Vocabulary/ZeeLocale
"Factory words": the z-locale and its contents
J does not have "reserved words" as such. On the other hand certain "factory" J words (nouns, verbs, adverbs or conjunctions) come shipped with the product.
You can rely on a subset of these words being always present (unless deliberately erased or redefined by some action you take).
The J Dictionary says: "It is convenient to supplement the primitives or primaries provided in a language by secondaries whose names belong to an easily recognized class."
This recognises the fact that some J words are to be considered part of the J language.
For instance, words like LF, load, each, require and exit.
Alas, there is no universal agreement on precisely which words these are. However they all reside in the z-locale.
Full documentation of the contents of the z-locale is now available in:
What is the z-locale and why is it important?
Here's where the J Primer explains what a locale is. And here's what the J Primer has to say about the z-locale.
It follows from these explanations that the z-locale is the ideal home for a J word that is to behave as if it's really part of the J language. But not all the words in the z-locale can properly be called secondaries of the J language. Some words are not defined until you require them to be present:
plot_z_ |value error: plot_z_ require 'plot' plot_z_ 3 : 0 caller_jwplot_=. coname'' '' plot_jwplot_ y : caller_jwplot_=. coname'' x plot_jwplot_ y )
Where do the words in the z-locale come from?
The z-locale is populated when J is started up.
The core set of words, such as LF, load, names and open, are defined in a script: stdlib.ijs -- the so-called standard library.
- In J602, stdlib.ijs carries full information on the usage of each verb in the form of comments preceding each definition.
- In J803, stdlib.ijs has been stripped of comments and isn't very informative.
Refer instead to (J User Guide) Standard Library Documentation.
View this script by:
open 'stdlib' NB. in J602 open '~system/main/stdlib.ijs' NB. in J803
In J602 stdlib.ijs resides in the folder: ~system/main/. Find its full pathname on your computer by:
jpath '~system/main' /Applications/j602/system/main
(J's response will vary.)
In addition, strings.ijs generally also gets loaded (into the z-locale) by default. It resides in the same folder as stdlib.ijs.
View this script by:
open 'strings'
Additionally, several packages and add-ons define one or more words in the z-locale, to let you run them easily from within any locale, without needing to know the locale(s) where they actually reside.
Example: the plot package:
conames'' 0 2 base j jgl2 jijs jregex jzgrid lint rgsdatetime tte z zulu load 'plot' conames'' NB. note the extra locale names that appear... 0 2 base j jafm jbmp jgl2 jijs jregex jwplot jzgrid jzplot lint rgsdatetime tte z zulu plot_z_ 3 : 0 caller_jwplot_=. coname'' '' plot_jwplot_ y : caller_jwplot_=. coname'' x plot_jwplot_ y )
Such cover verbs are often very simple ones:
jpath_z_ jpath_j_
Where can I read details of a given word in the z-locale?
Open the script in which you know the word is defined (say: deb).
In J602, the verb edit will help you:
edit 'deb'
In later J versions, edit may not be defined. In that case, try to find the script that loaded deb by:
(4!:3'') {~ 4!:4 <'deb'
+------------------------------------------+
|/Applications/j602/system/main/strings.ijs|
+------------------------------------------+
If the above phrase works, then so will this:
open (4!:3'') {~ 4!:4 <'deb'
Can I define my own words in the z-locale?
Yes, freely.
But be careful not to accidentally overwrite a word already there:
myedit_z_ |value error: myedit_z_ NB. --okay, it's not already there
Just define it as you would in the base locale, but make your name a locative by appending _z_ to your chosen name:
myedit_z_ =: 3 : 'open (4!:3'''') {~ 4!:4 boxopen y'
myedit 'deb'
Which words in the z-locale can I rely on being there for my client?
This is a hard call.
Some words you expect to find in jqt801.app (say) may be absent in jcons801.app (say).
wd for instance.
There is no substitute for starting up the actual J version your client will be using, and verifying the presence (and definition!) of the words you hope s/he'll find.
First make sure that your startup script is either absent or empty:
You may have favorite private words defined which other users won't possess.
open '~config/startup.ijs'
In j602 the Project Manager will build you a script containing all the "factory" words your project needs.