Language.Haskell.Syntax.Expr

RecordDotSyntax field updates

Haskell Record Update Fields.

Located Haskell Expression

Syntax Expression

SyntaxExpr is represents the function used in interpreting rebindable syntax. In the parser, we have no information to supply; in the renamer, we have the name of the function (but see Note [Monad fail : Rebindable syntax, overloaded strings] for a wrinkle) and in the type-checker we have a more elaborate structure SyntaxExprTc.

In some contexts, rebindable syntax is not implemented, and so we have constructors to represent that possibility in both the renamer and typechecker instantiations.

E.g. (>>=) is filled in before the renamer by the appropriate Name for (>>=), and then instantiated by the type checker with its type args etc

A Haskell expression.

A pragma, written as {-# ... #-}, that may appear within an expression.

Located Haskell Tuple Argument

HsTupArg is used for tuple sections (,a,) is represented by ExplicitTuple [Missing ty1, Present a, Missing ty3] Which in turn stands for (x:ty1 y:ty2. (x,a,y))

Haskell Tuple Argument

Which kind of lambda case are we dealing with?

Located Haskell Command (for arrow syntax)

Haskell Command (e.g. a "statement" in an Arrow proc block)

Haskell arrow application type.

Top-level command, introducing a new arrow. This may occur inside a proc (where the stack is empty) or as an argument of a command-forming operator.

Located Haskell Top-level Command

Haskell Top-level Command

Haskell Record Bindings

Located Match

Guarded Right-Hand Sides

GRHSs are used both for pattern bindings and for Matches

Located Guarded Right-Hand Side

Guarded Right Hand Side.

Located do block Statement

Located Statement with separate Left and Right id's

do block Statement

Command Located Statement

Command Statement

Expression Located Statement

Expression Statement

Guard Located Statement

Guard Statement

Ghci Located Statement

Ghci Statement

Parenthesised Statement Block

The fail operator

This is used for `.. <-` "bind statements" in do notation, including non-monadic "binds" in applicative.

The fail operator is 'Just expr' if it potentially fail monadically. if the pattern match cannot fail, or shouldn't fail monadically (regular incomplete pattern exception), it is Nothing.

See Note [Monad fail : Rebindable syntax, overloaded strings] for the type of expression in the Just case, and why it is so.

See Note [Failing pattern matches in Stmts] for which contexts for 'BindStmt's should use the monadic fail and which shouldn't.

Haskell Splice

Haskell (Untyped) Quote = Expr + Pat + Type + Var

Arithmetic Sequence Information

Haskell Match Context

Context of a pattern match. This is more subtle than it would seem. See Note [FunBind vs PatBind].

Haskell Statement Context.

Haskell arrow match context.

Is this a monadic context?