This is a very handy overview. If this isn't already similarly organized on the wiki (and I can't recall seeing anything like this) it would be well worth adding. I imagine it should either fall into the Beginner FAQ or be linked from it.
On Sun, May 31, 2009 at 2:29 PM, Raul Miller <[email protected]> wrote: > ... > > I think it's important to distinguish between two three different entities in > J. > > One entity is a "sentence". > > Another entity is a "script". > > And the third entity is a "block". > > In all three cases, these words have technical meanings, in > the context of J. > > A "sentence", in essence, is a single line of executable code. > Sentences follow J's grammatical rules, and may be evaluated. > When evaluated, they produce either a noun, verb, adverb or > conjunction. > > A "script" is the thing that you terminate with an isolated > right parenthesis. A script is preceded by a sentence and > thus represents a noun, verb, adverb or conjunction. > > example=: 0 :0 > This is an example script, > which is being used in a sentence > which produces a noun > ) > > Scripts which represent verbs adverbs or conjunctions must > contain legal sentences. Since a line beginning with > a left parenthesis can not be a legal sentence, any > legal sentence may contained in a script, without > conflicting with the terminator. > > A "block" is somewhere in between a sentence and a > script. It is a sequence of sentences and is delimited > by control words (such as if. while. do. or end.) Blocks > may be nested. Since control words may not be a part > of a legal sentence, any legal sentence may be contained > in a block, without conflicting with any control words. > > If the script terminator could be a part of a legal > sentence, we would have problems. > > That said, interactive J does allow scripts to be > entered. > > ... ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
