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Remove maybe_protect_block kludge from pretty-printer

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It is no longer needed.
This commit is contained in:
Marijn Haverbeke 2011-09-15 09:52:13 +02:00
parent 0b34e0e60b
commit 3798b6f780
3 changed files with 1 additions and 121 deletions
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86
src/comp/syntax/print/pprust.rs
View file

@ -576,15 +576,11 @@ fn print_possibly_embedded_block(s: ps, blk: ast::blk, embedded: embed_type,
block_normal. { bopen(s); }
}
let last_stmt = option::none;
for st: @ast::stmt in blk.node.stmts {
maybe_protect_block(s, last_stmt, stmt_(st));
print_stmt(s, *st);
last_stmt = option::some(st);
}
alt blk.node.expr {
some(expr) {
maybe_protect_block(s, last_stmt, expr_(expr));
space_if_not_bol(s);
print_expr(s, expr);
maybe_print_trailing_comment(s, expr.span, some(blk.span.hi));
@ -593,88 +589,6 @@ fn print_possibly_embedded_block(s: ps, blk: ast::blk, embedded: embed_type,
}
bclose_(s, blk.span, indented);
s.ann.post(ann_node);
tag expr_or_stmt { stmt_(@ast::stmt); expr_(@ast::expr); }
// The Rust syntax has an ambiguity when an if, alt, or block statement is
// followed by a unary op, square bracket, or paren. In those cases we
// have to add an extra semi to make sure the output retains the same
// meaning.
fn maybe_protect_block(s: ps, last: option::t<@ast::stmt>,
next: expr_or_stmt) {
let last_expr_is_block =
alt last {
option::some(@{node: ast::stmt_expr(e, _), _}) {
alt e.node {
ast::expr_if(_, _, _) | ast::expr_alt(_, _) |
ast::expr_block(_) {
true
}
_ { false }
}
}
_ { false }
};
if !last_expr_is_block { ret; }
let next_expr_is_ambig =
alt next {
expr_(e) { expr_is_ambig(e) }
stmt_(@{node: ast::stmt_expr(e, _), _}) { expr_is_ambig(e) }
_ { false }
};
if last_expr_is_block && next_expr_is_ambig { word(s.s, ";"); }
fn expr_is_ambig(ex: @ast::expr) -> bool {
// We're going to walk the expression to the 'left' looking for
// various properties that might indicate ambiguity
type env = @mutable bool;
let visitor =
visit::mk_vt(@{visit_expr: visit_expr
with *visit::default_visitor()});
let env = @mutable false;
visit_expr(ex, env, visitor);
ret *env;
fn visit_expr(ex: @ast::expr, e: env, v: visit::vt<env>) {
assert (*e == false);
if expr_is_ambig(ex) { *e = true; ret; }
alt ex.node {
ast::expr_assign(x, _) { v.visit_expr(x, e, v); }
ast::expr_assign_op(_, x, _) { visit_expr(x, e, v); }
ast::expr_move(x, _) { v.visit_expr(x, e, v); }
ast::expr_field(x, _) { v.visit_expr(x, e, v); }
ast::expr_index(x, _) { v.visit_expr(x, e, v); }
ast::expr_binary(op, x, _) {
if need_parens(x, operator_prec(op)) { *e = true; ret; }
v.visit_expr(x, e, v);
}
ast::expr_cast(x, _) {
if need_parens(x, parse::parser::as_prec) {
*e = true;
ret;
}
}
ast::expr_ternary(x, _, _) { v.visit_expr(x, e, v); }
_ { }
}
}
fn expr_is_ambig(ex: @ast::expr) -> bool {
alt ex.node {
ast::expr_unary(_, _) { true }
ast::expr_tup(_) { true }
ast::expr_vec(_, _) { true }
_ { false }
}
}
}
}
}
// ret and fail, without arguments cannot appear is the discriminant of if,

35
src/test/pretty/block-disambig.rs
View file

@ -1,35 +0,0 @@
// Tests that the pretty printer correctly disambiguates various scenarios
// involving block statements by ending them with a semi-colon
fn test1() { let val = @0; { }; *val; }
fn test2() -> int { let val = @0; { }; *val }
fn test3() {
let regs = @{mutable eax: 0};
alt true { true { } };
(*regs).eax = 1;
}
fn test4() -> bool { let regs = @true; if true { }; *regs || false }
fn test5() -> (int, int) { { }; (0, 1) }
fn test6() -> bool { { }; (true || false) && true }
fn test7() -> uint {
let regs = @0;
alt true { true { } };
(*regs < 2) as uint
}
fn test8() -> int { let val = @0; alt true { true { } }; *val < 1 ? 0 : 1 }
fn test9() { let regs = @mutable 0; alt true { true { } }; *regs += 1; }
fn test10() -> int {
let regs = @mutable [0];
alt true { true { } };
(*regs)[0]
}
fn test11() -> [int] { if true { }; [1, 2] }

1
src/test/run-pass/block-expr-precedence.rs
View file

@ -2,6 +2,7 @@
// reproduce so we don't want to automatically reformat it
// no-reformat
// xfail-pretty
/*
*