Safe Haskell | None |
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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 the pattern.
- 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] -> PatternSource
Create a Pattern
from a list of Identifier
s it should match.
Warning: use this carefully with hasNoVersion
and hasVersion
. The
Identifier
s 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 Identifier
s 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 -> PatternSource
Create a pattern which matches all items with the given version.
hasVersion :: String -> PatternSource
Specify a version, e.g.
"foo/*.markdown" .&&. hasVersion "pdf"
Match only if the identifier has no version set, e.g.
"foo/*.markdown" .&&. hasNoVersion
Composing patterns
(.&&.) :: Pattern -> Pattern -> PatternSource
&&
for patterns: the given identifier must match both subterms
(.||.) :: Pattern -> Pattern -> PatternSource
||
for patterns: the given identifier must match any subterm
complement :: Pattern -> PatternSource
Inverts a pattern, e.g.
complement "foo/bar.html"
will match anything except "foo/bar.html"
Applying patterns
matches :: Pattern -> Identifier -> BoolSource
Check if an identifier matches a pattern
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 against a pattern, generating a list of captures
fromCapture :: Pattern -> String -> IdentifierSource
Create an identifier from a pattern by filling in the captures with a given string
Example:
fromCapture (parseGlob "tags/*") "foo"
Result:
"tags/foo"
fromCaptures :: Pattern -> [String] -> IdentifierSource
Create an identifier from a pattern by filling in the captures with the given list of strings