safe navigation operatorとは 意味・読み方・使い方

名詞

safe navigation operator (複数形 safe navigation operators)

1. (programming) A binary operator that returns its second argument, unless the first argument is null, in which case it returns null; used to simplify code that would otherwise need multiple explicit checks for nullity.
   • 2009, Bashar Jawad, Groovy and Grails Recipes (page 57)

     One operator I haven't talked about yet is the safe navigation operator (?.). By preceding a dot with a question mark, you can safely navigate to methods or properties of an object even if that object is null.

   • 2015, Mert Caliskan, ‎Kenan Sevindik, Beginning Spring (page 278)

     The safe navigation operator (?.) provides navigation on the nested properties without getting any exception when a null value is evaluated from any of the properties iterated.

   • 2017, Gary McLean Hall, Adaptive Code: Agile coding with design patterns and SOLID principles

     C# 6 introduced a cascading nulls operator, also called the null-conditional operator and the safe navigation operator.