[GHC] #13437: Easier editing of multi-line GHCi-commands

[GHC]

#13437: Easier editing of multi-line GHCi-commands
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        Reporter:  fredefox          |                Owner:  (none)
            Type:  feature request   |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.0.1
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Description changed by fredefox:

Old description:

> In my terminal emulator I can write something like:
>
> {{{
> cat > /dev/null << EOF
> bla
> bla
> bla
> EOF
> }}}
>
> If I later want to edit something in this command I can recall the
> command from history and I can navigate to the line I want to change. In
> GHCi this is not possible, the history only recalls *one line* at a time.
> It would be nice if it recognized commands entered using {{{ :{ ... }:
> }}} and would give you that whole command when recalling commands from
> the history.
>
> Also, it would be very handy if doing e.g. Shift+Enter would insert a
> newline into your multi-line command rather than run the command.
>
> Furthermore, it could also serve as a handy shortcut for engaging the
> multi-line command mode. So say you were sitting at the prompt {{{ > }}}
> and you then hit enter, then GHCi moves to a new-line but has inserted
> the {{{ :{ }}} part for you, it could similarly close the command for you
> when you hit Enter (without holding down the modifier key).
>
> I believe this change would make GHCi's multi-line command mode way more
> useful. Currently I very seldomly (if ever) use GHCi for anything other
> than one-liners. This means that I usually have to edit the source-file
> I'm currently working on to put things into scope (or try and formulate a
> long and awkward expression).

New description:

 In my terminal emulator I can write something like:

 {{{
 cat > /dev/null << EOF
 bla
 bla
 bla
 EOF
 }}}

 If I later want to edit something in this command I can recall the command
 from history and I can navigate to the line I want to change. In GHCi this
 is not possible, the history only recalls *one line* at a time. It would
 be nice if it recognized commands entered using {{{ :{ ... }: }}} and
 would give you that whole command when recalling commands from the
 history.

 Also, it would be very handy if doing holding down a modifier key when
 hitting enter (e.g. Shift) would insert a newline into your multi-line
 command rather than run the command.

 Furthermore, it could also serve as a handy shortcut for engaging the
 multi-line command mode. So say you were sitting at the prompt {{{ > }}}
 and you then hit Shift+Enter, then GHCi moves to a new-line but has
 inserted the {{{ :{ }}} part for you, it could similarly close the command
 for you when you hit Enter (without holding down the modifier key).

 I believe this change would make GHCi's multi-line command mode way more
 useful. Currently I very seldomly (if ever) use GHCi for anything other
 than one-liners. This means that I usually have to edit the source-file
 I'm currently working on to put things into scope (or try and formulate a
 long and awkward expression).

--

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13437#comment:1>
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