HELP ALPHABETICISER                                    A. Sloman, March 1983

A character can be made into an alphabeticiser character by altering its
"itemiser character type" to be 12. E.g. the backslash is commonly used as an
alphabeticiser, and this is achieved by:

    item_chartype(`"`) =>
    12 -> item_chartype(`\\`);

It is important to duplicate the "\" symbol to make it stand for itself in
this context.

-- TURNING AN ARBITRARY CHARACTER INTO AN ALPHABETIC CHARACTER ---------------

If you try to mix sign characters, or the string quote character, with
letters, to form a word, this will not succeed, and depending on the context
may produce a syntactic error message. E.g.

    "don't"

is not a legal word in POP-11, as the symbol "'" is taken as the beginning of a
string. If you wish it to be treated in a word as if it were an alphabetic
character, then it needs to be preceded by an alphabeticiser. A character can
be made into an alphabeticiser character by altering its "itemiser character
type" to be 12. E.g. the backslash is commonly used as an alphabeticiser, and
this is achieved by:

    item_chartype(`"`) =>
    12 -> item_chartype(`\\`);

It is important to duplicate the "\" symbol to make it stand for itself in
this context.

Having altered the item_chartype, you can put the symbol "\" in front of
any character which is to be treated as an alphabetic character for the
purposes of word formation. E.g. "don\'t" will then become a legal word which
prints as:

    ** don't

See REF *ITEMISE for details of itemisation procedures.

See also HELP
    *ASCII          - character codes in POP-11
    *ITEM_CHARTYPE  - updating 'type' information associated with a character
