Vocabulary/eqco
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=: Is (Global) Other
Attaches a value to a name to yield a definition.
This is called assignment.
myname =: 99 NB. defines: myname to be a noun: 99 myname 99 myname + 1 100
Unlike Is (Local) (=.), the definition will not go away when the "process" executing the assignment terminates.
This is called public assignment.
"Process" here means either executing an explicitly defined verb, or loading a J script.
The value assigned need not be a noun. It can also be a verb
sum =: +/ type 'sum' +----+ |verb| +----+ sum 1 10 20.1 31.1
Or it can be a modifier (i.e. an adverb or a conjunction)
tabulated =: / atop =: @ type 'tabulated' ; 'atop' +------+-----------+ |adverb|conjunction| +------+-----------+ MultiplicationTable =: * tabulated ] z =: 1 + i.6 1 2 3 4 5 6 z MultiplicationTable z 1 2 3 4 5 6 2 4 6 8 10 12 3 6 9 12 15 18 4 8 12 16 20 24 5 10 15 20 25 30 6 12 18 24 30 36
You can place other constructs besides a bare name to the left of =:
'a b c' =: 1 10 20.1 a ; b ; c +-+--+----+ |1|10|20.1| +-+--+----+ z =: 'd e f' (z) =: 1 10 20.1 d ; e ; f +-+--+----+ |1|10|20.1| +-+--+----+
Common uses
Used to create nouns, adverbs, conjunctions and verbs which persist until you deliberately erase them.
Nouns, adverbs, conjunctions and verbs are the building-blocks of an application.
More Information
See Private and Public Assignment
Find time to study Private and Public Assignment carefully. (It describes and explains all uses of =. and =:)
CategoryVoc CategoryVocAssign CategoryVocValue CategoryVocVariable