[Haskell-cafe] Bikeshedding request for GHCi's :type

Eric Seidel eric at seidel.io
Mon May 2 20:47:35 UTC 2016

On Mon, May 2, 2016, at 13:39, Richard Eisenberg wrote:
> On May 2, 2016, at 4:36 PM, Eric Seidel <eric at seidel.io> wrote:
> > Also, I'd suggest making (1) and (2) optional flags for :type rather
> > than new top-level commands. The shared prefix already suggests a common
> > purpose, printing out the type of something, so why not make it even
> > clearer that (1) and (2) are just specializations (heh) of :type?
> Others have echoed this and I'm open to the idea. But I, personally,
> dislike this. All three commands are useful, and I expect I'll want to
> frequently interleave which one I want during a GHCi session. Controlling
> via a flag makes this awkward.
> But that's just my 2¢.

Ah, I was talking about a different kind of flag this time.

Instead of a GHCi-level flag (or maybe in addition to..), I was thinking
about a flag specifically associated with an invocation of :type, e.g.

  ghci> :type length
  Foldable t => t a -> Int
  ghci> :type -default length
  [a] -> Int

It's very nitpicky, I know, but I think the added grouping would be
nice, in particular w.r.t. the output of :help.


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