Ormolu.Printer.Operators

This module helps handle operator chains composed of different operators that may have different precedence and fixities.

Documentation

data OpTree ty op

Intermediate representation of operator trees, where a branching is not just a binary branching (with a left node, right node, and operator like in the GHC's AST), but rather a n-ary branching, with n + 1 nodes and n operators (n >= 1).

This representation allows us to put all the operators with the same precedence level as direct siblings in this tree, to better represent the idea of a chain of operators.

Constructors

OpNode ty

A node which is not an operator application

OpBranches [OpTree ty op] [op]

A subtree of operator application(s); the invariant is: length exprs == length ops + 1. OpBranches [x, y, z] [op1, op2] represents the expression x op1 y op2 z.

Instances

(Show ty, Show op) => Show (OpTree ty op)

Defined in Ormolu.Printer.Operators

Methods

showsPrec :: Int -> OpTree ty op -> ShowS

show :: OpTree ty op -> String

showList :: [OpTree ty op] -> ShowS

(Eq ty, Eq op) => Eq (OpTree ty op)

Defined in Ormolu.Printer.Operators

Methods

(==) :: OpTree ty op -> OpTree ty op -> Bool

(/=) :: OpTree ty op -> OpTree ty op -> Bool

data OpInfo op

Wrapper for an operator, carrying information about its name and fixity.

Constructors

OpInfo

Fields

• opiOp :: op

  The actual operator

• opiName :: Maybe String

  Its name, if available. We use 'Maybe String' here instead of String because the name-fetching function received by reassociateOpTree returns a Maybe

• opiFix :: FixityInfo

  Information about the fixity direction and precedence level of the operator

Instances

Eq op => Eq (OpInfo op)

Defined in Ormolu.Printer.Operators

Methods

(==) :: OpInfo op -> OpInfo op -> Bool

(/=) :: OpInfo op -> OpInfo op -> Bool

opTreeLoc :: HasSrcSpan l => OpTree (GenLocated l a) b -> SrcSpan

Return combined SrcSpans of all elements in this OpTree.

reassociateOpTree

Arguments

:: (op -> Maybe RdrName)

How to get name of an operator

-> FixityMap

Fixity overrides

-> LazyFixityMap

Fixity Map

-> OpTree ty op

Original OpTree

-> OpTree ty (OpInfo op)

Re-associated OpTree, with added context and info around operators

Re-associate an OpTree taking into account precedence of operators. Users are expected to first construct an initial OpTree, then re-associate it using this function before printing.

isHardSplitterOp :: FixityInfo -> Bool

Indicate if an operator has InfixR 0 fixity. We special-case this class of operators because they often have, like ($), a specific “separator” use-case, and we sometimes format them differently than other operators.