Safe Haskell | None |
---|---|
Language | Haskell2010 |
Overloaded plugin, which makes magic possible.
Documentation
Overloaded
plugin.
To enable plugin put the following at top of the module:
{-# OPTIONS -fplugin=Overloaded -fplugin-opt=Overloaded:Symbols #-}
At least one option is required, multiple can given
either using multiple -fplugin-opt
options, or by separating options
with colon:
{-# OPTIONS -fplugin=Overloaded -fplugin-opt=Overloaded:Symbols:Numerals #-}
Options also take optional desugaring names, for example
{-# OPTIONS -fplugin=Overloaded -fplugin-opt=Overloaded:Labels=Data.Generics.ProductFields.field #-}
to desugar OverloadedLabels
directly into field
from generics-lens
(no need to import orphan instance!)
Supported options
Symbols
desugars literal strings tofromSymbol
@symStrings
works like built-inOverloadedStrings
(but you can use different method thanfromString
)Numerals
desugars literal numbers tofromNumeral
@natNaturals
desugars literal numbers to
(i.e. likefromNatural
natfromString
)Chars
desugars literal characters to
. Note: there isn't type-level alternative: we cannot promotefromChars
cChar
s.Lists
is not like built-inOverloadedLists
, but desugars explicit lists tocons
andnil
If
desugarsif
-expressions toifte
b t eLabels
works like built-inOverloadedLabels
(you should enableOverloadedLabels
so parser recognises the syntax)
Known limitations
- Doesn't desugar inside patterns