[Jprogramming] local packages

[Devon McCormick]

J has some globals in the "j" namespace it uses for locating items and for
providing shortcuts for loading them.  In J7, these are
SystemFolders_j_, UserFolders_j_ and Public_j_.

These are all two-column "name-value" pairs.  For example, my SystemFolders
has an entry like 'addons';'C:/Program Files/J701/addons' which tells J
where to look when I do something like " load
'~addons/graphics/viewmat/viewmat.ijs' ".  Also, Public_j_ has an entry
like 'viewmat';'~addons/graphics/viewmat/viewmat.ijs' so I can simply enter
" load 'viewmat' ".

UserFolders is just like SystemFolders but it has your own idiosyncratic
folders.

You can update these in the gtk interface for J7by selecting
"Edit/Configure/Folders".  J6 has analogs to these with the names all in
upper-case (though USERFOLDERS_j_ has a third column which is some kind of
flag).