| use crate::pp::Breaks::Inconsistent; |
| use crate::pprust::state::{AnnNode, IterDelimited, 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(..) |
| | ast::ExprKind::Yeet(..) => 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, |
| attrs: &[ast::Attribute], |
| ) { |
| self.ibox(INDENT_UNIT); |
| self.word("const"); |
| self.nbsp(); |
| if let ast::ExprKind::Block(block, None) = &expr.value.kind { |
| self.cbox(0); |
| self.ibox(0); |
| self.print_block_with_attrs(block, attrs); |
| } else { |
| 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.nbsp(); |
| self.word("{"); |
| let has_rest = match rest { |
| ast::StructRest::Base(_) | ast::StructRest::Rest(_) => true, |
| ast::StructRest::None => false, |
| }; |
| if fields.is_empty() && !has_rest { |
| self.word("}"); |
| return; |
| } |
| self.cbox(0); |
| for field in fields.iter().delimited() { |
| self.maybe_print_comment(field.span.hi()); |
| self.print_outer_attributes(&field.attrs); |
| if field.is_first { |
| self.space_if_not_bol(); |
| } |
| if !field.is_shorthand { |
| self.print_ident(field.ident); |
| self.word_nbsp(":"); |
| } |
| self.print_expr(&field.expr); |
| if !field.is_last || has_rest { |
| self.word_space(","); |
| } else { |
| self.trailing_comma_or_space(); |
| } |
| } |
| if has_rest { |
| if fields.is_empty() { |
| self.space(); |
| } |
| self.word(".."); |
| if let ast::StructRest::Base(expr) = rest { |
| self.print_expr(expr); |
| } |
| self.space(); |
| } |
| self.offset(-INDENT_UNIT); |
| self.end(); |
| 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, |
| receiver: &ast::Expr, |
| base_args: &[P<ast::Expr>], |
| ) { |
| self.print_expr_maybe_paren(receiver, 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, attrs); |
| } |
| 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 receiver, ref args, _) => { |
| self.print_expr_method_call(segment, &receiver, &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.cbox(0); |
| self.ibox(0); |
| self.word_nbsp("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.cbox(0); |
| self.ibox(0); |
| self.word_nbsp("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.cbox(0); |
| self.ibox(0); |
| self.word_nbsp("loop"); |
| self.print_block_with_attrs(blk, attrs); |
| } |
| ast::ExprKind::Match(ref expr, ref arms) => { |
| self.cbox(0); |
| self.ibox(0); |
| 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( |
| ref binder, |
| capture_clause, |
| asyncness, |
| movability, |
| ref decl, |
| ref body, |
| _, |
| ) => { |
| self.print_closure_binder(binder); |
| 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(0); |
| // 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(0); |
| 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::Yeet(ref result) => { |
| self.word("do"); |
| self.word(" "); |
| self.word("yeet"); |
| 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.cbox(0); |
| self.ibox(0); |
| self.word_nbsp("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_closure_binder(&mut self, binder: &ast::ClosureBinder) { |
| match binder { |
| ast::ClosureBinder::NotPresent => {} |
| ast::ClosureBinder::For { generic_params, .. } => { |
| self.print_formal_generic_params(&generic_params) |
| } |
| } |
| } |
| |
| 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 => {} |
| } |
| } |
| } |
