Preserve parenthesization in the AST
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
parent
17a5d0f3a0
commit
62f98c8ff8
20 changed files with 148 additions and 217 deletions
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@ -773,7 +773,7 @@ fn print_variant(s: ps, v: ast::variant) {
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match v.node.kind {
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ast::tuple_variant_kind(args) => {
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print_ident(s, v.node.name);
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if vec::len(args) > 0u {
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if args.is_not_empty() {
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popen(s);
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fn print_variant_arg(s: ps, arg: ast::variant_arg) {
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print_type(s, arg.ty);
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@ -951,25 +951,11 @@ fn print_possibly_embedded_block_(s: ps, blk: ast::blk, embedded: embed_type,
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s.ann.post(ann_node);
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}
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// return and fail, without arguments cannot appear is the discriminant of if,
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// alt, do, & while unambiguously without being parenthesized
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fn print_maybe_parens_discrim(s: ps, e: @ast::expr) {
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let disambig = match e.node {
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ast::expr_ret(None)
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| ast::expr_fail(None)
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| ast::expr_again(*) => true,
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_ => false
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};
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if disambig { popen(s); }
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print_expr(s, e);
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if disambig { pclose(s); }
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}
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fn print_if(s: ps, test: @ast::expr, blk: ast::blk,
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elseopt: Option<@ast::expr>, chk: bool) {
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head(s, ~"if");
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if chk { word_nbsp(s, ~"check"); }
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print_maybe_parens_discrim(s, test);
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print_expr(s, test);
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space(s.s);
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print_block(s, blk);
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fn do_else(s: ps, els: Option<@ast::expr>) {
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@ -981,7 +967,7 @@ fn print_if(s: ps, test: @ast::expr, blk: ast::blk,
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cbox(s, indent_unit - 1u);
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ibox(s, 0u);
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word(s.s, ~" else if ");
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print_maybe_parens_discrim(s, i);
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print_expr(s, i);
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space(s.s);
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print_block(s, t);
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do_else(s, e);
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@ -1154,8 +1140,8 @@ fn print_expr(s: ps, &&expr: @ast::expr) {
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}
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Some(blk_arg)
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} else { None };
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print_expr_parens_if_not_bot(s, func);
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if !has_block || vec::len(base_args) > 0u {
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print_expr(s, func);
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if !has_block || base_args.is_not_empty() {
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popen(s);
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commasep_exprs(s, inconsistent, base_args);
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pclose(s);
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@ -1178,15 +1164,14 @@ fn print_expr(s: ps, &&expr: @ast::expr) {
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}
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}
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ast::expr_binary(op, lhs, rhs) => {
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let prec = operator_prec(op);
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print_op_maybe_parens(s, lhs, prec);
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print_expr(s, lhs);
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space(s.s);
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word_space(s, ast_util::binop_to_str(op));
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print_op_maybe_parens(s, rhs, prec + 1u);
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print_expr(s, rhs);
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}
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ast::expr_unary(op, expr) => {
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word(s.s, ast_util::unop_to_str(op));
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print_op_maybe_parens(s, expr, parse::prec::unop_prec);
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print_expr(s, expr);
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}
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ast::expr_addr_of(m, expr) => {
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word(s.s, ~"&");
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@ -1195,7 +1180,7 @@ fn print_expr(s: ps, &&expr: @ast::expr) {
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}
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ast::expr_lit(lit) => print_literal(s, lit),
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ast::expr_cast(expr, ty) => {
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print_op_maybe_parens(s, expr, parse::prec::as_prec);
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print_expr(s, expr);
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space(s.s);
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word_space(s, ~"as");
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print_type_ex(s, ty, true);
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@ -1205,7 +1190,7 @@ fn print_expr(s: ps, &&expr: @ast::expr) {
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}
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ast::expr_while(test, blk) => {
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head(s, ~"while");
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print_maybe_parens_discrim(s, test);
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print_expr(s, test);
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space(s.s);
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print_block(s, blk);
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}
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@ -1220,9 +1205,9 @@ fn print_expr(s: ps, &&expr: @ast::expr) {
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}
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ast::expr_match(expr, arms) => {
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cbox(s, alt_indent_unit);
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ibox(s, 4u);
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ibox(s, 4);
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word_nbsp(s, ~"match");
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print_maybe_parens_discrim(s, expr);
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print_expr(s, expr);
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space(s.s);
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bopen(s);
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let len = arms.len();
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@ -1335,12 +1320,9 @@ fn print_expr(s: ps, &&expr: @ast::expr) {
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print_block(s, blk);
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}
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ast::expr_copy(e) => { word_space(s, ~"copy"); print_expr(s, e); }
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// shouldn't parenthesize unless it's needed
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ast::expr_unary_move(e) => {
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popen(s);
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word_space(s, ~"move");
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print_expr(s, e);
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pclose(s);
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}
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ast::expr_assign(lhs, rhs) => {
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print_expr(s, lhs);
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@ -1362,12 +1344,7 @@ fn print_expr(s: ps, &&expr: @ast::expr) {
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print_expr(s, rhs);
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}
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ast::expr_field(expr, id, tys) => {
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// Deal with '10.x'
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if ends_in_lit_int(expr) {
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popen(s); print_expr(s, expr); pclose(s);
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} else {
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print_expr_parens_if_not_bot(s, expr);
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}
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print_expr(s, expr);
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word(s.s, ~".");
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print_ident(s, id);
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if vec::len(tys) > 0u {
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@ -1377,7 +1354,7 @@ fn print_expr(s: ps, &&expr: @ast::expr) {
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}
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}
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ast::expr_index(expr, index) => {
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print_expr_parens_if_not_bot(s, expr);
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print_expr(s, expr);
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word(s.s, ~"[");
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print_expr(s, index);
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word(s.s, ~"]");
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@ -1427,27 +1404,16 @@ fn print_expr(s: ps, &&expr: @ast::expr) {
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print_expr(s, expr);
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}
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ast::expr_mac(m) => print_mac(s, m),
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ast::expr_paren(e) => {
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popen(s);
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print_expr(s, e);
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pclose(s);
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}
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}
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s.ann.post(ann_node);
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end(s);
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}
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fn print_expr_parens_if_not_bot(s: ps, ex: @ast::expr) {
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let parens = match ex.node {
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ast::expr_fail(_) | ast::expr_ret(_) |
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ast::expr_binary(_, _, _) | ast::expr_unary(_, _) |
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ast::expr_copy(_) | ast::expr_assign(_, _) |
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ast::expr_assign_op(_, _, _) | ast::expr_swap(_, _) |
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ast::expr_log(_, _, _) | ast::expr_assert(_) |
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ast::expr_call(_, _, true) |
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ast::expr_vstore(_, _) => true,
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_ => false
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};
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if parens { popen(s); }
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print_expr(s, ex);
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if parens { pclose(s); }
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}
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fn print_local_decl(s: ps, loc: @ast::local) {
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print_pat(s, loc.node.pat);
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match loc.node.ty.node {
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@ -1557,7 +1523,7 @@ fn print_pat(s: ps, &&pat: @ast::pat) {
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match args_ {
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None => word(s.s, ~"(*)"),
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Some(args) => {
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if vec::len(args) > 0u {
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if args.is_not_empty() {
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popen(s);
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commasep(s, inconsistent, args, print_pat);
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pclose(s);
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@ -1813,7 +1779,7 @@ fn print_view_item(s: ps, item: @ast::view_item) {
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ast::view_item_use(id, mta, _) => {
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head(s, ~"extern mod");
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print_ident(s, id);
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if vec::len(mta) > 0u {
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if mta.is_not_empty() {
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popen(s);
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commasep(s, consistent, mta, print_meta_item);
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pclose(s);
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@ -1835,13 +1801,6 @@ fn print_view_item(s: ps, item: @ast::view_item) {
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end(s); // end outer head-block
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}
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fn print_op_maybe_parens(s: ps, expr: @ast::expr, outer_prec: uint) {
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let add_them = need_parens(expr, outer_prec);
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if add_them { popen(s); }
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print_expr(s, expr);
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if add_them { pclose(s); }
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}
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fn print_mutability(s: ps, mutbl: ast::mutability) {
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match mutbl {
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ast::m_mutbl => word_nbsp(s, ~"mut"),
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