The IsIdentifier(char) command determines whether char is valid as a character in an unquoted Maple identifier.

If char is a valid character, IsIdentifier returns true. Otherwise, false is returned.

The IsIdentifier1(char) command determines whether char is valid as the first character of an unquoted Maple identifier.

If char is valid as the first character, IsIdentifier1 returns true. Otherwise, false is returned.

For these functions, if char is a string that contains more than one character, then all the characters in the string are tested. The commands returns true if the condition is true of all characters in the input string. For the empty string, the tested condition is vacuously true.

All of the StringTools package commands treat strings as (null-terminated) sequences of $8$-bit (ASCII) characters.  Thus, there is no support for multibyte character encodings, such as unicode encodings.

The StringTools[IsIdentifier] command is thread-safe as of Maple 15.

For more information on thread safety, see index/threadsafe.

$\mathrm{with}\left(\mathrm{StringTools}\right)\:$

$s≔\mathrm{convert}\left(\left[\mathrm{`\$`}\left(1..255\right)\right]\,'\mathrm{bytes}'\right)\:$

$\mathrm{length}\left(s\right)$

$255$

$\mathrm{Select}\left(\mathrm{IsIdentifier}\,s\right)$

$''0123456789?ABCDEFGHIJKLMNOPQRSTUVWXYZ\_abcdefghijklmnopqrstuvwxyz''$

$\mathrm{Select}\left(\mathrm{IsIdentifier1}\,s\right)$

$''\%ABCDEFGHIJKLMNOPQRSTUVWXYZ\_abcdefghijklmnopqrstuvwxyz''$

$\mathrm{IsIdentifier}\left(''myproc''\right)$

$\mathrm{true}$

$\mathrm{IsIdentifier}\left(''this/that''\right)$

$\mathrm{false}$