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.
It's generally a bad idea to use equality on enum variants because this won't trigger any compiler errors in the future yet could have hazardous effects if adding new variants. So it's usually preferrable to use exauhstive pattern matching and let the compiler warn missing cases in places where it matters.
It is now possible to leave a hole in a type annotation and have the compiler fill-in the expected type of us.
This is a pretty useful debugging tool when playing with complex functions.
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.
-Builitins IR now acts like Record IR in terms of argument consumption
-UnConstrData returns as Pair(Data,Data) to conform with how pairs are treated behind the scenes.
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).
This is not supported by the code generation, so it's a bit of a lie
to have them in the language in the first place. There's arguably not
even any use for constant records, list and tuples to begin with. So
this cleans this up everywhere for the sake of moving forward with the
alpha release.
This now reduces constants to:
- Integer
- ByteArray
- String
Anything else can be declared via a function anyway. We can revisit
this choice later.... or not.
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) }
```
The goal is to handle this without bothering the code generation down the line. That is, we can handle it when transforming from the untyped AST to the typed one. That's why there's no 'TraceIfFalse' constructor in the typed AST. It has disappeared during type-check.
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.
There's arguably no use case ever for that in the context of on-chain
Plutus. Strings are really just meant to be used for tracing. They
aren't meant to be manipulated as heavily as in classic programming
languages.
Before that commit, the type-checker would allow unsafe list patterns
such as:
```
let [x] = xs
when xs is {
[x] -> ...
[x, ..] -> ...
}
```
This is quite unsafe and can lead to confusing situations. Now at
least the compiler warns about this. It isn't perfect though,
especially in the presence of clause guards. But that's a start.
rvcas