This section covers various techniques of context-aware code completion that allow you to speed up the coding process.
Basic code completion. Completing names and keywords
Basic code completion helps you complete names of classes, methods, and keywords within the visibility scope. When you invoke code completion, RubyMine analyses the context and suggests the choices that are reachable from the current caret position.
Code completion covers supported and custom file types. However, RubyMine does not recognize the structure of custom file types and suggests completion options regardless of whether a specific type is appropriate in the current context.
If basic code completion is applied to part of a parameter, or a variable declaration, RubyMine suggests a list of possible names depending on the item type.
Invoking Basic code completion for the second time shows the list of all declared names.
To use basic code completion
- Start typing a name.
- Press Ctrl+Space or choose Code | Completion | Basic from the main menu.
- If necessary, press Ctrl+Space for the second time (this action produces the same effect as pressing Ctrl+Alt+Space).
This shows the list of all declared names.
To configure automatic code completion
You can configure RubyMine to automatically invoke the suggestions list, without having to call basic completion explicitly.
- From the main menu select File | Settings (or press Ctrl+Alt+S).
- On the left choose Editor | General | Code Completion, and select the Autopopup code completion option.
- You can also select the Insert selected variant by typing dot, space, ect. option to use some keys to accept completion. These keys depend on the language, your context, etc.
Note that while this setting helps you save time, turning it on may result in items being inserted accidentally.
Smart code completion. Completing code based on type information
Smart code completion filters the suggestions list and shows only the types applicable to the current context.
To use smart code completion:
- Start typing. Press Ctrl+Shift+Space or choose Code | Completion | SmartType from the main menu.
SmartType code completion automatically highlights the selection in the suggestions list that is most suitable for the current context.
- If necessary, press Ctrl+Shift+Space once again.
Completing tag names
RubyMine automatically completes tags and attributes names and values in the following file types:
If there is no schema association, RubyMine will use the file content (tag and attribute names and their values) to complete your input.
In XML/XSL files, completion for taglibs and namespaces is available.
Completing tag names
- Press < and start typing the tag name. RubyMine displays the list of tag names appropriate in the current context. Use the ArrowUp and ArrowDown buttons to scroll through the list.
- Press Enter to accept a selection from the list.
RubyMine automatically inserts the mandatory attributes according to the schema.
Inserting a taglib declaration
- 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 the desired taglib and press Enter. RubyMine adds the declaration of the selected taglib:
Importing a taglib declaration
- 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.
Hippie completion. Expanding words based on context
Hippie completion is a completion engine that analyses your text in the visible scope and draws its completion proposals from the current context. It helps you complete a word with a keyword, class name, method or variable.
To expand a string at caret to an existing word, do the following:
- Type the initial string and do one of the following:
- Press Alt+Slash or choose Code | Completion | Cyclic Expand Word to search for matching words before the caret
- Press Shift+Alt+Slash or choose Code | Completion | Cyclic Expand Word (Backward) to search for matching words after the caret and in other open files.
- Press Enter to accept the suggestion, or hold the Alt key and keep pressing Slash until the desired word is found.
Postfix code completion
Postfix code completion helps you reduce backward caret jumps as you write code. It allows you to transform an already typed expression to a different one based on a postfix you type after a dot, the type of expression, and its context.
For example, the
.if postfix applied to an expression wraps it with an
| || |
To enable/disable the postfix completion feature or separate templates, in the Settings / Preferences Dialog dialog, go to Editor | General | Postifx completion. You can also choose which key you want to use to expand postfix templates: Tab, Space, or Enter.
Postfix completion suggestions are shown as part of the basic completion suggestions list. To see a full list of postfix completions applicable in the current context, press Ctrl+J.
Completion tips and tricks
Narrow down the suggestions list
You can narrow down the suggestions list by typing any part of a word (even characters from somewhere in the middle), or invoking code completion after a dot separator. RubyMine will show suggestions that include the characters you've entered in any positions.
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.
Accept a suggestion
You can accept a suggestion from the list in one of the following ways:
- Press Enter or double-click the desired choice to insert completion to the left from 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, etc.)
View reference information
Sort entries in the suggestions list
You can sort the suggestions list alphabetically or by relevance. To toggle between these modes, click or respectively in the lower-right corner of the list.
RubyMine will remember your choice. You can change the default behavior in the Code Completion settings page.
View code hierarchy
You can view code hierarchy when you've selected an entry from the suggestions list:
- Press Ctrl+H to view type hierarchy.
- Press Ctrl+Shift+H to view method hierarchy.