FXRex is a regular expression class implementing a NFA matcher. More...

#include <FXRex.h>

Public Types
enum	{ Normal = 0, Unicode = 1, Syntax = 2, Verbatim = 4, Capture = 8, IgnoreCase = 16, Newline = 32, Exact = 64, NotEmpty = 128, Reverse = 256, Words = 512, NotBol = 1024, NotEol = 2048 }
	Regular expression flags. More...

enum	Error { ErrOK = 0, ErrEmpty = 1, ErrMore = 2, ErrParent = 3, ErrBracket = 4, ErrBrace = 5, ErrRange = 6, ErrEscape = 7, ErrCount = 8, ErrNoAtom = 9, ErrRepeat = 10, ErrBackRef = 11, ErrClass = 12, ErrComplex = 13, ErrMemory = 14, ErrToken = 15, ErrLong = 16, ErrSupport = 17 }
	Regular expression error codes. More...

Public Member Functions
	FXRex ()
	Construct empty regular expression object, with the fallback program installed.

	FXRex (const FXRex &orig)
	Copy regular expression object from another.

	FXRex (const FXchar pattern, FXint mode=Normal, Error error=nullptr)
	Compile expression from pattern; if error is not NULL, error code is returned.

	FXRex (const FXString &pattern, FXint mode=Normal, Error *error=nullptr)
	Compile expression from pattern; if error is not NULL, error code is returned.

FXbool	empty () const
	See if regular expression is empty; the regular expression will be empty when it is unable to parse a pattern due to a syntax error.

Error	parse (const FXchar *pattern, FXint mode=Normal)
	Parse pattern, return error code if syntax error is found. More...

Error	parse (const FXString &pattern, FXint mode=Normal)

FXbool	amatch (const FXchar string, FXint len, FXint pos=0, FXint mode=Normal, FXint beg=nullptr, FXint *end=nullptr, FXint npar=0) const
	Perform anchored match of subject string of length len at position pos, returning true if the pattern matches at this point. More...

FXbool	amatch (const FXString &string, FXint pos=0, FXint mode=Normal, FXint beg=nullptr, FXint end=nullptr, FXint npar=0) const

FXint	search (const FXchar string, FXint len, FXint fm, FXint to, FXint mode=Normal, FXint beg=nullptr, FXint *end=nullptr, FXint npar=0) const
	Search subject string of length len for a pattern, returning the location where the pattern is found relative from the start of the string, or -1 if there is no match. More...

FXint	search (const FXString &string, FXint fm, FXint to, FXint mode=Normal, FXint beg=nullptr, FXint end=nullptr, FXint npar=0) const

FXRex &	operator= (const FXRex &orig)
	Assign another regular expression to this one.

FXbool	operator== (const FXRex &rex) const
	Comparison operators.

FXbool	operator!= (const FXRex &rex) const

void	clear ()
	Clear the expression object and reinstate the fallback program.

	~FXRex ()
	Delete.

Static Public Member Functions
static FXString	substitute (const FXchar string, FXint len, FXint beg, FXint end, const FXchar replace, FXint npar=1)
	After performing a regular expression match with capturing parentheses, a substitution string is build from the replace string, where where "&" is replaced by the entire matched pattern, and "\1" through "\9" are replaced by captured expressions. More...

static FXString	substitute (const FXchar string, FXint len, FXint beg, FXint *end, const FXString &replace, FXint npar=1)

static FXString	substitute (const FXString &string, FXint beg, FXint end, const FXchar *replace, FXint npar=1)

static FXString	substitute (const FXString &string, FXint beg, FXint end, const FXString &replace, FXint npar=1)

static const FXchar *	getError (Error err)
	Returns error message text for a given error code.

static FXString	escape (const FXString &str)
	Escape special regex-reserved characters in string. More...

Friends
FXAPI FXStream &	operator<< (FXStream &store, const FXRex &s)
	Saving and loading.

FXAPI FXStream &	operator>> (FXStream &store, FXRex &s)

Detailed Description

FXRex is a regular expression class implementing a NFA matcher.

It supports capturing parentheses, non-capturing parentheses, positive or negative lookahead, backreferences, case-insensitive matching, counted repetitions, greedy, lazy and possessive matches, and PERL-like matching operators. The subject string may be searched forwards or backwards, and may contain any of 256 possible byte values.

When parsing a regular expression pattern, the mode parameter is the bitwise OR of a set of flags and affects the match algorithm. Passing the flag Capture enables capturing parentheses and back references, and allows the matcher engine to return the locations of the string matching these sub-patterns. The flag IgnoreCase enables case-insensitive matching.

When the flag Newline is passed, newlines are treated like normal characters, and not line-separators. If Newline flag is not passed, character classes such as '.', '', '', [^a-z] etc. will NOT match newlines. The flag Verbatim disables all special character interpretation, making the entire pattern a literal string to be matched against a string.

When the Exact flag is passed, a match succeeds only if the entire string is matched, i.e. the entire input presented to FXRex must match against the pattern; otherwise, only a (possibly empty) substring of the input is matched against the pattern. If the NotEmpty flag is passed, the pattern must match at least one character in order to succeed, and empty matches are considered non-matching.

If the flag Syntax will check the pattern for correct syntax only, and not generate a matching engine; it will just reset the engine to the empty pattern; use this flag to verify the syntax of the pattern without compiling it.

When matching a compiled pattern, the mode parameter is the bitwise OR of a set of flags that affects how the match is performed. Passing the flags NotBol and/or NotEol causes the begin and end of the subject string NOT to be considered a line start or line end.

Patterns which cause inordinate amounts of recursion may cause FXRex to fail where otherwise it would succeed to match. FXRex uses no global variables, and thus multiple threads may simultaneously use it; moreover, multiple threads may use the same instance to perform a match.

Member Enumeration Documentation

◆ anonymous enum

anonymous enum

Regular expression flags.

Enumerator
Normal	Flags for both parse and match mode.
Unicode	Normal mode (default)
Syntax	Unicode mode. Regular expression parse flags
Verbatim	Perform syntax check only.
Capture	Literal pattern mode with no magic characters.
IgnoreCase	Perform capturing parentheses.
Newline	Ignore case differences.
Exact	Match-any operators match newline too.
NotEmpty	Exact match to entire string (..)
Reverse	A successful match must not be empty.
Words	Reverse expression mode.
NotBol	Match whole words (<..>) Regular expression match flags
NotEol	Start of string is NOT begin of line.

◆ Error

enum FX::FXRex::Error

Regular expression error codes.

Enumerator
ErrEmpty	No errors.
ErrMore	Empty pattern.
ErrParent	More characters after pattern.
ErrBracket	Unmatched parenthesis.
ErrBrace	Unmatched bracket.
ErrRange	Unmatched brace.
ErrEscape	Bad character range.
ErrCount	Bad escape sequence.
ErrNoAtom	Bad counted repeat.
ErrRepeat	No atom preceding repetition.
ErrBackRef	Repeat following repeat.
ErrClass	Bad backward reference.
ErrComplex	Bad character class.
ErrMemory	Expression too complex.
ErrToken	Out of memory.
ErrLong	Illegal token.
ErrSupport	Pattern too long.

Member Function Documentation

◆ amatch()

FXbool FX::FXRex::amatch	(	const FXchar *	string,
		FXint	len,
		FXint	pos = `0`,
		FXint	mode = `Normal`,
		FXint *	beg = `nullptr`,
		FXint *	end = `nullptr`,
		FXint	npar = `0`
	)		const

Perform anchored match of subject string of length len at position pos, returning true if the pattern matches at this point.

If there is a match, the pattern and subpatterns are captured in the arrays beg[] and end[] which must both be at least npar entries long.

◆ escape()

static FXString FX::FXRex::escape ( const FXString & str )

static

Escape special regex-reserved characters in string.

Useful when assembling a regular expression from strings.

◆ parse()

Error FX::FXRex::parse	(	const FXchar *	pattern,
		FXint	mode = `Normal`
	)

Parse pattern, return error code if syntax error is found.

The parse-mode flags control the compile options, and affect how the generated matcher behaves. If a parse fails, an error code is returned; in this case, the expression matcher will be set up to a fallback program.

◆ search()

FXint FX::FXRex::search	(	const FXchar *	string,
		FXint	len,
		FXint	fm,
		FXint	to,
		FXint	mode = `Normal`,
		FXint *	beg = `nullptr`,
		FXint *	end = `nullptr`,
		FXint	npar = `0`
	)		const

Search subject string of length len for a pattern, returning the location where the pattern is found relative from the start of the string, or -1 if there is no match.

In case of a successful match, the pattern and subpatterns are captured in the arrays beg[] and end[] which must be at least npar entries long. The string is searched forwards (or backwards) starting from position fm toward to, both of which must lie inside the string.

◆ substitute()

static FXString FX::FXRex::substitute	(	const FXchar *	string,
		FXint	len,
		FXint *	beg,
		FXint *	end,
		const FXchar *	replace,
		FXint	npar = `1`
	)

static

After performing a regular expression match with capturing parentheses, a substitution string is build from the replace string, where where "&" is replaced by the entire matched pattern, and "\1" through "\9" are replaced by captured expressions.

The original source string and its length, and the match arrays beg and end must be passed. The replace string may also contain regular escape sequences to embed special characters.

The documentation for this class was generated from the following file:

/home/jeroen/FOX/fox/fox-1.7.86/include/FXRex.h

Public Types

Public Member Functions

Static Public Member Functions

Friends