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Method Name

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When creating a New Method, the choice of a good selector name and the names of the parameters will promote the understanding of the method's purpose. It will also improve the readability of the method source and that of the methods which call it.


Choose a selector name which communicates what the method will do, not how it will do it. Avoid including any information about the implementation details.

Method names should always begin with a lowercase letter. If the name contains more than one word, then use Word Capitalization to form the name. The exception to this is when a method takes more than one parameter - each component of the method name which follows a parameter should start with a lowercase letter.

The method name should read as a description of what to do with the parameters being passed eg. #at:put:. Often, the parameter names can supply the type of the parameter and be of the form anInteger, aCharacter etc. You should end up with a method header which reads as a sentence:

#at: anInteger put: aCharacter

If there is more than one parameter of the same type, then the names should include further information to differentiate between them:

#from: startInteger to: stopInteger

In addition to the above guidelines, there is an informal convention for naming certain types of method.

Initialization Methods
use #initialize for an Instance Initialisation method.
Accessor Methods
Generally have the same name as the instance variable they access.
Testing Methods
Usually have the format #isXXX. eg. #isOpen, #isEmpty.
Converting Methods
Usually have the format #asXxxxxx. eg. #asString, #asFloat.
External Library Methods
Methods in the ExternalLibrary hierarchy have a special naming convention as described in External Method Selector.




includes: anObject

includesKey: aKey

at: anInteger put: aCharacter

from: startInteger to: stopInteger

associationAt: aKey ifAbsent: exceptionHandler

replaceFrom: start to: stop with: replacementElements startingAt: repStart

Related Patterns

Class Name, Word Capitalization