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internal: more reasonable grammar for blocks

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Consider these expples

        { 92 }
  async { 92 }
    'a: { 92 }
   #[a] { 92 }

Previously the tree for them were

  BLOCK_EXPR
    { ... }

  EFFECT_EXPR
    async
    BLOCK_EXPR
      { ... }

  EFFECT_EXPR
    'a:
    BLOCK_EXPR
      { ... }

  BLOCK_EXPR
    #[a]
    { ... }

As you see, it gets progressively worse :) The last two items are
especially odd. The last one even violates the balanced curleys
invariant we have (#10357) The new approach is to say that the stuff in
`{}` is stmt_list, and the block is stmt_list + optional modifiers

  BLOCK_EXPR
    STMT_LIST
      { ... }

  BLOCK_EXPR
    async
    STMT_LIST
      { ... }

  BLOCK_EXPR
    'a:
    STMT_LIST
      { ... }

  BLOCK_EXPR
    #[a]
    STMT_LIST
      { ... }
This commit is contained in:
Aleksey Kladov 2021-09-26 12:12:57 +03:00
parent c51a3c78cf
commit 2bf81922f7
233 changed files with 11762 additions and 11343 deletions
Download patch file Download diff file Expand all files Collapse all files

41
crates/ide_db/src/helpers.rs
View file

@ -139,26 +139,27 @@ impl SnippetCap {
pub fn for_each_tail_expr(expr: &ast::Expr, cb: &mut dyn FnMut(&ast::Expr)) {
match expr {
ast::Expr::BlockExpr(b) => {
if let Some(e) = b.tail_expr() {
for_each_tail_expr(&e, cb);
}
}
ast::Expr::EffectExpr(e) => match e.effect() {
ast::Effect::Label(label) => {
for_each_break_expr(Some(label), e.block_expr(), &mut |b| {
cb(&ast::Expr::BreakExpr(b))
});
if let Some(b) = e.block_expr() {
for_each_tail_expr(&ast::Expr::BlockExpr(b), cb);
match b.modifier() {
Some(
ast::BlockModifier::Async(_)
| ast::BlockModifier::Try(_)
| ast::BlockModifier::Const(_),
) => return cb(expr),
Some(ast::BlockModifier::Label(label)) => {
for_each_break_expr(Some(label), b.stmt_list(), &mut |b| {
cb(&ast::Expr::BreakExpr(b))
});
}
Some(ast::BlockModifier::Unsafe(_)) => (),
None => (),
}
ast::Effect::Unsafe(_) => {
if let Some(e) = e.block_expr().and_then(|b| b.tail_expr()) {
if let Some(stmt_list) = b.stmt_list() {
if let Some(e) = stmt_list.tail_expr() {
for_each_tail_expr(&e, cb);
}
}
ast::Effect::Async(_) | ast::Effect::Try(_) | ast::Effect::Const(_) => cb(expr),
},
}
ast::Expr::IfExpr(if_) => {
let mut if_ = if_.clone();
loop {
@ -176,7 +177,9 @@ pub fn for_each_tail_expr(expr: &ast::Expr, cb: &mut dyn FnMut(&ast::Expr)) {
}
}
ast::Expr::LoopExpr(l) => {
for_each_break_expr(l.label(), l.loop_body(), &mut |b| cb(&ast::Expr::BreakExpr(b)))
for_each_break_expr(l.label(), l.loop_body().and_then(|it| it.stmt_list()), &mut |b| {
cb(&ast::Expr::BreakExpr(b))
})
}
ast::Expr::MatchExpr(m) => {
if let Some(arms) = m.match_arm_list() {
@ -216,7 +219,7 @@ pub fn for_each_tail_expr(expr: &ast::Expr, cb: &mut dyn FnMut(&ast::Expr)) {
/// Calls `cb` on each break expr inside of `body` that is applicable for the given label.
pub fn for_each_break_expr(
label: Option<ast::Label>,
body: Option<ast::BlockExpr>,
body: Option<ast::StmtList>,
cb: &mut dyn FnMut(ast::BreakExpr),
) {
let label = label.and_then(|lbl| lbl.lifetime());
@ -236,7 +239,7 @@ pub fn for_each_break_expr(
ast::Expr::LoopExpr(_) | ast::Expr::WhileExpr(_) | ast::Expr::ForExpr(_) => {
depth += 1
}
ast::Expr::EffectExpr(e) if e.label().is_some() => depth += 1,
ast::Expr::BlockExpr(e) if e.label().is_some() => depth += 1,
ast::Expr::BreakExpr(b)
if (depth == 0 && b.lifetime().is_none()) || eq_label(b.lifetime()) =>
{
@ -248,7 +251,7 @@ pub fn for_each_break_expr(
ast::Expr::LoopExpr(_) | ast::Expr::WhileExpr(_) | ast::Expr::ForExpr(_) => {
depth -= 1
}
ast::Expr::EffectExpr(e) if e.label().is_some() => depth -= 1,
ast::Expr::BlockExpr(e) if e.label().is_some() => depth -= 1,
_ => (),
},
}