Logging variables in Java or Kotlin in most of the cases end up with duplicated content - one have to specify variable name first and then the variable itself:
Debug.i("index: $index, value: $value, direction: ${vector.direction}")
Debug.i("index: %s, value: %s, direction: %s", index, value, vector.direction);
Typing each variable twice takes time, slows down and seem to have a room for improvement. What if...
Intellij Live Templates can autocomplete certain actions to enhance code. For example, Debug Android logging library contains a live template to automatically generate a log statement with all method parameters.
This live template is implemented with a Groovy script. It receives a list of method parameters and turns them into a logging statement. The code, adjusted to the requirements for Groovy scripts in live templates, looks like this:
def a = _1.collect{ it + \": %s\"}.join(\", \");
def b = _1.collect{ it }.join(\", \");
def c = '\"' + a + '\", ' + b;
c
Most of the information on Live Templates focus on abbreviations. For example, when you type abbr a live template will be triggered. But there is also another type - surrounding live templates. They are triggered by code selection and a special shortcut: ⌥+⌘+J. This makes selected code available as an input for a live template.
A minimum sample, that takes selection and returns it unmodified will look like:
groovyScript("_1", SELECTION)
Now, let's take an enumeration of variables and turn them into a logging statement:
// Java
// `pattern` represent first argument to the String.format() call
def pattern = _1.split(', *')
.collect { '' + it + ': %s' }
.join(', ');
'java.lang.String.format(\"' + pattern + '\", ' + _1 + ')';
// Kotlin
'' + ((char) 34) + _1.split(', *')
.collect { '' + it + '=' + '${' + it + '}' }
.join(', ') + ((char) 34);
Note that scripts might look a bit more cryptic than Groovy itself. This comes from a limitation that seem to be applied to groovy scripts in live templates - cannot use unescaped double quote symbol ". (char) 34 is just double quote symbol with a twist.
The full live templates variables for both Java and Kotlin respectively:
groovyScript("def pattern = _1.split(', *').collect { '' + it + ': %s' }.join(', '); 'java.lang.String.format(\"' + pattern + '\", ' + _1 + ')';", SELECTION)
groovyScript("'' + ((char) 34) + _1.split(', *').collect { '' + it + '=' + '${' + it + '}' }.join(', ') + ((char) 34);", SELECTION)