Hledger.Utils.Regex

Easy regular expression helpers, currently based on regex-tdfa. These should:

• be cross-platform, not requiring C libraries
• support unicode
• support extended regular expressions
• support replacement, with backreferences etc.
• support splitting
• have mnemonic names
• have simple monomorphic types
• work with simple strings

Regex strings are automatically compiled into regular expressions the first time they are seen, and these are cached. If you use a huge number of unique regular expressions this might lead to increased memory usage. Several functions have memoised variants (*Memo), which also trade space for time.

Current limitations:

• (?i) and similar are not supported

type aliases

type Regexp = String

Regular expression. Extended regular expression-ish syntax ? But does not support eg (?i) syntax.

type Replacement = String

A replacement pattern. May include numeric backreferences (N).

standard regex operations

regexMatches :: Regexp -> String -> Bool

regexMatchesCI :: Regexp -> String -> Bool

regexReplace :: Regexp -> Replacement -> String -> String

Replace all occurrences of the regexp with the replacement pattern. The replacement pattern supports numeric backreferences (N) but no other RE syntax.

regexReplaceCI :: Regexp -> Replacement -> String -> String

regexReplaceMemo :: Regexp -> Replacement -> String -> String

A memoising version of regexReplace. Caches the result for each search pattern, replacement pattern, target string tuple.

regexReplaceCIMemo :: Regexp -> Replacement -> String -> String

regexReplaceBy :: Regexp -> (String -> String) -> String -> String

Replace all occurrences of the regexp, transforming each match with the given function.

regexReplaceByCI :: Regexp -> (String -> String) -> String -> String