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...)
Pass along a bindlib context to allow the variable names to be altered only when
disambiguation is needed. Partial fix to #240 (doesn't affect the backends, only
the printer for the intermediate ASTs).
This also has the benefit of making the output of the tests much more stable.
These are just variable renumberings, and type error message changes but still
pointing to the same information; the latter are slightly better in general,
pointing to actual expressions rather than scope declarations.
Nothing shocking here:
- division by zero now reported on the application rather than the
operator
- renumbering of printed bindlib variables
- some whitespace changes
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
```
