rb_isascii       1406 encoding.c         (rb_isascii(c) && ONIGENC_IS_ASCII_CODE_CTYPE((c), ctype))
rb_isascii       1424 encoding.c         return rb_isascii(c) ? ONIGENC_ASCII_CODE_TO_LOWER_CASE(c) : c;
rb_isascii       1430 encoding.c         return rb_isascii(c) ? ONIGENC_ASCII_CODE_TO_UPPER_CASE(c) : c;
rb_isascii       1193 include/ruby/ruby.h #define ISASCII(c) rb_isascii((unsigned char)(c))