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/*
Predicates on exprs and stmts that the pretty-printer and parser use
*/
import ast_util::*;
fn expr_requires_semi_to_be_stmt(e: @ast::expr) -> bool {
alt e.node {
ast::expr_if(_, _, _) | ast::expr_if_check(_, _, _)
| ast::expr_alt(_, _, _) | ast::expr_block(_)
| ast::expr_while(_, _) | ast::expr_loop(_)
| ast::expr_call(_, _, true) {
false
}
_ { true }
}
}
fn stmt_ends_with_semi(stmt: ast::stmt) -> bool {
alt stmt.node {
ast::stmt_decl(d, _) {
ret alt d.node {
ast::decl_local(_) { true }
ast::decl_item(_) { false }
}
}
ast::stmt_expr(e, _) {
ret expr_requires_semi_to_be_stmt(e);
}
ast::stmt_semi(e, _) {
ret false;
}
}
}
fn need_parens(expr: @ast::expr, outer_prec: uint) -> bool {
alt 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_move(_, _) { true }
ast::expr_swap(_, _) { true }
ast::expr_assign_op(_, _, _) { true }
ast::expr_ret(_) { true }
ast::expr_assert(_) { true }
ast::expr_check(_, _) { true }
ast::expr_log(_, _, _) { true }
_ { !parse::classify::expr_requires_semi_to_be_stmt(expr) }
}
}
fn ends_in_lit_int(ex: @ast::expr) -> bool {
alt ex.node {
ast::expr_lit(@{node: ast::lit_int(_, ast::ty_i), _}) { true }
ast::expr_binary(_, _, sub) | ast::expr_unary(_, sub) |
ast::expr_move(_, 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) |
ast::expr_check(_, sub) { ends_in_lit_int(sub) }
ast::expr_fail(osub) | ast::expr_ret(osub) {
alt osub {
some(ex) { ends_in_lit_int(ex) }
_ { false }
}
}
_ { false }
}
}
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