Preliminary Implementation: Metaprogramming with Quasiquote

[kkdlau]

Description

This pull request introduces a preliminary implementation of metaprogramming using the quasiquote concept.

Changes

Here's a brief summary of the changes:

• Token.scala: Introduce two new BracketKind sub classes: BracketKind.Quasiquote and BracketKind.QuasiquoteTriple.
• NewLexer.scala: Update the lexer to support lexing quasiquote syntax, including code"..." and code"""...""".
• NewParser.scala: Revise the parser to facilitate the generation of ASTs using the quasiquote tokens.
• Codegen.scala: Add a new class, JSQuasiquoteRunFunctionBody, which contains the source code of the quasiquote interpreter (the run function).
• JSBackend.scala: Extend translateTerm to support quasiquote translation to s-expressions.
• Polyfill.scala: Introduce two extra built-in functions - Const and run.
• Scope.scala: Modify Scope class to support tracing both bound and free variables in quasiquotes during the code generation process.
• quasiquote/*.mls: Add new test cases to validate the quasiquote implementation.
• typer.scala: Implement a new primitive, Code[T], which represents the type of a quasiquote. Here, T indicates the return type of the quasiquote execution.

Testing

Unit tests have been added to ensure the correct functionality of the quasiquote operations. These tests cover both basic use cases and edge cases. All the test cases can be found at shared/src/test/diff/quasiquote/.

Example

Here are some examples of using the new quasiquote feature.

Define a quasiquote:

code"1"

Define a quasiquote with a string inside:

code""" "github" """ // works without putting the space between """ and ", but we formatted for better readability

Define a quasiquote with a free variable:

code"a" // error - free variable is not allowed in this version

Execute a quasiquote:

code"1 + 1"
run(res) // res: 2

[LPTK]

The CI does not pass as the code has many warnings...

Question: what happened to the "context-tracking" part of this branch called kkdlau:quasiquote/context-tracking?

[LPTK]

Ok so when the CI does not pass you just remove the CI? Great job!

Let's revisit these changes later on. We'll probably selectively import what we need in a clean way.

Thanks for your work on this project anyway!

[kkdlau]

Ok so when the CI does not pass you just remove the CI? Great job!

Let's revisit these changes later on. We'll probably selectively import what we need in a clean way.

Thanks for your work on this project anyway!

For the clarification, I didn't remove the CI, instead as the CI runs only if I push something to branch mlscript / make a pull request on branch mlscript, I update the trigger condition to every push so everytime I push to my repo, I can see if the CI passes or not.

This also can help me understand why the CI by running it on my repo and get the full report of it. We will make sure the CI file is aligned with the parent repo

[LPTK]

I see, thanks for the clarification.