macro_rules! precedence {

($($op:ident,)*) => {

precedence!(@0, $($op,)*);

};

(@$i:expr, $op1:ident, $($op:ident,)*) => {

pub(crate) const $op1: u8 = $i;

precedence!(@$i + 1, $($op,)*);

};

(@$i:expr,) => {};

}

precedence!(

TUPLE, TEST, OR, AND, NOT, CMP, // "EXPR" =

BOR, BXOR, BAND, SHIFT, ARITH, TERM, FACTOR, POWER, AWAIT, ATOM,

);

pub(crate) const EXPR: u8 = BOR;

const fn new(f: &'b mut fmt::Formatter<'a>, source: &'c SourceFile) -> Self {

Self { f, source }

}

fn p(&mut self, s: &str) -> fmt::Result {

self.f.write_str(s)

}

fn p_id(&mut self, s: &ast::Identifier) -> fmt::Result {

self.f.write_str(s.as_str())

}

fn p_if(&mut self, cond: bool, s: &str) -> fmt::Result {

if cond {

self.f.write_str(s)?;

}

Ok(())

}

fn p_delim(&mut self, first: &mut bool, s: &str) -> fmt::Result {

self.p_if(!core::mem::take(first), s)

}

fn write_fmt(&mut self, f: fmt::Arguments<'_>) -> fmt::Result {

self.f.write_fmt(f)

}

fn unparse_float(&mut self, value: f64) -> fmt::Result {

#[allow(clippy::correctness, clippy::assertions_on_constants)]

const {

assert!(f64::MAX_10_EXP == 308)

};

if value.is_infinite() {

self.p("1e309")

} else {

self.p(&rustpython_literal::float::to_string(value))

}

}

fn unparse_complex(&mut self, real: f64, imag: f64) -> fmt::Result {

self.p(&rustpython_literal::complex::to_string(real, imag).replace("inf", "1e309"))

}

fn unparse_constant_value(&mut self, value: &ast::ConstantValue) -> fmt::Result {

match value {

ast::ConstantValue::None => self.p("None"),

ast::ConstantValue::Boolean(value) => self.p(if *value { "True" } else { "False" }),

ast::ConstantValue::Str(value) => UnicodeEscape::new_repr(value.as_ref().into())

.str_repr()

.fmt(self.f),

ast::ConstantValue::Bytes(value) => AsciiEscape::new_repr(value.as_ref())

.bytes_repr()

.fmt(self.f),

ast::ConstantValue::Integer(value) => self.p(value.as_ref()),

ast::ConstantValue::Tuple(elements) => {

self.p("(")?;

let mut first = true;

for element in elements {

self.p_delim(&mut first, ", ")?;

self.unparse_constant_value(element)?;

}

self.p_if(elements.len() == 1, ",")?;

self.p(")")

}

ast::ConstantValue::Frozenset(elements) => {

if elements.is_empty() {

self.p("frozenset()")

} else {

self.p("frozenset({")?;

let mut first = true;

for element in elements {

self.p_delim(&mut first, ", ")?;

self.unparse_constant_value(element)?;

}

self.p("})")

}

}

ast::ConstantValue::Float(value) => self.unparse_float(*value),

ast::ConstantValue::Complex { real, imag } => self.unparse_complex(*real, *imag),

ast::ConstantValue::Ellipsis => self.p("..."),

}

}

fn unparse_expr(&mut self, ast: &ast::Expr, level: u8) -> fmt::Result {

macro_rules! op_prec {

($op_ty:ident, $x:expr, $enu:path, $($var:ident($op:literal, $prec:ident)),*$(,)?) => {

match $x {

$(<$enu>::$var => (op_prec!(@space $op_ty, $op), precedence::$prec),)*

}

};

(@space bin, $op:literal) => {

concat!(" ", $op, " ")

};

(@space un, $op:literal) => {

$op

};

}

macro_rules! group_if {

($lvl:expr, $body:block) => {{

let group = level > $lvl;

self.p_if(group, "(")?;

let ret = $body;

self.p_if(group, ")")?;

ret

}};

}

match &ast {

ast::Expr::BoolOp(ast::ExprBoolOp {

op,

values,

node_index: _,

range: _range,

..

}) => {

let (op, prec) = op_prec!(bin, op, ast::BoolOp, And("and", AND), Or("or", OR));

group_if!(prec, {

let mut first = true;

for val in values {

self.p_delim(&mut first, op)?;

self.unparse_expr(val, prec + 1)?;

}

})

}

ast::Expr::Named(ast::ExprNamed {

target,

value,

node_index: _,

range: _range,

..

}) => {

group_if!(precedence::TUPLE, {

self.unparse_expr(target, precedence::ATOM)?;

self.p(" := ")?;

self.unparse_expr(value, precedence::ATOM)?;

})

}

ast::Expr::BinOp(ast::ExprBinOp {

left,

op,

right,

node_index: _,

range: _range,

..

}) => {

let right_associative = matches!(op, ast::Operator::Pow);

let (op, prec) = op_prec!(

bin,

op,

ast::Operator,

Add("+", ARITH),

Sub("-", ARITH),

Mult("*", TERM),

MatMult("@", TERM),

Div("/", TERM),

Mod("%", TERM),

Pow("**", POWER),

LShift("<<", SHIFT),

RShift(">>", SHIFT),

BitOr("|", BOR),

BitXor("^", BXOR),

BitAnd("&", BAND),

FloorDiv("//", TERM),

);

group_if!(prec, {

self.unparse_expr(left, prec + right_associative as u8)?;

self.p(op)?;

self.unparse_expr(right, prec + !right_associative as u8)?;

})

}

ast::Expr::UnaryOp(ast::ExprUnaryOp {

op,

operand,

node_index: _,

range: _range,

..

}) => {

let (op, prec) = op_prec!(

un,

op,

ast::UnaryOp,

Invert("~", FACTOR),

Not("not ", NOT),

UAdd("+", FACTOR),

USub("-", FACTOR)

);

group_if!(prec, {

self.p(op)?;

self.unparse_expr(operand, prec)?;

})

}

ast::Expr::Lambda(ast::ExprLambda {

parameters,

body,

node_index: _,

range: _range,

..

}) => {

group_if!(precedence::TEST, {

if let Some(parameters) = parameters {

self.p("lambda ")?;

self.unparse_arguments(parameters)?;

} else {

self.p("lambda")?;

}

write!(self, ": {}", UnparseExpr::new(body, self.source))?;

})

}

ast::Expr::If(ast::ExprIf {

test,

body,

orelse,

node_index: _,

range: _range,

..

}) => {

group_if!(precedence::TEST, {

self.unparse_expr(body, precedence::TEST + 1)?;

self.p(" if ")?;

self.unparse_expr(test, precedence::TEST + 1)?;

self.p(" else ")?;

self.unparse_expr(orelse, precedence::TEST)?;

})

}

ast::Expr::Dict(ast::ExprDict {

items,

node_index: _,

range: _range,

..

}) => {

self.p("{")?;

let mut first = true;

for item in items {

self.p_delim(&mut first, ", ")?;

if let Some(k) = &item.key {

write!(self, "{}: ", UnparseExpr::new(k, self.source))?;

} else {

self.p("**")?;

}

self.unparse_expr(&item.value, level)?;

}

self.p("}")?;

}

ast::Expr::Set(ast::ExprSet {

elts,

node_index: _,

range: _range,

..

}) => {

self.p("{")?;

let mut first = true;

for v in elts {

self.p_delim(&mut first, ", ")?;

self.unparse_expr(v, precedence::TEST)?;

}

self.p("}")?;

}

ast::Expr::ListComp(ast::ExprListComp {

elt,

generators,

node_index: _,

range: _range,

..

}) => {

self.p("[")?;

self.unparse_expr(elt, precedence::TEST)?;

self.unparse_comp(generators)?;

self.p("]")?;

}

ast::Expr::SetComp(ast::ExprSetComp {

elt,

generators,

node_index: _,

range: _range,

..

}) => {

self.p("{")?;

self.unparse_expr(elt, precedence::TEST)?;

self.unparse_comp(generators)?;

self.p("}")?;

}

ast::Expr::DictComp(ast::ExprDictComp {

key,

value,

generators,

node_index: _,

range: _range,

..

}) => {

self.p("{")?;

if let Some(key) = key {

self.unparse_expr(key, precedence::TEST)?;

self.p(": ")?;

} else {

self.p("**")?;

}

self.unparse_expr(value, precedence::TEST)?;

self.unparse_comp(generators)?;

self.p("}")?;

}

ast::Expr::Generator(ast::ExprGenerator {

parenthesized: _,

elt,

generators,

node_index: _,

range: _range,

..

}) => {

self.p("(")?;

self.unparse_expr(elt, precedence::TEST)?;

self.unparse_comp(generators)?;

self.p(")")?;

}

ast::Expr::Await(ast::ExprAwait {

value,

node_index: _,

range: _range,

..

}) => {

group_if!(precedence::AWAIT, {

self.p("await ")?;

self.unparse_expr(value, precedence::ATOM)?;

})

}

ast::Expr::Yield(ast::ExprYield {

value,

node_index: _,

range: _range,

..

}) => {

if let Some(value) = value {

write!(self, "(yield {})", UnparseExpr::new(value, self.source))?;

} else {

self.p("(yield)")?;

}

}

ast::Expr::YieldFrom(ast::ExprYieldFrom {

value,

node_index: _,

range: _range,

..

}) => {

write!(

self,

"(yield from {})",

UnparseExpr::new(value, self.source)

)?;

}

ast::Expr::Compare(compare) => {

group_if!(precedence::CMP, {

let new_lvl = precedence::CMP + 1;

self.unparse_expr(compare.first_operand(), new_lvl)?;

for (_, op, cmp) in compare.iter() {

self.p(" ")?;

self.p(op.as_str())?;

self.p(" ")?;

self.unparse_expr(cmp, new_lvl)?;

}

})

}

ast::Expr::Call(ast::ExprCall {

func,

arguments: ast::Arguments { args, keywords, .. },

node_index: _,

range_start: _range_start,

..

}) => {

self.unparse_expr(func, precedence::ATOM)?;

self.p("(")?;

if let (

[

ast::Expr::Generator(ast::ExprGenerator {

elt,

generators,

node_index: _,

range: _range,

..

}),

],

[],

) = (&**args, &**keywords)

{

// make sure a single genexpr doesn't get double parens

self.unparse_expr(elt, precedence::TEST)?;

self.unparse_comp(generators)?;

} else {

let mut first = true;

for arg in args {

self.p_delim(&mut first, ", ")?;

self.unparse_expr(arg, precedence::TEST)?;

}

for kw in keywords {

self.p_delim(&mut first, ", ")?;

if let Some(arg) = &kw.arg {

self.p_id(arg)?;

self.p("=")?;

} else {

self.p("**")?;

}

self.unparse_expr(&kw.value, precedence::TEST)?;

}

}

self.p(")")?;

}

ast::Expr::FString(ast::ExprFString { value, .. }) => self.unparse_fstring(value)?,

ast::Expr::TString(ast::ExprTString { value, .. }) => self.unparse_tstring(value)?,

ast::Expr::StringLiteral(ast::ExprStringLiteral { value, .. }) => {

if value.is_unicode() {

self.p("u")?

}

UnicodeEscape::new_repr(value.to_str().as_ref())

.str_repr()

.fmt(self.f)?

}

ast::Expr::BytesLiteral(ast::ExprBytesLiteral { value, .. }) => {

AsciiEscape::new_repr(&value.bytes().collect::<Vec<_>>())

.bytes_repr()

.fmt(self.f)?

}

ast::Expr::NumberLiteral(ast::ExprNumberLiteral { value, .. }) => match value {

ast::Number::Int(int) => int.fmt(self.f)?,

&ast::Number::Float(fp) => self.unparse_float(fp)?,

&ast::Number::Complex { real, imag } => self.unparse_complex(real, imag)?,

},

ast::Expr::Constant(ast::ExprConstant { value, .. }) => {

self.unparse_constant_value(value)?

}

ast::Expr::BooleanLiteral(ast::ExprBooleanLiteral { value, .. }) => {

self.p(if *value { "True" } else { "False" })?

}

ast::Expr::NoneLiteral(ast::ExprNoneLiteral { .. }) => self.p("None")?,

ast::Expr::EllipsisLiteral(ast::ExprEllipsisLiteral { .. }) => self.p("...")?,

ast::Expr::Attribute(ast::ExprAttribute { value, attr, .. }) => {

self.unparse_expr(value, precedence::ATOM)?;

let period = if let ast::Expr::NumberLiteral(ast::ExprNumberLiteral {

value: ast::Number::Int(_),

..

}) = value.as_ref()

{

" ."

} else {

"."

};

self.p(period)?;

self.p_id(attr)?;

}

ast::Expr::Subscript(ast::ExprSubscript { value, slice, .. }) => {

self.unparse_expr(value, precedence::ATOM)?;

let lvl = precedence::TUPLE;

self.p("[")?;

self.unparse_expr(slice, lvl)?;

self.p("]")?;

}

ast::Expr::Starred(ast::ExprStarred { value, .. }) => {

self.p("*")?;

self.unparse_expr(value, precedence::EXPR)?;

}

ast::Expr::Name(ast::ExprName { id, .. }) => self.p(id.as_str())?,

ast::Expr::List(ast::ExprList { elts, .. }) => {

self.p("[")?;

let mut first = true;

for elt in elts {

self.p_delim(&mut first, ", ")?;

self.unparse_expr(elt, precedence::TEST)?;

}

self.p("]")?;

}

ast::Expr::Tuple(ast::ExprTuple { elts, .. }) => {

if elts.is_empty() {

self.p("()")?;

} else {

group_if!(precedence::TUPLE, {

let mut first = true;

for elt in elts {

self.p_delim(&mut first, ", ")?;

self.unparse_expr(elt, precedence::TEST)?;

}

self.p_if(elts.len() == 1, ",")?;

})

}

}

ast::Expr::Slice(ast::ExprSlice {

lower,

upper,

step,

node_index: _,

range: _range,

..

}) => {

if let Some(lower) = lower {

self.unparse_expr(lower, precedence::TEST)?;

}

self.p(":")?;

if let Some(upper) = upper {

self.unparse_expr(upper, precedence::TEST)?;

}

if let Some(step) = step {

self.p(":")?;

self.unparse_expr(step, precedence::TEST)?;

}

}

ast::Expr::IpyEscapeCommand(_) => {}

}

Ok(())

}

fn unparse_arguments(&mut self, args: &ast::Parameters) -> fmt::Result {

let mut first = true;

for (i, arg) in args.posonlyargs.iter().chain(&args.args).enumerate() {

self.p_delim(&mut first, ", ")?;

self.unparse_function_arg(arg)?;

self.p_if(i + 1 == args.posonlyargs.len(), ", /")?;

}

if args.vararg.is_some() || !args.kwonlyargs.is_empty() {

self.p_delim(&mut first, ", ")?;

self.p("*")?;

}

if let Some(vararg) = &args.vararg {

self.unparse_arg(vararg)?;

}

for kwarg in &args.kwonlyargs {

self.p_delim(&mut first, ", ")?;

self.unparse_function_arg(kwarg)?;

}

if let Some(kwarg) = &args.kwarg {

self.p_delim(&mut first, ", ")?;

self.p("**")?;

self.unparse_arg(kwarg)?;

}

Ok(())

}

fn unparse_function_arg(&mut self, arg: &ast::ParameterWithDefault) -> fmt::Result {

self.unparse_arg(&arg.parameter)?;

if let Some(default) = &arg.default {

write!(self, "={}", UnparseExpr::new(default, self.source))?;

}

Ok(())

}

fn unparse_arg(&mut self, arg: &ast::Parameter) -> fmt::Result {

self.p_id(&arg.name)?;

if let Some(ann) = &arg.annotation {

write!(self, ": {}", UnparseExpr::new(ann, self.source))?;

}

Ok(())

}

fn unparse_comp(&mut self, generators: &[ast::Comprehension]) -> fmt::Result {

for comp in generators {

self.p(if comp.is_async {

" async for "

} else {

" for "

})?;

self.unparse_expr(&comp.target, precedence::TUPLE)?;

self.p(" in ")?;

self.unparse_expr(&comp.iter, precedence::TEST + 1)?;

for cond in &comp.ifs {

self.p(" if ")?;

self.unparse_expr(cond, precedence::TEST + 1)?;

}

}

Ok(())

}

fn unparse_fstring_body(&mut self, elements: &[ast::InterpolatedStringElement]) -> fmt::Result {

for elem in elements {

self.unparse_fstring_elem(elem)?;

}

Ok(())

}

fn unparse_formatted(

&mut self,

val: &ast::Expr,

debug_text: Option<&ast::DebugText>,

mut conversion: ast::ConversionFlag,

spec: Option<&ast::InterpolatedStringFormatSpec>,

) -> fmt::Result {

let buffered =

fmt::from_fn(|f| Unparser::new(f, self.source).unparse_expr(val, precedence::TEST + 1))

.to_string();

if let Some(debug_text) = debug_text {

let (text, _) = interpolation_debug_text(self.source, debug_text, val.range());

self.unparse_fstring_str(&text)?;

if conversion == ast::ConversionFlag::None && spec.is_none() {

conversion = ast::ConversionFlag::Repr;

}

}

let brace = if buffered.starts_with('{') {

// put a space to avoid escaping the bracket

"{ "

} else {

"{"

};

self.p(brace)?;

self.p(&buffered)?;

drop(buffered);

if conversion != ast::ConversionFlag::None {

self.p("!")?;

let buf = &[conversion as u8];

let c = core::str::from_utf8(buf).unwrap();

self.p(c)?;

}

if let Some(spec) = spec {

self.p(":")?;

self.unparse_fstring_body(&spec.elements)?;

}

self.p("}")?;

Ok(())

}

fn unparse_fstring_elem(&mut self, elem: &ast::InterpolatedStringElement) -> fmt::Result {

match elem {

ast::InterpolatedStringElement::Interpolation(ast::InterpolatedElement {

expression,

debug_text,

conversion,

format_spec,

..

}) => self.unparse_formatted(

expression,

debug_text.as_ref(),

*conversion,

format_spec.as_deref(),

),

ast::InterpolatedStringElement::Literal(ast::InterpolatedStringLiteralElement {

value,

..

}) => self.unparse_fstring_str(value),

}

}

fn unparse_fstring_str(&mut self, s: &str) -> fmt::Result {

let s = s.replace('{', "{{").replace('}', "}}");

self.p(&s)

}

fn unparse_fstring(&mut self, value: &ast::FStringValue) -> fmt::Result {

self.p("f")?;

let body = fmt::from_fn(|f| {

value.iter().try_for_each(|part| match part {

ast::FStringPartRef::Literal(lit) => f.write_str(lit),

ast::FStringPartRef::FString(ast::FString { elements, .. }) => {

Unparser::new(f, self.source).unparse_fstring_body(elements)

}

})

})

.to_string();

// .unparse_fstring_body(elements));

UnicodeEscape::new_repr(body.as_str().as_ref())

.str_repr()

.write(self.f)

}

fn unparse_tstring(&mut self, value: &ast::TStringValue) -> fmt::Result {

self.p("t")?;

let body = fmt::from_fn(|f| {

value.iter().try_for_each(|tstring| {

Unparser::new(f, self.source).unparse_tstring_body(&tstring.elements)

})

})

.to_string();

UnicodeEscape::new_repr(body.as_str().as_ref())

.str_repr()

.write(self.f)

}

fn unparse_tstring_body(&mut self, elements: &[ast::InterpolatedStringElement]) -> fmt::Result {

for element in elements {

match element {

ast::InterpolatedStringElement::Literal(literal) => {

self.unparse_fstring_str(literal)?;

}

ast::InterpolatedStringElement::Interpolation(interpolation) => {

self.unparse_tstring_interpolation(interpolation)?;

}

}

}

Ok(())

}

fn unparse_tstring_interpolation(

&mut self,

interpolation: &ast::InterpolatedElement,

) -> fmt::Result {

let mut conversion = interpolation.conversion;

if let Some(debug_text) = &interpolation.debug_text {

let (text, _) =

interpolation_debug_text(self.source, debug_text, interpolation.expression.range());

self.unparse_fstring_str(&text)?;

if conversion == ast::ConversionFlag::None && interpolation.format_spec.is_none() {

conversion = ast::ConversionFlag::Repr;

}

}

let expression = if let Some(ast::ConstantValue::Str(value)) = &interpolation.runtime_str {

value.to_string()

} else if let Some(expression) = interpolation_expression_text(self.source, interpolation) {

expression

} else {

fmt::from_fn(|f| {

Unparser::new(f, self.source)

.unparse_expr(&interpolation.expression, precedence::TEST + 1)

})

.to_string()

};

self.p(if expression.starts_with('{') {

"{ "

} else {

"{"

})?;

self.p(&expression)?;

if conversion != ast::ConversionFlag::None {

self.p("!")?;

let conversion_byte = [conversion as u8];

self.p(core::str::from_utf8(&conversion_byte).unwrap())?;

}

if let Some(format_spec) = &interpolation.format_spec {

self.p(":")?;

self.unparse_fstring_body(&format_spec.elements)?;

}

self.p("}")

}

pub(crate) const fn new(expr: &'a ast::Expr, source: &'a SourceFile) -> Self {

Self { expr, source }

}

fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {

Unparser::new(f, self.source).unparse_expr(self.expr, precedence::TEST)

}