fish-shell/src/parse_productions.h
ridiculousfish 8c707a4e2f Simplify parser implementation
Rather than returning a list of productions and an index,
return the relevant production directly from the rule function.

Also introduce a tag value (replacing production_idx) which tracks
information like command decorations, etc. with more clarity.
2015-12-19 11:17:13 -08:00

64 lines
1.9 KiB
C++

/**\file parse_tree.h
Programmatic representation of fish code.
*/
#ifndef FISH_PARSE_TREE_CONSTRUCTION_H
#define FISH_PARSE_TREE_CONSTRUCTION_H
#include <stdint.h> // for uint8_t, uint32_t
#include "common.h" // for wcstring
#include "parse_constants.h" // for parse_token_type_t, etc
struct parse_token_t;
namespace parse_productions
{
#define MAX_SYMBOLS_PER_PRODUCTION 6
/* A production is an array of unsigned char. Symbols are encoded directly as their symbol value. Keywords are encoded with an offset of LAST_TOKEN_OR_SYMBOL + 1. So essentially we glom together keywords and symbols. */
typedef uint8_t production_element_t;
typedef production_element_t const production_t[MAX_SYMBOLS_PER_PRODUCTION];
/* Resolve the type from a production element */
inline parse_token_type_t production_element_type(production_element_t elem)
{
if (elem > LAST_TOKEN_OR_SYMBOL)
{
return parse_token_type_string;
}
else
{
return static_cast<parse_token_type_t>(elem);
}
}
/* Resolve the keyword from a production element */
inline parse_keyword_t production_element_keyword(production_element_t elem)
{
if (elem > LAST_TOKEN_OR_SYMBOL)
{
// First keyword is LAST_TOKEN_OR_SYMBOL + 1
return static_cast<parse_keyword_t>(elem - LAST_TOKEN_OR_SYMBOL - 1);
}
else
{
return parse_keyword_none;
}
}
/* Check if an element is valid */
inline bool production_element_is_valid(production_element_t elem)
{
return elem != token_type_invalid;
}
/* Fetch a production. We are passed two input tokens. The first input token is guaranteed to not be invalid; the second token may be invalid if there's no more tokens. We may also set flags. */
const production_t *production_for_token(parse_token_type_t node_type, const parse_token_t &input1, const parse_token_t &input2, uint8_t *out_tag);
}
#endif