Many programming languages have a facility (usually called “static”) to allow the programmer to declare a variable which is visible only to some particular object but has storage at the program’s scope – i.e. its value is the same for all instances of that object and when it changes for one it changes for all the other instances too.<\/p>\n
One programming language feature I’ve never seen (but which I think would be useful) is a generalization of this – the ability to declare a variable which is only visible in a particular object but whose scope is the (lexical) parent object. I call this “outer”. For top-level objects, this would be the same as static but for nested classes the scope would be that of the outer class.<\/p>\n
One could even use the “outer” keyword multiple times to put the variable in any particular level in the object nesting tree. This doesn’t violate encapsulation, since members can still only be declared inside their classes.<\/p>\n
If you have “outer” instead of “static” (and maybe a few other more minor tweaks) any program can be turned into an isolated object inside another program – i.e. you can easily turn a program into a multi-instance version of that program with all the instances running in the same process.<\/p>\n","protected":false},"excerpt":{"rendered":"
Many programming languages have a facility (usually called “static”) to allow the programmer to declare a variable which is visible only to some particular object but has storage at the program’s scope – i.e. its value is the same for all instances of that object and when it changes for one it changes for all […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[27],"tags":[],"class_list":["post-630","post","type-post","status-publish","format-standard","hentry","category-language"],"_links":{"self":[{"href":"https:\/\/www.reenigne.org\/blog\/wp-json\/wp\/v2\/posts\/630","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.reenigne.org\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.reenigne.org\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.reenigne.org\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.reenigne.org\/blog\/wp-json\/wp\/v2\/comments?post=630"}],"version-history":[{"count":2,"href":"https:\/\/www.reenigne.org\/blog\/wp-json\/wp\/v2\/posts\/630\/revisions"}],"predecessor-version":[{"id":739,"href":"https:\/\/www.reenigne.org\/blog\/wp-json\/wp\/v2\/posts\/630\/revisions\/739"}],"wp:attachment":[{"href":"https:\/\/www.reenigne.org\/blog\/wp-json\/wp\/v2\/media?parent=630"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.reenigne.org\/blog\/wp-json\/wp\/v2\/categories?post=630"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.reenigne.org\/blog\/wp-json\/wp\/v2\/tags?post=630"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}