ppx_js_style is an identity ppx rewriter that enforces Jane Street coding styles.
The following rules are enforced by ppx_js_style:
-
Enabled by -dated-deprecation:
[@@deprecated]
attributes must contain the date of deprecation, using the format"[since MM-YYYY] ..."
N.B. this check, on by default at janestreet, but off by default externally, can also be disabled with the flag -no-dated-deprecation -
Enabled by -annotated-ignores: Ignored expressions must come with a type annotation, such as:
ignore (expr : typ)
let _ : type = expr
Note that aliases need not be annotated:let _ = Foo.bar in
-
Enabled by -check-doc-comments: Comments in mli must either be documentation comments or explicitely "ignored":
(** documentation comment *)
(*_ ignored comment *)
Normal(* comment *)
comments are disallowed.This flag additionally enables warning 50, which checks the placement of documentation comments.
Finally, doc comments are checked to be syntactically valid.
-
Enabled by -compat-32: Checks that calling ocamlc on the input would produce bytecode that works on 32 bits architectures (including js_of_ocaml), ie that all constant are representable on 32 bits architectures. Compared to the compiler flag by the same name, it allows to perform this check without building any bytecode.
-
Enabled by default, disabled by -dont-check-underscored-literal Check for misleading usage of underscores in number literals. Currrently it means that underscores must be:
- in positions that are multiple of 3 for numbers in decimal notation.
- in positions that are multiple of 2 for numbers in hexadecimal, octal or binary notation.
Two consecutive underscores in a number disables the check for that number. This is useful to turn off the check for integers that are really fixed point decimals, like
1_000__0000
to represent1000.0
with four implied decimal places.