8 releases
0.1.7 | Mar 23, 2023 |
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0.1.6 | Feb 27, 2023 |
0.1.4 | Oct 11, 2022 |
0.1.3 | Aug 21, 2022 |
0.1.0 | Dec 31, 2021 |
#111 in Procedural macros
27KB
631 lines
rustfmt_if_chain
A wrapper around rustfmt
to format inside if_chain
invocations
rustfmt_if_chain
is not guaranteed to work on all Rust source files, but it should work on most of Clippy's source files.
cargo install rustfmt_if_chain
Usage: rustfmt_if_chain [ARGS]
Arguments ending with `.rs` are considered source files and are
formatted. All other arguments are forwarded to `rustfmt`, with
one exception.
The one argument not forwarded to `rustfmt` is
`--preformat-failure-is-warning`. If this option is passed and
`rustfmt` fails on an unmodified source file, a warning results
instead of an error.
Example
-
Before
fn main() -> PhilosophicalResult<()> { if_chain! { if let Some (it) = tree . falls_in (forest) ; if ! listeners . any (| one | one . around_to_hear (it)) ; if ! it . makes_a_sound () ; then { return Err (PhilosophicalError :: new ()) ; } } Ok(()) }
-
After
fn main() -> PhilosophicalResult<()> { if_chain! { if let Some(it) = tree.falls_in(forest); if !listeners.any(|one| one.around_to_hear(it)); if !it.makes_a_sound(); then { return Err(PhilosophicalError::new()); } } Ok(()) }
How it works
- Preformat check:
rustfmt
is run on the original source file to verify that it can be formatted.* - The
if_chain
invocations in the original source file are rewritten according to the following rules, wherex
is an identifier that does not appear elsewhere in the file:if_chain!
->fn x()
or|x|
(depending on whether the invocation is an item or expression)if ... ;
->if ... { x; }
then
->if x
rustfmt
is run on the file resulting from step 1.- In the file resulting from step 2, the rewrites of step 1 are undone.
* Step 0 is not strictly necessary, but it helps to identify failures of step 2 caused by the limitations of step 1.
Known problems
rustfmt_if_chain --check FILENAME
does not work correctly. A workaround is to userustfmt_if_chain FILENAME && git diff --exit-code
.- Nested uses of
if_chain
are not handled correctly: only the outer-most use is formatted.
Dependencies
~4–14MB
~186K SLoC