Module

Prim.TypeError

The Prim.TypeError module is embedded in the PureScript compiler. Unlike Prim, it is not imported implicitly. It contains type classes that provide custom type error and warning functionality.

#Warn

class Warn (message :: Doc) 

The Warn type class allows a custom compiler warning to be displayed.

For more information, see the Custom Type Errors guide.

#Fail

class Fail (message :: Doc) 

The Fail type class is part of the custom type errors feature. To provide a custom type error when someone tries to use a particular instance, write that instance out with a Fail constraint.

For more information, see the Custom Type Errors guide.

#Doc

kind Doc

Doc is the kind of type-level documents.

This kind is used with the Fail and Warn type clases. Build up a Doc with Text, Quote, QuoteLabel, Beside, and Above.

#Text

data Text :: Symbol -> Doc

The Text type constructor makes a Doc from a Symbol to be used in a custom type error.

For more information, see the Custom Type Errors guide.

#Quote

data Quote :: Type -> Doc

The Quote type constructor renders any concrete type as a Doc to be used in a custom type error.

For more information, see the Custom Type Errors guide.

#QuoteLabel

data QuoteLabel :: Symbol -> Doc

The QuoteLabel type constructor will produce a Doc when given a Symbol. When the resulting Doc is rendered for a Warn or Fail constraint, a syntactically valid label will be produced, escaping with quotes as needed.

For more information, see the Custom Type Errors guide.

#Beside

data Beside :: Doc -> Doc -> Doc

The Beside type constructor combines two Docs horizontally to be used in a custom type error.

For more information, see the Custom Type Errors guide.

#Above

data Above :: Doc -> Doc -> Doc

The Above type constructor combines two Docs vertically in a custom type error.

For more information, see the Custom Type Errors guide.