IntelliJ IDEA 2021.3 Help

Language injections

Language injections let you work with pieces of code in other languages embedded in your code. When you inject a language (such as HTML, CSS, XML, RegExp, and so on) into a string literal, you get comprehensive code assistance for editing that literal.

Temporarily inject a language

By default, the IDE injects a language temporarily. It means that if you delete the embedded element, the injection will be lost as well.

  1. Place the caret inside the string literal, tag, or attribute, in which you want to inject a language and press Alt+Enter (or use the intention action icon Intention action icon).

  2. Select Inject language or reference and choose the language you want to inject.

Inject a language permanently using @Language

  1. If you want to keep the injection permanently, select Inject language or reference, and choose the language you want to inject.

  2. Press Alt+Enter again when you see the popup prompting you to replace the injection with an annotation.

    Alternatively, on a blank line before the target string literal, type @Language("language_ID").

The IDE inserts the @Language annotation with the corresponding language ID.

Open an injection editor

  1. Position the caret within the injected code piece and press Alt+Enter (or use the intention action icon Intention action icon).

  2. Select Edit <language ID> Fragment.

    IntelliJ IDEA will open a dedicated editor section for editing the code with the injected language. This editor provides full code assistance, including code completion, inspections, intentions and code style actions.

    Editing the injected code fragment in the dedicated editor

Use language injection comments

  • Add a blank line before the target string literal, and type the following comment:

    // language=<language_ID>

    For comments, use the syntax of the language you want to inject. Language IDs are generally intuitive, for example, SQL, RegExp, XML, HTML.

    Use language injection comments

A language fragment may be combined with a prefix and a suffix that act together as a wrapper, turning the fragment into a syntactically complete language unit. When editing your code, you can see prefixes and suffixes only in the fragment editor. They are not shown in the main editor.

The prefix and the suffix can be included in the injection comment as follows:

// language=<language_ID> prefix=<prefix> suffix=<suffix>
Using prefixes and suffixes in language injection

Cancel injections

  1. Position the caret at the code fragment and press Alt+Enter (or use the intention action icon the Intention action button).

  2. Select Uninject language or reference.

To cancel a language injection, you can also delete the injection comment or annotation.

Configure rules for automatic injections

In IntelliJ IDEA, there is a set of predefined rules according to which the IDE automatically injects languages in certain places in your code.

You can configure language injection rules on the Editor | Language Injections page of the IDE settings Ctrl+Alt+S.

Language injections settings

All pre-defined injection rules are configured for the Built-in scope. In other words, they are global (and therefore available in all IntelliJ IDEA projects). Custom rules can be configured for the IDE or for one project only. To change the scope of custom injections, use the the Move to Project/IDE scope button.

To share a custom rule through VCS, move it to the Project scope using the corresponding option on the toolbar. By doing so, you will create a new file in the .idea directory named IntelliLang.xml with your custom rules that you can place under version control.

If you don’t use a VCS, you can share your rules by exporting them to XML files (click Export on the toolbar) and then importing them to another project.

To configure custom injection rules, click the Add button to add a new rule, or copy a predefined rule and change its settings.

For more information on controls, refer to Language injections.

Example: inject SQL in Java

You can configure the settings so that each time you use a certain method, the IDE will inject the selected language, for example, SQL.

  1. In the Setting/Preferences dialog Ctrl+Alt+S, go to Editor | Language Injections.

  2. Click the Add button and select Java Parameter.

  3. From the ID list, select SQL.

  4. In the Class Methods field, enter the method that you want to take an SQL parameter. You can type the method manually, or click the Browse button and select the method in the Select Class dialog.

    If the method takes multiple parameters, they will be displayed in the dialog. Select the ones that you want to use.

  5. Apply the changes and close the dialog.

Last modified: 11 November 2021