oop - Is public variable all that bad? -


i've read lot of articles "public vs getter/setter", still wonder if there part public variable.

or question is:

if you're going make new awesome programming languange, still going support public variable , why??

a public variable means have global accessible/changeable variable within scope of object. there use case this?

take example: have class databasequeryhandler has variable databaseaccessor. under circumstances want variable be:

  1. publicly accessible (i.e. gettable)
  2. publicly settable

option #1 can think of few - may want last insert id after insert operation, may want check errors last query generated, commit or rollback transactions, etc., , might make more logical sense have these methods written in class databaseaccessor databasequeryhandler.

option #2 less desirable, if doing oop , abiding solid principles, in particular regards isp , dip principles. in case, when want set variable databaseaccessor in databasequeryhandler? on construction only, , never @ time after that. want type-hinted @ interface level well, can code interfaces. also, why need arbitrary object able alter database accessor? happens if foo changes variable databasequeryhandler->databaseaccessor null , bar tries call databasequeryhandler->databaseaccessor->begintransaction()?

i'm giving 1 example here, , no means bullet proof. program in php (dodges hurled rotten fruit) , take oop , solid given looseness of language. i'm sure there arguments on both sides of fence, if you're considering using public class variable, instead consider needs access it, , how variable used. in cases functionality can exposed via public methods without allowing unexpected alteration of variable type.


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