regex-posix-0.94.4: Replaces/Enhances Text.Regex

Portabilitynon-portable (regex-base needs MPTC+FD)
Stabilityexperimental
Maintainerlibraries@haskell.org, textregexlazy@personal.mightyreason.com

Text.Regex.Posix.ByteString.Lazy

Contents

Description

This provides ByteString.Lazy instances for RegexMaker and RegexLike based on Text.Regex.Posix.Wrap, and a (RegexContext Regex ByteString ByteString) instance.

To use these instance, you would normally import Text.Regex.Posix. You only need to import this module to use the medium level API of the compile, regexec, and execute functions. All of these report error by returning Left values instead of undefined or error or fail.

A Lazy ByteString with more than one chunk cannot be be passed to the library efficiently (as a pointer). It will have to converted via a full copy to a temporary normal bytestring (with a null byte appended if necessary).

Synopsis

Types

data Regex

A compiled regular expression.

Instances

type MatchOffset = Int

0 based index from start of source, or (-1) for unused

type MatchLength = Int

non-negative length of a match

data ReturnCode

ReturnCode is an enumerated CInt, corresponding to the error codes from man 3 regex:

  • retBadbr (REG_BADBR) invalid repetition count(s) in { }
  • retBadpat (REG_BADPAT) invalid regular expression
  • retBadrpt (REG_BADRPT) ?, *, or + operand invalid
  • retEcollate (REG_ECOLLATE) invalid collating element
  • retEctype (REG_ECTYPE) invalid character class
  • retEescape (REG_EESCAPE) \ applied to unescapable character
  • retEsubreg (REG_ESUBREG) invalid backreference number
  • retEbrack (REG_EBRACK) brackets [ ] not balanced
  • retEparen (REG_EPAREN) parentheses ( ) not balanced
  • retEbrace (REG_EBRACE) braces { } not balanced
  • retErange (REG_ERANGE) invalid character range in [ ]
  • retEspace (REG_ESPACE) ran out of memory
  • retNoMatch (REG_NOMATCH) The regexec() function failed to match

Instances

type WrapError = (ReturnCode, String)

The return code will be retOk when it is the Haskell wrapper and not the underlying library generating the error message.

Miscellaneous

unusedOffset :: Int

Medium level API functions

compile

Arguments

:: CompOption

Flags (summed together)

-> ExecOption

Flags (summed together)

-> ByteString

The regular expression to compile

-> IO (Either WrapError Regex)

Returns: the compiled regular expression

Compiles a regular expression

execute

Arguments

:: Regex

Compiled regular expression

-> ByteString

String to match against

-> IO (Either WrapError (Maybe (Array Int (MatchOffset, MatchLength))))

Returns: Nothing if the regex did not match the string, or: Just an array of (offset,length) pairs where index 0 is whole match, and the rest are the captured subexpressions.

Matches a regular expression against a buffer, returning the buffer indicies of the match, and any submatches

| Matches a regular expression against a string

regexec

Arguments

:: Regex

Compiled regular expression

-> ByteString

String to match against

-> IO (Either WrapError (Maybe (ByteString, ByteString, ByteString, [ByteString]))) 

Compilation options

newtype CompOption

A bitmapped CInt containing options for compilation of regular expressions. Option values (and their man 3 regcomp names) are

  • compBlank which is a completely zero value for all the flags. This is also the blankCompOpt value.
  • compExtended (REG_EXTENDED) which can be set to use extended instead of basic regular expressions. This is set in the defaultCompOpt value.
  • compNewline (REG_NEWLINE) turns on newline sensitivity: The dot (.) and inverted set [^ ] never match newline, and ^ and $ anchors do match after and before newlines. This is set in the defaultCompOpt value.
  • compIgnoreCase (REG_ICASE) which can be set to match ignoring upper and lower distinctions.
  • compNoSub (REG_NOSUB) which turns off all information from matching except whether a match exists.

Constructors

CompOption CInt 

Instances

compBlank :: CompOption

A completely zero value for all the flags. This is also the blankCompOpt value.

compExtended :: CompOption

compIgnoreCase :: CompOption

compNoSub :: CompOption

compNewline :: CompOption

Execution options

newtype ExecOption

A bitmapped CInt containing options for execution of compiled regular expressions. Option values (and their man 3 regexec names) are

  • execBlank which is a complete zero value for all the flags. This is the blankExecOpt value.
  • execNotBOL (REG_NOTBOL) can be set to prevent ^ from matching at the start of the input.
  • execNotEOL (REG_NOTEOL) can be set to prevent $ from matching at the end of the input (before the terminating NUL).

Constructors

ExecOption CInt 

Instances

execBlank :: ExecOption

A completely zero value for all the flags. This is also the blankExecOpt value.

execNotBOL :: ExecOption

execNotEOL :: ExecOption