ruff/crates/ruff_python_formatter/src/expression/mod.rs

427 lines
16 KiB
Rust

use rustpython_parser::ast;
use rustpython_parser::ast::{Expr, Operator};
use std::cmp::Ordering;
use crate::builders::parenthesize_if_expands;
use ruff_formatter::{FormatOwnedWithRule, FormatRefWithRule, FormatRule, FormatRuleWithOptions};
use ruff_python_ast::node::AnyNodeRef;
use ruff_python_ast::visitor::preorder::{walk_expr, PreorderVisitor};
use crate::context::NodeLevel;
use crate::expression::expr_tuple::TupleParentheses;
use crate::expression::parentheses::{
is_expression_parenthesized, optional_parentheses, parenthesized, NeedsParentheses,
Parentheses, Parenthesize,
};
use crate::expression::string::StringLayout;
use crate::prelude::*;
pub(crate) mod expr_attribute;
pub(crate) mod expr_await;
pub(crate) mod expr_bin_op;
pub(crate) mod expr_bool_op;
pub(crate) mod expr_call;
pub(crate) mod expr_compare;
pub(crate) mod expr_constant;
pub(crate) mod expr_dict;
pub(crate) mod expr_dict_comp;
pub(crate) mod expr_formatted_value;
pub(crate) mod expr_generator_exp;
pub(crate) mod expr_if_exp;
pub(crate) mod expr_joined_str;
pub(crate) mod expr_lambda;
pub(crate) mod expr_list;
pub(crate) mod expr_list_comp;
pub(crate) mod expr_name;
pub(crate) mod expr_named_expr;
pub(crate) mod expr_set;
pub(crate) mod expr_set_comp;
pub(crate) mod expr_slice;
pub(crate) mod expr_starred;
pub(crate) mod expr_subscript;
pub(crate) mod expr_tuple;
pub(crate) mod expr_unary_op;
pub(crate) mod expr_yield;
pub(crate) mod expr_yield_from;
pub(crate) mod parentheses;
pub(crate) mod string;
#[derive(Default)]
pub struct FormatExpr {
parenthesize: Parenthesize,
}
impl FormatRuleWithOptions<Expr, PyFormatContext<'_>> for FormatExpr {
type Options = Parenthesize;
fn with_options(mut self, options: Self::Options) -> Self {
self.parenthesize = options;
self
}
}
impl FormatRule<Expr, PyFormatContext<'_>> for FormatExpr {
fn fmt(&self, item: &Expr, f: &mut PyFormatter) -> FormatResult<()> {
let parentheses = item.needs_parentheses(self.parenthesize, f.context());
let format_expr = format_with(|f| match item {
Expr::BoolOp(expr) => expr.format().with_options(Some(parentheses)).fmt(f),
Expr::NamedExpr(expr) => expr.format().fmt(f),
Expr::BinOp(expr) => expr.format().with_options(Some(parentheses)).fmt(f),
Expr::UnaryOp(expr) => expr.format().fmt(f),
Expr::Lambda(expr) => expr.format().fmt(f),
Expr::IfExp(expr) => expr.format().fmt(f),
Expr::Dict(expr) => expr.format().fmt(f),
Expr::Set(expr) => expr.format().fmt(f),
Expr::ListComp(expr) => expr.format().fmt(f),
Expr::SetComp(expr) => expr.format().fmt(f),
Expr::DictComp(expr) => expr.format().fmt(f),
Expr::GeneratorExp(expr) => expr.format().fmt(f),
Expr::Await(expr) => expr.format().fmt(f),
Expr::Yield(expr) => expr.format().fmt(f),
Expr::YieldFrom(expr) => expr.format().fmt(f),
Expr::Compare(expr) => expr.format().with_options(Some(parentheses)).fmt(f),
Expr::Call(expr) => expr.format().fmt(f),
Expr::FormattedValue(expr) => expr.format().fmt(f),
Expr::JoinedStr(expr) => expr.format().fmt(f),
Expr::Constant(expr) => expr
.format()
.with_options(StringLayout::Default(Some(parentheses)))
.fmt(f),
Expr::Attribute(expr) => expr.format().fmt(f),
Expr::Subscript(expr) => expr.format().fmt(f),
Expr::Starred(expr) => expr.format().fmt(f),
Expr::Name(expr) => expr.format().fmt(f),
Expr::List(expr) => expr.format().fmt(f),
Expr::Tuple(expr) => expr
.format()
.with_options(TupleParentheses::Expr(parentheses))
.fmt(f),
Expr::Slice(expr) => expr.format().fmt(f),
});
let result = match parentheses {
Parentheses::Always => parenthesized("(", &format_expr, ")").fmt(f),
// Add optional parentheses. Ignore if the item renders parentheses itself.
Parentheses::Optional => {
if can_omit_optional_parentheses(item, f.context()) {
optional_parentheses(&format_expr).fmt(f)
} else {
parenthesize_if_expands(&format_expr).fmt(f)
}
}
Parentheses::Custom | Parentheses::Never => {
let saved_level = f.context().node_level();
let new_level = match saved_level {
NodeLevel::TopLevel | NodeLevel::CompoundStatement => {
NodeLevel::Expression(None)
}
level @ (NodeLevel::Expression(_) | NodeLevel::ParenthesizedExpression) => {
level
}
};
f.context_mut().set_node_level(new_level);
let result = Format::fmt(&format_expr, f);
f.context_mut().set_node_level(saved_level);
result
}
};
result
}
}
impl NeedsParentheses for Expr {
fn needs_parentheses(
&self,
parenthesize: Parenthesize,
context: &PyFormatContext,
) -> Parentheses {
match self {
Expr::BoolOp(expr) => expr.needs_parentheses(parenthesize, context),
Expr::NamedExpr(expr) => expr.needs_parentheses(parenthesize, context),
Expr::BinOp(expr) => expr.needs_parentheses(parenthesize, context),
Expr::UnaryOp(expr) => expr.needs_parentheses(parenthesize, context),
Expr::Lambda(expr) => expr.needs_parentheses(parenthesize, context),
Expr::IfExp(expr) => expr.needs_parentheses(parenthesize, context),
Expr::Dict(expr) => expr.needs_parentheses(parenthesize, context),
Expr::Set(expr) => expr.needs_parentheses(parenthesize, context),
Expr::ListComp(expr) => expr.needs_parentheses(parenthesize, context),
Expr::SetComp(expr) => expr.needs_parentheses(parenthesize, context),
Expr::DictComp(expr) => expr.needs_parentheses(parenthesize, context),
Expr::GeneratorExp(expr) => expr.needs_parentheses(parenthesize, context),
Expr::Await(expr) => expr.needs_parentheses(parenthesize, context),
Expr::Yield(expr) => expr.needs_parentheses(parenthesize, context),
Expr::YieldFrom(expr) => expr.needs_parentheses(parenthesize, context),
Expr::Compare(expr) => expr.needs_parentheses(parenthesize, context),
Expr::Call(expr) => expr.needs_parentheses(parenthesize, context),
Expr::FormattedValue(expr) => expr.needs_parentheses(parenthesize, context),
Expr::JoinedStr(expr) => expr.needs_parentheses(parenthesize, context),
Expr::Constant(expr) => expr.needs_parentheses(parenthesize, context),
Expr::Attribute(expr) => expr.needs_parentheses(parenthesize, context),
Expr::Subscript(expr) => expr.needs_parentheses(parenthesize, context),
Expr::Starred(expr) => expr.needs_parentheses(parenthesize, context),
Expr::Name(expr) => expr.needs_parentheses(parenthesize, context),
Expr::List(expr) => expr.needs_parentheses(parenthesize, context),
Expr::Tuple(expr) => expr.needs_parentheses(parenthesize, context),
Expr::Slice(expr) => expr.needs_parentheses(parenthesize, context),
}
}
}
impl<'ast> AsFormat<PyFormatContext<'ast>> for Expr {
type Format<'a> = FormatRefWithRule<'a, Expr, FormatExpr, PyFormatContext<'ast>>;
fn format(&self) -> Self::Format<'_> {
FormatRefWithRule::new(self, FormatExpr::default())
}
}
impl<'ast> IntoFormat<PyFormatContext<'ast>> for Expr {
type Format = FormatOwnedWithRule<Expr, FormatExpr, PyFormatContext<'ast>>;
fn into_format(self) -> Self::Format {
FormatOwnedWithRule::new(self, FormatExpr::default())
}
}
/// Tests if it is safe to omit the optional parentheses.
///
/// We prefer parentheses at least in the following cases:
/// * The expression contains more than one unparenthesized expression with the same priority. For example,
/// the expression `a * b * c` contains two multiply operations. We prefer parentheses in that case.
/// `(a * b) * c` or `a * b + c` are okay, because the subexpression is parenthesized, or the expression uses operands with a lower priority
/// * The expression contains at least one parenthesized sub expression (optimization to avoid unnecessary work)
///
/// This mimics Black's [`_maybe_split_omitting_optional_parens`](https://github.com/psf/black/blob/d1248ca9beaf0ba526d265f4108836d89cf551b7/src/black/linegen.py#L746-L820)
fn can_omit_optional_parentheses(expr: &Expr, context: &PyFormatContext) -> bool {
let mut visitor = MaxOperatorPriorityVisitor::new(context.source());
visitor.visit_subexpression(expr);
let (max_operator_priority, operation_count, any_parenthesized_expression) = visitor.finish();
if operation_count > 1 {
false
} else if max_operator_priority == OperatorPriority::Attribute {
true
} else {
// Only use the more complex IR when there is any expression that we can possibly split by
any_parenthesized_expression
}
}
#[derive(Clone, Debug)]
struct MaxOperatorPriorityVisitor<'input> {
max_priority: OperatorPriority,
max_priority_count: u32,
any_parenthesized_expressions: bool,
source: &'input str,
}
impl<'input> MaxOperatorPriorityVisitor<'input> {
fn new(source: &'input str) -> Self {
Self {
source,
max_priority: OperatorPriority::None,
max_priority_count: 0,
any_parenthesized_expressions: false,
}
}
fn update_max_priority(&mut self, current_priority: OperatorPriority) {
self.update_max_priority_with_count(current_priority, 1);
}
fn update_max_priority_with_count(&mut self, current_priority: OperatorPriority, count: u32) {
match self.max_priority.cmp(&current_priority) {
Ordering::Less => {
self.max_priority_count = count;
self.max_priority = current_priority;
}
Ordering::Equal => {
self.max_priority_count += count;
}
Ordering::Greater => {}
}
}
// Visits a subexpression, ignoring whether it is parenthesized or not
fn visit_subexpression(&mut self, expr: &'input Expr) {
match expr {
Expr::Dict(_) | Expr::List(_) | Expr::Tuple(_) | Expr::Set(_) => {
self.any_parenthesized_expressions = true;
// The values are always parenthesized, don't visit.
return;
}
Expr::ListComp(_) | Expr::SetComp(_) | Expr::DictComp(_) => {
self.any_parenthesized_expressions = true;
self.update_max_priority(OperatorPriority::Comprehension);
return;
}
// It's impossible for a file smaller or equal to 4GB to contain more than 2^32 comparisons
// because each comparison requires a left operand, and `n` `operands` and right sides.
#[allow(clippy::cast_possible_truncation)]
Expr::BoolOp(ast::ExprBoolOp {
range: _,
op: _,
values,
}) => self.update_max_priority_with_count(
OperatorPriority::BooleanOperation,
values.len().saturating_sub(1) as u32,
),
Expr::BinOp(ast::ExprBinOp {
op,
left: _,
right: _,
range: _,
}) => self.update_max_priority(OperatorPriority::from(*op)),
Expr::IfExp(_) => {
// + 1 for the if and one for the else
self.update_max_priority_with_count(OperatorPriority::Conditional, 2);
}
// It's impossible for a file smaller or equal to 4GB to contain more than 2^32 comparisons
// because each comparison requires a left operand, and `n` `operands` and right sides.
#[allow(clippy::cast_possible_truncation)]
Expr::Compare(ast::ExprCompare {
range: _,
left: _,
ops,
comparators: _,
}) => {
self.update_max_priority_with_count(OperatorPriority::Comparator, ops.len() as u32);
}
Expr::Call(ast::ExprCall {
range: _,
func,
args: _,
keywords: _,
}) => {
self.any_parenthesized_expressions = true;
// Only walk the function, the arguments are always parenthesized
self.visit_expr(func);
return;
}
Expr::Subscript(_) => {
// Don't walk the value. Splitting before the value looks weird.
// Don't walk the slice, because the slice is always parenthesized.
return;
}
Expr::UnaryOp(ast::ExprUnaryOp {
range: _,
op,
operand: _,
}) => {
if op.is_invert() {
self.update_max_priority(OperatorPriority::BitwiseInversion);
}
}
// `[a, b].test[300].dot`
Expr::Attribute(ast::ExprAttribute {
range: _,
value,
attr: _,
ctx: _,
}) => {
if has_parentheses(value, self.source) {
self.update_max_priority(OperatorPriority::Attribute);
}
}
Expr::NamedExpr(_)
| Expr::GeneratorExp(_)
| Expr::Lambda(_)
| Expr::Await(_)
| Expr::Yield(_)
| Expr::YieldFrom(_)
| Expr::FormattedValue(_)
| Expr::JoinedStr(_)
| Expr::Constant(_)
| Expr::Starred(_)
| Expr::Name(_)
| Expr::Slice(_) => {}
};
walk_expr(self, expr);
}
fn finish(self) -> (OperatorPriority, u32, bool) {
(
self.max_priority,
self.max_priority_count,
self.any_parenthesized_expressions,
)
}
}
impl<'input> PreorderVisitor<'input> for MaxOperatorPriorityVisitor<'input> {
fn visit_expr(&mut self, expr: &'input Expr) {
// Rule only applies for non-parenthesized expressions.
if is_expression_parenthesized(AnyNodeRef::from(expr), self.source) {
self.any_parenthesized_expressions = true;
} else {
self.visit_subexpression(expr);
}
}
}
fn has_parentheses(expr: &Expr, source: &str) -> bool {
matches!(
expr,
Expr::Dict(_)
| Expr::List(_)
| Expr::Tuple(_)
| Expr::Set(_)
| Expr::ListComp(_)
| Expr::SetComp(_)
| Expr::DictComp(_)
| Expr::Call(_)
| Expr::Subscript(_)
) || is_expression_parenthesized(AnyNodeRef::from(expr), source)
}
#[derive(Debug, Copy, Clone, Ord, PartialOrd, Eq, PartialEq)]
enum OperatorPriority {
None,
Attribute,
Comparator,
Exponential,
BitwiseInversion,
Multiplicative,
Additive,
Shift,
BitwiseAnd,
BitwiseOr,
BitwiseXor,
// TODO(micha)
#[allow(unused)]
String,
BooleanOperation,
Conditional,
Comprehension,
}
impl From<ast::Operator> for OperatorPriority {
fn from(value: Operator) -> Self {
match value {
Operator::Add | Operator::Sub => OperatorPriority::Additive,
Operator::Mult
| Operator::MatMult
| Operator::Div
| Operator::Mod
| Operator::FloorDiv => OperatorPriority::Multiplicative,
Operator::Pow => OperatorPriority::Exponential,
Operator::LShift | Operator::RShift => OperatorPriority::Shift,
Operator::BitOr => OperatorPriority::BitwiseOr,
Operator::BitXor => OperatorPriority::BitwiseXor,
Operator::BitAnd => OperatorPriority::BitwiseAnd,
}
}
}