ds_put_char (&lexer->tokstr, *lexer->prog++);
if (*lexer->prog == '+' || *lexer->prog == '-')
ds_put_char (&lexer->tokstr, *lexer->prog++);
ds_put_char (&lexer->tokstr, *lexer->prog++);
if (*lexer->prog == '+' || *lexer->prog == '-')
ds_put_char (&lexer->tokstr, *lexer->prog++);