fix problems with negative numbers (sf.net id #2644593) (thanks Zhoushen Huang)

diff --git a/src/algebra.c b/src/algebra.c
index 56b889a..78654f5 100644 (file)
--- a/src/algebra.c
+++ b/src/algebra.c
@@ -134,6 +134,8 @@ enum arg_type get_arg_type(const char *arg)
        if (*p == '"' && *e == '"')
                return ARG_STRING;
 
+       if (*p == '-')  //allow negative values
+               p++;
        while (p != e) {
                if (!isdigit(*p))
                        break;