Package Info


Make functions consume Proxy instead of undefined


'proxied' is a simple library that exports a function to convert constant functions to ones that take a 'proxy' value in the "Data.Proxied" module. This is useful for retrofiting typeclasses that have functions that return a constant value for any value of a particular type (but still need to consume some value, since one of the parameterized types must appear in a typeclass function). Often, these functions are given 'undefined' as an argument, which might be considered poor design.

'Proxy', however, does not carry any of the error-throwing risks of 'undefined', so it is much more preferable to take 'Proxy' as an argument to a constant function instead of 'undefined'. Unfortunately, 'Proxy' was included in 'base' until GHC 7.8, so many of 'base''s typeclasses still contain constant functions that aren't amenable to passing 'Proxy'. 'proxied' addresses this issue by providing variants of those typeclass functions that take an explicit 'proxy' value.

This library also contains the "Data.Proxyless" module, which works in the opposite direction. That is, one can take functions which take 'Proxy' (or 'undefined') as an argument and convert them to functions which take no arguments. This trick relies on the '-XTypeApplications' extension, so it is only available with GHC 8.0 or later.

License: BSD-3-Clause



Package Version Update ID Released Package Hub Version Platforms Subpackages
0.3-bp150.2.4 info GA Release 2018-08-01 15
  • AArch64
  • ghc-proxied
  • ghc-proxied-devel
0.3-bp150.2.6 info GA Release 2018-07-30 15
  • ppc64le
  • x86-64
  • ghc-proxied
  • ghc-proxied-devel