[Agda] Quirk: C-c C-n thinks that some symbols are not in scope

[Jesper Cockx]

Hi Eduardo,

C-c c-n evaluates the given expression in the scope of the current module
as it looks like from the outside (i.e. as if you import the module
somewhere else). In particular, this scope does not include symbols from
modules you have opened, unless they have been opened publicly. So I expect
you can solve your problem by adding 'public' to the end of your open
statements, e.g. 'open Add "2" public'.

-- Jesper

On Tue, Feb 1, 2022 at 8:12 PM Eduardo Ochs <eduardoochs at gmail.com> wrote:

> Hello list,
>
> I think that I found a quirk on the behavior of `C-c C-n'. When I was
> trying to write a minimal example that showed the problem I wrote
> this, that isn't really minimal but that should be minimal enough...
>
>   module NameOfThisFile where
>
>   open import Agda.Builtin.String
>   open import Agda.Builtin.String.Properties
>
>   infixl 4 _++_
>   _++_ : String -> String -> String
>   _++_ str1 str2 = primStringAppend str1 str2
>
>   module Add (i : String) where
>     infixl 4 _+++_
>     add   : String -> String -> String
>     add   a b = "(" ++ a ++ " +_" ++ i ++ " " ++ b ++ ")"
>     _+++_ : String -> String -> String
>     _+++_ a b = add a b
>
>   module Add0 = Add "0"
>   module Add1 = Add "1"
>   -- open Add0
>   open          Add "2"
>
>   aa : String
>   aa = "AAA"
>   bb : String
>   bb = "BBB"
>   cc : String
>   cc = aa +++ bb
>
>   -- (find-agdanorm "aa ++ bb")
>   -- (find-agdanorm "Add.add   \"4\" aa bb")
>   -- (find-agdanorm "Add0.add        aa bb")
>   -- (find-agdanorm "Add._+++_ \"9\" aa bb")
>   -- (find-agdanorm "Add0._+++_      aa bb")
>   -- (find-agdanorm "aa Add0.+++ bb")
>   -- (find-agdanorm "aa +++ bb")
>   -- (find-agdanorm "_+++_")
>   -- (find-agdatype "_+++_")
>   -- (find-agdanorm "cc")
>
> The sexps like (find-agdanorm "<expr>") in comments use a hack that I
> wrote that is simple to explain. The docstring of find-agdanorm is:
>
>   (find-agdanorm AGDAEXPR &rest REST)
>
>   Show the normalized value  of AGDAEXPR in the buffer "*Normal Form*".
>   This function goes to the beginning of the Agda comment in the
>   current line, i.e., to the first occurrence of "--" in the
>   current line, and the runs ‘C-c C-n AGDAEXPR RET’ there.
>   This only works in agda2-mode. This is a quick hack!
>
> If I go to the beginning of the line with the
>
>   -- (find-agdanorm "aa +++ bb")
>
> and I type `C-c C-n aa +++ bb RET' there - or if I execute the sexp -
> Agda tells me that the _+++_ is not in scope, and the same happens
> with this one here:
>
>   -- (find-agdanorm "_+++_")
>
> I get the same "Not in scope" if I use `C-c C-d _+++_' to get the type
> of _+++_... but the last sexp,
>
>   -- (find-agdanorm "cc")
>
> works, and it shows that the normalized value of cc is this:
>
>   "(AAA +_2 BBB)"
>
> All the other sexps work as expected without errors.
>
> Is that behavior documented? It seems that `C-c C-n' and `C-c C-d' are
> ignoring some symbols that were brought into scope by this line,
>
>   open          Add "2"
>
> and for me this is unexpected & bad.
>
> I am using Agda 2.6.1.3 - I don't have the current version here.
> I've put more info, links, and a screenshot in this page:
>
>   http://angg.twu.net/eev-agda.html
>
> Thanks in advance!
>   Eduardo Ochs
>   http://angg.twu.net/#eev
>
> _______________________________________________
> Agda mailing list
> Agda at lists.chalmers.se
> https://lists.chalmers.se/mailman/listinfo/agda
>
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