Extract Method

Basics

When the Extract Method refactoring is invoked, RubyMine analyses the selected block of code and detects variables that are the input for the selected code fragment and the variables that are output for it.

The detected output variable is used as a return value for the extracted function.

Examples

Before	After
`name = "RubyMine" puts "Hello world from #{name}"`	`name = "RubyMine" def greet name puts "Hello world from #{name}" end greet(name)`
`def foo a = 0 b = 1 c = 2 return a * b + c * 123 end`	`def bar(a, b, c) return a * b + c * 123 end def foo b = 1 a = 0 c = 2 return bar(a, b, c) end`
`class Bar def foo a = 11 + 2 b = 11 + 2 end end`	`class Bar def foo a = addition() b = addition() end def addition 11+2 end end`

Extracting a method

To extract a method, follow these steps

In the editor, select a block of code to be transformed into a method or a function.

The code fragment to form the method does not necessarily have to be a set of statements. It may also be an expression used somewhere in the code.
On the main menu or on the context menu of the selection, choose Refactor | Extract | Method or press Ctrl+Alt+M.
In the Extract Method dialog box that opens, specify the name of the new function.
In the Parameters area, do the following:
- Specify the variables to be passed as method parameters, by selecting/clearing the corresponding check boxes.
- Rename the desired parameters, by double-clicking the corresponding parameter lines and entering new names.
Check the result in the Signature Preview pane and click OK to create the required function.
The selected code fragment will be replaced with a function call.

Processing duplicates

If duplicate code fragments are encountered, RubyMine suggests to replace them with the calls to the extracted method:

/help/img/idea/2017.2/rm_extract_method_duplicates.png

Last modified: 26 October 2017

Reference:

Extract Method Dialog

RubyMine 2017.2 Help