@MartinSchere noticed a weird error
where an unknown variable wasn't being reported
the type checker was incorrectly scoping
arguments for anonymous function definitions.
Luckily his compilation failed due to a FreeUnique
error during code gen which is good. But this may
have been the source of other mysterious FreeUnique
errors.
I also noticed that anonymous function allowed
arguments with the same name to be defined.
`fn(arg, arg)`
This now returns an error.
Params being unused were being incorrectly reported.
This was because params need to be initialized
at a scope above both the validator functions. This
manifested when using a multi-validator where one of
the params was not used in both validators.
The easy fix was to add a field called
`is_validator_param` to `ArgName`. Then
when infering a function we don't initialize args
that are validator params. We now handle this
in a scope that is created before in the match branch for
validator in the `infer_definition` function. In there
we call `.in_new_scope` and initialize params for usage
detection.
And disable multi-patterns clauses. I was originally just controlling
whether we did disable that from the parser but then I figured we
could actually support multi-patterns clauses quite easily by simply
desugaring a multi-pattern into multiple clauses.
This is only a syntactic sugar, which means that the cost of writing
that on-chain is as expensive as writing the fully expanded form; yet
it seems like a useful shorthand; especially for short clause
expressions.
This commit however disables multi-pattern when clauses, which we do
not support in the code-generation. Instead, one pattern on tuples for
that.
Isolated doc comments causes the compiler to panic with:
```
'no consecutive empty lines'
```
This is reproducible when doc comments are wrapped in sandwich between
comments and newlines.
The typed-AST produced as a result of type-checking the program will
no longer contain unused let-bindings. They still raise warnings in
the code so that developers are aware that they are being ignore.
This is mainly done to prevent mistakes for people coming from an
imperative background who may think that things like:
```
let _ = foo(...)
```
should have some side-effects. It does not, and it's similar to
assigned variables that are never used / evaluated. We now properly
strip those elements from the AST when encountered and raise proper
warnings, even for discarded values.
This leads to more consistent formatting across entire Aiken programs.
Before that commit, only long expressions would be formatted on a
newline, causing non-consistent formatting and additional reading
barrier when looking at source code.
Programs also now take more vertical space, which is better for more
friendly diffing in version control systems (especially git).
Rules are now as follows:
- If a pipeline contains a newline, then the entire pipeline is formatted over multiple lines.
- If it doesn't, then it's formatted as a single-line UNLESS it cannot fit; in which case, we fallback to multiline again.
This has been bothering me and the more I thought of it the more I
disliked the idea of a warning. The rationale being that in this very
context, there's absolutely no ambiguity. So it is only frustrating
that the parser is even able to make the exact suggestion of what
should be fixed, but still fails.
I can imagine it is going to be very common for people to type:
```
trace "foo"
```
...yet terribly frustrating if they have to remember each time that
this should actually be a string. Because of the `trace`, `todo` and
`error` keywords, we know exactly the surrounding context and what to
expect here. So we can work it nicely.
However, the formatter will re-format it to:
```
trace @"foo"
```
Just for the sake of remaining consistent with the type-system. This
way, we still only manipulate `String` in the AST, but we conveniently
parse a double-quote utf-8 literal when coupled with one of the
specific keywords.
I believe that's the best of both worlds.
This will probably save people minutes/hours of puzzled debugging. This is only a warning because there may be cases where one do actually want to specify an hex-encoded bytearray. In which case, they can get rid of the warning by using the plain bytearray syntax (i.e. as an array of bytes).
The core observation is that **in the context of Aiken** (i.e. on-chain logic)
people do not generally want to use String. Instead, they want
bytearrays.
So, it should be easy to produce bytearrays when needed and it should
be the default. Before this commit, `"foo"` would parse as a `String`.
Now, it parses as a `ByteArray`, whose bytes are the UTF-8 bytes
encoding of "foo".
Now, to make this change really "fool-proof", we now want to:
- [ ] Emit a parse error if we parse a UTF-8 bytearray literal in
place where we would expect a `String`. For example, `trace`,
`error` and `todo` can only be followed by a `String`.
So when we see something like:
```
trace "foo"
```
we know it's a mistake and we can suggest users to use:
```
trace @"foo"
```
instead.
- [ ] Emit a warning if we ever see a bytearray literals UTF-8, which
is either 56 or 64 character long and is a valid hexadecimal string.
For example:
```
let policy_id = "29d222ce763455e3d7a09a665ce554f00ac89d2e99a1a83d267170c6"
```
This is _most certainly_ a mistake, as this generates a ByteArray of
56 bytes, which is effectively the hex-encoding of the provided string.
In this scenario, we want to warn the user and inform them they probably meant to use:
```
let policy_id = #"29d222ce763455e3d7a09a665ce554f00ac89d2e99a1a83d267170c6"
```
This caused me some trouble. In my first approach, I ended up having
multiple traces because nested values would be evaluated twice; once
as condition, and once as part of the continuation.
To prevent this, we can simply evaluate the condition once, and return
plain True / False boolean as outcome. So this effectively transforms any
expression:
```
expr
```
as
```
if expr { True } else { trace("...", False) }
```
Interestingly enough, chumsky seems to fail when given a 'choice' with
more than 25 elements. That's why this commit groups together some of
the choices as another nested 'choice'.
Todo is fundamentally just a trace and an error. The only reason we kept it as a separate element in the AST is for the formatter to work out whether it should format something back to a todo or something else.
However, this introduces redundancy in the code internally and makes the AIR more complicated than it needs to be. Both todo and errors can actually be represented as trace + errors, and we only need to record their preferred shape when parsing so that we can format them back to what's expected.
We now parse errors as a combination of a trace plus and error term. This is a baby step in order to simplify the code generation down the line and the internal representation of todo / errors.
This however enforces that the argument unifies to a `String`. So this
is more flexible than the previous form, but does fundamentally the
same thing.
Fixes#378.
Not sure what this special case was trying to achieve, but it's not right. There's no need to handle function call with a single argument differently than the others.
Whoopsie... || and && were treated with the same precedence, causing very surprising behavior down the line.
I noticed this because of the auto-formatter adding parenthesis where it really shouldn't. The problem came actually from the parser and how it constructed the AST.
Weirdly enough, we got the parsing wrong for byte literals in expressions (but did okay in constants). But got the formatting wrong in constants (yet did okay for formatting expressions). I've factored out the code in both cases to avoid the duplication that led to this in the first place. Plus added test coverage to make sure this doesn't happen in the future.
With pretty parse errors on failures. The type-checker was already
implemented for those, so it now only requires some work in the code
generation.
Fixes#297.
