lexer_lookahead.h File Reference

#include <stddef.h>
#include "rcl/allocator.h"
#include "rcl/lexer.h"
#include "rcl/macros.h"
#include "rcl/types.h"
#include "rcl/visibility_control.h"

Include dependency graph for lexer_lookahead.h:

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Classes
struct	rcl_lexer_lookahead2_t
	Track lexical analysis and allow looking ahead 2 lexemes. More...

Typedefs
typedef struct rcl_lexer_lookahead2_t	rcl_lexer_lookahead2_t
	Track lexical analysis and allow looking ahead 2 lexemes. More...

Functions
rcl_lexer_lookahead2_t	rcl_get_zero_initialized_lexer_lookahead2 ()
	Get a zero initialized rcl_lexer_lookahead2_t instance. More...
rcl_ret_t	rcl_lexer_lookahead2_init (rcl_lexer_lookahead2_t *buffer, const char *text, rcl_allocator_t allocator)
	Initialize an rcl_lexer_lookahead2_t instance. More...
rcl_ret_t	rcl_lexer_lookahead2_fini (rcl_lexer_lookahead2_t *buffer)
	Finalize an instance of an rcl_lexer_lookahead2_t structure. More...
rcl_ret_t	rcl_lexer_lookahead2_peek (rcl_lexer_lookahead2_t *buffer, rcl_lexeme_t *next_type)
	Look ahead at the next lexeme in the string. More...
rcl_ret_t	rcl_lexer_lookahead2_peek2 (rcl_lexer_lookahead2_t *buffer, rcl_lexeme_t *next_type1, rcl_lexeme_t *next_type2)
	Look ahead at the next two lexemes in the string. More...
rcl_ret_t	rcl_lexer_lookahead2_accept (rcl_lexer_lookahead2_t *buffer, const char **lexeme_text, size_t *lexeme_text_length)
	Accept a lexeme and advance analysis. More...
rcl_ret_t	rcl_lexer_lookahead2_expect (rcl_lexer_lookahead2_t *buffer, rcl_lexeme_t type, const char **lexeme_text, size_t *lexeme_text_length)
	Require the next lexeme to be a certain type and advance analysis. More...
const char *	rcl_lexer_lookahead2_get_text (const rcl_lexer_lookahead2_t *buffer)
	Get the text at the point where it is currently being analyzed. More...

Typedef Documentation

rcl_lexer_lookahead2_t

typedef struct rcl_lexer_lookahead2_t rcl_lexer_lookahead2_t

Track lexical analysis and allow looking ahead 2 lexemes.

Function Documentation

rcl_get_zero_initialized_lexer_lookahead2()

rcl_lexer_lookahead2_t rcl_get_zero_initialized_lexer_lookahead2

(

)

Get a zero initialized rcl_lexer_lookahead2_t instance.

See also

rcl_lexer_lookahead2_init()

---

Attribute	Adherence
Allocates Memory	No
Thread-Safe	Yes
Uses Atomics	No
Lock-Free	Yes

Returns

zero initialized lookahead2 buffer.

rcl_lexer_lookahead2_init()

rcl_ret_t rcl_lexer_lookahead2_init	(	rcl_lexer_lookahead2_t *	buffer,
		const char *	text,
		rcl_allocator_t	allocator
	)

Initialize an rcl_lexer_lookahead2_t instance.

The lookahead2 buffer borrows a reference to the provided text. The text must not be freed before the buffer is finalized. The lookahead2 buffer only needs to be finalized if this function does not return RCL_RET_OK.

See also

rcl_lexer_lookahead2_fini()

---

Attribute	Adherence
Allocates Memory	Yes
Thread-Safe	No
Uses Atomics	No
Lock-Free	Yes

Parameters

[in]

buffer

A buffer that is zero initialized.

See also

rcl_get_zero_initialized_lexer_lookahead2()

Parameters

[in]	text	The string to analyze.
[in]	allocator	An allocator to use if an error occurs.

Returns

RCL_RET_OK if the buffer is successfully initialized, or

RCL_RET_INVALID_ARGUMENT if any function arguments are invalid, or

RCL_RET_BAD_ALLOC if allocating memory failed, or

RCL_RET_ERROR if an unspecified error occurrs.

rcl_lexer_lookahead2_fini()

rcl_ret_t rcl_lexer_lookahead2_fini

(

rcl_lexer_lookahead2_t *

buffer

)

Finalize an instance of an rcl_lexer_lookahead2_t structure.

See also

rcl_lexer_lookahead2_init()

---

Attribute	Adherence
Allocates Memory	Yes [1]
Thread-Safe	No
Uses Atomics	No
Lock-Free	Yes

[1] Only allocates if an argument is invalid.

Parameters

[in]

buffer

The structure to be deallocated.

Returns

RCL_RET_OK if the structure was successfully finalized, or

RCL_RET_INVALID_ARGUMENT if any function arguments are invalid, or

RCL_RET_ERROR if an unspecified error occurs.

rcl_lexer_lookahead2_peek()

rcl_ret_t rcl_lexer_lookahead2_peek	(	rcl_lexer_lookahead2_t *	buffer,
		rcl_lexeme_t *	next_type
	)

Look ahead at the next lexeme in the string.

Repeated calls to peek will return the same lexeme. A parser that deems the next lexeme as valid must accept it to advance lexing.

See also

rcl_lexer_lookahead2_accept()

---

Attribute	Adherence
Allocates Memory	Yes [1]
Thread-Safe	No
Uses Atomics	No
Lock-Free	Yes

[1] Only allocates if an argument is invalid or an internal bug is detected.

Parameters

[in]	buffer	the lookahead2 buffer being used to analyze a string.
[out]	next_type	an output variable for the next lexeme in the string.

Returns

RCL_RET_OK if peeking was successfull, or

RCL_RET_INVALID_ARGUMENT if any function arguments are invalid, or

RCL_RET_ERROR if an unspecified error occurs.

rcl_lexer_lookahead2_peek2()

rcl_ret_t rcl_lexer_lookahead2_peek2	(	rcl_lexer_lookahead2_t *	buffer,
		rcl_lexeme_t *	next_type1,
		rcl_lexeme_t *	next_type2
	)

Look ahead at the next two lexemes in the string.

Repeated calls to peek2 will return the same two lexemes. A parser that deems the next two lexemes as valid must accept twice to advance lexing.

See also

rcl_lexer_lookahead2_accept()

---

Attribute	Adherence
Allocates Memory	Yes [1]
Thread-Safe	No
Uses Atomics	No
Lock-Free	Yes

[1] Only allocates if an argument is invalid or an internal bug is detected.

Parameters

[in]	buffer	the lookahead2 buffer being used to analyze a string.
[out]	next_type1	an output variable for the next lexeme in the string.
[out]	next_type2	an output variable for the lexeme after the next lexeme in the string.

Returns

RCL_RET_OK if peeking was successfull, or

RCL_RET_INVALID_ARGUMENT if any function arguments are invalid, or

RCL_RET_ERROR if an unspecified error occurs.

rcl_lexer_lookahead2_accept()

rcl_ret_t rcl_lexer_lookahead2_accept	(	rcl_lexer_lookahead2_t *	buffer,
		const char **	lexeme_text,
		size_t *	lexeme_text_length
	)

Accept a lexeme and advance analysis.

A token must have been peeked before it can be accepted.

See also

rcl_lexer_lookahead2_peek()

rcl_lexer_lookahead2_peek2()

---

Attribute	Adherence
Allocates Memory	Yes [1]
Thread-Safe	No
Uses Atomics	No
Lock-Free	Yes

[1] Only allocates if an argument is invalid or an error occurs.

Parameters

[in]	buffer	the lookahead2 buffer being used to analyze a string.
[out]	lexeme_text	pointer to where lexeme begins in string.
[out]	lexeme_text_length	length of lexeme_text.

Returns

RCL_RET_OK if peeking was successfull, or

RCL_RET_INVALID_ARGUMENT if any function arguments are invalid, or

RCL_RET_ERROR if an unspecified error occurs.

rcl_lexer_lookahead2_expect()

rcl_ret_t rcl_lexer_lookahead2_expect	(	rcl_lexer_lookahead2_t *	buffer,
		rcl_lexeme_t	type,
		const char **	lexeme_text,
		size_t *	lexeme_text_length
	)

Require the next lexeme to be a certain type and advance analysis.

This method is a shortcut to peeking and accepting a lexeme. It should be used by a parser when there is only one valid lexeme that could come next.

See also

rcl_lexer_lookahead2_peek()

rcl_lexer_lookahead2_accept()

---

Attribute	Adherence
Allocates Memory	Yes [1]
Thread-Safe	No
Uses Atomics	No
Lock-Free	Yes

[1] Only allocates if an argument is invalid or an error occurs.

Parameters

[in]	buffer	the lookahead2 buffer being used to analyze a string.
[in]	type	the type the next lexeme must be.
[out]	lexeme_text	pointer to where lexeme begins in string.
[out]	lexeme_text_length	length of lexeme_text.

Returns

RCL_RET_OK if the next lexeme was the expected one, or

RCL_RET_WRONG_LEXEME if the next lexeme was not the expected one, or

RCL_RET_INVALID_ARGUMENT if any function arguments are invalid, or

RCL_RET_ERROR if an unspecified error occurs.

rcl_lexer_lookahead2_get_text()

const char* rcl_lexer_lookahead2_get_text

(

const rcl_lexer_lookahead2_t *

buffer

)

Get the text at the point where it is currently being analyzed.

---

Attribute	Adherence
Allocates Memory	No
Thread-Safe	Yes
Uses Atomics	No
Lock-Free	Yes

Parameters

[in]

buffer

the lookahead2 buffer being used to analyze a string.

Returns

a pointer inside the original text at the position being analyzed, or

NULL if buffer is itself NULL or zero initialized, or

an undefined value if buffer is not initialized or has been finalized.