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Move expr-related pretty printing functions to module

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David Tolnay 2022-01-14 20:41:20 -08:00
parent 9ad5d82f82
commit b1605643e3
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GPG key ID: F9BA143B95FF6D82
2 changed files with 574 additions and 564 deletions
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567
compiler/rustc_ast_pretty/src/pprust/state.rs
View file

@ -1,3 +1,5 @@
mod expr;
use crate::pp::Breaks::{Consistent, Inconsistent}; use crate::pp::Breaks::{Consistent, Inconsistent};
use crate::pp::{self, Breaks}; use crate::pp::{self, Breaks};
@ -6,7 +8,7 @@ use rustc_ast::token::{self, BinOpToken, CommentKind, DelimToken, Nonterminal, T
use rustc_ast::tokenstream::{TokenStream, TokenTree}; use rustc_ast::tokenstream::{TokenStream, TokenTree};
use rustc_ast::util::classify; use rustc_ast::util::classify;
use rustc_ast::util::comments::{gather_comments, Comment, CommentStyle}; use rustc_ast::util::comments::{gather_comments, Comment, CommentStyle};
use rustc_ast::util::parser::{self, AssocOp, Fixity}; use rustc_ast::util::parser;
use rustc_ast::{self as ast, BlockCheckMode, PatKind, RangeEnd, RangeSyntax}; use rustc_ast::{self as ast, BlockCheckMode, PatKind, RangeEnd, RangeSyntax};
use rustc_ast::{attr, Term}; use rustc_ast::{attr, Term};
use rustc_ast::{GenericArg, MacArgs, ModKind}; use rustc_ast::{GenericArg, MacArgs, ModKind};
@ -1682,42 +1684,6 @@ impl<'a> State<'a> {
self.print_expr_cond_paren(expr, Self::cond_needs_par(expr) || npals()) self.print_expr_cond_paren(expr, Self::cond_needs_par(expr) || npals())
} }
fn print_else(&mut self, els: Option<&ast::Expr>) {
if let Some(_else) = els {
match _else.kind {
// Another `else if` block.
ast::ExprKind::If(ref i, ref then, ref e) => {
self.cbox(INDENT_UNIT - 1);
self.ibox(0);
self.word(" else if ");
self.print_expr_as_cond(i);
self.space();
self.print_block(then);
self.print_else(e.as_deref())
}
// Final `else` block.
ast::ExprKind::Block(ref b, _) => {
self.cbox(INDENT_UNIT - 1);
self.ibox(0);
self.word(" else ");
self.print_block(b)
}
// Constraints would be great here!
_ => {
panic!("print_if saw if with weird alternative");
}
}
}
}
crate fn print_if(&mut self, test: &ast::Expr, blk: &ast::Block, elseopt: Option<&ast::Expr>) {
self.head("if");
self.print_expr_as_cond(test);
self.space();
self.print_block(blk);
self.print_else(elseopt)
}
crate fn print_mac(&mut self, m: &ast::MacCall) { crate fn print_mac(&mut self, m: &ast::MacCall) {
self.print_mac_common( self.print_mac_common(
Some(MacHeader::Path(&m.path)), Some(MacHeader::Path(&m.path)),
@ -1730,477 +1696,6 @@ impl<'a> State<'a> {
); );
} }
fn print_call_post(&mut self, args: &[P<ast::Expr>]) {
self.popen();
self.commasep_exprs(Inconsistent, args);
self.pclose()
}
crate fn print_expr_maybe_paren(&mut self, expr: &ast::Expr, prec: i8) {
self.print_expr_cond_paren(expr, expr.precedence().order() < prec)
}
/// Prints an expr using syntax that's acceptable in a condition position, such as the `cond` in
/// `if cond { ... }`.
crate fn print_expr_as_cond(&mut self, expr: &ast::Expr) {
self.print_expr_cond_paren(expr, Self::cond_needs_par(expr))
}
// Does `expr` need parentheses when printed in a condition position?
//
// These cases need parens due to the parse error observed in #26461: `if return {}`
// parses as the erroneous construct `if (return {})`, not `if (return) {}`.
fn cond_needs_par(expr: &ast::Expr) -> bool {
match expr.kind {
ast::ExprKind::Break(..) | ast::ExprKind::Closure(..) | ast::ExprKind::Ret(..) => true,
_ => parser::contains_exterior_struct_lit(expr),
}
}
/// Prints `expr` or `(expr)` when `needs_par` holds.
fn print_expr_cond_paren(&mut self, expr: &ast::Expr, needs_par: bool) {
if needs_par {
self.popen();
}
self.print_expr(expr);
if needs_par {
self.pclose();
}
}
fn print_expr_vec(&mut self, exprs: &[P<ast::Expr>]) {
self.ibox(INDENT_UNIT);
self.word("[");
self.commasep_exprs(Inconsistent, exprs);
self.word("]");
self.end();
}
fn print_expr_anon_const(&mut self, expr: &ast::AnonConst) {
self.ibox(INDENT_UNIT);
self.word("const");
self.print_expr(&expr.value);
self.end();
}
fn print_expr_repeat(&mut self, element: &ast::Expr, count: &ast::AnonConst) {
self.ibox(INDENT_UNIT);
self.word("[");
self.print_expr(element);
self.word_space(";");
self.print_expr(&count.value);
self.word("]");
self.end();
}
fn print_expr_struct(
&mut self,
qself: &Option<ast::QSelf>,
path: &ast::Path,
fields: &[ast::ExprField],
rest: &ast::StructRest,
) {
if let Some(qself) = qself {
self.print_qpath(path, qself, true);
} else {
self.print_path(path, true, 0);
}
self.word("{");
self.commasep_cmnt(
Consistent,
fields,
|s, field| {
s.print_outer_attributes(&field.attrs);
s.ibox(INDENT_UNIT);
if !field.is_shorthand {
s.print_ident(field.ident);
s.word_space(":");
}
s.print_expr(&field.expr);
s.end();
},
|f| f.span,
);
match rest {
ast::StructRest::Base(_) | ast::StructRest::Rest(_) => {
self.ibox(INDENT_UNIT);
if !fields.is_empty() {
self.word(",");
self.space();
}
self.word("..");
if let ast::StructRest::Base(ref expr) = *rest {
self.print_expr(expr);
}
self.end();
}
ast::StructRest::None if !fields.is_empty() => self.word(","),
_ => {}
}
self.word("}");
}
fn print_expr_tup(&mut self, exprs: &[P<ast::Expr>]) {
self.popen();
self.commasep_exprs(Inconsistent, exprs);
if exprs.len() == 1 {
self.word(",");
}
self.pclose()
}
fn print_expr_call(&mut self, func: &ast::Expr, args: &[P<ast::Expr>]) {
let prec = match func.kind {
ast::ExprKind::Field(..) => parser::PREC_FORCE_PAREN,
_ => parser::PREC_POSTFIX,
};
self.print_expr_maybe_paren(func, prec);
self.print_call_post(args)
}
fn print_expr_method_call(&mut self, segment: &ast::PathSegment, args: &[P<ast::Expr>]) {
let base_args = &args[1..];
self.print_expr_maybe_paren(&args[0], parser::PREC_POSTFIX);
self.word(".");
self.print_ident(segment.ident);
if let Some(ref args) = segment.args {
self.print_generic_args(args, true);
}
self.print_call_post(base_args)
}
fn print_expr_binary(&mut self, op: ast::BinOp, lhs: &ast::Expr, rhs: &ast::Expr) {
let assoc_op = AssocOp::from_ast_binop(op.node);
let prec = assoc_op.precedence() as i8;
let fixity = assoc_op.fixity();
let (left_prec, right_prec) = match fixity {
Fixity::Left => (prec, prec + 1),
Fixity::Right => (prec + 1, prec),
Fixity::None => (prec + 1, prec + 1),
};
let left_prec = match (&lhs.kind, op.node) {
// These cases need parens: `x as i32 < y` has the parser thinking that `i32 < y` is
// the beginning of a path type. It starts trying to parse `x as (i32 < y ...` instead
// of `(x as i32) < ...`. We need to convince it _not_ to do that.
(&ast::ExprKind::Cast { .. }, ast::BinOpKind::Lt | ast::BinOpKind::Shl) => {
parser::PREC_FORCE_PAREN
}
// We are given `(let _ = a) OP b`.
//
// - When `OP <= LAnd` we should print `let _ = a OP b` to avoid redundant parens
// as the parser will interpret this as `(let _ = a) OP b`.
//
// - Otherwise, e.g. when we have `(let a = b) < c` in AST,
// parens are required since the parser would interpret `let a = b < c` as
// `let a = (b < c)`. To achieve this, we force parens.
(&ast::ExprKind::Let { .. }, _) if !parser::needs_par_as_let_scrutinee(prec) => {
parser::PREC_FORCE_PAREN
}
_ => left_prec,
};
self.print_expr_maybe_paren(lhs, left_prec);
self.space();
self.word_space(op.node.to_string());
self.print_expr_maybe_paren(rhs, right_prec)
}
fn print_expr_unary(&mut self, op: ast::UnOp, expr: &ast::Expr) {
self.word(ast::UnOp::to_string(op));
self.print_expr_maybe_paren(expr, parser::PREC_PREFIX)
}
fn print_expr_addr_of(
&mut self,
kind: ast::BorrowKind,
mutability: ast::Mutability,
expr: &ast::Expr,
) {
self.word("&");
match kind {
ast::BorrowKind::Ref => self.print_mutability(mutability, false),
ast::BorrowKind::Raw => {
self.word_nbsp("raw");
self.print_mutability(mutability, true);
}
}
self.print_expr_maybe_paren(expr, parser::PREC_PREFIX)
}
pub fn print_expr(&mut self, expr: &ast::Expr) {
self.print_expr_outer_attr_style(expr, true)
}
fn print_expr_outer_attr_style(&mut self, expr: &ast::Expr, is_inline: bool) {
self.maybe_print_comment(expr.span.lo());
let attrs = &expr.attrs;
if is_inline {
self.print_outer_attributes_inline(attrs);
} else {
self.print_outer_attributes(attrs);
}
self.ibox(INDENT_UNIT);
self.ann.pre(self, AnnNode::Expr(expr));
match expr.kind {
ast::ExprKind::Box(ref expr) => {
self.word_space("box");
self.print_expr_maybe_paren(expr, parser::PREC_PREFIX);
}
ast::ExprKind::Array(ref exprs) => {
self.print_expr_vec(exprs);
}
ast::ExprKind::ConstBlock(ref anon_const) => {
self.print_expr_anon_const(anon_const);
}
ast::ExprKind::Repeat(ref element, ref count) => {
self.print_expr_repeat(element, count);
}
ast::ExprKind::Struct(ref se) => {
self.print_expr_struct(&se.qself, &se.path, &se.fields, &se.rest);
}
ast::ExprKind::Tup(ref exprs) => {
self.print_expr_tup(exprs);
}
ast::ExprKind::Call(ref func, ref args) => {
self.print_expr_call(func, &args);
}
ast::ExprKind::MethodCall(ref segment, ref args, _) => {
self.print_expr_method_call(segment, &args);
}
ast::ExprKind::Binary(op, ref lhs, ref rhs) => {
self.print_expr_binary(op, lhs, rhs);
}
ast::ExprKind::Unary(op, ref expr) => {
self.print_expr_unary(op, expr);
}
ast::ExprKind::AddrOf(k, m, ref expr) => {
self.print_expr_addr_of(k, m, expr);
}
ast::ExprKind::Lit(ref lit) => {
self.print_literal(lit);
}
ast::ExprKind::Cast(ref expr, ref ty) => {
let prec = AssocOp::As.precedence() as i8;
self.print_expr_maybe_paren(expr, prec);
self.space();
self.word_space("as");
self.print_type(ty);
}
ast::ExprKind::Type(ref expr, ref ty) => {
let prec = AssocOp::Colon.precedence() as i8;
self.print_expr_maybe_paren(expr, prec);
self.word_space(":");
self.print_type(ty);
}
ast::ExprKind::Let(ref pat, ref scrutinee, _) => {
self.print_let(pat, scrutinee);
}
ast::ExprKind::If(ref test, ref blk, ref elseopt) => {
self.print_if(test, blk, elseopt.as_deref())
}
ast::ExprKind::While(ref test, ref blk, opt_label) => {
if let Some(label) = opt_label {
self.print_ident(label.ident);
self.word_space(":");
}
self.head("while");
self.print_expr_as_cond(test);
self.space();
self.print_block_with_attrs(blk, attrs);
}
ast::ExprKind::ForLoop(ref pat, ref iter, ref blk, opt_label) => {
if let Some(label) = opt_label {
self.print_ident(label.ident);
self.word_space(":");
}
self.head("for");
self.print_pat(pat);
self.space();
self.word_space("in");
self.print_expr_as_cond(iter);
self.space();
self.print_block_with_attrs(blk, attrs);
}
ast::ExprKind::Loop(ref blk, opt_label) => {
if let Some(label) = opt_label {
self.print_ident(label.ident);
self.word_space(":");
}
self.head("loop");
self.print_block_with_attrs(blk, attrs);
}
ast::ExprKind::Match(ref expr, ref arms) => {
self.cbox(INDENT_UNIT);
self.ibox(INDENT_UNIT);
self.word_nbsp("match");
self.print_expr_as_cond(expr);
self.space();
self.bopen();
self.print_inner_attributes_no_trailing_hardbreak(attrs);
for arm in arms {
self.print_arm(arm);
}
let empty = attrs.is_empty() && arms.is_empty();
self.bclose(expr.span, empty);
}
ast::ExprKind::Closure(
capture_clause,
asyncness,
movability,
ref decl,
ref body,
_,
) => {
self.print_movability(movability);
self.print_asyncness(asyncness);
self.print_capture_clause(capture_clause);
self.print_fn_params_and_ret(decl, true);
self.space();
self.print_expr(body);
self.end(); // need to close a box
// a box will be closed by print_expr, but we didn't want an overall
// wrapper so we closed the corresponding opening. so create an
// empty box to satisfy the close.
self.ibox(0);
}
ast::ExprKind::Block(ref blk, opt_label) => {
if let Some(label) = opt_label {
self.print_ident(label.ident);
self.word_space(":");
}
// containing cbox, will be closed by print-block at }
self.cbox(INDENT_UNIT);
// head-box, will be closed by print-block after {
self.ibox(0);
self.print_block_with_attrs(blk, attrs);
}
ast::ExprKind::Async(capture_clause, _, ref blk) => {
self.word_nbsp("async");
self.print_capture_clause(capture_clause);
// cbox/ibox in analogy to the `ExprKind::Block` arm above
self.cbox(INDENT_UNIT);
self.ibox(0);
self.print_block_with_attrs(blk, attrs);
}
ast::ExprKind::Await(ref expr) => {
self.print_expr_maybe_paren(expr, parser::PREC_POSTFIX);
self.word(".await");
}
ast::ExprKind::Assign(ref lhs, ref rhs, _) => {
let prec = AssocOp::Assign.precedence() as i8;
self.print_expr_maybe_paren(lhs, prec + 1);
self.space();
self.word_space("=");
self.print_expr_maybe_paren(rhs, prec);
}
ast::ExprKind::AssignOp(op, ref lhs, ref rhs) => {
let prec = AssocOp::Assign.precedence() as i8;
self.print_expr_maybe_paren(lhs, prec + 1);
self.space();
self.word(op.node.to_string());
self.word_space("=");
self.print_expr_maybe_paren(rhs, prec);
}
ast::ExprKind::Field(ref expr, ident) => {
self.print_expr_maybe_paren(expr, parser::PREC_POSTFIX);
self.word(".");
self.print_ident(ident);
}
ast::ExprKind::Index(ref expr, ref index) => {
self.print_expr_maybe_paren(expr, parser::PREC_POSTFIX);
self.word("[");
self.print_expr(index);
self.word("]");
}
ast::ExprKind::Range(ref start, ref end, limits) => {
// Special case for `Range`. `AssocOp` claims that `Range` has higher precedence
// than `Assign`, but `x .. x = x` gives a parse error instead of `x .. (x = x)`.
// Here we use a fake precedence value so that any child with lower precedence than
// a "normal" binop gets parenthesized. (`LOr` is the lowest-precedence binop.)
let fake_prec = AssocOp::LOr.precedence() as i8;
if let Some(ref e) = *start {
self.print_expr_maybe_paren(e, fake_prec);
}
if limits == ast::RangeLimits::HalfOpen {
self.word("..");
} else {
self.word("..=");
}
if let Some(ref e) = *end {
self.print_expr_maybe_paren(e, fake_prec);
}
}
ast::ExprKind::Underscore => self.word("_"),
ast::ExprKind::Path(None, ref path) => self.print_path(path, true, 0),
ast::ExprKind::Path(Some(ref qself), ref path) => self.print_qpath(path, qself, true),
ast::ExprKind::Break(opt_label, ref opt_expr) => {
self.word("break");
if let Some(label) = opt_label {
self.space();
self.print_ident(label.ident);
}
if let Some(ref expr) = *opt_expr {
self.space();
self.print_expr_maybe_paren(expr, parser::PREC_JUMP);
}
}
ast::ExprKind::Continue(opt_label) => {
self.word("continue");
if let Some(label) = opt_label {
self.space();
self.print_ident(label.ident);
}
}
ast::ExprKind::Ret(ref result) => {
self.word("return");
if let Some(ref expr) = *result {
self.word(" ");
self.print_expr_maybe_paren(expr, parser::PREC_JUMP);
}
}
ast::ExprKind::InlineAsm(ref a) => {
self.word("asm!");
self.print_inline_asm(a);
}
ast::ExprKind::MacCall(ref m) => self.print_mac(m),
ast::ExprKind::Paren(ref e) => {
self.popen();
self.print_expr(e);
self.pclose();
}
ast::ExprKind::Yield(ref e) => {
self.word("yield");
if let Some(ref expr) = *e {
self.space();
self.print_expr_maybe_paren(expr, parser::PREC_JUMP);
}
}
ast::ExprKind::Try(ref e) => {
self.print_expr_maybe_paren(e, parser::PREC_POSTFIX);
self.word("?")
}
ast::ExprKind::TryBlock(ref blk) => {
self.head("try");
self.print_block_with_attrs(blk, attrs)
}
ast::ExprKind::Err => {
self.popen();
self.word("/*ERROR*/");
self.pclose()
}
}
self.ann.post(self, AnnNode::Expr(expr));
self.end();
}
fn print_inline_asm(&mut self, asm: &ast::InlineAsm) { fn print_inline_asm(&mut self, asm: &ast::InlineAsm) {
enum AsmArg<'a> { enum AsmArg<'a> {
Template(String), Template(String),
@ -2496,48 +1991,6 @@ impl<'a> State<'a> {
self.ann.post(self, AnnNode::Pat(pat)) self.ann.post(self, AnnNode::Pat(pat))
} }
fn print_arm(&mut self, arm: &ast::Arm) {
// Note, I have no idea why this check is necessary, but here it is.
if arm.attrs.is_empty() {
self.space();
}
self.cbox(INDENT_UNIT);
self.ibox(0);
self.maybe_print_comment(arm.pat.span.lo());
self.print_outer_attributes(&arm.attrs);
self.print_pat(&arm.pat);
self.space();
if let Some(ref e) = arm.guard {
self.word_space("if");
self.print_expr(e);
self.space();
}
self.word_space("=>");
match arm.body.kind {
ast::ExprKind::Block(ref blk, opt_label) => {
if let Some(label) = opt_label {
self.print_ident(label.ident);
self.word_space(":");
}
// The block will close the pattern's ibox.
self.print_block_unclosed_indent(blk);
// If it is a user-provided unsafe block, print a comma after it.
if let BlockCheckMode::Unsafe(ast::UserProvided) = blk.rules {
self.word(",");
}
}
_ => {
self.end(); // Close the ibox for the pattern.
self.print_expr(&arm.body);
self.word(",");
}
}
self.end(); // Close enclosing cbox.
}
fn print_explicit_self(&mut self, explicit_self: &ast::ExplicitSelf) { fn print_explicit_self(&mut self, explicit_self: &ast::ExplicitSelf) {
match explicit_self.node { match explicit_self.node {
SelfKind::Value(m) => { SelfKind::Value(m) => {
@ -2608,26 +2061,12 @@ impl<'a> State<'a> {
self.print_fn_ret_ty(&decl.output) self.print_fn_ret_ty(&decl.output)
} }
crate fn print_movability(&mut self, movability: ast::Movability) {
match movability {
ast::Movability::Static => self.word_space("static"),
ast::Movability::Movable => {}
}
}
crate fn print_asyncness(&mut self, asyncness: ast::Async) { crate fn print_asyncness(&mut self, asyncness: ast::Async) {
if asyncness.is_async() { if asyncness.is_async() {
self.word_nbsp("async"); self.word_nbsp("async");
} }
} }
crate fn print_capture_clause(&mut self, capture_clause: ast::CaptureBy) {
match capture_clause {
ast::CaptureBy::Value => self.word_space("move"),
ast::CaptureBy::Ref => {}
}
}
pub fn print_type_bounds(&mut self, prefix: &'static str, bounds: &[ast::GenericBound]) { pub fn print_type_bounds(&mut self, prefix: &'static str, bounds: &[ast::GenericBound]) {
if !bounds.is_empty() { if !bounds.is_empty() {
self.word(prefix); self.word(prefix);

571
compiler/rustc_ast_pretty/src/pprust/state/expr.rs Normal file
View file

@ -0,0 +1,571 @@
use crate::pp::Breaks::{Consistent, Inconsistent};
use crate::pprust::state::{AnnNode, PrintState, State, INDENT_UNIT};
use rustc_ast::ptr::P;
use rustc_ast::util::parser::{self, AssocOp, Fixity};
use rustc_ast::{self as ast, BlockCheckMode};
impl<'a> State<'a> {
fn print_else(&mut self, els: Option<&ast::Expr>) {
if let Some(_else) = els {
match _else.kind {
// Another `else if` block.
ast::ExprKind::If(ref i, ref then, ref e) => {
self.cbox(INDENT_UNIT - 1);
self.ibox(0);
self.word(" else if ");
self.print_expr_as_cond(i);
self.space();
self.print_block(then);
self.print_else(e.as_deref())
}
// Final `else` block.
ast::ExprKind::Block(ref b, _) => {
self.cbox(INDENT_UNIT - 1);
self.ibox(0);
self.word(" else ");
self.print_block(b)
}
// Constraints would be great here!
_ => {
panic!("print_if saw if with weird alternative");
}
}
}
}
fn print_if(&mut self, test: &ast::Expr, blk: &ast::Block, elseopt: Option<&ast::Expr>) {
self.head("if");
self.print_expr_as_cond(test);
self.space();
self.print_block(blk);
self.print_else(elseopt)
}
fn print_call_post(&mut self, args: &[P<ast::Expr>]) {
self.popen();
self.commasep_exprs(Inconsistent, args);
self.pclose()
}
fn print_expr_maybe_paren(&mut self, expr: &ast::Expr, prec: i8) {
self.print_expr_cond_paren(expr, expr.precedence().order() < prec)
}
/// Prints an expr using syntax that's acceptable in a condition position, such as the `cond` in
/// `if cond { ... }`.
fn print_expr_as_cond(&mut self, expr: &ast::Expr) {
self.print_expr_cond_paren(expr, Self::cond_needs_par(expr))
}
// Does `expr` need parentheses when printed in a condition position?
//
// These cases need parens due to the parse error observed in #26461: `if return {}`
// parses as the erroneous construct `if (return {})`, not `if (return) {}`.
pub(super) fn cond_needs_par(expr: &ast::Expr) -> bool {
match expr.kind {
ast::ExprKind::Break(..) | ast::ExprKind::Closure(..) | ast::ExprKind::Ret(..) => true,
_ => parser::contains_exterior_struct_lit(expr),
}
}
/// Prints `expr` or `(expr)` when `needs_par` holds.
pub(super) fn print_expr_cond_paren(&mut self, expr: &ast::Expr, needs_par: bool) {
if needs_par {
self.popen();
}
self.print_expr(expr);
if needs_par {
self.pclose();
}
}
fn print_expr_vec(&mut self, exprs: &[P<ast::Expr>]) {
self.ibox(INDENT_UNIT);
self.word("[");
self.commasep_exprs(Inconsistent, exprs);
self.word("]");
self.end();
}
pub(super) fn print_expr_anon_const(&mut self, expr: &ast::AnonConst) {
self.ibox(INDENT_UNIT);
self.word("const");
self.print_expr(&expr.value);
self.end();
}
fn print_expr_repeat(&mut self, element: &ast::Expr, count: &ast::AnonConst) {
self.ibox(INDENT_UNIT);
self.word("[");
self.print_expr(element);
self.word_space(";");
self.print_expr(&count.value);
self.word("]");
self.end();
}
fn print_expr_struct(
&mut self,
qself: &Option<ast::QSelf>,
path: &ast::Path,
fields: &[ast::ExprField],
rest: &ast::StructRest,
) {
if let Some(qself) = qself {
self.print_qpath(path, qself, true);
} else {
self.print_path(path, true, 0);
}
self.word("{");
self.commasep_cmnt(
Consistent,
fields,
|s, field| {
s.print_outer_attributes(&field.attrs);
s.ibox(INDENT_UNIT);
if !field.is_shorthand {
s.print_ident(field.ident);
s.word_space(":");
}
s.print_expr(&field.expr);
s.end();
},
|f| f.span,
);
match rest {
ast::StructRest::Base(_) | ast::StructRest::Rest(_) => {
self.ibox(INDENT_UNIT);
if !fields.is_empty() {
self.word(",");
self.space();
}
self.word("..");
if let ast::StructRest::Base(ref expr) = *rest {
self.print_expr(expr);
}
self.end();
}
ast::StructRest::None if !fields.is_empty() => self.word(","),
_ => {}
}
self.word("}");
}
fn print_expr_tup(&mut self, exprs: &[P<ast::Expr>]) {
self.popen();
self.commasep_exprs(Inconsistent, exprs);
if exprs.len() == 1 {
self.word(",");
}
self.pclose()
}
fn print_expr_call(&mut self, func: &ast::Expr, args: &[P<ast::Expr>]) {
let prec = match func.kind {
ast::ExprKind::Field(..) => parser::PREC_FORCE_PAREN,
_ => parser::PREC_POSTFIX,
};
self.print_expr_maybe_paren(func, prec);
self.print_call_post(args)
}
fn print_expr_method_call(&mut self, segment: &ast::PathSegment, args: &[P<ast::Expr>]) {
let base_args = &args[1..];
self.print_expr_maybe_paren(&args[0], parser::PREC_POSTFIX);
self.word(".");
self.print_ident(segment.ident);
if let Some(ref args) = segment.args {
self.print_generic_args(args, true);
}
self.print_call_post(base_args)
}
fn print_expr_binary(&mut self, op: ast::BinOp, lhs: &ast::Expr, rhs: &ast::Expr) {
let assoc_op = AssocOp::from_ast_binop(op.node);
let prec = assoc_op.precedence() as i8;
let fixity = assoc_op.fixity();
let (left_prec, right_prec) = match fixity {
Fixity::Left => (prec, prec + 1),
Fixity::Right => (prec + 1, prec),
Fixity::None => (prec + 1, prec + 1),
};
let left_prec = match (&lhs.kind, op.node) {
// These cases need parens: `x as i32 < y` has the parser thinking that `i32 < y` is
// the beginning of a path type. It starts trying to parse `x as (i32 < y ...` instead
// of `(x as i32) < ...`. We need to convince it _not_ to do that.
(&ast::ExprKind::Cast { .. }, ast::BinOpKind::Lt | ast::BinOpKind::Shl) => {
parser::PREC_FORCE_PAREN
}
// We are given `(let _ = a) OP b`.
//
// - When `OP <= LAnd` we should print `let _ = a OP b` to avoid redundant parens
// as the parser will interpret this as `(let _ = a) OP b`.
//
// - Otherwise, e.g. when we have `(let a = b) < c` in AST,
// parens are required since the parser would interpret `let a = b < c` as
// `let a = (b < c)`. To achieve this, we force parens.
(&ast::ExprKind::Let { .. }, _) if !parser::needs_par_as_let_scrutinee(prec) => {
parser::PREC_FORCE_PAREN
}
_ => left_prec,
};
self.print_expr_maybe_paren(lhs, left_prec);
self.space();
self.word_space(op.node.to_string());
self.print_expr_maybe_paren(rhs, right_prec)
}
fn print_expr_unary(&mut self, op: ast::UnOp, expr: &ast::Expr) {
self.word(ast::UnOp::to_string(op));
self.print_expr_maybe_paren(expr, parser::PREC_PREFIX)
}
fn print_expr_addr_of(
&mut self,
kind: ast::BorrowKind,
mutability: ast::Mutability,
expr: &ast::Expr,
) {
self.word("&");
match kind {
ast::BorrowKind::Ref => self.print_mutability(mutability, false),
ast::BorrowKind::Raw => {
self.word_nbsp("raw");
self.print_mutability(mutability, true);
}
}
self.print_expr_maybe_paren(expr, parser::PREC_PREFIX)
}
pub fn print_expr(&mut self, expr: &ast::Expr) {
self.print_expr_outer_attr_style(expr, true)
}
pub(super) fn print_expr_outer_attr_style(&mut self, expr: &ast::Expr, is_inline: bool) {
self.maybe_print_comment(expr.span.lo());
let attrs = &expr.attrs;
if is_inline {
self.print_outer_attributes_inline(attrs);
} else {
self.print_outer_attributes(attrs);
}
self.ibox(INDENT_UNIT);
self.ann.pre(self, AnnNode::Expr(expr));
match expr.kind {
ast::ExprKind::Box(ref expr) => {
self.word_space("box");
self.print_expr_maybe_paren(expr, parser::PREC_PREFIX);
}
ast::ExprKind::Array(ref exprs) => {
self.print_expr_vec(exprs);
}
ast::ExprKind::ConstBlock(ref anon_const) => {
self.print_expr_anon_const(anon_const);
}
ast::ExprKind::Repeat(ref element, ref count) => {
self.print_expr_repeat(element, count);
}
ast::ExprKind::Struct(ref se) => {
self.print_expr_struct(&se.qself, &se.path, &se.fields, &se.rest);
}
ast::ExprKind::Tup(ref exprs) => {
self.print_expr_tup(exprs);
}
ast::ExprKind::Call(ref func, ref args) => {
self.print_expr_call(func, &args);
}
ast::ExprKind::MethodCall(ref segment, ref args, _) => {
self.print_expr_method_call(segment, &args);
}
ast::ExprKind::Binary(op, ref lhs, ref rhs) => {
self.print_expr_binary(op, lhs, rhs);
}
ast::ExprKind::Unary(op, ref expr) => {
self.print_expr_unary(op, expr);
}
ast::ExprKind::AddrOf(k, m, ref expr) => {
self.print_expr_addr_of(k, m, expr);
}
ast::ExprKind::Lit(ref lit) => {
self.print_literal(lit);
}
ast::ExprKind::Cast(ref expr, ref ty) => {
let prec = AssocOp::As.precedence() as i8;
self.print_expr_maybe_paren(expr, prec);
self.space();
self.word_space("as");
self.print_type(ty);
}
ast::ExprKind::Type(ref expr, ref ty) => {
let prec = AssocOp::Colon.precedence() as i8;
self.print_expr_maybe_paren(expr, prec);
self.word_space(":");
self.print_type(ty);
}
ast::ExprKind::Let(ref pat, ref scrutinee, _) => {
self.print_let(pat, scrutinee);
}
ast::ExprKind::If(ref test, ref blk, ref elseopt) => {
self.print_if(test, blk, elseopt.as_deref())
}
ast::ExprKind::While(ref test, ref blk, opt_label) => {
if let Some(label) = opt_label {
self.print_ident(label.ident);
self.word_space(":");
}
self.head("while");
self.print_expr_as_cond(test);
self.space();
self.print_block_with_attrs(blk, attrs);
}
ast::ExprKind::ForLoop(ref pat, ref iter, ref blk, opt_label) => {
if let Some(label) = opt_label {
self.print_ident(label.ident);
self.word_space(":");
}
self.head("for");
self.print_pat(pat);
self.space();
self.word_space("in");
self.print_expr_as_cond(iter);
self.space();
self.print_block_with_attrs(blk, attrs);
}
ast::ExprKind::Loop(ref blk, opt_label) => {
if let Some(label) = opt_label {
self.print_ident(label.ident);
self.word_space(":");
}
self.head("loop");
self.print_block_with_attrs(blk, attrs);
}
ast::ExprKind::Match(ref expr, ref arms) => {
self.cbox(INDENT_UNIT);
self.ibox(INDENT_UNIT);
self.word_nbsp("match");
self.print_expr_as_cond(expr);
self.space();
self.bopen();
self.print_inner_attributes_no_trailing_hardbreak(attrs);
for arm in arms {
self.print_arm(arm);
}
let empty = attrs.is_empty() && arms.is_empty();
self.bclose(expr.span, empty);
}
ast::ExprKind::Closure(
capture_clause,
asyncness,
movability,
ref decl,
ref body,
_,
) => {
self.print_movability(movability);
self.print_asyncness(asyncness);
self.print_capture_clause(capture_clause);
self.print_fn_params_and_ret(decl, true);
self.space();
self.print_expr(body);
self.end(); // need to close a box
// a box will be closed by print_expr, but we didn't want an overall
// wrapper so we closed the corresponding opening. so create an
// empty box to satisfy the close.
self.ibox(0);
}
ast::ExprKind::Block(ref blk, opt_label) => {
if let Some(label) = opt_label {
self.print_ident(label.ident);
self.word_space(":");
}
// containing cbox, will be closed by print-block at }
self.cbox(INDENT_UNIT);
// head-box, will be closed by print-block after {
self.ibox(0);
self.print_block_with_attrs(blk, attrs);
}
ast::ExprKind::Async(capture_clause, _, ref blk) => {
self.word_nbsp("async");
self.print_capture_clause(capture_clause);
// cbox/ibox in analogy to the `ExprKind::Block` arm above
self.cbox(INDENT_UNIT);
self.ibox(0);
self.print_block_with_attrs(blk, attrs);
}
ast::ExprKind::Await(ref expr) => {
self.print_expr_maybe_paren(expr, parser::PREC_POSTFIX);
self.word(".await");
}
ast::ExprKind::Assign(ref lhs, ref rhs, _) => {
let prec = AssocOp::Assign.precedence() as i8;
self.print_expr_maybe_paren(lhs, prec + 1);
self.space();
self.word_space("=");
self.print_expr_maybe_paren(rhs, prec);
}
ast::ExprKind::AssignOp(op, ref lhs, ref rhs) => {
let prec = AssocOp::Assign.precedence() as i8;
self.print_expr_maybe_paren(lhs, prec + 1);
self.space();
self.word(op.node.to_string());
self.word_space("=");
self.print_expr_maybe_paren(rhs, prec);
}
ast::ExprKind::Field(ref expr, ident) => {
self.print_expr_maybe_paren(expr, parser::PREC_POSTFIX);
self.word(".");
self.print_ident(ident);
}
ast::ExprKind::Index(ref expr, ref index) => {
self.print_expr_maybe_paren(expr, parser::PREC_POSTFIX);
self.word("[");
self.print_expr(index);
self.word("]");
}
ast::ExprKind::Range(ref start, ref end, limits) => {
// Special case for `Range`. `AssocOp` claims that `Range` has higher precedence
// than `Assign`, but `x .. x = x` gives a parse error instead of `x .. (x = x)`.
// Here we use a fake precedence value so that any child with lower precedence than
// a "normal" binop gets parenthesized. (`LOr` is the lowest-precedence binop.)
let fake_prec = AssocOp::LOr.precedence() as i8;
if let Some(ref e) = *start {
self.print_expr_maybe_paren(e, fake_prec);
}
if limits == ast::RangeLimits::HalfOpen {
self.word("..");
} else {
self.word("..=");
}
if let Some(ref e) = *end {
self.print_expr_maybe_paren(e, fake_prec);
}
}
ast::ExprKind::Underscore => self.word("_"),
ast::ExprKind::Path(None, ref path) => self.print_path(path, true, 0),
ast::ExprKind::Path(Some(ref qself), ref path) => self.print_qpath(path, qself, true),
ast::ExprKind::Break(opt_label, ref opt_expr) => {
self.word("break");
if let Some(label) = opt_label {
self.space();
self.print_ident(label.ident);
}
if let Some(ref expr) = *opt_expr {
self.space();
self.print_expr_maybe_paren(expr, parser::PREC_JUMP);
}
}
ast::ExprKind::Continue(opt_label) => {
self.word("continue");
if let Some(label) = opt_label {
self.space();
self.print_ident(label.ident);
}
}
ast::ExprKind::Ret(ref result) => {
self.word("return");
if let Some(ref expr) = *result {
self.word(" ");
self.print_expr_maybe_paren(expr, parser::PREC_JUMP);
}
}
ast::ExprKind::InlineAsm(ref a) => {
self.word("asm!");
self.print_inline_asm(a);
}
ast::ExprKind::MacCall(ref m) => self.print_mac(m),
ast::ExprKind::Paren(ref e) => {
self.popen();
self.print_expr(e);
self.pclose();
}
ast::ExprKind::Yield(ref e) => {
self.word("yield");
if let Some(ref expr) = *e {
self.space();
self.print_expr_maybe_paren(expr, parser::PREC_JUMP);
}
}
ast::ExprKind::Try(ref e) => {
self.print_expr_maybe_paren(e, parser::PREC_POSTFIX);
self.word("?")
}
ast::ExprKind::TryBlock(ref blk) => {
self.head("try");
self.print_block_with_attrs(blk, attrs)
}
ast::ExprKind::Err => {
self.popen();
self.word("/*ERROR*/");
self.pclose()
}
}
self.ann.post(self, AnnNode::Expr(expr));
self.end();
}
fn print_arm(&mut self, arm: &ast::Arm) {
// Note, I have no idea why this check is necessary, but here it is.
if arm.attrs.is_empty() {
self.space();
}
self.cbox(INDENT_UNIT);
self.ibox(0);
self.maybe_print_comment(arm.pat.span.lo());
self.print_outer_attributes(&arm.attrs);
self.print_pat(&arm.pat);
self.space();
if let Some(ref e) = arm.guard {
self.word_space("if");
self.print_expr(e);
self.space();
}
self.word_space("=>");
match arm.body.kind {
ast::ExprKind::Block(ref blk, opt_label) => {
if let Some(label) = opt_label {
self.print_ident(label.ident);
self.word_space(":");
}
// The block will close the pattern's ibox.
self.print_block_unclosed_indent(blk);
// If it is a user-provided unsafe block, print a comma after it.
if let BlockCheckMode::Unsafe(ast::UserProvided) = blk.rules {
self.word(",");
}
}
_ => {
self.end(); // Close the ibox for the pattern.
self.print_expr(&arm.body);
self.word(",");
}
}
self.end(); // Close enclosing cbox.
}
fn print_movability(&mut self, movability: ast::Movability) {
match movability {
ast::Movability::Static => self.word_space("static"),
ast::Movability::Movable => {}
}
}
fn print_capture_clause(&mut self, capture_clause: ast::CaptureBy) {
match capture_clause {
ast::CaptureBy::Value => self.word_space("move"),
ast::CaptureBy::Ref => {}
}
}
}