bc: fix "...; return}" to work, disallow "return ()"

function                                             old     new   delta
zbc_parse_expr                                        24    1865   +1841
zbc_parse_stmt_possibly_auto                        1425    1413     -12
bc_parse_expr_empty_ok                              1843       -   -1843
------------------------------------------------------------------------------
(add/remove: 0/1 grow/shrink: 1/1 up/down: 1841/-1855)        Total: -14 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 5 insertions, 8 deletions

diff --git a/miscutils/bc.c b/miscutils/bc.c
index e5726ca40..6d8e2d991 100644
--- a/miscutils/bc.c
+++ b/miscutils/bc.c
@@ -4121,18 +4121,15 @@ static BC_STATUS zbc_parse_return(void)
         if (s) RETURN_STATUS(s);
 
         t = p->lex;
-        if (t == XC_LEX_NLINE || t == BC_LEX_SCOLON)
+        if (t == XC_LEX_NLINE || t == BC_LEX_SCOLON || t == BC_LEX_RBRACE)
                 xc_parse_push(BC_INST_RET0);
         else {
-                bool paren = (t == BC_LEX_LPAREN);
-                s = bc_parse_expr_empty_ok(0);
-                if (s == BC_STATUS_PARSE_EMPTY_EXP) {
-                        xc_parse_push(BC_INST_RET0);
-                        s = zxc_lex_next();
-                }
+                s = zbc_parse_expr(0);
                 if (s) RETURN_STATUS(s);
 
-                if (!paren || p->lex_last != BC_LEX_RPAREN) {
+                if (t != BC_LEX_LPAREN   // "return EXPR", no ()
+                 || p->lex_last != BC_LEX_RPAREN  // example: "return (a) + b"
+                ) {
                         s = zbc_POSIX_requires("parentheses around return expressions");
                         if (s) RETURN_STATUS(s);
                 }