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|
/*
Predicates on exprs and stmts that the pretty-printer and parser use
*/
use ast_util::operator_prec;
fn expr_requires_semi_to_be_stmt(e: @ast::expr) -> bool {
match e.node {
ast::expr_if(*) | ast::expr_match(*) | ast::expr_block(_)
| ast::expr_while(*) | ast::expr_loop(*)
| ast::expr_call(_, _, true) => false,
_ => true
}
}
fn expr_is_simple_block(e: @ast::expr) -> bool {
match e.node {
ast::expr_block({node: {rules: ast::default_blk, _}, _}) => true,
_ => false
}
}
fn stmt_ends_with_semi(stmt: ast::stmt) -> bool {
match stmt.node {
ast::stmt_decl(d, _) => {
return match d.node {
ast::decl_local(_) => true,
ast::decl_item(_) => false
}
}
ast::stmt_expr(e, _) => {
return expr_requires_semi_to_be_stmt(e);
}
ast::stmt_semi(*) => {
return false;
}
}
}
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_move(_, _) => 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_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) => {
ends_in_lit_int(sub)
}
ast::expr_fail(osub) | ast::expr_ret(osub) => match osub {
Some(ex) => ends_in_lit_int(ex),
_ => false
},
_ => false
}
}
|
