22. Regular expression library

The experimental REGEX module implement regular expression parser and pattern matching functionality.

Currently its in very early stage and implements only very few basic regex operations.

All functions and symbols are in “regex” module, use require to get access to it.

require daslib/regex

22.1. Type aliases

CharSet = uint[8]

Bit array which represents an 8-bit character set.

MaybeReNode is a variant type

value	regex::ReNode ?
nothing	void?

Single regular expression node or nothing.

22.2. Enumerations

ReOp

Char	0
Set	1
Any	2
Eos	3
Group	4
Plus	5
Star	6
Question	7
Concat	8
Union	9

Type of regular expression operation.

ReNode

ReNode fields are

op	regex::ReOp
id	int
fun2	function<(regex: regex::Regex ;node: regex::ReNode ?;str:uint8? const):uint8?>
at	range
text	string
textLen	int
all	array< regex::ReNode ?>
left	regex::ReNode ?
right	regex::ReNode ?
subexpr	regex::ReNode ?
next	regex::ReNode ?
cset	CharSet
index	int
tail	uint8?

Single node in regular expression parsing tree.

Regex

Regex fields are

root	regex::ReNode ?
match	uint8?
groups	array<tuple<range;string>>
earlyOut	CharSet
canEarlyOut	bool

Regular expression.

22.3. Compilation and validation

• is_valid (re:regex::Regex -const) : bool

• regex_compile (re:regex::Regex -const;expr:string const) : bool

• regex_compile (expr:string const) : regex::Regex

• regex_compile (re:regex::Regex -const) : regex::Regex

• regex_debug (regex:regex::Regex const) : void

• debug_set (cset:uint const[8]) : void

is_valid(re: Regex)

is_valid returns bool

argument	argument type
re	regex::Regex

returns true if enumeration compiled correctly

regex_compile(re: Regex; expr: string const)

regex_compile returns bool

argument	argument type
re	regex::Regex
expr	string const

Compile regular expression. Validity of the compiled expression is checked by is_valid.

regex_compile(expr: string const)

regex_compile returns regex::Regex

argument	argument type
expr	string const

Compile regular expression. Validity of the compiled expression is checked by is_valid.

regex_compile(re: Regex)

regex_compile returns regex::Regex

argument	argument type
re	regex::Regex

Compile regular expression. Validity of the compiled expression is checked by is_valid.

regex_debug(regex: Regex const)

argument	argument type
regex	regex::Regex const

Prints regular expression and its related information in human readable form.

debug_set(cset: CharSet)

argument	argument type
cset	CharSet

Prints character set in human readable form.

22.4. Access

• regex_group (regex:regex::Regex const;index:int const;match:string const) : string

• regex_foreach (regex:regex::Regex -const;str:string const;blk:block<(at:range const):bool> const) : void

regex_group(regex: Regex const; index: int const; match: string const)

regex_group returns string

argument	argument type
regex	regex::Regex const
index	int const
match	string const

Returns string for the given group index and match result.

regex_foreach(regex: Regex; str: string const; blk: block<(at:range const):bool> const)

argument	argument type
regex	regex::Regex
str	string const
blk	block<(at:range const):bool> const

Iterates through all matches for the given regular expression in str.

22.5. Match

• regex_match (regex:regex::Regex -const;str:string const;offset:int const) : int

regex_match(regex: Regex; str: string const; offset: int const)

regex_match returns int

argument	argument type
regex	regex::Regex
str	string const
offset	int const

Returns first match for the regular expression in str. If offset is specified, first that many number of symbols will not be matched.