77 lines
2.2 KiB
Rust
77 lines
2.2 KiB
Rust
/*
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Predicates on exprs and stmts that the pretty-printer and parser use
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*/
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import ast_util::operator_prec;
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fn expr_requires_semi_to_be_stmt(e: @ast::expr) -> bool {
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match e.node {
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ast::expr_if(*) | ast::expr_match(*) | ast::expr_block(_)
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| ast::expr_while(*) | ast::expr_loop(*)
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| ast::expr_call(_, _, true) => false,
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_ => true
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}
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}
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fn expr_is_simple_block(e: @ast::expr) -> bool {
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match e.node {
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ast::expr_block({node: {rules: ast::default_blk, _}, _}) => true,
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_ => false
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}
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}
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fn stmt_ends_with_semi(stmt: ast::stmt) -> bool {
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match stmt.node {
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ast::stmt_decl(d, _) => {
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return match d.node {
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ast::decl_local(_) => true,
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ast::decl_item(_) => false
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}
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}
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ast::stmt_expr(e, _) => {
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return expr_requires_semi_to_be_stmt(e);
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}
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ast::stmt_semi(*) => {
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return false;
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}
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}
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}
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fn need_parens(expr: @ast::expr, outer_prec: uint) -> bool {
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match expr.node {
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ast::expr_binary(op, _, _) => operator_prec(op) < outer_prec,
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ast::expr_cast(_, _) => parse::prec::as_prec < outer_prec,
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// This may be too conservative in some cases
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ast::expr_assign(_, _) => true,
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ast::expr_move(_, _) => true,
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ast::expr_swap(_, _) => true,
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ast::expr_assign_op(_, _, _) => true,
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ast::expr_ret(_) => true,
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ast::expr_assert(_) => true,
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ast::expr_log(_, _, _) => true,
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_ => !parse::classify::expr_requires_semi_to_be_stmt(expr)
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}
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}
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fn ends_in_lit_int(ex: @ast::expr) -> bool {
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match ex.node {
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ast::expr_lit(node) => match node {
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@{node: ast::lit_int(_, ast::ty_i), _}
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| @{node: ast::lit_int_unsuffixed(_), _} => true,
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_ => false
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},
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ast::expr_binary(_, _, sub) | ast::expr_unary(_, sub) |
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ast::expr_move(_, sub) | ast::expr_copy(sub) |
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ast::expr_assign(_, sub) |
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ast::expr_assign_op(_, _, sub) | ast::expr_swap(_, sub) |
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ast::expr_log(_, _, sub) | ast::expr_assert(sub) => {
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ends_in_lit_int(sub)
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}
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ast::expr_fail(osub) | ast::expr_ret(osub) => match osub {
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some(ex) => ends_in_lit_int(ex),
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_ => false
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},
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_ => false
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}
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}
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