Text.Regex.Posix.Wrap

WrapPosix.hsc exports a wrapped version of the ffi imports. To increase type safety, the flags are newtype'd. The other important export is a Regex type that is specific to the Posix library backend. The flags are documented in Text.Regex.Posix. The defaultCompOpt is (compExtended .|. compNewline).

The Regex, CompOption, and ExecOption types and their RegexOptions instance is declared. The =~ and =~~ convenience functions are defined.

The exported symbols are the same whether 1 is defined, but when it is not defined then getVersion == Nothing and all other exported values will call error or fail.

This module will fail or error only if allocation fails or a nullPtr is passed in.

High-level API

data Regex

A compiled regular expression.

Instances

RegexLike Regex String

RegexLike Regex ByteString

RegexOptions Regex CompOption ExecOption

RegexContext Regex String String

RegexContext Regex ByteString ByteString

RegexMaker Regex CompOption ExecOption String

RegexMaker Regex CompOption ExecOption ByteString

type RegOffset = Int64

RegOffset is typedef int regoff_t on Linux and ultimately typedef long long __int64_t on Max OS X. So rather than saying 2,147,483,647 is all the length you need, I'll take the larger: 9,223,372,036,854,775,807 should be enough bytes for anyone, no need for Integer. The alternative is to compile to different sizes in a platform dependent manner with type RegOffset = (, which I do not want to do.

There is also a special value unusedRegOffset :: RegOffset which is (-1) and as a starting index means that the subgroup capture was unused. Otherwise the RegOffset indicates a character boundary that is before the character at that index offset, with the first character at index offset 0. So starting at 1 and ending at 2 means to take only the second character.

(=~) :: (RegexMaker Regex CompOption ExecOption source, RegexContext Regex source1 target) => source1 -> source -> target

(=~~) :: (RegexMaker Regex CompOption ExecOption source, RegexContext Regex source1 target, Monad m) => source1 -> source -> m target

Low-level API

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.

wrapCompile

Arguments

:: CompOption

Flags (bitmapped)

-> ExecOption

Flags (bitmapped)

-> CString

The regular expression to compile (ASCII only, no null bytes)

-> IO (Either WrapError Regex)

Returns: the compiled regular expression

wrapTest :: Regex -> CString -> IO (Either WrapError Bool)

wrapMatch :: Regex -> CString -> IO (Either WrapError (Maybe [(RegOffset, RegOffset)]))

wrapMatch returns offsets for the begin and end of each capture. Unused captures have offsets of unusedRegOffset which is (-1)

wrapMatchAll :: Regex -> CString -> IO (Either WrapError [MatchArray])

wrapMatchAll returns the offset and length of each capture. Unused captures have an offset of unusedRegOffset which is (-1) and length of 0.

wrapCount :: Regex -> CString -> IO (Either WrapError Int)

Miscellaneous

unusedRegOffset :: RegOffset

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

Eq CompOption

Num CompOption

Show CompOption

Bits CompOption

RegexOptions Regex CompOption ExecOption

RegexMaker Regex CompOption ExecOption String

RegexMaker Regex CompOption ExecOption ByteString

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

Eq ExecOption

Num ExecOption

Show ExecOption

Bits ExecOption

RegexOptions Regex CompOption ExecOption

RegexMaker Regex CompOption ExecOption String

RegexMaker Regex CompOption ExecOption ByteString

execBlank :: ExecOption

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

execNotBOL :: ExecOption

execNotEOL :: ExecOption

Return codes

newtype 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

Constructors

ReturnCode CInt

Instances

Eq ReturnCode

Show ReturnCode

retBadbr :: ReturnCode

retBadpat :: ReturnCode

retBadrpt :: ReturnCode

retEcollate :: ReturnCode

retEctype :: ReturnCode

retEescape :: ReturnCode

retEsubreg :: ReturnCode

retEbrack :: ReturnCode

retEparen :: ReturnCode

retEbrace :: ReturnCode

retErange :: ReturnCode

retEspace :: ReturnCode