39 lines
1.9 KiB
Markdown
39 lines
1.9 KiB
Markdown
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'`ppxlib_jane`'
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===============
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A library for use in ppxes for constructing and matching on ASTs corresponding to the
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augmented parsetree that is recognized by the [Jane Street OCaml compiler][JaneStreetOCaml].
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ASTs constructed using this library are compatible with the standard OCaml compiler. Any
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syntax change known to this library is encoded as attributes, and the standard OCaml
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compiler's interpretation of the ASTs constructed by these library (which amounts to
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ignoring the attributes) is reasonable. That is, we only expose "unsurprising" things in
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this library. For example, if you construct an *n*-ary function using this library, the
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standard OCaml compiler will interpret it as *n* nested unary functions in the normal way.
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Likewise, ppxes that use this library to match on Jane Street ASTs can also be used with
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the standard OCaml compiler. (The Jane Street AST cases of the match will just never be
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triggered when using the standard OCaml compiler.)
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This is how we intend this library to fit into the broader ppx ecosystem:
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```
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+-------------+ +--------------+ +------------------+
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| ppxes +------>| ppxlib +----->+ compiler libs, |
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| | | | | ppxlib_ast, etc. |
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+------+------+ +--------------+ | |
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| +---------+--------+
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| +---------------+ ^
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+------------->+ ppxlib_jane +---------------+
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+---------------+
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```
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That is, there is no dependency between `ppxlib` and `ppxlib_jane`, and ppx authors
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are free to use `ppxlib_jane` if they want to construct AST nodes recognized by the
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Jane Street OCaml compiler.
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[JaneStreetOCaml]: https://github.com/ocaml-flambda/flambda-backend
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