I am working on emancipating the in-place operations so that they can be
performed inside sentences, not just in the special forms. Thus, in
a =. ({."1 b) , c
the , would be performed in-place. In-place operations will be
recognized whenever the arguments are results (rather than names or
constants). As another example, something like
a =. b + , >: c
will perform the , in place.
In-place operations will also be recognized when one argument is being
reassigned:
a =: a , blah NB. This has always been handled in place
a =. b =: b , blah NB. This would not have been in place
Here's the catch: in-place assignments will be recognized ONLY FOR LINES
EXECUTED IN EXPLICIT DEFINITIONS. If you type those in from the
keyboard, you will get new blocks allocated.
This makes the implementation easier, and I reasoned that lines from the
console are not performance-critical anyway.
But now I'm thinking I should ask, in case this would cause trouble for
people with applications like mapped files. If you really need
append-in-place from the console you will have to use something like
apip =. 4 : '3 : (x , ''=:'' , x , '', y'') y'
and type
'name' apip value
Anybody got a problem with that?
Henry Rich
----------------------------------------------------------------------
For information about J forums see http://www.jsoftware.com/forums.htm
