bjoernager/rust
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Preserve parenthesization in the AST

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Maintain explicit "paren" nodes in the AST so we can pretty-print
without having to guess where parens should go. We may revisit this
in the future.

r=graydon
This commit is contained in:
Tim Chevalier 2012-10-27 17:14:09 -07:00
parent 17a5d0f3a0
commit 62f98c8ff8
20 changed files with 148 additions and 217 deletions
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36
src/libsyntax/parse/classify.rs
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@ -36,39 +36,3 @@ fn stmt_ends_with_semi(stmt: ast::stmt) -> bool {
}
}
}
fn need_parens(expr: @ast::expr, outer_prec: uint) -> bool {
match expr.node {
ast::expr_binary(op, _, _) => operator_prec(op) < outer_prec,
ast::expr_cast(_, _) => parse::prec::as_prec < outer_prec,
// This may be too conservative in some cases
ast::expr_assign(_, _) => true,
ast::expr_swap(_, _) => true,
ast::expr_assign_op(_, _, _) => true,
ast::expr_ret(_) => true,
ast::expr_assert(_) => true,
ast::expr_log(_, _, _) => true,
_ => !parse::classify::expr_requires_semi_to_be_stmt(expr)
}
}
fn ends_in_lit_int(ex: @ast::expr) -> bool {
match ex.node {
ast::expr_lit(node) => match node {
@{node: ast::lit_int(_, ast::ty_i), _}
| @{node: ast::lit_int_unsuffixed(_), _} => true,
_ => false
},
ast::expr_binary(_, _, sub) | ast::expr_unary(_, sub) |
ast::expr_copy(sub) | ast::expr_assign(_, sub) |
ast::expr_assign_op(_, _, sub) | ast::expr_swap(_, sub) |
ast::expr_log(_, _, sub) | ast::expr_assert(sub) => {
ends_in_lit_int(sub)
}
ast::expr_fail(osub) | ast::expr_ret(osub) => match osub {
Some(ex) => ends_in_lit_int(ex),
_ => false
},
_ => false
}
}