That's fine. I'm comfortable with the Unix/ASCII conventions. I was mainly wondering whether dependence on ⎕TC might break my program on a different APL.
On Sun, 2014-06-01 at 12:02 +0200, Juergen Sauermann wrote: > Hi David, > > I believe that the IBM specified behavior is only achievable (if at > all) > with platform specific (actually terminal specific) APL variants. The > header > on page 335 says: > > ⎕TC Contains a three-item character vector of terminal control > characters: > ⎕TC[1]—backspace > ⎕TC[2]—new line (return) > ⎕TC[3]—line feed > > This is what GNU APL has implemented, taking ASCII verbatim: > > ⎕UCS ⎕TC > 8 13 10 > > These numbers come from ASCII rather than from Unix. Then the purpose > of ⎕TC is explained: > > Use ⎕TC rather than ⎕AV to avoid system dependencies (because the > order of ⎕AV is different in different APL implementations). > > This assumes that the same character - take newline as an example - > may be located at different positions > of the ⎕AV but behaves identically otherwise. But then the display vs. > typewriter example shows that this is > not the case. I would add the Windows vs. Unix example where newline > may or may not imply a carriage > return. > > If we would use curses as Elias suggested earlier that we could easily > violate the 'three-item character vector' > spec in the header. > > Taking this all together tells me that ⎕TC, which was mainly provided > for IBM code compatibility and not for real > use in new programs, is a stone-age left-over (I remember having it > seen in classical APL but never used) should > remain as is. > > Thank you nevertheless for pointing this out! > /// Jürgen > > > > On 05/31/2014 08:50 PM, David B. Lamkins wrote: > > > See IBM Reference, page 335. > > > > ⎕tc[2] and ⎕tc[3] differ from the IBM-specified behavior, presenting as > > Unix format effectors rather than as APL format effectors. > > > > In particular, APL specifies that ⎕tc[2] should advance the print > > position to the start of the next line and ⎕tc[3] should advance the > > print position downward one line while retaining the current column > > position. > > > > The current behavior of ⎕tc[1] is acceptable according to the IBM > > Reference. > > > > > > > > >
