Language.Haskell.Syntax.Pat

Wildcard Pattern, i.e. _

Variable Pattern, e.g. x

Lazy Pattern, e.g. ~x

As pattern, e.g. x@pat

Parenthesised pattern, e.g. (x)

Bang pattern, e.g. !x

Syntactic List, e.g. [x] or [x,y]. Note that [] and (x:xs) patterns are both represented using ConPat.

Tuple pattern, e.g. (x, y) (boxed tuples) or (# x, y #) (requires -XUnboxedTuples)

Or Pattern, e.g. (pat_1; ...; pat_n). Used by -XOrPatterns

Anonymous sum pattern, e.g. (# x | #). Used by -XUnboxedSums

Constructor Pattern, e.g. (), [] or Nothing

View Pattern, e.g. someFun -> pat. Used by -XViewPatterns

Splice Pattern, e.g. $(pat)

Literal Pattern

Used for non-overloaded literal patterns: Int#, Char#, Int, Char, String, etc.

Qualified Literal Pattern

Natural Pattern, used for all overloaded literals, including overloaded Strings with -XOverloadedStrings

n+k pattern, e.g. n+1, used by -XNPlusKPatterns

Pattern with a type signature, e.g. x :: Int

Embed the syntax of types into patterns, e.g. fn (type t) = rhs. Enabled by -XExplicitNamespaces in conjunction with -XRequiredTypeArguments.

Type abstraction which brings into scope type variables associated with invisible forall. E.g. fn @t ... = rhs. Used by -XTypeAbstractions.

Pattern with attached modifiers. See Note [Overview of Modifiers] and Note [Modifiers on patterns vs bindings]. E.g. (%X x) = ...

TTG Extension point; see Note [Trees That Grow] in Language.Haskell.Syntax.Extension