rustc: Pretty-print ternary operator

Author: brson

src/comp/front/parser.rs

@@ -1119,6 +1119,7 @@ fn parse_binops(&parser p) -> @ast::expr {
 const int unop_prec = 100;
 
 const int as_prec = 5;
+const int ternary_prec = 0;
 
 fn parse_more_binops(&parser p, @ast::expr lhs, int min_prec) -> @ast::expr {
     auto peeked = p.peek();
@@ -1552,6 +1553,7 @@ fn stmt_ends_with_semi(&ast::stmt stmt) -> bool {
                 case (ast::expr_lit(_)) { true }
                 case (ast::expr_cast(_, _)) { true }
                 case (ast::expr_if(_, _, _)) { false }
+                case (ast::expr_ternary(_, _, _)) { true }
                 case (ast::expr_for(_, _, _)) { false }
                 case (ast::expr_for_each(_, _, _)) { false }
                 case (ast::expr_while(_, _)) { false }

src/comp/pretty/pprust.rs

@@ -673,6 +673,15 @@ fn print_expr(&ps s, &@ast::expr expr) {
         case (ast::expr_if_check(?test, ?block, ?elseopt)) {
             print_if(s, test, block, elseopt, true);
         }
+        case (ast::expr_ternary(?test, ?then, ?els)) {
+            print_expr(s, test);
+            space(s.s);
+            word_space(s, "?");
+            print_expr(s, then);
+            space(s.s);
+            word_space(s, ":");
+            print_expr(s, els);
+        }
         case (ast::expr_while(?test, ?block)) {
             head(s, "while");
             popen(s);
@@ -1113,6 +1122,9 @@ fn print_maybe_parens(&ps s, &@ast::expr expr, int outer_prec) {
         case (ast::expr_cast(_, _)) {
             add_them = front::parser::as_prec < outer_prec;
         }
+        case (ast::expr_ternary(_, _, _)) {
+            add_them = front::parser::ternary_prec < outer_prec;
+        }
         case (_) { add_them = false; }
     }
     if (add_them) { popen(s); }