The module is renamed to `Mark`, and functions renamed to avoid redundancy:
`Marked.mark` is now `Mark.add`
`Marked.unmark` is now `Mark.remove`
`Marked.map_under_mark` is now simply `Mark.map`
etc.
`Marked.same_mark_as` is replaced by `Mark.copy`, but with the arguments
swapped (which seemed more convenient throughout)
Since a type `Mark.t` would indicate a mark, and to avoid confusion, the type
`Marked.t` is renamed to `Mark.ed` as a shorthand for `Mark.marked` ; this part
can easily be removed if that's too much quirkiness.
The phantom polymorphic variant qualifying AST nodes is reversed:
- previously, we were explicitely restricting each AST node to the passes where it belonged using a closed type (e.g. `[< dcalc | lcalc]`)
- now, each node instead declares the "feature" it provides using an open type (e.g. `[> 'Exceptions ]`)
- then the AST for a specific pass limits the features it allows with a closed type
The result is that you can mix and match all features if you wish,
even if the result is not a valid AST for any given pass. More
interestingly, it's now easier to write a function that works on
different ASTs at once (it's the inferred default if you don't write a
type restriction).
The opportunity was also taken to simplify the encoding of the
operators, which don't need a second type parameter anymore.
Previously the `state` marker for rules was in a weird position:
```catala
rule foo under condition bar
consequence state st fulfilled
```
This patch unifies the syntax with definitions, now using instead:
```catala
rule foo state st
under condition bar
consequence fulfilled.
```
This adds a few positions to the parser, and tweaks some others, vastly
improving the reporting of some errors (inconsistent functions definitions, but
also exceptions cycles, etc.)
* temporary and undocumented while waiting for discussion an approval
* previous patches already allowed definition (at toplevel) but there was no
syntax for calls
* no syntax for multi-args _local_ functions yet
... that's one less thing to do
Two notes:
- Updated the syntax errors in
examples/NSW_community_gaming/tests/test_nsw_social_housie.catala_en ; those
probably aren't expected though, but fixing them is outside my purpose here
- There is consensus on keeping the error messages in English; however, here,
the error messages include hints on the syntax to use, which are only valid
for users of the English syntax.
* A possible solution would be to apply cppo on parser.messages, using the
macros already defined in lexer_LANG.cppo.ml. However, we would then need to
tweak (or duplicate!) the parser to use the messages for the correct language.
Furthermore, updating and merging the file on parser updates would need
special care.
* Another, maybe easier solution would be manual processing, using a custom
escape in the parser messages and rewriting that at runtime when printing
the message. We would need to extract a runtime version of the macro
definitions though.
Using them will lead to "not supported yet" errors soon after, but it's a start
to get to handling separate modules.
The idea is that `foo` can now also be `Bar.foo`, `Bar.Baz.foo`, `foo.Struc.fld`
can be `foo.Bar.Baz.Struc.fld`, etc.
The next steps are to enable the lookups to handle this paths, and to provide
ways to load the external modules to feed these lookups.
Closes#373
This forbids expressions such as `a and b or c`, avoiding the need to set an
implicit priority between `and`, `or` and `xor`, which I find error-prone.
Instead, when that appears, a message asking for explicit parentheses will be
shown to the user.
Implementation note: since that would be extremely tedious to do in the parser
directly, the parser is set to allow right-associativity without discrimination
for the logical operators, and the check is done during desugaring. This
required to explicit parentheses in the surface AST to discriminate the case
where the priority was explicit.
In particular `CONSTRUCTOR` is no longer valid for paths & modules, so let's
switch to the more usual LIDENT / UIDENT for lower- or upper- case idents.
cd compiler/surface
sed -i 's/VERTICAL/BAR/g' *
sed -i 's/BRACKET/BRACE/g' *
sed -i 's/SQUARE/BRACKET/g' *
sed -i 's/IDENT/LIDENT/g' *
sed -i 's/CONSTRUCTOR/UIDENT/g' *
Define a single expression rule with disambiguation using token priorities
instead of the many layers of intermediate rules with explicit sub-terms.
Also replaces `in` for collection operations (`x+1 for foo in [1;2]`) with
`among` which helps a lot.
This uses the same disambiguation mechanism put in place for
structures, calling the typer on individual rules on the desugared AST
to propagate types, in order to resolve ambiguous operators like `+`
to their strongly typed counterparts (`+!`, `+.`, `+$`, `+@`, `+$`) in
the translation to scopelang.
The patch includes some normalisation of the definition of all the
operators, and classifies them based on their typing policy instead of
their arity. It also adds a little more flexibility:
- a couple new operators, like `-` on date and duration
- optional type annotation on some aggregation constructions
The `Shared_ast` lib is also lightly restructured, with the `Expr`
module split into `Type`, `Operator` and `Expr`.
Many changes got bundled in here and would be too tedious to separate.
Closes#330
See changes in `shared_ast/definitions.ml` to check the main point.
- the biggest change is a modification of the struct and enum types in
expressions: they are now stored as `Map`s throughout passes, and no longer
converted to indexed lists after scopelang. Their accessors are also changed,
and tuples only exist in Lcalc (they're used for closure conversion).
This implied adding some more information in the contexts, to keep the mapping
between struct fields and scope output variables. It should also be much more
robust (no longer relying on assumptions upon different orderings).
- another very pervasive change is more cosmetic: the rewrite of the main AST to
use inline records, labelling individual subfields.
- moved the checks for correct definitions and accesses of structures from
`Scope_to_dcalc` to `Typing`
- defining some new shallow iterators in module `Shared_ast.Expr`, and
factorising a few same-pass rewriting functions accordingly (closure
conversion, optimisations, etc.)
- some smaller style improvements (ensuring we use the proper compare/equal
functions instead of `=` in a few `when` closes, for example)
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...)
This was the only reasonable solution I found to the issue raised
[here](https://github.com/CatalaLang/catala/pull/334#discussion_r987175884).
This was a pretty tedious rewrite, but it should now ensure we are doing things
correctly. As a bonus, the "smart" expression constructors are now used
everywhere to build expressions (so another refactoring like this one should be
much easier) and this makes the code overall feel more
straightforward (`Bindlib.box_apply` or `let+` no longer need to be visible!)
---
Basically, we were using values of type `gexpr box = naked_gexpr marked box`
throughout when (re-)building expressions. This was done 99% of the time by
using `Bindlib.box_apply add_mark naked_e` right after building `naked_e`. In
lots of places, we needed to recover the annotation of this expression later on,
typically to build its parent term (to inherit the position, or build the type).
Since it wasn't always possible to wrap these uses within `box_apply` (esp. as
bindlib boxes aren't a monad), here and there we had to call `Bindlib.unbox`,
just to recover the position or type. This had the very unpleasant effect of
forcing the resolution of the whole box (including applying any stored closures)
to reach the top-level annotation which isn't even dependant on specific
variable bindings. Then, generally, throwing away the result.
Therefore, the change proposed here transforms
- `naked_gexpr marked Bindlib.box` into
- `naked_gexpr Bindlib.box marked` (aliased to `boxed_gexpr` or `gexpr boxed` for
convenience)
This means only
1. not fitting the mark into the box right away when building, and
2. accessing the top-level mark directly without unboxing
The functions for building terms from module `Shared_ast.Expr` could be changed
easily. But then they needed to be consistently used throughout, without
manually building terms through `Bindlib.apply_box` -- which covers most of the
changes in this patch.
`Expr.Box.inj` is provided to swap back to a box, before binding for example.
Additionally, this gives a 40% speedup on `make -C examples pass_all_tests`,
which hints at the amount of unnecessary work we were doing --'
Note that this is incomplete in the case of desugared/scopelang because we only
have typing for expressions yet, and the scope/program structure is different.
The code allows passing an environment of types for scope/subscope variables in
order to resolve `ELocation` terms, but that's unused until we implement
scopelang typing at the scope level.
Also add some safeguards against bad propagation of types (e.g. checking the
arrow type of functions upon application); partly disabled at the moment since
they don't pass yet but that'll be further work.
