@char_is_alnum(string)
@char_is_alpha(string)
@char_is_ascii(string)
@char_is_blank(string)
@char_is_cntrl(string)
@char_is_digit(string)
@char_is_graph(string)
@char_is_lower(string)
@char_is_print(string)
@char_is_punct(string)
@char_is_space(string)
@char_is_upper(string)
@char_is_xdigit(string)

The predicates @char_is_xxx(s) returns true if all characters in s are in the class xxx. These classes are defined as follows:

• alnum Any alphanumeric character
• alpha Any alphabetic character
• ascii Anay character between 0 and octal 0177 inclusive.
• blank Any whitespace character that is not a line separator
• cntrl Any control character
• digit Any decimal digit
• graph Any graphical character
• lower Any lowercase character
• print Any printable character
• punct Any punctuation character
• space Any whitespace character
• upper Any uppercase character
• xdigit Any hexadecimal digit character

See also String Management @car    @cdr    @char_is_alnum    @char_is_alpha    @char_is_ascii    @char_is_blank    @char_is_cntrl    @char_is_digit    @char_is_graph    @char_is_lower    @char_is_print    @char_is_punct    @char_is_space    @char_is_upper    @char_is_xdigit    @copy    @count    @drop    @dump    @dumpvar    @empty    @explode    @find    @is_prefix    @is_string    @is_subsequence    @is_suffix    @last    @member    @occurs    @parse    @permute    @push_back    @r_compile    @r_findall    @r_match    @r_search    @remove    @remove_duplicate    @replace    @scramble    @slice    @sort    @split    @sputter    @string2fun    @string2proc    @strip_path    @stutter    @system    @take    @to_num    @Tracing    @UnTracing   

Most functions acting on tabs operate also on strings.