Update Gradle to 8.5 and IntelliJ to 2023.3

build.gradle.kts

@@ -8,7 +8,7 @@ plugins {
 }
 
 group = "org.acejump"
-version = "chylex-15"
+version = "chylex-14"
 
 repositories {
   mavenCentral()

src/main/kotlin/org/acejump/action/AceTagAction.kt

@@ -13,35 +13,40 @@ import com.intellij.openapi.fileEditor.ex.FileEditorManagerEx
 import com.intellij.openapi.fileEditor.ex.IdeDocumentHistory
 import com.intellij.openapi.project.Project
 import com.intellij.openapi.ui.playback.commands.ActionCommand
-import org.acejump.search.Tag
+import org.acejump.search.SearchProcessor
 
 /**
  * Base class for actions available after typing a tag.
  */
 sealed class AceTagAction {
-  abstract operator fun invoke(tag: Tag, shiftMode: Boolean, isFinal: Boolean)
+  abstract operator fun invoke(editor: Editor, searchProcessor: SearchProcessor, offset: Int, shiftMode: Boolean, isFinal: Boolean)
   
   abstract class BaseJumpAction : AceTagAction() {
-    override fun invoke(tag: Tag, shiftMode: Boolean, isFinal: Boolean) {
-      val editor = tag.editor
+    override fun invoke(editor: Editor, searchProcessor: SearchProcessor, offset: Int, shiftMode: Boolean, isFinal: Boolean) {
       val caretModel = editor.caretModel
       val oldCarets = if (shiftMode) caretModel.caretsAndSelections else emptyList()
       
-      editor.project?.let { addCurrentPositionToHistory(it, editor.document) }
+      recordCaretPosition(editor)
       
       if (isFinal) {
         ensureEditorFocused(editor)
       }
       
-      moveCaretTo(editor, tag.offset)
+      moveCaretTo(editor, getCaretOffset(editor, searchProcessor, offset))
       
       if (shiftMode) {
         caretModel.caretsAndSelections = oldCarets + caretModel.caretsAndSelections
       }
     }
+    
+    abstract fun getCaretOffset(editor: Editor, searchProcessor: SearchProcessor, offset: Int): Int
   }
   
   private companion object {
+    fun recordCaretPosition(editor: Editor) = with(editor) {
+      project?.let { addCurrentPositionToHistory(it, document) }
+    }
+    
     fun moveCaretTo(editor: Editor, offset: Int) = with(editor) {
       selectionModel.removeSelection(true)
       caretModel.removeSecondaryCarets()
@@ -83,7 +88,11 @@ sealed class AceTagAction {
    * On default action, places the caret at the first character of the search query.
    * On shift action, adds the new caret to existing carets.
    */
-  object JumpToSearchStart : BaseJumpAction()
+  object JumpToSearchStart : BaseJumpAction() {
+    override fun getCaretOffset(editor: Editor, searchProcessor: SearchProcessor, offset: Int): Int {
+      return offset
+    }
+  }
   
   /**
    * On default action, performs the Go To Declaration action, available via `Navigate | Declaration or Usages`.
@@ -91,8 +100,8 @@ sealed class AceTagAction {
    * Always places the caret at the start of the word.
    */
   object GoToDeclaration : AceTagAction() {
-    override fun invoke(tag: Tag, shiftMode: Boolean, isFinal: Boolean) {
-      JumpToSearchStart.invoke(tag, shiftMode = false, isFinal = isFinal)
+    override fun invoke(editor: Editor, searchProcessor: SearchProcessor, offset: Int, shiftMode: Boolean, isFinal: Boolean) {
+      JumpToSearchStart(editor, searchProcessor, offset, shiftMode = false, isFinal = isFinal)
       ApplicationManager.getApplication().invokeLater { performAction(if (shiftMode) IdeActions.ACTION_GOTO_TYPE_DECLARATION else IdeActions.ACTION_GOTO_DECLARATION) }
     }
   }

src/main/kotlin/org/acejump/action/AceVimAction.kt

@@ -44,8 +44,8 @@ sealed class AceVimAction : DumbAwareAction() {
     session.defaultBoundary = mode.boundaries
     session.startJumpMode {
       object : JumpMode() {
-        override fun accept(state: SessionState, acceptedTag: Tag) {
-          AceTagAction.JumpToSearchStart.invoke(acceptedTag, shiftMode = wasUpperCase, isFinal = true)
+        override fun accept(state: SessionState, acceptedTag: Tag): Boolean {
+          state.act(AceTagAction.JumpToSearchStart, acceptedTag, wasUpperCase, isFinal = true)
           
           if (selectionStart != null) {
             caret.vim.vimSetSelection(selectionStart, caret.offset, moveCaretToSelectionEnd = true)
@@ -88,6 +88,7 @@ sealed class AceVimAction : DumbAwareAction() {
           
           injector.scroll.scrollCaretIntoView(editor.vim)
           mode.finishSession(editor, session)
+          return true
         }
       }
     }
@@ -175,8 +176,9 @@ sealed class AceVimAction : DumbAwareAction() {
       session.defaultBoundary = VISIBLE_ON_SCREEN
       session.startJumpMode {
         object : JumpMode() {
-          override fun accept(state: SessionState, acceptedTag: Tag) {
-            AceTagAction.GoToDeclaration.invoke(acceptedTag, shiftMode = wasUpperCase, isFinal = true)
+          override fun accept(state: SessionState, acceptedTag: Tag): Boolean {
+            state.act(AceTagAction.GoToDeclaration, acceptedTag, shiftMode = wasUpperCase, isFinal = true)
+            return true
           }
         }
       }

src/main/kotlin/org/acejump/config/AceConfig.kt

@@ -21,8 +21,10 @@ class AceConfig : PersistentStateComponent<AceSettings> {
     val layout get() = settings.layout
     val minQueryLength get() = settings.minQueryLength
     val jumpModeColor get() = settings.jumpModeColor
+    val textHighlightColor get() = settings.textHighlightColor
     val tagForegroundColor get() = settings.tagForegroundColor
-    val searchHighlightColor get() = settings.searchHighlightColor
+    val tagBackgroundColor get() = settings.tagBackgroundColor
+    val acceptedTagColor get() = settings.acceptedTagColor
   }
   
   override fun getState(): AceSettings {

src/main/kotlin/org/acejump/config/AceConfigurable.kt

@@ -16,16 +16,20 @@ class AceConfigurable : Configurable {
       panel.keyboardLayout != settings.layout ||
       panel.minQueryLengthInt != settings.minQueryLength ||
       panel.jumpModeColor != settings.jumpModeColor ||
+      panel.textHighlightColor != settings.textHighlightColor ||
       panel.tagForegroundColor != settings.tagForegroundColor ||
-      panel.searchHighlightColor != settings.searchHighlightColor
+      panel.tagBackgroundColor != settings.tagBackgroundColor ||
+      panel.acceptedTagColor != settings.acceptedTagColor
   
   override fun apply() {
     settings.allowedChars = panel.allowedChars
     settings.layout = panel.keyboardLayout
     settings.minQueryLength = panel.minQueryLengthInt ?: settings.minQueryLength
     panel.jumpModeColor?.let { settings.jumpModeColor = it }
+    panel.textHighlightColor?.let { settings.textHighlightColor = it }
     panel.tagForegroundColor?.let { settings.tagForegroundColor = it }
-    panel.searchHighlightColor?.let { settings.searchHighlightColor = it }
+    panel.tagBackgroundColor?.let { settings.tagBackgroundColor = it }
+    panel.acceptedTagColor?.let { settings.acceptedTagColor = it }
     KeyLayoutCache.reset(settings)
   }
   

src/main/kotlin/org/acejump/config/AceSettings.kt

@@ -13,9 +13,15 @@ data class AceSettings(
   @OptionTag("jumpModeRGB", converter = ColorConverter::class)
   var jumpModeColor: Color = Color(0xFFFFFF),
   
+  @OptionTag("textHighlightRGB", converter = ColorConverter::class)
+  var textHighlightColor: Color = Color(0x394B58),
+  
   @OptionTag("tagForegroundRGB", converter = ColorConverter::class)
   var tagForegroundColor: Color = Color(0xFFFFFF),
   
-  @OptionTag("searchHighlightRGB", converter = ColorConverter::class)
-  var searchHighlightColor: Color = Color(0x008299),
+  @OptionTag("tagBackgroundRGB", converter = ColorConverter::class)
+  var tagBackgroundColor: Color = Color(0x008299),
+  
+  @OptionTag("acceptedTagRGB", converter = ColorConverter::class)
+  var acceptedTagColor: Color = Color(0x394B58)
 )

src/main/kotlin/org/acejump/config/AceSettingsPanel.kt

@@ -27,8 +27,10 @@ internal class AceSettingsPanel {
   private val keyboardLayoutArea = JBTextArea().apply { isEditable = false }
   private val minQueryLengthField = JBTextField()
   private val jumpModeColorWheel = ColorPanel()
+  private val textHighlightColorWheel = ColorPanel()
   private val tagForegroundColorWheel = ColorPanel()
-  private val searchHighlightColorWheel = ColorPanel()
+  private val tagBackgroundColorWheel = ColorPanel()
+  private val acceptedTagColorWheel = ColorPanel()
   
   init {
     tagCharsField.apply { font = Font("monospaced", font.style, font.size) }
@@ -52,8 +54,10 @@ internal class AceSettingsPanel {
     
     titledRow("Colors") {
       row("Caret background:") { short(jumpModeColorWheel) }
+      row("Searched text background:") { short(textHighlightColorWheel) }
       row("Tag foreground:") { short(tagForegroundColorWheel) }
-      row("Search highlight:") { short(searchHighlightColorWheel) }
+      row("Tag background:") { short(tagBackgroundColorWheel) }
+      row("Accepted tag position background:") { short(acceptedTagColorWheel) }
     }
   }
   
@@ -63,8 +67,10 @@ internal class AceSettingsPanel {
   internal var keyChars by keyboardLayoutArea
   internal var minQueryLength by minQueryLengthField
   internal var jumpModeColor by jumpModeColorWheel
+  internal var textHighlightColor by textHighlightColorWheel
   internal var tagForegroundColor by tagForegroundColorWheel
-  internal var searchHighlightColor by searchHighlightColorWheel
+  internal var tagBackgroundColor by tagBackgroundColorWheel
+  internal var acceptedTagColor by acceptedTagColorWheel
   
   internal var minQueryLengthInt
     get() = minQueryLength.toIntOrNull()?.coerceIn(1, 10)
@@ -75,8 +81,10 @@ internal class AceSettingsPanel {
     keyboardLayout = settings.layout
     minQueryLength = settings.minQueryLength.toString()
     jumpModeColor = settings.jumpModeColor
+    textHighlightColor = settings.textHighlightColor
     tagForegroundColor = settings.tagForegroundColor
-    searchHighlightColor = settings.searchHighlightColor
+    tagBackgroundColor = settings.tagBackgroundColor
+    acceptedTagColor = settings.acceptedTagColor
   }
   
   // Removal pending support for https://youtrack.jetbrains.com/issue/KT-8575

src/main/kotlin/org/acejump/input/KeyLayout.kt

@@ -1,5 +1,10 @@
 package org.acejump.input
 
+import it.unimi.dsi.fastutil.objects.Object2IntMap
+import it.unimi.dsi.fastutil.objects.Object2IntOpenHashMap
+import java.awt.geom.Point2D
+import kotlin.math.floor
+
 /**
  * Defines common keyboard layouts. Each layout has a key priority order, based on each key's distance from the home row and how
  * ergonomically difficult they are to press.
@@ -18,7 +23,38 @@ enum class KeyLayout(internal val rows: Array<String>, priority: String) {
   internal val allChars = rows.joinToString("").toCharArray().apply(CharArray::sort).joinToString("")
   internal val allPriorities = priority.mapIndexed { index, char -> char to index }.toMap()
   
+  private val keyDistances: Map<Char, Object2IntMap<Char>> by lazy {
+    val keyDistanceMap = mutableMapOf<Char, Object2IntMap<Char>>()
+    val keyLocations = mutableMapOf<Char, Point2D>()
+    
+    for ((rowIndex, rowChars) in rows.withIndex()) {
+      val keyY = rowIndex * 1.2F // Slightly increase cost of traveling between rows.
+      
+      for ((columnIndex, char) in rowChars.withIndex()) {
+        val keyX = columnIndex + (0.25F * rowIndex) // Assume a 1/4-key uniform stagger.
+        keyLocations[char] = Point2D.Float(keyX, keyY)
+      }
+    }
+    
+    for (fromChar in allChars) {
+      val distances = Object2IntOpenHashMap<Char>()
+      val fromLocation = keyLocations.getValue(fromChar)
+      
+      for (toChar in allChars) {
+        distances[toChar] = floor(2F * fromLocation.distanceSq(keyLocations.getValue(toChar))).toInt()
+      }
+      
+      keyDistanceMap[fromChar] = distances
+    }
+    
+    keyDistanceMap
+  }
+  
   internal inline fun priority(crossinline tagToChar: (String) -> Char): (String) -> Int? {
     return { allPriorities[tagToChar(it)] }
   }
+  
+  internal fun distanceBetweenKeys(char1: Char, char2: Char): Int {
+    return keyDistances.getValue(char1).getValue(char2)
+  }
 }

src/main/kotlin/org/acejump/input/KeyLayoutCache.kt

@@ -34,17 +34,18 @@ internal object KeyLayoutCache {
    */
   fun reset(settings: AceSettings) {
     tagOrder = compareBy(
-      String::length,
-      settings.layout.priority(String::last)
+      { it[0].isDigit() || it[1].isDigit() },
+      { settings.layout.distanceBetweenKeys(it[0], it[1]) },
+      settings.layout.priority { it[0] }
     )
     
-    @Suppress("ConvertLambdaToReference")
     val allPossibleChars = settings.allowedChars
       .toCharArray()
       .filter(Char::isLetterOrDigit)
       .distinct()
-      .ifEmpty { settings.layout.allChars.toCharArray().toList() }
+      .joinToString("")
+      .ifEmpty(settings.layout::allChars)
     
-    allPossibleTags = allPossibleChars.flatMap { listOf("$it", ";$it") }.sortedWith(tagOrder)
+    allPossibleTags = allPossibleChars.flatMap { a -> allPossibleChars.map { b -> "$a$b".intern() } }.sortedWith(tagOrder)
   }
 }

src/main/kotlin/org/acejump/modes/JumpMode.kt

@@ -18,7 +18,8 @@ open class JumpMode : SessionMode {
     return state.type(charTyped)
   }
   
-  override fun accept(state: SessionState, acceptedTag: Tag) {
-    AceTagAction.JumpToSearchStart.invoke(acceptedTag, shiftMode = wasUpperCase, isFinal = true)
+  override fun accept(state: SessionState, acceptedTag: Tag): Boolean {
+    state.act(AceTagAction.JumpToSearchStart, acceptedTag, wasUpperCase, isFinal = true)
+    return true
   }
 }

src/main/kotlin/org/acejump/modes/SessionMode.kt

@@ -9,5 +9,5 @@ interface SessionMode {
   val caretColor: Color
   
   fun type(state: SessionState, charTyped: Char, acceptedTag: Tag?): TypeResult
-  fun accept(state: SessionState, acceptedTag: Tag)
+  fun accept(state: SessionState, acceptedTag: Tag): Boolean
 }

src/main/kotlin/org/acejump/search/SearchProcessor.kt

@@ -3,18 +3,17 @@ package org.acejump.search
 import com.intellij.openapi.editor.Editor
 import it.unimi.dsi.fastutil.ints.IntArrayList
 import org.acejump.boundaries.Boundaries
-import org.acejump.clone
-import org.acejump.config.AceConfig
 import org.acejump.immutableText
+import org.acejump.isWordPart
 import org.acejump.matchesAt
 
 /**
- * Searches editor text for matches of a [SearchQuery], and updates previous results when the user [refineQuery]s a character.
+ * Searches editor text for matches of a [SearchQuery], and updates previous results when the user [type]s a character.
  */
-class SearchProcessor private constructor(query: SearchQuery, private val results: MutableMap<Editor, IntArrayList>) {
+class SearchProcessor private constructor(query: SearchQuery, results: MutableMap<Editor, IntArrayList>) {
   companion object {
-    fun fromString(editors: List<Editor>, query: String, boundaries: Boundaries): SearchProcessor {
-      return SearchProcessor(editors, SearchQuery.Literal(query), boundaries)
+    fun fromChar(editors: List<Editor>, char: Char, boundaries: Boundaries): SearchProcessor {
+      return SearchProcessor(editors, SearchQuery.Literal(char.toString()), boundaries)
     }
     
     fun fromRegex(editors: List<Editor>, pattern: String, boundaries: Boundaries): SearchProcessor {
@@ -54,40 +53,97 @@ class SearchProcessor private constructor(query: SearchQuery, private val result
   internal var query = query
     private set
   
-  val resultsCopy
-    get() = results.clone()
+  internal var results = results
+    private set
   
-  val isQueryFinished
-    get() = query.rawText.length >= AceConfig.minQueryLength
+  /**
+   * Appends a character to the search query and removes all search results that no longer match the query. If the last typed character
+   * transitioned the search query from a non-word to a word, it notifies the [Tagger] to reassign all tags. If the new query does not
+   * make sense because it would remove every result, the change is reverted and this function returns false.
+   */
+  fun type(char: Char, tagger: Tagger): Boolean {
+    val newQuery = query.rawText + char
+    val canMatchTag = tagger.canQueryMatchAnyTag(newQuery)
     
-  fun refineQuery(char: Char): Boolean {
-    if (char == '\n') {
-      return true
+    // If the typed character is not compatible with any existing tag or as a continuation of any previous occurrence, reject the query
+    // change and return false to indicate that nothing else should happen.
+    
+    if (newQuery.length > 1 && !canMatchTag && !isContinuation(newQuery)) {
+      return false
+    }
+    
+    // If the typed character transitioned the search query from a non-word to a word, and the typed character does not belong to an
+    // existing tag, we basically restart the search at the beginning of every new word, and unmark existing results so that all tags get
+    // regenerated immediately afterwards. Although this causes tags to change, it is one solution for conflicts between tag characters and
+    // search query characters, and moving searches across word boundaries during search should be fairly uncommon.
+    
+    if (!canMatchTag && newQuery.length >= 2 && !newQuery[newQuery.length - 2].isWordPart && char.isWordPart) {
+      query = SearchQuery.Literal(char.toString())
+      tagger.unmark()
+      
+      for ((editor, offsets) in results) {
+        val chars = editor.immutableText
+        val iter = offsets.iterator()
+        
+        while (iter.hasNext()) {
+          val movedOffset = iter.nextInt() + newQuery.length - 1
+          
+          if (movedOffset < chars.length && chars[movedOffset].equals(char, ignoreCase = true)) {
+            iter.set(movedOffset)
           }
           else {
-      query = SearchQuery.Literal(query.rawText + char)
-      removeObsoleteResults()
-      return isQueryFinished
+            iter.remove()
           }
         }
+      }
+    }
+    else {
+      removeObsoleteResults(newQuery, tagger)
+      query = SearchQuery.Literal(newQuery)
+    }
+    
+    return true
+  }
+  
+  /**
+   * Returns true if the new query is a continuation of any remaining search query.
+   */
+  private fun isContinuation(newQuery: String): Boolean {
+    for ((editor, offsets) in results) {
+      val chars = editor.immutableText
+      if (offsets.any { chars.matchesAt(it, newQuery, ignoreCase = true) }) {
+        return true
+      }
+    }
+    
+    return false
+  }
   
   /**
    * After updating the query, removes all results that no longer match the search query.
    */
-  private fun removeObsoleteResults() {
-    val query = query.rawText
+  private fun removeObsoleteResults(newQuery: String, tagger: Tagger) {
+    val lastCharOffset = newQuery.lastIndex
+    val lastChar = newQuery[lastCharOffset]
+    val ignoreCase = newQuery[0].isLowerCase()
     
-    for (entry in results) {
-      val editor = entry.key
-      val offsetIter = entry.value.iterator()
+    for ((editor, offsets) in results.entries.toList()) {
+      val chars = editor.immutableText
       
-      while (offsetIter.hasNext()) {
-        val offset = offsetIter.nextInt()
+      val remaining = IntArrayList()
+      val iter = offsets.iterator()
       
-        if (!editor.immutableText.matchesAt(offset, query, ignoreCase = true)) {
-          offsetIter.remove()
-        }
-      }
+      while (iter.hasNext()) {
+        val offset = iter.nextInt()
+        val endOffset = offset + lastCharOffset
+        val lastTypedCharMatches = endOffset < chars.length && chars[endOffset].equals(lastChar, ignoreCase)
+        
+        if (lastTypedCharMatches || tagger.isQueryCompatibleWithTagAt(newQuery, Tag(editor, offset))) {
+          remaining.add(offset)
+        }
+      }
+      
+      results[editor] = remaining
     }
   }
 }

src/main/kotlin/org/acejump/search/Solver.kt

@@ -0,0 +1,231 @@
+package org.acejump.search
+
+import com.intellij.openapi.editor.Editor
+import it.unimi.dsi.fastutil.ints.IntList
+import it.unimi.dsi.fastutil.ints.IntOpenHashSet
+import org.acejump.boundaries.EditorOffsetCache
+import org.acejump.boundaries.StandardBoundaries
+import org.acejump.config.AceConfig
+import org.acejump.immutableText
+import org.acejump.input.KeyLayoutCache
+import org.acejump.isWordPart
+import org.acejump.wordEndPlus
+import java.util.IdentityHashMap
+import kotlin.math.max
+
+/*
+ * Solves the Tag Assignment Problem. The tag assignment problem can be stated
+ * thusly: Given a set of indices I in document d, and a set of tags T, find a
+ * bijection f: T*⊂T → I*⊂I s.t. d[i..k] + t ∉ d[i'..(k + |t|)], ∀ i' ∈ I\{i},
+ * ∀ k ∈ (i, |d|-|t|], where t ∈ T, i ∈ I. Maximize |I*|. This can be relaxed
+ * to t=t[0] and ∀ k ∈ (i, i+K] for some fixed K, in most natural documents.
+ *
+ * More concretely, tags are typically two-character strings containing alpha-
+ * numeric symbols. Documents are plaintext files. Indices are produced by a
+ * search query of length N, i.e. the preceding N characters of every index i in
+ * document d are identical. For characters proceeding d[i], all bets are off.
+ * We can assume that P(d[i]|d[i-1]) has some structure for d~D. Ultimately, we
+ * want a fast algorithm which maximizes the number of tagged document indices.
+ *
+ * Tags are used by the typist to select indices within a document. To select an
+ * index, the typist starts by activating AceJump and searching for a character.
+ * As soon as the first character is received, we begin to scan the document for
+ * matching locations and assign as many valid tags as possible. When subsequent
+ * characters are received, we refine the search results to match either:
+ *
+ *    1.) The plaintext query alone, or
+ *    2.) The concatenation of plaintext query and partial tag
+ *
+ * The constraint in paragraph no. 1 tries to impose the following criteria:
+ *
+ *    1.) All valid key sequences will lead to a unique location in the document
+ *    2.) All indices in the document will be reachable by a short key sequence
+ *
+ * If there is an insufficient number of two-character tags to cover every index
+ * (which typically occurs when the user searches for a common character within
+ * a long document), then we attempt to maximize the number of tags assigned to
+ * document indices. The key is, all tags must be assigned as soon as possible,
+ * i.e. as soon as the first character is received or whenever the user ceases
+ * typing (at the very latest). Once assigned, a visible tag must never change
+ * at any time during the selection process, so as not to confuse the user.
+ */
+
+internal class Solver private constructor(
+  private val editorPriority: List<Editor>,
+  private val queryLength: Int,
+  private val newResults: Map<Editor, IntList>,
+  private val allResults: Map<Editor, IntList>,
+) {
+  companion object {
+    fun solve(
+      editorPriority: List<Editor>,
+      query: SearchQuery,
+      newResults: Map<Editor, IntList>,
+      allResults: Map<Editor, IntList>,
+      tags: List<String>,
+      caches: Map<Editor, EditorOffsetCache>,
+    ): Map<String, Tag> {
+      return Solver(editorPriority, max(1, query.rawText.length), newResults, allResults).map(tags, caches)
+    }
+  }
+  
+  private var newTags = HashMap<String, Tag>(KeyLayoutCache.allPossibleTags.size)
+  private val newTagIndices = newResults.keys.associateWith { IntOpenHashSet() }
+  
+  private var allWordFragments = HashSet<String>(allResults.values.sumBy(IntList::size)).apply {
+    for ((editor, offsets) in allResults) {
+      val chars = editor.immutableText
+      val iter = offsets.iterator()
+      while (iter.hasNext()) {
+        forEachWordFragment(chars, iter.nextInt(), this::add)
+      }
+    }
+  }
+  
+  private fun generateEligibleSites(availableTags: List<String>): Map<String, MutableList<Tag>> {
+    val eligibleSitesByTag = HashMap<String, MutableList<Tag>>(100)
+    val tagsByFirstLetter = availableTags.groupBy { it[0] }
+    
+    for ((editor, offsets) in newResults) {
+      val chars = editor.immutableText
+      val iter = offsets.iterator()
+      while (iter.hasNext()) {
+        val site = iter.nextInt()
+        
+        for ((firstLetter, tags) in tagsByFirstLetter.entries) {
+          if (canTagBeginWithChar(chars, site, firstLetter)) {
+            for (tag in tags) {
+              eligibleSitesByTag.getOrPut(tag, ::mutableListOf).add(Tag(editor, site))
+            }
+          }
+        }
+      }
+    }
+    
+    return eligibleSitesByTag
+  }
+  
+  private fun generateMatchingSites(
+    eligibleSites: Map<String, MutableList<Tag>>,
+    caches: Map<Editor, EditorOffsetCache>,
+  ): Map<String, Iterator<Tag>> {
+    val matchingSites = HashMap<MutableList<Tag>, Iterator<Tag>>()
+    val matchingSitesSorted = IdentityHashMap<String, Iterator<Tag>>() // Keys are guaranteed to be from a single collection.
+    
+    val siteOrder = siteOrder(caches)
+    
+    for ((mark, tags) in eligibleSites.entries) {
+      matchingSitesSorted[mark] = matchingSites.getOrPut(tags) {
+        @Suppress("ConvertLambdaToReference")
+        tags.toMutableList().apply { sortWith(siteOrder) }.iterator()
+      }
+    }
+    
+    return matchingSitesSorted
+  }
+  
+  fun map(availableTags: List<String>, caches: Map<Editor, EditorOffsetCache>): Map<String, Tag> {
+    val eligibleSitesByTag = generateEligibleSites(availableTags)
+    val matchingSitesSorted = generateMatchingSites(eligibleSitesByTag, caches)
+    
+    val tagOrder = KeyLayoutCache.tagOrder
+      .thenComparingInt { eligibleSitesByTag.getValue(it).size }
+      .thenBy(AceConfig.layout.priority(String::last))
+    
+    val sortedTags = eligibleSitesByTag.keys.toMutableList().apply {
+      sortWith(tagOrder)
+    }
+    
+    var totalAssigned = 0
+    val totalResults = newResults.values.sumBy(IntList::size)
+    
+    for (tag in sortedTags) {
+      if (totalAssigned == totalResults) {
+        break
+      }
+      
+      if (tryToAssignTag(tag, matchingSitesSorted.getValue(tag))) {
+        totalAssigned++
+      }
+    }
+    
+    return newTags
+  }
+  
+  private fun tryToAssignTag(mark: String, tags: Iterator<Tag>): Boolean {
+    if (newTags.containsKey(mark)) {
+      return false
+    }
+    
+    while (tags.hasNext()) {
+      val tag = tags.next()
+      val assigned = newTagIndices.getValue(tag.editor)
+      
+      if (tag.offset !in assigned) {
+        newTags[mark] = tag
+        assigned.add(tag.offset)
+        return true
+      }
+    }
+    
+    return false
+  }
+  
+  private fun siteOrder(caches: Map<Editor, EditorOffsetCache>) = Comparator<Tag> { a, b ->
+    val aEditor = a.editor
+    val bEditor = b.editor
+    
+    if (aEditor !== bEditor) {
+      val aEditorIndex = editorPriority.indexOf(aEditor)
+      val bEditorIndex = editorPriority.indexOf(bEditor)
+      // For multiple editors, prioritize them based on the provided order.
+      return@Comparator if (aEditorIndex < bEditorIndex) -1 else 1
+    }
+    
+    val aIsVisible = StandardBoundaries.VISIBLE_ON_SCREEN.isOffsetInside(aEditor, a.offset, caches.getValue(aEditor))
+    val bIsVisible = StandardBoundaries.VISIBLE_ON_SCREEN.isOffsetInside(bEditor, b.offset, caches.getValue(bEditor))
+    if (aIsVisible != bIsVisible) {
+      // Sites in immediate view should come first.
+      return@Comparator if (aIsVisible) -1 else 1
+    }
+    
+    val aIsNotWordStart = aEditor.immutableText[max(0, a.offset - 1)].isWordPart
+    val bIsNotWordStart = bEditor.immutableText[max(0, b.offset - 1)].isWordPart
+    if (aIsNotWordStart != bIsNotWordStart) {
+      // Ensure that the first letter of a word is prioritized for tagging.
+      return@Comparator if (bIsNotWordStart) -1 else 1
+    }
+    
+    when {
+      a.offset < b.offset -> -1
+      a.offset > b.offset -> 1
+      else                -> 0
+    }
+  }
+  
+  private fun canTagBeginWithChar(chars: CharSequence, site: Int, char: Char): Boolean {
+    if (char.toString() in allWordFragments) {
+      return false
+    }
+    
+    forEachWordFragment(chars, site) {
+      if (it + char in allWordFragments) {
+        return false
+      }
+    }
+    
+    return true
+  }
+  
+  private inline fun forEachWordFragment(chars: CharSequence, site: Int, callback: (String) -> Unit) {
+    val left = max(0, site + queryLength - 1)
+    val right = chars.wordEndPlus(site)
+    
+    val builder = StringBuilder(1 + right - left)
+    
+    for (i in left..right) {
+      builder.append(chars[i].toLowerCase())
+      callback(builder.toString())
+    }
+  }
+}

src/main/kotlin/org/acejump/search/Tagger.kt

@@ -1,76 +1,93 @@
 package org.acejump.search
 
 import com.google.common.collect.ArrayListMultimap
+import com.google.common.collect.HashBiMap
 import com.intellij.openapi.editor.Editor
+import it.unimi.dsi.fastutil.ints.IntArrayList
 import it.unimi.dsi.fastutil.ints.IntList
+import org.acejump.ExternalUsage
 import org.acejump.boundaries.EditorOffsetCache
-import org.acejump.boundaries.StandardBoundaries.VISIBLE_ON_SCREEN
+import org.acejump.boundaries.StandardBoundaries
 import org.acejump.immutableText
-import org.acejump.input.KeyLayoutCache
+import org.acejump.input.KeyLayoutCache.allPossibleTags
 import org.acejump.isWordPart
+import org.acejump.matchesAt
 import org.acejump.view.TagMarker
+import java.util.AbstractMap.SimpleImmutableEntry
 import kotlin.collections.component1
 import kotlin.collections.component2
-import kotlin.math.max
 import kotlin.math.min
 
 /**
- * Assigns tags to search occurrences.
+ * Assigns tags to search occurrences, updates them when the search query changes, and requests a jump if the search query matches a tag.
  * The ordering of [editors] may be used to prioritize tagging editors earlier in the list in case of conflicts.
  */
-class Tagger(private val editors: List<Editor>, results: Map<Editor, IntList>) {
-  private var tagMap: Map<String, Tag>
-  private var typedTag = ""
+class Tagger(private val editors: List<Editor>) {
+  private var tagMap = HashBiMap.create<String, Tag>()
   
-  internal val markers: Map<Editor, Collection<TagMarker>>
-    get() {
-      val markers = ArrayListMultimap.create<Editor, TagMarker>(editors.size, min(tagMap.values.size, 40))
+  val hasTags
+    get() = tagMap.isNotEmpty()
   
-      for ((mark, tag) in tagMap) {
-        val marker = TagMarker.create(mark, tag.offset, typedTag)
-        markers.put(tag.editor, marker)
+  @ExternalUsage
+  internal val tags
+    get() = tagMap.map { SimpleImmutableEntry(it.key, it.value) }.sortedBy { it.value.offset }
+  
+  /**
+   * Removes all markers, allowing them to be regenerated from scratch.
+   */
+  internal fun unmark() {
+    tagMap = HashBiMap.create()
   }
   
-      return markers.asMap()
+  /**
+   * Assigns tags to as many results as possible, keeping previously assigned tags. Returns a [TaggingResult.Accept] if the current search
+   * query matches any existing tag and we should jump to it and end the session, or [TaggingResult.Mark] to continue the session with
+   * updated tag markers.
+   *
+   * Note that the [results] collection will be mutated.
+   */
+  internal fun update(query: SearchQuery, results: Map<Editor, IntList>): TaggingResult {
+    val isRegex = query is SearchQuery.RegularExpression
+    val queryText = if (isRegex) " ${query.rawText}" else query.rawText[0] + query.rawText.drop(1).toLowerCase()
+    
+    val availableTags = allPossibleTags.filter { !queryText.endsWith(it[0]) && it !in tagMap }
+    
+    if (!isRegex) {
+      for (entry in tagMap.entries) {
+        if (entry solves queryText) {
+          return TaggingResult.Accept(entry.value)
+        }
       }
       
-  init {
+      if (queryText.length == 1) {
+        for ((editor, offsets) in results) {
+          removeResultsWithOverlappingTags(editor, offsets)
+        }
+      }
+    }
+    
+    if (!isRegex || tagMap.isEmpty()) {
+      tagMap = assignTagsAndMerge(results, availableTags, query, queryText)
+    }
+    
+    val resultTags = results.flatMap { (editor, offsets) -> offsets.map { Tag(editor, it) } }
+    return TaggingResult.Mark(createTagMarkers(resultTags, query.rawText.ifEmpty { null }))
+  }
+  
+  /**
+   * Assigns as many unassigned tags as possible, and merges them with the existing compatible tags.
+   */
+  private fun assignTagsAndMerge(
+    results: Map<Editor, IntList>, availableTags: List<String>, query: SearchQuery, queryText: String,
+  ): HashBiMap<String, Tag> {
     val caches = results.keys.associateWith { EditorOffsetCache.new() }
     
-    sortResults(results, caches)
-    
-    val tagSites = results
-      .flatMap { (editor, sites) -> sites.map { site -> Tag(editor, site) } }
-      .sortedWith(siteOrder(editors, caches))
-    
-    tagMap = KeyLayoutCache.allPossibleTags.zip(tagSites).toMap()
-  }
-  
-  internal fun type(char: Char): TaggingResult {
-    val newTypedTag = typedTag + char
-    val matchingTag = tagMap[newTypedTag]
-    if (matchingTag != null) {
-      return TaggingResult.Accept(matchingTag)
-    }
-    
-    val newTagMap = tagMap.filter { it.key.startsWith(newTypedTag, ignoreCase = true) }
-    if (newTagMap.isEmpty()) {
-      return TaggingResult.Nothing
-    }
-    
-    typedTag = newTypedTag
-    tagMap = newTagMap
-    return TaggingResult.Mark(markers)
-  }
-  
-  private companion object {
-    private fun sortResults(results: Map<Editor, IntList>, caches: Map<Editor, EditorOffsetCache>) {
     for ((editor, offsets) in results) {
       val cache = caches.getValue(editor)
       
       offsets.sort { a, b ->
-          val aIsVisible = VISIBLE_ON_SCREEN.isOffsetInside(editor, a, cache)
-          val bIsVisible = VISIBLE_ON_SCREEN.isOffsetInside(editor, b, cache)
+        val aIsVisible = StandardBoundaries.VISIBLE_ON_SCREEN.isOffsetInside(editor, a, cache)
+        val bIsVisible = StandardBoundaries.VISIBLE_ON_SCREEN.isOffsetInside(editor, b, cache)
         
         when {
           aIsVisible && !bIsVisible -> -1
@@ -79,39 +96,134 @@ class Tagger(private val editors: List<Editor>, results: Map<Editor, IntList>) {
         }
       }
     }
+    
+    val allAssignedTags = mutableMapOf<String, Tag>()
+    val oldCompatibleTags = tagMap.filter { (mark, tag) ->
+      isTagCompatibleWithQuery(mark, tag, queryText) || results[tag.editor]?.contains(tag.offset) == true
     }
     
-    private fun siteOrder(editorPriority: List<Editor>, caches: Map<Editor, EditorOffsetCache>) = Comparator<Tag> { a, b ->
-      val aEditor = a.editor
-      val bEditor = b.editor
+    val vacantResults: Map<Editor, IntList>
     
-      if (aEditor !== bEditor) {
-        val aEditorIndex = editorPriority.indexOf(aEditor)
-        val bEditorIndex = editorPriority.indexOf(bEditor)
-        // For multiple editors, prioritize them based on the provided order.
-        return@Comparator if (aEditorIndex < bEditorIndex) -1 else 1
+    if (oldCompatibleTags.isEmpty()) {
+      vacantResults = results
     }
+    else {
+      val vacant = mutableMapOf<Editor, IntList>()
       
-      val aIsVisible = VISIBLE_ON_SCREEN.isOffsetInside(aEditor, a.offset, caches.getValue(aEditor))
-      val bIsVisible = VISIBLE_ON_SCREEN.isOffsetInside(bEditor, b.offset, caches.getValue(bEditor))
-      if (aIsVisible != bIsVisible) {
-        // Sites in immediate view should come first.
-        return@Comparator if (aIsVisible) -1 else 1
-      }
+      for ((editor, offsets) in results) {
+        val list = IntArrayList()
+        val iter = offsets.iterator()
         
-      val aIsNotWordStart = aEditor.immutableText[max(0, a.offset - 1)].isWordPart
-      val bIsNotWordStart = bEditor.immutableText[max(0, b.offset - 1)].isWordPart
-      if (aIsNotWordStart != bIsNotWordStart) {
-        // Ensure that the first letter of a word is prioritized for tagging.
-        return@Comparator if (bIsNotWordStart) -1 else 1
-      }
-      
-      when {
-        a.offset < b.offset -> -1
-        a.offset > b.offset -> 1
-        else                -> 0
+        while (iter.hasNext()) {
+          val tag = Tag(editor, iter.nextInt())
+          if (tag !in oldCompatibleTags.values) {
+            list.add(tag.offset)
           }
         }
         
+        vacant[editor] = list
+      }
+      
+      vacantResults = vacant
+    }
+    
+    allAssignedTags.putAll(oldCompatibleTags)
+    allAssignedTags.putAll(Solver.solve(editors, query, vacantResults, results, availableTags, caches))
+    
+    val assignedMarkers = allAssignedTags.keys.groupBy { it[0] }
+    
+    return allAssignedTags.mapKeysTo(HashBiMap.create(allAssignedTags.size)) { (tag, _) ->
+      if (canShortenTag(tag, assignedMarkers, queryText))
+        tag[0].toString()
+      else
+        tag
+    }
+  }
+  
+  private infix fun Map.Entry<String, Tag>.solves(query: String): Boolean {
+    return query.endsWith(key, true) && isTagCompatibleWithQuery(key, value, query)
+  }
+  
+  private fun isTagCompatibleWithQuery(marker: String, tag: Tag, query: String): Boolean {
+    return tag.editor.immutableText.matchesAt(tag.offset, getPlaintextPortion(query, marker), ignoreCase = true)
+  }
+  
+  fun isQueryCompatibleWithTagAt(query: String, tag: Tag): Boolean {
+    return tagMap.inverse()[tag].let { it != null && isTagCompatibleWithQuery(it, tag, query) }
+  }
+  
+  fun canQueryMatchAnyTag(query: String): Boolean {
+    return tagMap.any { (tag, offset) ->
+      val tagPortion = getTagPortion(query, tag)
+      tagPortion.isNotEmpty() && tag.startsWith(tagPortion, ignoreCase = true) && isTagCompatibleWithQuery(tag, offset, query)
+    }
+  }
+  
+  private fun removeResultsWithOverlappingTags(editor: Editor, offsets: IntList) {
+    val iter = offsets.iterator()
+    val chars = editor.immutableText
+    
+    while (iter.hasNext()) {
+      if (!chars.canTagWithoutOverlap(iter.nextInt())) {
+        iter.remove() // Very uncommon, so slow removal is fine.
+      }
+    }
+  }
+  
+  private fun createTagMarkers(tags: Collection<Tag>, literalQueryText: String?): MutableMap<Editor, Collection<TagMarker>> {
+    val tagMapInv = tagMap.inverse()
+    val markers = ArrayListMultimap.create<Editor, TagMarker>(editors.size, min(tags.size, 50))
+    
+    for (tag in tags) {
+      val mark = tagMapInv[tag] ?: continue
+      val editor = tag.editor
+      val marker = TagMarker.create(editor, mark, tag.offset, literalQueryText)
+      markers.put(editor, marker)
+    }
+    
+    return markers.asMap()
+  }
+  
+  private companion object {
+    private fun CharSequence.canTagWithoutOverlap(loc: Int) = when {
+      loc - 1 < 0                                                                             -> true
+      loc + 1 >= length                                                                       -> true
+      this[loc] isUnlike this[loc - 1]                                                        -> true
+      this[loc] isUnlike this[loc + 1]                                                        -> true
+      this[loc] != this[loc - 1]                                                              -> true
+      this[loc] != this[loc + 1]                                                              -> true
+      this[loc + 1] == '\r' || this[loc + 1] == '\n'                                          -> true
+      this[loc - 1] == this[loc] && this[loc] == this[loc + 1]                                -> false
+      this[loc + 1].isWhitespace() && this[(loc + 2).coerceAtMost(length - 1)].isWhitespace() -> true
+      else                                                                                    -> false
+    }
+    
+    private infix fun Char.isUnlike(other: Char): Boolean {
+      return this.isWordPart xor other.isWordPart || this.isWhitespace() xor other.isWhitespace()
+    }
+    
+    private fun getPlaintextPortion(query: String, marker: String) = when {
+      query.endsWith(marker, true)         -> query.dropLast(marker.length)
+      query.endsWith(marker.first(), true) -> query.dropLast(1)
+      else                                 -> query
+    }
+    
+    private fun getTagPortion(query: String, marker: String) = when {
+      query.endsWith(marker, true)         -> query.takeLast(marker.length)
+      query.endsWith(marker.first(), true) -> query.takeLast(1)
+      else                                 -> ""
+    }
+    
+    private fun canShortenTag(marker: String, markers: Map<Char, List<String>>, queryText: String): Boolean {
+      // Avoid matching query - will trigger a jump.
+      // TODO: lift this constraint.
+      val queryEndsWith = queryText.endsWith(marker[0]) || queryText.endsWith(marker)
+      if (queryEndsWith) {
+        return false
+      }
+      
+      val startingWithSameLetter = markers[marker[0]]
+      return startingWithSameLetter == null || startingWithSameLetter.singleOrNull() == marker
+    }
   }
 }

src/main/kotlin/org/acejump/search/TaggingResult.kt

@@ -4,7 +4,6 @@ import com.intellij.openapi.editor.Editor
 import org.acejump.view.TagMarker
 
 internal sealed class TaggingResult {
-  object Nothing : TaggingResult()
   class Accept(val tag: Tag) : TaggingResult()
-  class Mark(val markers: Map<Editor, Collection<TagMarker>>) : TaggingResult()
+  class Mark(val markers: MutableMap<Editor, Collection<TagMarker>>) : TaggingResult()
 }

src/main/kotlin/org/acejump/session/Session.kt

@@ -1,29 +1,23 @@
 package org.acejump.session
 
 import com.intellij.codeInsight.hint.HintManagerImpl
+import com.intellij.openapi.actionSystem.DataContext
 import com.intellij.openapi.editor.Editor
 import com.intellij.openapi.editor.ScrollType
+import com.intellij.openapi.editor.actionSystem.TypedActionHandler
 import com.intellij.openapi.editor.colors.EditorColors
 import com.intellij.openapi.editor.colors.impl.AbstractColorsScheme
-import it.unimi.dsi.fastutil.ints.IntList
+import org.acejump.ExternalUsage
 import org.acejump.boundaries.Boundaries
 import org.acejump.boundaries.StandardBoundaries
+import org.acejump.clone
 import org.acejump.config.AceConfig
 import org.acejump.input.EditorKeyListener
 import org.acejump.input.KeyLayoutCache
 import org.acejump.modes.JumpMode
 import org.acejump.modes.SessionMode
-import org.acejump.search.Pattern
-import org.acejump.search.SearchProcessor
-import org.acejump.search.SearchQuery
-import org.acejump.search.Tag
-import org.acejump.session.TypeResult.AcceptTag
-import org.acejump.session.TypeResult.ChangeMode
-import org.acejump.session.TypeResult.ChangeState
-import org.acejump.session.TypeResult.EndSession
-import org.acejump.session.TypeResult.Nothing
+import org.acejump.search.*
 import org.acejump.view.TagCanvas
-import org.acejump.view.TagMarker
 import org.acejump.view.TextHighlighter
 
 /**
@@ -33,7 +27,8 @@ class Session(private val mainEditor: Editor, private val jumpEditors: List<Edit
   private val editorSettings = EditorSettings.setup(mainEditor)
   private lateinit var mode: SessionMode
   
-  private var state: SessionState? = null
+  private var state: SessionStateImpl? = null
+  private var tagger = Tagger(jumpEditors)
   
   private var acceptedTag: Tag? = null
     set(value) {
@@ -48,48 +43,69 @@ class Session(private val mainEditor: Editor, private val jumpEditors: List<Edit
   private val textHighlighter = TextHighlighter()
   private val tagCanvases = jumpEditors.associateWith(::TagCanvas)
   
+  @ExternalUsage
+  val tags
+    get() = tagger.tags
+  
   var defaultBoundary: Boundaries = StandardBoundaries.VISIBLE_ON_SCREEN
   
-  private val actions = object : SessionActions {
-    override fun showHighlights(results: Map<Editor, IntList>, query: SearchQuery) {
-      textHighlighter.renderOccurrences(results, query)
-    }
-    
-    override fun hideHighlights() {
-      textHighlighter.reset()
-    }
-    
-    override fun setTagMarkers(markers: Map<Editor, Collection<TagMarker>>) {
-      for ((editor, canvas) in tagCanvases) {
-        canvas.setMarkers(markers[editor].orEmpty())
-      }
-    }
-  }
-  
   init {
     KeyLayoutCache.ensureInitialized(AceConfig.settings)
-    EditorKeyListener.attach(mainEditor) { editor, charTyped, _ -> typeCharacter(editor, charTyped) }
-  }
     
-  private fun typeCharacter(editor: Editor, charTyped: Char) {
+    EditorKeyListener.attach(mainEditor, object : TypedActionHandler {
+      override fun execute(editor: Editor, charTyped: Char, context: DataContext) {
         val state = state ?: return
+        val hadTags = tagger.hasTags
         
         editorSettings.startEditing(editor)
         val result = mode.type(state, charTyped, acceptedTag)
         editorSettings.stopEditing(editor)
         
         when (result) {
-      Nothing        -> return
-      is ChangeState -> this.state = result.state
-      is ChangeMode  -> setMode(result.mode)
+          TypeResult.Nothing          -> return;
+          is TypeResult.UpdateResults -> updateSearch(result.processor, markImmediately = hadTags)
+          is TypeResult.ChangeMode    -> setMode(result.mode)
           
-      is AcceptTag   -> {
-        acceptedTag = result.tag
-        mode.accept(state, result.tag)
-        end()
+          TypeResult.RestartSearch    -> restart().also {
+            this@Session.state = SessionStateImpl(jumpEditors, tagger, defaultBoundary)
           }
           
-      EndSession     -> end()
+          TypeResult.EndSession       -> end()
+        }
+      }
+    })
+  }
+  
+  /**
+   * Updates text highlights and tag markers according to the current search state. Dispatches jumps if the search query matches a tag.
+   */
+  private fun updateSearch(processor: SearchProcessor, markImmediately: Boolean) {
+    val query = processor.query
+    val results = processor.results
+    
+    if (!markImmediately && query.rawText.let { it.length < AceConfig.minQueryLength && it.all(Char::isLetterOrDigit) }) {
+      textHighlighter.renderOccurrences(results, query)
+      return
+    }
+    
+    when (val result = tagger.update(query, results.clone())) {
+      is TaggingResult.Accept -> {
+        acceptedTag = result.tag
+        textHighlighter.renderFinal(result.tag, processor.query)
+        
+        if (state?.let { mode.accept(it, result.tag) } == true) {
+          end()
+          return
+        }
+      }
+      
+      is TaggingResult.Mark   -> {
+        for ((editor, canvas) in tagCanvases) {
+          canvas.setMarkers(result.markers[editor].orEmpty())
+        }
+        
+        textHighlighter.renderOccurrences(results, query)
+      }
     }
   }
   
@@ -113,7 +129,7 @@ class Session(private val mainEditor: Editor, private val jumpEditors: List<Edit
     }
     
     setMode(mode())
-    state = SessionState.WaitForKey(actions, jumpEditors, defaultBoundary)
+    state = SessionStateImpl(jumpEditors, tagger, defaultBoundary)
   }
   
   /**
@@ -124,18 +140,22 @@ class Session(private val mainEditor: Editor, private val jumpEditors: List<Edit
       setMode(JumpMode())
     }
     
-    for (canvas in tagCanvases.values) {
-      canvas.setMarkers(emptyList())
-    }
+    tagger = Tagger(jumpEditors)
+    tagCanvases.values.forEach { it.setMarkers(emptyList()) }
     
     val processor = SearchProcessor.fromRegex(jumpEditors, pattern.regex, defaultBoundary)
-    textHighlighter.renderOccurrences(processor.resultsCopy, processor.query)
+    state = SessionStateImpl(jumpEditors, tagger, defaultBoundary, processor)
     
-    state = SessionState.SelectTag(actions, jumpEditors, processor)
+    updateSearch(processor, markImmediately = true)
   }
   
   fun tagImmediately() {
-    typeCharacter(mainEditor, '\n')
+    val state = state ?: return
+    val processor = state.currentProcessor
+    
+    if (processor != null) {
+      updateSearch(processor, markImmediately = true)
+    }
   }
   
   /**
@@ -150,6 +170,7 @@ class Session(private val mainEditor: Editor, private val jumpEditors: List<Edit
    */
   fun restart() {
     state = null
+    tagger = Tagger(jumpEditors)
     acceptedTag = null
     tagCanvases.values.forEach(TagCanvas::removeMarkers)
     textHighlighter.reset()
@@ -164,6 +185,7 @@ class Session(private val mainEditor: Editor, private val jumpEditors: List<Edit
    * Should only be used from [SessionManager] to dispose a successfully ended session.
    */
   internal fun dispose() {
+    tagger = Tagger(jumpEditors)
     tagCanvases.values.forEach(TagCanvas::unbind)
     textHighlighter.reset()
     EditorKeyListener.detach(mainEditor)

src/main/kotlin/org/acejump/session/SessionActions.kt

@@ -1,13 +0,0 @@
-package org.acejump.session
-
-import com.intellij.openapi.editor.Editor
-import it.unimi.dsi.fastutil.ints.IntList
-import org.acejump.search.SearchQuery
-import org.acejump.view.TagMarker
-
-internal interface SessionActions {
-  fun showHighlights(results: Map<Editor, IntList>, query: SearchQuery)
-  fun hideHighlights()
-  
-  fun setTagMarkers(markers: Map<Editor, Collection<TagMarker>>)
-}

src/main/kotlin/org/acejump/session/SessionState.kt

@@ -1,72 +1,9 @@
 package org.acejump.session
 
-import com.intellij.openapi.editor.Editor
-import org.acejump.boundaries.Boundaries
-import org.acejump.search.SearchProcessor
-import org.acejump.search.Tagger
-import org.acejump.search.TaggingResult
+import org.acejump.action.AceTagAction
+import org.acejump.search.Tag
 
-sealed interface SessionState {
+interface SessionState {
   fun type(char: Char): TypeResult
-  
-  class WaitForKey internal constructor(
-    private val actions: SessionActions,
-    private val jumpEditors: List<Editor>,
-    private val defaultBoundary: Boundaries,
-  ) : SessionState {
-    override fun type(char: Char): TypeResult {
-      val searchProcessor = SearchProcessor.fromString(jumpEditors, char.toString(), defaultBoundary)
-      
-      return if (searchProcessor.isQueryFinished) {
-        TypeResult.ChangeState(SelectTag(actions, jumpEditors, searchProcessor))
-      }
-      else {
-        TypeResult.ChangeState(RefineSearchQuery(actions, jumpEditors, searchProcessor))
-      }
-    }
-  }
-  
-  class RefineSearchQuery internal constructor(
-    private val actions: SessionActions,
-    private val jumpEditors: List<Editor>,
-    private val searchProcessor: SearchProcessor,
-  ) : SessionState {
-    init {
-      actions.showHighlights(searchProcessor.resultsCopy, searchProcessor.query)
-    }
-    
-    override fun type(char: Char): TypeResult {
-      return if (searchProcessor.refineQuery(char)) {
-        actions.hideHighlights()
-        TypeResult.ChangeState(SelectTag(actions, jumpEditors, searchProcessor))
-      }
-      else {
-        actions.showHighlights(searchProcessor.resultsCopy, searchProcessor.query)
-        TypeResult.Nothing
-      }
-    }
-  }
-  
-  class SelectTag internal constructor(
-    private val actions: SessionActions,
-    jumpEditors: List<Editor>,
-    searchProcessor: SearchProcessor,
-  ) : SessionState {
-    private val tagger = Tagger(jumpEditors, searchProcessor.resultsCopy)
-    
-    init {
-      actions.setTagMarkers(tagger.markers)
-    }
-    
-    override fun type(char: Char): TypeResult {
-      return when (val result = tagger.type(char)) {
-        is TaggingResult.Nothing -> TypeResult.Nothing
-        is TaggingResult.Accept  -> TypeResult.AcceptTag(result.tag)
-        is TaggingResult.Mark    -> {
-          actions.setTagMarkers(result.markers)
-          TypeResult.Nothing
-        }
-      }
-    }
-  }
+  fun act(action: AceTagAction, tag: Tag, shiftMode: Boolean, isFinal: Boolean)
 }

src/main/kotlin/org/acejump/session/SessionStateImpl.kt

@@ -0,0 +1,36 @@
+package org.acejump.session
+
+import com.intellij.openapi.editor.Editor
+import org.acejump.action.AceTagAction
+import org.acejump.boundaries.Boundaries
+import org.acejump.search.SearchProcessor
+import org.acejump.search.Tag
+import org.acejump.search.Tagger
+
+internal class SessionStateImpl(
+  private val jumpEditors: List<Editor>,
+  private val tagger: Tagger,
+  private val defaultBoundary: Boundaries,
+  processor: SearchProcessor? = null
+) : SessionState {
+  internal var currentProcessor: SearchProcessor? = processor
+  
+  override fun type(char: Char): TypeResult {
+    val processor = currentProcessor
+    
+    if (processor == null) {
+      val newProcessor = SearchProcessor.fromChar(jumpEditors, char, defaultBoundary)
+      return TypeResult.UpdateResults(newProcessor.also { currentProcessor = it })
+    }
+    
+    if (processor.type(char, tagger)) {
+      return TypeResult.UpdateResults(processor)
+    }
+    
+    return TypeResult.Nothing
+  }
+  
+  override fun act(action: AceTagAction, tag: Tag, shiftMode: Boolean, isFinal: Boolean) {
+    currentProcessor?.let { action(tag.editor, it, tag.offset, shiftMode, isFinal) }
+  }
+}

src/main/kotlin/org/acejump/session/TypeResult.kt

@@ -1,12 +1,12 @@
 package org.acejump.session
 
 import org.acejump.modes.SessionMode
-import org.acejump.search.Tag
+import org.acejump.search.SearchProcessor
 
 sealed class TypeResult {
   object Nothing : TypeResult()
-  class ChangeState(val state: SessionState) : TypeResult()
+  class UpdateResults(val processor: SearchProcessor) : TypeResult()
   class ChangeMode(val mode: SessionMode) : TypeResult()
-  class AcceptTag(val tag: Tag) : TypeResult()
+  object RestartSearch : TypeResult()
   object EndSession : TypeResult()
 }

src/main/kotlin/org/acejump/view/TagCanvas.kt

@@ -2,7 +2,8 @@ package org.acejump.view
 
 import com.intellij.openapi.application.ApplicationInfo
 import com.intellij.openapi.editor.Editor
-import com.intellij.ui.ColorUtil
+import com.intellij.openapi.editor.event.CaretEvent
+import com.intellij.openapi.editor.event.CaretListener
 import org.acejump.boundaries.EditorOffsetCache
 import org.acejump.boundaries.StandardBoundaries
 import java.awt.Graphics
@@ -15,9 +16,8 @@ import javax.swing.SwingUtilities
 /**
  * Holds all active tag markers and renders them on top of the editor.
  */
-internal class TagCanvas(private val editor: Editor) : JComponent() {
-  private var markers: Collection<TagMarker> = emptyList()
-  private var visible = false
+internal class TagCanvas(private val editor: Editor) : JComponent(), CaretListener {
+  private var markers: Collection<TagMarker>? = null
   
   init {
     val contentComponent = editor.contentComponent
@@ -27,38 +27,43 @@ internal class TagCanvas(private val editor: Editor) : JComponent() {
     if (ApplicationInfo.getInstance().build.components.first() < 173) {
       SwingUtilities.convertPoint(this, location, editor.component.rootPane).let { setLocation(-it.x, -it.y) }
     }
+    
+    editor.caretModel.addCaretListener(this)
   }
   
   fun unbind() {
+    markers = null
     editor.contentComponent.remove(this)
-    editor.contentComponent.repaint()
+    editor.caretModel.removeCaretListener(this)
+  }
+  
+  /**
+   * Ensures that all tags and the outline around the selected tag are repainted. It should not be necessary to repaint the entire tag
+   * canvas, but the cost of repainting visible tags is negligible.
+   */
+  override fun caretPositionChanged(event: CaretEvent) {
+    repaint()
   }
   
   fun setMarkers(markers: Collection<TagMarker>) {
     this.markers = markers
-    this.visible = true
     repaint()
   }
   
   fun removeMarkers() {
     this.markers = emptyList()
-    this.visible = false
-    repaint()
+  }
+  
+  override fun paint(g: Graphics) {
+    if (!markers.isNullOrEmpty()) {
+      super.paint(g)
+    }
   }
   
   override fun paintChildren(g: Graphics) {
     super.paintChildren(g)
     
-    if (!visible) {
-      return
-    }
-    
-    g.color = ColorUtil.withAlpha(editor.colorsScheme.defaultBackground, 0.6)
-    g.fillRect(0, 0, width - 1, height - 1)
-    
-    if (markers.isEmpty()) {
-      return
-    }
+    val markers = markers ?: return
     
     (g as Graphics2D).setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON)
     
@@ -68,8 +73,18 @@ internal class TagCanvas(private val editor: Editor) : JComponent() {
     val viewRange = StandardBoundaries.VISIBLE_ON_SCREEN.getOffsetRange(editor, cache)
     val occupied = mutableListOf<Rectangle>()
     
+    // If there is a tag at the caret location, prioritize its rendering over all other tags. This is helpful for seeing which tag is
+    // currently selected while navigating highly clustered tags, although it does end up rearranging nearby tags which can be confusing.
+    
+    // TODO instead of immediately painting, we could calculate the layout of everything first, and then remove tags that interfere with
+    //      the caret tag to avoid changing the alignment of the caret tag
+    
+    val caretOffset = editor.caretModel.offset
+    val caretMarker = markers.find { it.offsetL == caretOffset || it.offsetR == caretOffset }
+    caretMarker?.paint(g, editor, cache, font, occupied)
+    
     for (marker in markers) {
-      if (marker.offset in viewRange) {
+      if (marker.isOffsetInRange(viewRange) && marker !== caretMarker) {
         marker.paint(g, editor, cache, font, occupied)
       }
     }

src/main/kotlin/org/acejump/view/TagFont.kt

@@ -2,18 +2,23 @@ package org.acejump.view
 
 import com.intellij.openapi.editor.Editor
 import com.intellij.openapi.editor.colors.EditorFontType
+import com.intellij.ui.ColorUtil
 import org.acejump.config.AceConfig
 import java.awt.Font
+import java.awt.FontMetrics
 
 /**
  * Stores font metrics for aligning and rendering [TagMarker]s.
  */
 internal class TagFont(editor: Editor) {
-  val tagFont: Font = editor.colorsScheme.getFont(EditorFontType.PLAIN)
+  val tagFont: Font = editor.colorsScheme.getFont(EditorFontType.BOLD)
   val tagCharWidth = editor.component.getFontMetrics(tagFont).charWidth('W')
   
   val foregroundColor = AceConfig.tagForegroundColor
+  var backgroundColor = AceConfig.tagBackgroundColor
+  val isForegroundDark = ColorUtil.isDark(foregroundColor)
   
+  val editorFontMetrics: FontMetrics = editor.component.getFontMetrics(editor.colorsScheme.getFont(EditorFontType.PLAIN))
   val lineHeight = editor.lineHeight
   val baselineDistance = editor.ascent
 }

src/main/kotlin/org/acejump/view/TagMarker.kt

@@ -2,38 +2,54 @@ package org.acejump.view
 
 import com.intellij.openapi.editor.Editor
 import com.intellij.openapi.util.SystemInfo
+import com.intellij.ui.scale.JBUIScale
 import org.acejump.boundaries.EditorOffsetCache
+import org.acejump.boundaries.StandardBoundaries
+import org.acejump.countMatchingCharacters
+import org.acejump.immutableText
 import java.awt.Color
 import java.awt.Graphics2D
 import java.awt.Point
 import java.awt.Rectangle
+import kotlin.math.max
 
 /**
  * Describes a 1 or 2 character shortcut that points to a specific character in the editor.
  */
 internal class TagMarker(
   private val tag: String,
-  val offset: Int
+  val offsetL: Int,
+  val offsetR: Int,
+  private val shiftR: Int,
+  private val hasSpaceRight: Boolean
 ) {
   private val length = tag.length
   
   companion object {
+    private const val ARC = 1
+    
     /**
      * TODO This might be due to DPI settings.
      */
     private val HIGHLIGHT_OFFSET = if (SystemInfo.isMac) -0.5 else 0.0
     
+    private val SHADOW_COLOR = Color(0F, 0F, 0F, 0.35F)
+    
     /**
      * Creates a new tag, precomputing some information about the nearby characters to reduce rendering overhead. If the last typed
-     * character ([typedTag]) matches the first [tag] character, only the second [tag] character is displayed.
+     * character ([literalQueryText]) matches the first [tag] character, only the second [tag] character is displayed.
      */
-    fun create(tag: String, offset: Int, typedTag: String): TagMarker {
-      val displayedTag = if (typedTag.isNotEmpty() && typedTag.last().equals(tag.first(), ignoreCase = true))
-        tag.drop(1).uppercase()
-      else
-        tag.uppercase()
+    fun create(editor: Editor, tag: String, offset: Int, literalQueryText: String?): TagMarker {
+      val chars = editor.immutableText
+      val matching = literalQueryText?.let { chars.countMatchingCharacters(offset, it) } ?: 0
+      val hasSpaceRight = offset + 1 >= chars.length || chars[offset + 1].isWhitespace()
       
-      return TagMarker(displayedTag, offset)
+      val displayedTag = if (literalQueryText != null && literalQueryText.last().equals(tag.first(), ignoreCase = true))
+        tag.drop(1).toUpperCase()
+      else
+        tag.toUpperCase()
+      
+      return TagMarker(displayedTag, offset, offset + max(0, matching - 1), tag.length - displayedTag.length, hasSpaceRight)
     }
     
     /**
@@ -42,7 +58,7 @@ internal class TagMarker(
     private fun drawHighlight(g: Graphics2D, rect: Rectangle, color: Color) {
       g.color = color
       g.translate(0.0, HIGHLIGHT_OFFSET)
-      g.fillRect(rect.x, rect.y, rect.width, rect.height + 1)
+      g.fillRoundRect(rect.x, rect.y, rect.width, rect.height + 1, ARC, ARC)
       g.translate(0.0, -HIGHLIGHT_OFFSET)
     }
     
@@ -50,10 +66,27 @@ internal class TagMarker(
      * Renders the tag text.
      */
     private fun drawForeground(g: Graphics2D, font: TagFont, point: Point, text: String) {
-      g.color = font.foregroundColor
+      val x = point.x + 2
+      val y = point.y + font.baselineDistance
+      
       g.font = font.tagFont
-      g.drawString(text, point.x, point.y + font.baselineDistance)
+      
+      if (!font.isForegroundDark) {
+        g.color = SHADOW_COLOR
+        g.drawString(text, x + 1, y + 1)
       }
+      
+      g.color = font.foregroundColor
+      g.drawString(text, x, y)
+    }
+  }
+  
+  /**
+   * Returns true if the left-aligned offset is in the range. Use to cull tags outside visible range.
+   * Only the left offset is checked, because if the tag was right-aligned on the last index of the range, it would not be visible anyway.
+   */
+  fun isOffsetInRange(range: IntRange): Boolean {
+    return offsetL in range
   }
   
   /**
@@ -63,16 +96,43 @@ internal class TagMarker(
   fun paint(g: Graphics2D, editor: Editor, cache: EditorOffsetCache, font: TagFont, occupied: MutableList<Rectangle>): Rectangle? {
     val rect = alignTag(editor, cache, font, occupied) ?: return null
     
-    drawHighlight(g, rect, editor.colorsScheme.defaultBackground)
+    drawHighlight(g, rect, font.backgroundColor)
     drawForeground(g, font, rect.location, tag)
     
-    occupied.add(rect)
+    occupied.add(JBUIScale.scale(2).let { Rectangle(rect.x - it, rect.y, rect.width + (2 * it), rect.height) })
     return rect
   }
   
   private fun alignTag(editor: Editor, cache: EditorOffsetCache, font: TagFont, occupied: List<Rectangle>): Rectangle? {
-    val pos = cache.offsetToXY(editor, offset)
-    val rect = Rectangle(pos.x, pos.y, font.tagCharWidth * length, font.lineHeight)
-    return rect.takeIf { occupied.none(it::intersects) }
+    val boundaries = StandardBoundaries.VISIBLE_ON_SCREEN
+    
+    if (hasSpaceRight || offsetL == 0 || editor.immutableText[offsetL - 1].let { it == '\n' || it == '\r' }) {
+      val rectR = createRightAlignedTagRect(editor, cache, font)
+      return rectR.takeIf { boundaries.isOffsetInside(editor, offsetR, cache) && occupied.none(rectR::intersects) }
+    }
+    
+    val rectL = createLeftAlignedTagRect(editor, cache, font)
+    if (occupied.none(rectL::intersects)) {
+      return rectL.takeIf { boundaries.isOffsetInside(editor, offsetL, cache) }
+    }
+    
+    val rectR = createRightAlignedTagRect(editor, cache, font)
+    if (occupied.none(rectR::intersects)) {
+      return rectR.takeIf { boundaries.isOffsetInside(editor, offsetR, cache) }
+    }
+    
+    return null
+  }
+  
+  private fun createRightAlignedTagRect(editor: Editor, cache: EditorOffsetCache, font: TagFont): Rectangle {
+    val pos = cache.offsetToXY(editor, offsetR)
+    val shift = font.editorFontMetrics.charWidth(editor.immutableText[offsetR]) + (font.tagCharWidth * shiftR)
+    return Rectangle(pos.x + shift, pos.y, (font.tagCharWidth * length) + 4, font.lineHeight)
+  }
+  
+  private fun createLeftAlignedTagRect(editor: Editor, cache: EditorOffsetCache, font: TagFont): Rectangle {
+    val pos = cache.offsetToXY(editor, offsetL)
+    val shift = -(font.tagCharWidth * length)
+    return Rectangle(pos.x + shift - 4, pos.y, (font.tagCharWidth * length) + 4, font.lineHeight)
   }
 }

src/main/kotlin/org/acejump/view/TextHighlighter.kt

@@ -6,12 +6,13 @@ import com.intellij.openapi.editor.markup.CustomHighlighterRenderer
 import com.intellij.openapi.editor.markup.HighlighterLayer
 import com.intellij.openapi.editor.markup.HighlighterTargetArea
 import com.intellij.openapi.editor.markup.RangeHighlighter
-import com.intellij.ui.ColorUtil
+import it.unimi.dsi.fastutil.ints.IntArrayList
 import it.unimi.dsi.fastutil.ints.IntList
 import org.acejump.boundaries.EditorOffsetCache
 import org.acejump.config.AceConfig
 import org.acejump.immutableText
 import org.acejump.search.SearchQuery
+import org.acejump.search.Tag
 import java.awt.Color
 import java.awt.Graphics
 
@@ -31,6 +32,13 @@ internal class TextHighlighter {
     }, query::getHighlightLength)
   }
   
+  /**
+   * Removes all current highlights and re-adds a single highlight at the position of the accepted tag with a different color.
+   */
+  fun renderFinal(tag: Tag, query: SearchQuery) {
+    render(mutableMapOf(tag.editor to IntArrayList(intArrayOf(tag.offset))), AcceptedTagRenderer, query::getHighlightLength)
+  }
+  
   private inline fun render(results: Map<Editor, IntList>, renderer: CustomHighlighterRenderer, getHighlightLength: (CharSequence, Int) -> Int) {
     for ((editor, offsets) in results) {
       val highlights = previousHighlights[editor]
@@ -80,7 +88,7 @@ internal class TextHighlighter {
    */
   private object SearchedWordRenderer : CustomHighlighterRenderer {
     override fun paint(editor: Editor, highlighter: RangeHighlighter, g: Graphics) {
-      drawFilled(g, editor, highlighter.startOffset, highlighter.endOffset, AceConfig.searchHighlightColor)
+      drawFilled(g, editor, highlighter.startOffset, highlighter.endOffset, AceConfig.textHighlightColor)
     }
   }
   
@@ -89,7 +97,16 @@ internal class TextHighlighter {
    */
   private object RegexRenderer : CustomHighlighterRenderer {
     override fun paint(editor: Editor, highlighter: RangeHighlighter, g: Graphics) {
-      drawSingle(g, editor, highlighter.startOffset, AceConfig.searchHighlightColor)
+      drawSingle(g, editor, highlighter.startOffset, AceConfig.textHighlightColor)
+    }
+  }
+  
+  /**
+   * Renders a filled highlight in the background of the accepted tag position and search query.
+   */
+  private object AcceptedTagRenderer : CustomHighlighterRenderer {
+    override fun paint(editor: Editor, highlighter: RangeHighlighter, g: Graphics) {
+      drawFilled(g, editor, highlighter.startOffset, highlighter.endOffset, AceConfig.acceptedTagColor)
     }
   }
   
@@ -100,10 +117,10 @@ internal class TextHighlighter {
       val start = EditorOffsetCache.Uncached.offsetToXY(editor, startOffset)
       val end = EditorOffsetCache.Uncached.offsetToXY(editor, endOffset)
       
-      g.color = ColorUtil.withAlpha(AceConfig.searchHighlightColor, 0.2)
+      g.color = color
       g.fillRect(start.x, start.y + 1, end.x - start.x, editor.lineHeight - 1)
       
-      g.color = color
+      g.color = AceConfig.tagBackgroundColor
       g.drawRect(start.x, start.y, end.x - start.x, editor.lineHeight)
     }
     
@@ -113,10 +130,10 @@ internal class TextHighlighter {
       val font = editor.colorsScheme.getFont(EditorFontType.PLAIN)
       val lastCharWidth = editor.component.getFontMetrics(font).charWidth(char)
       
-      g.color = ColorUtil.withAlpha(AceConfig.searchHighlightColor, 0.2)
+      g.color = color
       g.fillRect(pos.x, pos.y + 1, lastCharWidth, editor.lineHeight - 1)
       
-      g.color = color
+      g.color = AceConfig.tagBackgroundColor
       g.drawRect(pos.x, pos.y, lastCharWidth, editor.lineHeight)
     }
   }

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

@@ -24,7 +24,7 @@
                          implementationClass="org.acejump.action.AceEditorAction$Reset"/>
     <editorActionHandler action="EditorBackSpace" order="first"
                          implementationClass="org.acejump.action.AceEditorAction$ClearSearch"/>
-    <editorActionHandler action="EditorEnter" order="first, before terminalEnter"
+    <editorActionHandler action="EditorEnter" order="first"
                          implementationClass="org.acejump.action.AceEditorAction$TagImmediately"/>
   </extensions>
   

src/test/kotlin/AceTest.kt

@@ -0,0 +1,36 @@
+
+import org.acejump.test.util.BaseTest
+
+/**
+ * Functional test cases and end-to-end performance tests.
+ *
+ * TODO: Add more structure to test cases, use test resources to define files.
+ */
+
+class AceTest : BaseTest() {
+  fun `test that scanner finds all occurrences of single character`() =
+    assertEquals("test test test".search("t"), setOf(0, 3, 5, 8, 10, 13))
+
+  fun `test empty results for an absent query`() =
+    assertEmpty("test test test".search("best"))
+
+  fun `test sticky results on a query with extra characters`() =
+    assertEquals("test test test".search("testz"), setOf(0, 5, 10))
+
+  fun `test a query inside text with some variations`() =
+    assertEquals("abcd dabc cdab".search("cd"), setOf(2, 10))
+
+  fun `test a query containing a space character`() =
+    assertEquals("abcd dabc cdab".search("cd "), setOf(2))
+
+  fun `test a query containing a { character`() =
+    assertEquals("abcd{dabc cdab".search("cd{"), setOf(2))
+
+  fun `test tag selection`() {
+    "<caret>testing 1234".search("g")
+
+    typeAndWaitForResults(session.tags[0].key)
+
+    myFixture.checkResult("testin<caret>g 1234")
+  }
+}