summaryrefslogtreecommitdiffstats
path: root/compiler/rustc_ast_pretty/src/pprust/state/expr.rs
diff options
context:
space:
mode:
Diffstat (limited to 'compiler/rustc_ast_pretty/src/pprust/state/expr.rs')
-rw-r--r--compiler/rustc_ast_pretty/src/pprust/state/expr.rs621
1 files changed, 621 insertions, 0 deletions
diff --git a/compiler/rustc_ast_pretty/src/pprust/state/expr.rs b/compiler/rustc_ast_pretty/src/pprust/state/expr.rs
new file mode 100644
index 000000000..ead38caee
--- /dev/null
+++ b/compiler/rustc_ast_pretty/src/pprust/state/expr.rs
@@ -0,0 +1,621 @@
+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, 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, 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 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.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 => {}
+ }
+ }
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-06-11 19:53:27 +0000