Allow selecting code completion items by typing digits

src/main/kotlin/com/chylex/intellij/keyboardmaster/lookup/LookupTypedActionHandler.kt

@@ -0,0 +1,33 @@
+package com.chylex.intellij.keyboardmaster.lookup
+
+import com.intellij.codeInsight.lookup.LookupManager
+import com.intellij.codeInsight.lookup.impl.LookupImpl
+import com.intellij.codeInsight.template.impl.editorActions.TypedActionHandlerBase
+import com.intellij.openapi.actionSystem.DataContext
+import com.intellij.openapi.editor.Editor
+import com.intellij.openapi.editor.actionSystem.TypedActionHandler
+
+/**
+ * When typing digits inside a code completion popup menu, selects the n-th item (or 10th item if the digit is 0) in the list.
+ */
+class LookupTypedActionHandler(originalHandler: TypedActionHandler?) : TypedActionHandlerBase(originalHandler) {
+	override fun execute(editor: Editor, charTyped: Char, dataContext: DataContext) {
+		if (!executeImpl(editor, charTyped)) {
+			myOriginalHandler?.execute(editor, charTyped, dataContext)
+		}
+	}
+	
+	private fun executeImpl(editor: Editor, charTyped: Char): Boolean {
+		if (charTyped !in '0'..'9') {
+			return false
+		}
+		
+		val lookup = LookupManager.getActiveLookup(editor)
+		if (lookup !is LookupImpl) {
+			return false
+		}
+		
+		lookup.selectedIndex = if (charTyped == '0') 9 else charTyped - '1'
+		return true
+	}
+}

src/main/kotlin/com/chylex/intellij/keyboardmaster/lookup/ProjectLookupListener.kt

@@ -0,0 +1,41 @@
+package com.chylex.intellij.keyboardmaster.lookup
+
+import com.intellij.codeInsight.lookup.Lookup
+import com.intellij.codeInsight.lookup.LookupElementPresentation
+import com.intellij.codeInsight.lookup.LookupManagerListener
+import com.intellij.codeInsight.lookup.impl.LookupImpl
+import com.intellij.openapi.util.Key
+
+/**
+ * Adds hints to code completion items with the digit that selects it.
+ */
+class ProjectLookupListener : LookupManagerListener {
+	companion object {
+		private val IS_MODIFIED_KEY = Key.create<Boolean>("chylexKeyboardMasterModified")
+		private val HINT_TEXT = Array(10) { " [${(it + 1) % 10}]" }
+	}
+	
+	override fun activeLookupChanged(oldLookup: Lookup?, newLookup: Lookup?) {
+		if (newLookup !is LookupImpl || newLookup.getUserData(IS_MODIFIED_KEY) == true) {
+			return
+		}
+		
+		newLookup.putUserData(IS_MODIFIED_KEY, true)
+		
+		@Suppress("UnstableApiUsage")
+		newLookup.addPresentationCustomizer { item, presentation ->
+			val items = newLookup.list.model
+			
+			for (index in 0 until items.size.coerceAtMost(10)) {
+				if (item === items.getElementAt(index)) {
+					val customized = LookupElementPresentation()
+					customized.copyFrom(presentation)
+					customized.appendTailTextItalic(HINT_TEXT[index], true)
+					return@addPresentationCustomizer customized
+				}
+			}
+			
+			presentation
+		}
+	}
+}

src/main/resources/META-INF/plugin.xml

@@ -5,7 +5,19 @@
   
   <description><![CDATA[
     Collection of keyboard-centric additions.
+    <ul>
+      <li>Code completion items can be jumped to using numbers.</li>
+    </ul>
   ]]></description>
   
   <depends>com.intellij.modules.platform</depends>
+  
+  <projectListeners>
+    <listener class="com.chylex.intellij.keyboardmaster.lookup.ProjectLookupListener" topic="com.intellij.codeInsight.lookup.LookupManagerListener" />
+  </projectListeners>
+  
+  <extensions defaultExtensionNs="com.intellij">
+    <!--suppress PluginXmlValidity, PluginXmlDynamicPlugin -->
+    <editorTypedHandler implementationClass="com.chylex.intellij.keyboardmaster.lookup.LookupTypedActionHandler" />
+  </extensions>
 </idea-plugin>