Named parameter

In computer programming, naming of parameters (or named parameters) means that the method signature clearly states the name (meaning) of each parameter. This is not used in languages like Java_programming_language and C_plus_plus. It is supported in languages like Smalltalk and Objective_C_programming_language.

For example, here is a Java method call:

window.addNewControl( Title , 20, 50, 100, 50, true);

Here is the same method call in ObjC:

[window addNewControlWithTitle:@ Title xPosition:20 yPosition:50 width:100 height:50 drawingNow:YES];

The Objective-C version is easier to read as each parameter s meaning is more clearly stated in the method call itself. It does mean that the method call is somewhat messier and longer to type, but it is easier to read. Code that is easy to read is easier to maintain and fix, which provides benefits in large programs.

Note that the named parameters in Smalltalk and Objective-C refers to the syntactical presentation and not to the underlying implementation. Neither language supports named parameters in the sense that, say, Python programming language supports key=value style parameters.

For example, in the above Objective-C fragment, the method name is literally addNewControlWithTitle:xPosition:yPosition:width:height:drawingNow: .