rdesc.h File Reference

The deterministic recursive descent parser. More...

#include "detail.h"
#include <stdbool.h>
#include <stdint.h>
#include <stddef.h>

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Classes
struct	rdesc
	Recursive descent parser state. More...

Macros
#define	RDESC_VERSION_MAJOR   0
	Major version.
#define	RDESC_VERSION_MINOR   2
	Minor version.
#define	RDESC_VERSION_PATCH   0
	Patch version.
#define	RDESC_VERSION_PRE_RELEASE   "rc.2"
	Prerelease identifier.

Enumerations
enum	rdesc_result { RDESC_ENOMEM = -1 , RDESC_READY = 0 , RDESC_CONTINUE = 1 , RDESC_NOMATCH = 2 }
	Parse operation result codes. More...

Functions
const char *	rdesc_version (void)
	rdesc version
int	rdesc_init (struct rdesc *parser, const struct rdesc_grammar *grammar, size_t seminfo_size, void(*token_destroyer)(uint16_t id, void *seminfo)) _rdesc_wur
	Initializes a new parser.
void	rdesc_destroy (struct rdesc *parser)
	Frees memory allocated by the parser and destroys the parser instance.
int	rdesc_start (struct rdesc *parser, uint16_t start_symbol) _rdesc_wur
	Sets start symbol for the next match.
void	rdesc_reset (struct rdesc *parser)
	Resets the parser to its initial state.
enum rdesc_result	rdesc_pump (struct rdesc *parser, uint16_t id, void *seminfo) _rdesc_wur
	Drives the parsing process, the pump.
enum rdesc_result	rdesc_resume (struct rdesc *parser) _rdesc_wur
	Resume parsing without providing a new token.
struct rdesc_node *	rdesc_root (struct rdesc *parser)
	Returns the root of the CST.

Detailed Description

The deterministic recursive descent parser.

Enumeration Type Documentation

rdesc_result

enum rdesc_result

Parse operation result codes.

Enumerator
RDESC_ENOMEM	Memory allocation failed.
RDESC_READY	A CST is ready for consumption.
RDESC_CONTINUE	New tokens should be provided.
RDESC_NOMATCH	No grammar rule matches the provided tokens.

Function Documentation

rdesc_init()

int rdesc_init	(	struct rdesc *	parser,
		const struct rdesc_grammar *	grammar,
		size_t	seminfo_size,
		void(*)(uint16_t id, void *seminfo)	token_destroyer
	)

Initializes a new parser.

Parameters

parser	Parser instance to initialize.
grammar	Grammar defining production rules (must outlive parser).
seminfo_size	Size in bytes of token semantic information.
token_destroyer	Optional callback to free token seminfo (can be NULL).

Returns

Non-zero value if memory allocation fails.

rdesc_pump()

enum rdesc_result rdesc_pump	(	struct rdesc *	parser,
		uint16_t	id,
		void *	seminfo
	)

Drives the parsing process, the pump.

As the central engine of the parser, it consumes tokens from either the internal backtracking stack or the provided id.

Parameters

parser	Pointer to the parser instance.
id	Identifier of the next token to consume.
seminfo	Extra semantic information for the token. Semantic information pointer. The parser copies this data internally, so passing a pointer to stack-allocated data is valid. NULL is acceptable.

Returns

The current status of the parse operation.

Warning

Raises an error if the parser is not started.

rdesc_resume()

enum rdesc_result rdesc_resume

(

struct rdesc *

parser

)

Resume parsing without providing a new token.

Resumes using either:

• The saved token from a previous ENOMEM error, or
• A token from the backtrack stack

rdesc_root()

struct rdesc_node * rdesc_root

(

struct rdesc *

parser

)

Returns the root of the CST.

Note

Returns NULL if no CST has been created yet.

rdesc_start()

int rdesc_start	(	struct rdesc *	parser,
		uint16_t	start_symbol
	)

Sets start symbol for the next match.

Returns

Non-zero value if memory allocation fails.