References: FORMAT description (p386)
Edit history: Version 1 by Pitman 02/27/87
Version 2 by cleanup committee 15-Mar-87
Version 3 by Masinter 15-Mar-87
Version 4 by Masinter 5-Jun-87
CLtL describes the format op syntax as:
"a format directive consists of a tilde (~), optional prefix parameters
separated by commas, optional colon (:) and atsign (@) modifiers, and a
single character indicating what kind of directive this is."
CLtL uses :@ fairly consistently throughout without saying whether @: is
legal. Is @: allowed?
There is no required ordering between the @ and : modifier.
This is currently underspecified, and this way of specifying it will
cause the least disruption to user code.
Most implementations accept these in either order. Some implementations
have been known to expect only :@.
The change to accept either syntax is probably quite trivial.
Having @: and :@ mean different things would be awkward.
Existing user code would be unaffected.
Leaving these unordered is slightly simpler conceptually.
The cleanup committee supports this clarification.