GoLand 2019.2 Help

Code completion

This section covers various techniques of context-aware code completion that allow you to speed up your coding process.

Basic completion

Basic code completion helps you complete names of types, interfaces, methods, and keywords within the visibility scope. When you invoke code completion, GoLand analyses the context and suggests the choices that are reachable from the current caret position (suggestions also include Live templates).

If basic code completion is applied to a part of a field, parameter, or variable declaration, GoLand suggests a list of possible names depending on the item type.

Invoke basic completion

By default, GoLand displays the code completion popup automatically as you type. Alternatively, you can press Ctrl+Space or select Code | Completion | Basic from the main menu.

Basic completion

Code completion for functions

Invoke completion for functions

You can view and complete functions that are suitable for a value of the certain type.

For example, you have the t variable of the string type. When you type t., hold Ctrl and press Space twice, you see a list of functions that accept the string type as the first argument.

Smart completion

Invoke smart completion

Smart code completion filters the suggestions list and shows only the types applicable to the current context. To invoke smart completion, start typing your code and press Ctrl+Shift+Space. Alternatively, select Code | Completion | SmartType from the main menu. The following animation shows the difference between basic and smart completion.

Statement completion

You can create syntactically correct code constructs by using statement completion. It inserts the necessary syntax elements (parentheses, braces, and semicolons) and gets you in a position where you can start typing the next statement. To invoke statement completion, start typing a code construct and press Ctrl+Shift+Enter.

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

  1. Type the initial string and do one of the following:

    • Press Alt+/ or choose Code | Completion | Cyclic Expand Word to search for matching words before the caret.

    • Press Shift+Alt+/ or choose Code | Completion | Cyclic Expand Word (Backward) 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.

  2. Accept the suggestion, or hold the Alt key and keep pressing / until the desired word is found.

Postfix code completion

With post-fix templates, you can transform an already-typed expression to a different one based on a postfix after the dot, the type of the expression, and its context. GoLand includes a set of predefined post-fix completion templates that you can use for other programming languages as well. You can copy, enable, and disable these templates.

  • To view a full list of available postfix templates, in the Settings/Preferences dialog Ctrl+Alt+S, go to Editor | General | Postfix Completion.

  • Select Tab, Space, or Enter to expand postfix templates.

    Postfix completion for Go

Transform a statement with a postfix

Type an expression and then type a postfix after a dot, for example, .if:

func m(b bool) { b.if }

The initial expression gets wrapped with an if statement:

To disable certain postfix completion templates, in the Settings/Preferences dialog Ctrl+Alt+S select Editor | General | Postfix Completion.

You can selectTab, Space, or Enter to expand postfix templates.

You can edit the predefined postfix templates, for example, to replace a long key with a shorter one, or to expand the list of applicable expression types.

Create custom postfix templates

  1. In the Settings/Preferences dialog Ctrl+Alt+S, go to Editor | General | Postfix Completion.

  2. Click the Add button on the toolbar.

  3. Specify the Key, that is the combination of symbols that will invoke the template, select which expression types the new template will be applicable to, and type the target expression in the following format: $EXPR$ <target_expression>, for example, $EXPR$ != nil.

    Inside your template, you can use two predefined variables, $EXPR$ and $END$:

    • $EXPR$ captures the expression before the dot.

    • $END$ defines the position of the cursor after the template is expanded.

    The Apply to the topmost expression checkbox applies your template to the entire expression ignoring the scope. So you do not need to select the scope for the template each time.

Completion of tags and attributes

GoLand automatically completes names and values of tags and attributes in HTML/XHTML, XML/XSL, and JSON.

Completion of tags and attribute names is based on the DTD or Schema the file is associated with. If there is no schema association, GoLand will use the file content (tag and attribute names and their values) to complete your input.

Configure code completion settings

Configure completion options

  1. In the Settings/Preferences dialog Ctrl+Alt+S, select Editor | General | Code Completion.

  2. Do the following:

    • To automatically display the suggestions list, select the Show suggestions as you type checkbox. If the checkbox is cleared, you have to call code completion explicitly by pressing Ctrl+Space for basic completion or Ctrl+Shift+Space for smart completion.

      You can also choose to automatically insert suggestions when there's just one option: select the completion type under Automatically insert single suggestions for.

    • To sort suggestions in the alphabetical order, instead of sorting them by relevance, select the Sort suggestions alphabetically checkbox.

      You can also toggle these modes by clicking the Sort Alphabetically button or the Sort by Relevance button respectively in the lower-right corner of the suggestions list.

    • If you want the documentation popup to be displayed automatically for each item in the suggestions list as you scroll it, select the Show documentation popup in option. In the field to the right, specify the delay (in milliseconds), after which the popup should appear.

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. GoLand 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. GoLand 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 a 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).

You can also use specific keys to insert the selected completion suggestion: in the Settings/Preferences dialog Ctrl+Alt+S choose Editor | General | Code Completion and select the Insert selected suggestion by pressing space, dot, or other context-dependent keys option. These keys depend on the language, your context, and so on.

View reference

  • You can use the by pressing Ctrl+Shift+I when you select an entry in the suggestions list:

  • You can use the Quick Information View by pressing Ctrl+Q when you select an entry in the suggestions list:

View code hierarchy

You can view code hierarchy when you've selected an entry from the suggestions list:

  • Ctrl+H: view type hierarchy

  • Ctrl+Shift+H: view method hierarchy.

Fill struct fields

When you create a new struct, you can automatically generate field names for it.

  1. Start typing the struct name, select it from the completion list.

  2. Place a caret between braces of a struct.

  3. Press Alt+Enter.

  4. Select between the following options:

  5. Click OK.

Troubleshooting

If code completion doesn't work, this may be due to one of the following reasons:

  • The Power Save Mode is on (File | Power Save Mode). 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 SDK is not configured for your project.

  • Your file doesn't reside in a content root, so it doesn't get the required class definitions and resources needed for code completion.

  • A file containing types and functions that you want to appear in completion suggestions list is marked as a plain text file.

  • External libraries that contain functions that you want to appear in the completion suggestions list are not added as dependencies or global libraries.

Last modified: 21 August 2019

See Also

Reference:

Getting Started: