37ea010b0d
As per a FIXME in syntax::parse::classify, move predicates on exprs and stmts into classify, out of pprust
77 lines
2.3 KiB
Rust
77 lines
2.3 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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fn expr_requires_semi_to_be_stmt(e: @ast::expr) -> bool {
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alt e.node {
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ast::expr_if(_, _, _) | ast::expr_if_check(_, _, _)
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| ast::expr_alt(_, _, _) | ast::expr_block(_)
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| ast::expr_do_while(_, _) | ast::expr_while(_, _)
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| ast::expr_loop(_) | ast::expr_call(_, _, true) {
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false
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}
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_ { true }
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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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alt stmt.node {
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ast::stmt_decl(d, _) {
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ret alt 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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ret expr_requires_semi_to_be_stmt(e);
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}
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ast::stmt_semi(e, _) {
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ret false;
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}
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}
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}
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fn operator_prec(op: ast::binop) -> int {
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for vec::each(*parse::prec::binop_prec_table()) {|spec|
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if spec.op == op { ret spec.prec; }
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}
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core::unreachable();
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}
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fn need_parens(expr: @ast::expr, outer_prec: int) -> bool {
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alt 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_be(_) { true }
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ast::expr_assert(_) { true }
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ast::expr_check(_, _) { 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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alt ex.node {
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ast::expr_lit(@{node: ast::lit_int(_, ast::ty_i), _}) { true }
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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) | ast::expr_be(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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ast::expr_check(_, sub) { ends_in_lit_int(sub) }
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ast::expr_fail(osub) | ast::expr_ret(osub) {
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alt 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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}
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_ { false }
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}
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}
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