shell/math: improve comments

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

1 files changed, 4 insertions, 2 deletions

diff --git a/shell/math.c b/shell/math.c
index 0426e2daa..9e81d604c 100644
--- a/shell/math.c
+++ b/shell/math.c
@@ -856,9 +856,11 @@ evaluate_string(arith_state_t *math_state, const char *expr)
                  */
                 prec = PREC(op);
                 if (prec != PREC_LPAREN && prec < UNARYPREC) {
-                        /* binary, ternary or RPAREN */
+                        /* Binary, ternary or RPAREN */
                         if (lasttok != TOK_VALUE) {
-                                /* must be preceded by a num (example?) */
+                                /* Must be preceded by a value.
+                                 * $((2 2 + * 3)) would be accepted without this.
+                                 */
                                 goto syntax_err;
                         }
                         /* if op is RPAREN: