Intelligent Ruby Coding Assistance
Braces, brackets & quotes auto-insertion
If you start a code block with an opening curly brace character and press Enter, the corresponding closing brace is automatically inserted with the indentation specified in your preferences.
When you type (, [, ", <, <%, or ' in the editor a paired character is inserted automatically (whenever appropriate). This feature may be easily switched off, but you should not be afraid of inserting too many closing parentheses, brackets, or quotes by mistake: RubyMine will recognize that the closing bracket or quotation mark already exists and will leave only one character printed.
Surround with braces, brackets & quotes
With a single key press you can surround the selected text with braces, quotes and convert a selection inside literals into expression substitution by pressing #.
Matched brace/bracket highlighting
Place the editor caret just after a closing (or just before an opening) brace or bracket of any type. If it is correctly matched, the matching pair highlights with light blue. If there is no matching bracket, the unpaired bracket highlights as a compile error. (You can change the default highlight colors in your configuration).
Express code commenting
Quickly comment/uncomment a selected line or block with comments using Ctrl+/ ⌘/ and Ctrl+Shift+/⌘⇧/ shortcuts, respectively. Comments insert at the first column, or at the indentation level, depending on your code style settings.
RubyMine provides a convenient feature that allows you select the word at caret with a single shortcut (Ctrl+W⌥Up). Subsequently pressing this key combination you can expand the selection up to a logical expression, method or class. Conversely, the Ctrl+Shift+W ⌥Down key allows you to shrink the selection back.
Live Templates / Snippets
Live templates are the snippets that allow creating code constructs from several letters and one TAB key press.
Parameter Info popup
Parameter Info popup automatically shows method parameters once you type an opening ( in a method call, or position the caret inside of ( ).
Quick documentation lookup
Quick documentation lookup allows to quickly read the RDoc without leaving the IDE and it even works in code completion lists.
The editor understands YARD tag annotations syntax in Ruby comments as well as in plain RDoc files. RubyMine supports any syntax of types annotations supported by YARD.
Also RubyMine uses http://rubydoc.info to show external documentation for almost everything in your code, just navigate to an item and use either View | External Documentation from the menu or a corresponding shortcut.