Claus Reinke wrote:
ghci's :def takes a 'String -> IO String' and converts it into a ghci command. this makes it possible to pass a command parameter to a haskell function, and to interpret the result of the call as a ghci command.
that is nice, but how do i get access to the command's output? that is, i'd like to run a ghci command, and capture its ouput as a haskell String, eg, to pass it on to another ghci command, or to a haskell function.
perhaps something simple, like an additional ghci top-level binding:
GHCi.cmd :: String -> IO String
so that i could write things like
let doSomething output = .. :def mymodules \_->GHCi.cmd ":show modules" >>= doSomething
or a way to compose ghci commands, so that i could write
:def doSomething \output->.. :def mymodules \_->return ":show modules :>>= :doSomething"
would that be difficult to provide?
It would be possible, but needs a bit of refactoring because all the output is currently just sent to stdout. I'd go with something like your second option, but perhaps add some new syntax:
:def mymodules \_->return "str <- :show modules; doSomething str"
Write up a feature request? Cheers, Simon