info-vax@ucbvax.ARPA (01/08/85)
From: cugini@NBS-VMS
Regarding the PL/I standard: Page 48 of the standard contains the
following production:
CL24. <simple-character-string-constant> ::=
'[<string-or-picture-symbol-list>]'
The square brackets indicate an optional list, i.e., the null
string - '' - is OK. However, just when you thought it was safe
to rely on the standard, p. 14 has under implementation-defined
features:
(9) Collating sequence, hardware representations, graphic
representations, and symbol names of an implementation's
character set (2.6 and 9.4.4.17).
Sooo... I guess that the apostrophe (not the quote) is more in the
spirit of the standard, but that technically, implementations can
bind the logical characters of the standard to any physical
character they like (all A's are B's, all B's are A's).
This is my personal opinion only, and does not have the sanction
of NBS.
John Cugini <cugini@nbs-vms>