Normally I would make sure this is not by default, or at leat disableable; but
here the code we print may contain utf8 anyway, so the terminal really needs to
support it. Anyway, it's just a little fancier, doesn't add much.
a quick fix for now, ideally we want an option for editor-friendly output.
But for now this is a very cheap way to at least have clickable error messages
which are a big time-saver.
Quite a few changes are included here, some of which have some extra
implications visible in the language:
- adds the `Scope of { -- input_v: value; ... }` construct in the language
- handle it down the pipeline:
* `ScopeCall` in the surface AST
* `EScopeCall` in desugared and scopelang
* expressions are now traversed to detect dependencies between scopes
* transformed into a normal function call in dcalc
- defining a scope now implicitely defines a structure with the same name, with
the output variables of the scope defined as fields. This allows us to type
the return value from a scope call and access its fields easily.
* the implications are mostly in surface/name_resolution.ml code-wise
* the `Scope_out` struct that was defined in scope_to_dcalc is no longer
needed/used and the fields are no longer renamed (changes some outputs; the
explicit suffix for variables with multiple states is ignored as well)
* one benefit is that disambiguation works just like for structures when there
are conflicts on field names
* however, it's now a conflict if a scope and a structure have the same
name (side-note: issues with conflicting enum / struct names or scope
variables / subscope names were silent and are now properly reported)
- you can consequently use scope names as types for variables as well. Writing
literals is not allowed though, they can only be obtained by calling the
scope.
Remaining TODOs:
- context variables are not handled properly at the moment
- error handling on invalid calls
- tests show a small error message regression; lots of examples will need
tweaking to avoid scope/struct name or struct fields / output variable
conflicts
- add a `->` syntax to make struct field access distinct from scope output var
access, enforced with typing. This is expected to reduce confusion of users
and add a little typing precision.
- document the new syntax & implications (tutorial, cheat-sheet)
- a consequence of the changes is that subscope variables also can now be typed.
A possible future evolution / simplification would be to rewrite subscopes as
explicit scope calls early in the pipeline. That could also allow to manipulate
them as expressions (bind them in let-ins, return them...)
I removed the '.out' extension for now to preserve the test output file names and avoid a million file renames.
This makes the patch easier to read, and we can do the rename easily in another patch afterwards, without mixing with semantic changes.
(beautiful script àlarrache:
```bash
for f in */*/output/*; do
target_base=${f##*/}
target_base=${target_base%%.*}
echo $f | awk -F. '{
f=$1"."$2; if ($4 == "") { mode=$3; id=$3 } else { scope="-s "$3; mode=$4; id=$3"."$4}
printf "\n```catala-test {id=\"%s\"}\ncatala %s %s\n```\n",id,mode,scope;
}' >> $(dirname $f)/../${target_base}.*; done
```
