Code completion
Basic code completion helps you complete the names of classes, methods, and keywords within the visibility scope.
RubyMine analyzes the context and suggests the choices that are reachable from the current caret position. Suggestions also include Live templates. Completion is available for a non-English keyboard layout.
Invoke basic completion
By default, RubyMine displays the code completion popup automatically as you type.
Alternatively, you can press Ctrl+Space or select from the main menu.
Code completion is available for custom file types. However, RubyMine does not recognize the structure of such files and suggests options regardless of whether they are appropriate in the current context.
Accept a suggestion from the list
Press Enter or double-click the relevant list item to insert it to the left of the caret.
Press Tab to replace the characters to the right from the caret.
Use Ctrl+Shift+Enter to make the current code construct syntactically correct (balance parentheses, add missing braces and semicolons, and so on).
Use specific keys and custom characters to accept the selected completion suggestion. To enable these features, go to the Editor | General | Code Completion settings page Ctrl+Alt+S and do the following:
To use specific keys, select the Insert selected suggestion by pressing space, dot, or other context-dependent keys checkbox. These keys depend on the language, your context, and so on.
To also use custom characters, enter the characters into the Additional characters to accept the completion field.
Hippie completion
Hippie completion is a completion engine that analyses your text in the visible scope and generates suggestions from the current context. It helps you complete any word from any of the currently opened files.
Expand a string at caret to an existing word
Type the initial string and do one of the following:
Press Alt+/ or choose to search for matching words before the caret.
Press Alt+Shift+/ or choose to search for matching words after the caret and in other open files.
The first suggested value appears, and the prototype is highlighted in the source code.
Accept the suggestion or hold the Alt key and keep pressing \ until you find the word you need.
Completion of tags and attributes
RubyMine automatically completes names and values of tags and attributes in many file types:
HTML/XHTML, including completion for CSS classes and for HTML tags inside JSX.
XML/XSL, including completion for namespaces.
JSON. For more information, refer to Editing package.json.
Complete tag names
Type the opening
<and then start typing the tag name. RubyMine displays the list of tag names appropriate in the current context.
Use the Up and Down keys to scroll through the list.
Press Enter to accept a selection from the list. If your file is associated with a schema or a DTD, RubyMine automatically inserts the mandatory attributes according to it.
Import a taglib declaration
If you need to use tags declared in a tag library, you need to import this taglib before any custom tag from it can be used.
Start typing a taglib prefix and press Alt+Insert.
Select a taglib from the list and press Enter.
RubyMine imports the selected taglib and adds the import statement automatically.
Insert a tag declared in a taglib
Start typing a tag and press Ctrl+Alt+Space.
Select a tag from the list. The
uriof the taglib it belongs to is displayed in brackets.
Select a taglib and press Enter. RubyMine adds the declaration of the selected taglib.
Machine learning-assisted completion ranking
RubyMine allows you to prioritize completion suggestions based on choices that other users made in similar situations.
The ML completion mechanism does not add any new elements but orders the elements retrieved from code. Data is not exposed anywhere; it is collected locally.
Enable ML completion ranking
Press Ctrl+Alt+S to open settings and select Editor | General | Code Completion.
Under Machine Learning-Assisted Completion, enable the Sort completion suggestions based on machine learning option and select the languages for which you want to use the ML completion.
Enable relevance markers
Press Ctrl+Alt+S to open settings and select Editor | General | Code Completion.
Enable the following options:
Mark position changes in the completion popup: use the
and 
icons to indicate whether the relevance of a suggestion is increasing or decreasing and therefore the suggestion has moved up or down the suggestion list.Mark the most relevant item in the completion popup: use the
icon to indicate the most suitable suggestion on the list.
The suggestion list will look as follows with the icons marking reordered and the most relevant items.
Configure code completion settings
To configure code completion options, go to the Editor | General | Code Completion settings page Ctrl+Alt+S.
You can choose the following settings:
Item | Description |
|---|---|
Match case | Select if you want the letter case to be taken into account for completion suggestions. Choose whether you want to match the case for the first letter or for all letters. |
Automatically insert single suggestions for | Automatically complete code if there's just one suggestion for basic and smart type-matching completion. |
Sort suggestions alphabetically | Select if you want to sort items in the suggestion list in the alphabetical order instead of sorting them by relevance. You can change this behavior at any time by clicking |
Show suggestions as you type | Select if you want the suggestion list to be invoked automatically, without having to call completion explicitly. This option is enabled by default. |
Insert selected suggestion by pressing space, dot, or other context-dependent keys | Select if you want to insert the selected suggestion by typing certain keys that depend on the language, your context, and so on. |
Show the documentation popup in | Select to automatically show a popup for each item in the suggestion list with the documentation for the class, method, or field currently highlighted in the lookup list. In the field to the right, specify the delay (in milliseconds), after which the popup should appear. |
Insert parentheses automatically when applicable | If this option is enabled, RubyMine automatically inserts a pair of opening and closing parentheses when you complete a function/method. Clear the checkbox to suppress inserting parentheses automatically. If you use an opening parentheses To use an opening parentheses For more information, refer to Use specific keys to insert suggestions. |
in the suggestion list and toggling the Completion tips and tricks
Narrow down the suggestion list
Narrow down the suggestion list by typing any part of a word (even characters from somewhere in the middle) or invoking code completion after a dot separator .
RubyMine displays suggestions containing the characters you've entered, regardless of their position. This makes the use of wildcards unnecessary.
In case of CamelCase or snake_case names, type the initial letters only. RubyMine automatically recognizes and matches the initial letters.
View reference
You can use the Quick Definition view by pressing Ctrl+Shift+I when you select an entry in the suggestion list:
You can use the Quick Information view by pressing Ctrl+Q when you select an entry in the suggestion list:
View code hierarchy
You can view code hierarchy when you've selected an entry from the suggestion list:
Ctrl+H: view type hierarchy
Ctrl+Shift+H: view method hierarchy.
Troubleshooting
If code completion doesn't work, this may be due to one of the following reasons:
The Power Save Mode is on (). Turning it on minimizes power consumption of your laptop by eliminating the background operations, including error highlighting, on-the-fly inspections, and code completion.
An interpreter is not configured for your project.
Your file does not reside in a content root , so it does not get the required class definitions and resources needed for code completion.
A file containing classes and functions that you want to appear in the completion suggestion list is marked as a plain text file.
External libraries that contain functions that you want to appear in the completion suggestion list are not added as dependencies or global libraries.
Code completion popup might not appear automatically if it takes too long to gather the completion options. For example, if the computer is busy with another task. In this case, you may still activate the completion popup manually via Ctrl+Space.