J program usually uses globals to share data. Encapsulation is a paradigm commonly used by other programming languages, but as said in other posts, J tends to focus on solving problems. Each programming language has its own style, J needs not imitate paradigm of other programming languages.
On 26 Apr, 2017 9:19 am, "Xiao-Yong Jin" <[email protected]> wrote: > On Apr 25, 2017, at 6:30 PM, Eric Iverson <[email protected]> wrote: > > I have not followed this discussion at all and am probably way off base. > > But how is: > > allocate a few structures, and pass their pointers to the same function in > separate callings > > different from: > > allocated a few globals in an agreed upon locale (call it the heap), and > pass their names (pointers) to the same verb in separate callings > > ? This question is actually right on spot, and I am struggling with this. There are two aspects of this problem in my opinion. 1. Unnecessary copying of data, given the current state of the in-place operations in J. To have a varied state in J, passing names to verb essentially amounts to the following operations, State =. State Verb Control NB. akin to usual functional style Most of the time J would make unnecessary copies of the data in State. I haven't found a reliable way to avoid extra copying, except for when the 'Verb' here is a primitive. 2. Inconvenience, if you want to maintain a set of inhomogeneous states. I can do 'State1A State1B State1C' = (State1A;State1B;State1C) Verb Control 'State2A State2B State2C' = (State2A;State2B;State2C) Verb Control Apart from copying/boxing, there are too many names to keep track of. I would rather do Verb_1_ Control Verb_2_ Control I guess I'm just more familiar with the latter, because it resembles a common C function: void Verb(*Locale, const *Control) Maybe I'm missing something in J. Please feel free to correct me. ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
