I looked through the jsoftware website but couldn't find any references
tocreating singleton objects in J.So I created my own singleton pattern for J.
It seems to work.
coclass 'Singleton'
NB. static instanceinstance =: 0
NB. private constructorcreate =. verb defineval =: 1)
NB. Public gettergetinstance =: verb defineif. instance = 0 do. instance =:
conew 'Singleton'instanceelse. instanceend.)
NB. Verb for checking.say =: verb defineval =: val + 100t =. 'HEY't)
destroy =: codestroy
One thing is, I'm not sure whether making create private stops conew being
called explicitly.To create THE instance or get it, the user should call
getinstance_Singleton_ ''
But users can still call conew 'Singleton' from outside the class without an
error being raised.
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