ruff/crates/ruff_python_formatter/src/pattern/pattern_arguments.rs

102 lines
3.7 KiB
Rust

use ruff_formatter::write;
use ruff_python_ast::{Pattern, PatternArguments};
use ruff_python_trivia::{SimpleTokenKind, SimpleTokenizer};
use ruff_text_size::{Ranged, TextRange, TextSize};
use crate::expression::parentheses::{Parentheses, empty_parenthesized, parenthesized};
use crate::prelude::*;
#[derive(Default)]
pub struct FormatPatternArguments;
impl FormatNodeRule<PatternArguments> for FormatPatternArguments {
fn fmt_fields(&self, item: &PatternArguments, f: &mut PyFormatter) -> FormatResult<()> {
// If there are no arguments, all comments are dangling:
// ```python
// case Point2D( # dangling
// # dangling
// )
// ```
if item.patterns.is_empty() && item.keywords.is_empty() {
let comments = f.context().comments().clone();
let dangling = comments.dangling(item);
return write!(f, [empty_parenthesized("(", dangling, ")")]);
}
let all_arguments = format_with(|f: &mut PyFormatter| {
let source = f.context().source();
let mut joiner = f.join_comma_separated(item.end());
match item.patterns.as_slice() {
[pattern] if item.keywords.is_empty() => {
let parentheses =
if is_single_argument_parenthesized(pattern, item.end(), source) {
Parentheses::Always
} else {
// Note: no need to handle opening-parenthesis comments, since
// an opening-parenthesis comment implies that the argument is
// parenthesized.
Parentheses::Never
};
joiner.entry(pattern, &pattern.format().with_options(parentheses));
}
patterns => {
joiner
.entries(patterns.iter().map(|pattern| {
(
pattern,
pattern.format().with_options(Parentheses::Preserve),
)
}))
.nodes(&item.keywords);
}
}
joiner.finish()
});
// If the arguments are non-empty, then a dangling comment indicates a comment on the
// same line as the opening parenthesis, e.g.:
// ```python
// case Point2D( # dangling
// ...
// )
// ```
let comments = f.context().comments().clone();
let dangling_comments = comments.dangling(item);
write!(
f,
[parenthesized("(", &group(&all_arguments), ")")
.with_dangling_comments(dangling_comments)]
)
}
}
/// Returns `true` if the pattern (which is the only argument to a
/// [`PatternMatchClass`](ruff_python_ast::PatternMatchClass)) is parenthesized.
/// Used to avoid falsely assuming that `x` is parenthesized in cases like:
/// ```python
/// case Point2D(x): ...
/// ```
fn is_single_argument_parenthesized(pattern: &Pattern, call_end: TextSize, source: &str) -> bool {
let mut has_seen_r_paren = false;
for token in SimpleTokenizer::new(source, TextRange::new(pattern.end(), call_end)).skip_trivia()
{
match token.kind() {
SimpleTokenKind::RParen => {
if has_seen_r_paren {
return true;
}
has_seen_r_paren = true;
}
// Skip over any trailing comma
SimpleTokenKind::Comma => continue,
_ => {
// Passed the arguments
break;
}
}
}
false
}