| Safe Haskell | None |
|---|---|
| Language | Haskell2010 |
Hakyll.Core.Identifier.Pattern
Description
As Identifier is used to specify a single item, a Pattern is used to
specify a list of items.
In most cases, globs are used for patterns.
A very simple pattern of such a pattern is "foo/bar". This pattern will
only match the exact foo/bar identifier.
To match more than one identifier, there are different captures that one can use:
"*": matches at most one element of an identifier;"**": matches one or more elements of an identifier.
Some examples:
"foo/*"will match"foo/bar"and"foo/foo", but not"foo/bar/qux";"**"will match any identifier;"foo/**"will match"foo/bar"and"foo/bar/qux", but not"bar/foo";"foo/*.html"will match all HTML files in the"foo/"directory.
The capture function allows the user to get access to the elements captured
by the capture elements in a glob or regex pattern.
Synopsis
- data Pattern
- fromGlob :: String -> Pattern
- fromList :: [Identifier] -> Pattern
- fromRegex :: String -> Pattern
- fromVersion :: Maybe String -> Pattern
- hasVersion :: String -> Pattern
- hasNoVersion :: Pattern
- (.&&.) :: Pattern -> Pattern -> Pattern
- (.||.) :: Pattern -> Pattern -> Pattern
- complement :: Pattern -> Pattern
- matches :: Pattern -> Identifier -> Bool
- filterMatches :: Pattern -> [Identifier] -> [Identifier]
- capture :: Pattern -> Identifier -> Maybe [String]
- fromCapture :: Pattern -> String -> Identifier
- fromCaptures :: Pattern -> [String] -> Identifier
The pattern type
Type that allows matching on identifiers
Creating patterns
fromList :: [Identifier] -> Pattern Source #
Create a Pattern from a list of Identifiers it should match.
Warning: use this carefully with hasNoVersion and hasVersion. The
Identifiers in the list already have versions assigned, and the pattern
will then only match the intersection of both versions.
A more concrete example,
fromList ["foo.markdown"] .&&. hasVersion "pdf"
will not match anything! The "foo.markdown" Identifier has no version
assigned, so the LHS of .&&. will only match this Identifier with no
version. The RHS only matches Identifiers with version set to "pdf" --
hence, this pattern matches nothing.
The correct way to use this is:
fromList $ map (setVersion $ Just "pdf") ["foo.markdown"]
fromVersion :: Maybe String -> Pattern Source #
Create a pattern which matches all items with the given version.
hasVersion :: String -> Pattern Source #
Specify a version, e.g.
"foo/*.markdown" .&&. hasVersion "pdf"
hasNoVersion :: Pattern Source #
Match only if the identifier has no version set, e.g.
"foo/*.markdown" .&&. hasNoVersion
Composing patterns
(.&&.) :: Pattern -> Pattern -> Pattern infixr 3 Source #
&& for patterns: the given identifier must match both subterms
(.||.) :: Pattern -> Pattern -> Pattern infixr 2 Source #
|| for patterns: the given identifier must match any subterm
complement :: Pattern -> Pattern Source #
Inverts a pattern, e.g.
complement "foo/bar.html"
will match anything except "foo/bar.html"
Applying patterns
filterMatches :: Pattern -> [Identifier] -> [Identifier] Source #
Given a list of identifiers, retain only those who match the given pattern
Capturing strings
capture :: Pattern -> Identifier -> Maybe [String] Source #
Match a glob or regex pattern against an identifier, generating a list of captures
fromCapture :: Pattern -> String -> Identifier Source #
Create an identifier from a pattern by filling in the captures with a given string
Example:
fromCapture (fromGlob "tags/*") "foo"
Result:
"tags/foo"
fromCaptures :: Pattern -> [String] -> Identifier Source #
Create an identifier from a pattern by filling in the captures with the given list of strings