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juvix/test/Scope
Jan Mas Rovira 2c8a364143
New syntax for function definitions (#2243)
- Closes #2060
- Closes #2189


- This pr adds support for the syntax described in #2189. It does not
drop support for the old syntax.

It is possible to automatically translate juvix files to the new syntax
by using the formatter with the `--new-function-syntax` flag. E.g.

```
juvix format --in-place --new-function-syntax
```
# Syntax changes
Type signatures follow this pattern:
```
f (a1 : Expr) .. (an : Expr) : Expr
```
where each `ai` is a non-empty list of symbols. Braces are used instead
of parentheses when the argument is implicit.

Then, we have these variants:
1. Simple body. After the signature we have `:= Expr;`.
2. Clauses. The function signature is followed by a non-empty sequence
of clauses. Each clause has the form:
```
| atomPat .. atomPat := Expr
```
# Mutual recursion
Now identifiers **do not need to be defined before they are used**,
making it possible to define mutually recursive functions/types without
any special syntax.
There are some exceptions to this. We cannot forward reference a symbol
`f` in some statement `s` if between `s` and the definition of `f` there
is one of the following statements:
1. Local module
2. Import statement
3. Open statement

I think it should be possible to drop the restriction for local modules
and import statements
2023-07-10 19:57:55 +02:00
..
Negative.hs New syntax for function definitions (#2243) 2023-07-10 19:57:55 +02:00
Positive.hs New syntax for function definitions (#2243) 2023-07-10 19:57:55 +02:00