include "xo/expression/Expression.hpp"
#include "xo/tokenizer/tokenizer.hpp"
namespace xo {
namespace scm {
/** @class parse_result
* @brief Result object returned from reader::read_expr
**/
struct reader_result {
using Expression = xo::ast::Expression;
using span_type = span<const char>;
/** parsed schematica expression **/
rp<Expression> expr_;
/** span giving text input consumed to construct expr,
* including any leading whitespace.
* This is the span returned in result of tokenizer<char>::scan()
**/
span_type rem_;
};
/**
* Use:
* @code
@ -21,7 +38,7 @@ namespace xo {
* // eof: true if no more input will be forthcoming from this stream
* eof = ins.eof();
*
* for (auto rem = input; ; !rem.empty()) {
* for (auto rem = input; !rem.empty();) {
* // res: (parsed-expr, used)
* auto res = rdr.read_expr(rem, eof);
*
@ -39,18 +56,32 @@ namespace xo {
* @endcode
**/
class reader {
public:
using tokenizer_type = tokenizer<char>;
using span_type = tokenizer_type::span_type;
public:
reader() = default;
/** Try to read one expression from @p input.
* Return struct containing parsed expression
* and span of characters comprising that expression
*
* @param input Supply this input span of chars
* @param eof. True if input stream supplying @p input
* reports end-of-file immediately after the last char
* in @p input.
**/
reader_result read_expr(const span_type & input, bool eof);
private:
/** tokenizer: text -> tokens **/
tokenizer tokenizer_;
tokenizer_type tokenizer_;
/** parser: tokens -> expressions (TODO: reanme ->reader) **/
/** parser: tokens -> expressions **/
parser parser_;
};
} /*namespace scm*/
} /*namespace xo*/
/* end Repl.hpp */
/* end reader.hpp */