[Agda] hints on switching between Agda versions

[Andrew Pitts]

Following up my own question, I did a bit of RTFM-style research and
found that one can use cabal to install into a sandbox. Combining this
with Jesper's suggerstion I did:

git clone https://github.com/agda/agda.git
cd agda
cabal update
cabal sandbox init
cabal install --program-suffix=-2.6.0

This creates some binaries in .cabal-sandbox/bin whose names end with
-2.6.0 (in particular agda-2.6.0 and agda-mode-2.6.0) that can then be
linked to wherever your main agda binaries reside. Switching version
within emacs is then just a matter of typing 2.6.0 RET after selecting
the "Switch to another version of Agda" item in the Agda menu (after
the switch that menu item acquires a key binding (^C^X^S) that it does
not have before -- which is somewhat weird).

Andy

On 17 November 2016 at 14:55, Andrew Pitts <Andrew.Pitts at cl.cam.ac.uk> wrote:
> Hi Jesper.
>
> On 17 November 2016 at 11:34, Jesper Cockx <Jesper at sikanda.be> wrote:
>> This is what I noticed:
>>
>> If you run 'cabal install' with the option '--program-suffix=-xxx', then
>> Agda will be installed under the name agda-xxx. You can then switch Agda versions using the emacs command by entering the name of the binary.
>
> Thanks for that tip, which sounds good. I currently have Agda-2.5.1.1
> installed and I want to install the development version (that's
> 2.6.0-something, I guess). So following instructions at
> <http://wiki.portal.chalmers.se/agda/agda.php?n=Main.Download> and
> then at <https://github.com/agda/agda/blob/master/README.md#installing-agda>
> I have typed the following at a command prompt:
>
> git clone https://github.com/agda/agda.git
> cd agda
> cabal update
>
>
> and then using your tip
>
> cabal install --program-suffix=-2.6.0
>
>
> and cabal says
>
> Resolving dependencies...
> In order, the following would be installed:
> fail-4.9.0.0 (via: Agda-2.6.0) (new package)
> gitrev-1.2.0 (via: Agda-2.6.0) (new package)
> ieee754-0.7.9 (via: Agda-2.6.0) (new package)
> murmur-hash-0.1.0.9 (via: Agda-2.6.0) (new package)
> regex-tdfa-1.2.2 (via: Agda-2.6.0) (new package)
> transformers-compat-0.5.1.4 (via: Agda-2.6.0 tagged-0.8.5
> equivalence-0.3.1) (new version)
> equivalence-0.3.1 (via: Agda-2.6.0) (reinstall) (changes:
> transformers-compat-0.4.0.4 -> 0.5.1.4)
> tagged-0.8.5 (via: semigroups-0.18.2) (new package)
> semigroups-0.18.2 -bytestring-builder (via: Agda-2.6.0) (new package)
> Agda-2.6.0 (new version)
> cabal: The following packages are likely to be broken by the reinstalls:
> Agda-2.5.1.1
> Agda-2.5.1
> Agda-2.4.2.5
> Use --force-reinstalls if you want to install anyway.
>
> and I'm not sure I really want to run
>
> cabal install --program-suffix=-2.6.0 --force-reinstalls
>
>
> in case cabal is right and my Agda-2.5.1.1 gets screwed up.
>
> Am I just being too faint hearted?
>
> Andy