lyng-idea/src/main/kotlin/net/sergeych/lyng/idea/annotators/LyngExternalAnnotator.kt

@@ -44,7 +44,10 @@ class LyngExternalAnnotator : ExternalAnnotator<LyngExternalAnnotator.Input, Lyn
 
     data class Span(val start: Int, val end: Int, val key: com.intellij.openapi.editor.colors.TextAttributesKey)
     data class Error(val start: Int, val end: Int, val message: String)
-    data class Result(val modStamp: Long, val spans: List<Span>, val error: Error? = null)
+    data class Result(val modStamp: Long, val spans: List<Span>, val error: Error? = null,
+                      val spellIdentifiers: List<IntRange> = emptyList(),
+                      val spellComments: List<IntRange> = emptyList(),
+                      val spellStrings: List<IntRange> = emptyList())
 
     override fun collectInformation(file: PsiFile): Input? {
         val doc: Document = file.viewProvider.document ?: return null
@@ -315,6 +318,62 @@ class LyngExternalAnnotator : ExternalAnnotator<LyngExternalAnnotator.Input, Lyn
             }
         }
 
+        // Build spell index payload: identifiers + comments/strings from simple highlighter.
+        // We limit identifier checks to declarations (val, var, fun, class, enum) and enum constants.
+        val spellIds = ArrayList<IntRange>()
+        fun addSpellId(pos: net.sergeych.lyng.Pos, name: String) {
+            if (pos.source == source) {
+                val s = source.offsetOf(pos)
+                val e = (s + name.length).coerceAtMost(text.length)
+                if (s < e) spellIds.add(s until e)
+            }
+        }
+
+        // Add declarations from MiniAst
+        mini.declarations.forEach { d ->
+            addSpellId(d.nameStart, d.name)
+            when (d) {
+                is MiniFunDecl -> {
+                    d.params.forEach { addSpellId(it.nameStart, it.name) }
+                    addTypeNames(d.returnType, ::addSpellId)
+                    addTypeNames(d.receiver, ::addSpellId)
+                }
+                is MiniValDecl -> {
+                    addTypeNames(d.type, ::addSpellId)
+                    addTypeNames(d.receiver, ::addSpellId)
+                }
+                is MiniEnumDecl -> {
+                    if (d.entries.size == d.entryPositions.size) {
+                        for (i in d.entries.indices) {
+                            addSpellId(d.entryPositions[i], d.entries[i])
+                        }
+                    }
+                }
+                is MiniClassDecl -> {
+                    d.ctorFields.forEach { addSpellId(it.nameStart, it.name) }
+                    d.classFields.forEach { addSpellId(it.nameStart, it.name) }
+                    d.members.forEach { m ->
+                        when (m) {
+                            is MiniMemberFunDecl -> {
+                                addSpellId(m.nameStart, m.name)
+                                m.params.forEach { addSpellId(it.nameStart, it.name) }
+                                addTypeNames(m.returnType, ::addSpellId)
+                            }
+                            is MiniMemberValDecl -> {
+                                addSpellId(m.nameStart, m.name)
+                                addTypeNames(m.type, ::addSpellId)
+                            }
+                            else -> {}
+                        }
+                    }
+                }
+                else -> {}
+            }
+        }
+
+        // Map Enum constants from token highlighter for highlighting only.
+        // We do NOT add them to spellIds here because they might be usages, 
+        // and declarations are already handled via MiniEnumDecl above.
         tokens.forEach { s ->
             if (s.kind == HighlightKind.EnumConstant) {
                 val start = s.range.start
@@ -325,9 +384,40 @@ class LyngExternalAnnotator : ExternalAnnotator<LyngExternalAnnotator.Input, Lyn
             }
         }
 
-        return Result(collectedInfo.modStamp, out, null)
+        val commentRanges = tokens.filter { it.kind == HighlightKind.Comment }.map { it.range.start until it.range.endExclusive }
+        val stringRanges = tokens.filter { it.kind == HighlightKind.String }.map { it.range.start until it.range.endExclusive }
+
+        return Result(collectedInfo.modStamp, out, null,
+            spellIdentifiers = spellIds,
+            spellComments = commentRanges,
+            spellStrings = stringRanges)
     }
 
+    /**
+     * Helper to add all segments of a type name to the spell index.
+     */
+    private fun addTypeNames(t: MiniTypeRef?, add: (net.sergeych.lyng.Pos, String) -> Unit) {
+        when (t) {
+            is MiniTypeName -> t.segments.forEach { add(it.range.start, it.name) }
+            is MiniGenericType -> {
+                addTypeNames(t.base, add)
+                t.args.forEach { addTypeNames(it, add) }
+            }
+
+            is MiniFunctionType -> {
+                addTypeNames(t.receiver, add)
+                t.params.forEach { addTypeNames(it, add) }
+                addTypeNames(t.returnType, add)
+            }
+
+            is MiniTypeVar -> {
+                // Type variables are declarations too
+                add(t.range.start, t.name)
+            }
+
+            null -> {}
+        }
+    }
 
     override fun apply(file: PsiFile, annotationResult: Result?, holder: AnnotationHolder) {
         if (annotationResult == null) return
@@ -339,6 +429,32 @@ class LyngExternalAnnotator : ExternalAnnotator<LyngExternalAnnotator.Input, Lyn
 
         val doc = file.viewProvider.document
 
+        // Store spell index for spell/grammar engines to consume (suspend until ready)
+        val ids = result.spellIdentifiers.map { TextRange(it.first, it.last + 1) }
+        val coms = result.spellComments.map { TextRange(it.first, it.last + 1) }
+        val strs = result.spellStrings.map { TextRange(it.first, it.last + 1) }
+        net.sergeych.lyng.idea.spell.LyngSpellIndex.store(file,
+            net.sergeych.lyng.idea.spell.LyngSpellIndex.Data(
+                modStamp = result.modStamp,
+                identifiers = ids,
+                comments = coms,
+                strings = strs
+            )
+        )
+
+        // Optional diagnostic overlay: visualize the ranges we will feed to spellcheckers
+        val settings = net.sergeych.lyng.idea.settings.LyngFormatterSettings.getInstance(file.project)
+        if (settings.debugShowSpellFeed) {
+            fun paint(r: TextRange, label: String) {
+                holder.newAnnotation(HighlightSeverity.WEAK_WARNING, "spell-feed: $label")
+                    .range(r)
+                    .create()
+            }
+            ids.forEach { paint(it, "id") }
+            coms.forEach { paint(it, "comment") }
+            if (settings.spellCheckStringLiterals) strs.forEach { paint(it, "string") }
+        }
+
         for (s in result.spans) {
             holder.newSilentAnnotation(HighlightSeverity.INFORMATION)
                 .range(TextRange(s.start, s.end))

lyng-idea/src/main/kotlin/net/sergeych/lyng/idea/grazie/AddToLyngDictionaryFix.kt

@@ -0,0 +1,43 @@
+/*
+ * Copyright 2025 Sergey S. Chernov real.sergeych@gmail.com
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+package net.sergeych.lyng.idea.grazie
+
+import com.intellij.codeInsight.daemon.DaemonCodeAnalyzer
+import com.intellij.codeInsight.intention.IntentionAction
+import com.intellij.openapi.editor.Editor
+import com.intellij.openapi.project.Project
+import com.intellij.psi.PsiFile
+import net.sergeych.lyng.idea.settings.LyngFormatterSettings
+
+/**
+ * Lightweight quick-fix that adds a word to the per-project Lyng dictionary.
+ */
+class AddToLyngDictionaryFix(private val word: String) : IntentionAction {
+    override fun getText(): String = "Add '$word' to Lyng dictionary"
+    override fun getFamilyName(): String = "Lyng Spelling"
+    override fun isAvailable(project: Project, editor: Editor?, file: PsiFile?): Boolean = word.isNotBlank()
+    override fun startInWriteAction(): Boolean = true
+
+    override fun invoke(project: Project, editor: Editor?, file: PsiFile?) {
+        val settings = LyngFormatterSettings.getInstance(project)
+        val learned = settings.learnedWords
+        learned.add(word.lowercase())
+        settings.learnedWords = learned
+        // Restart daemon to refresh highlights
+        if (file != null) DaemonCodeAnalyzer.getInstance(project).restart(file)
+    }
+}

lyng-idea/src/main/kotlin/net/sergeych/lyng/idea/grazie/LyngGrazieStrategy.kt

@@ -0,0 +1,137 @@
+/*
+ * Copyright 2026 Sergey S. Chernov real.sergeych@gmail.com
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+package net.sergeych.lyng.idea.grazie
+
+import com.intellij.grazie.grammar.strategy.GrammarCheckingStrategy
+import com.intellij.grazie.grammar.strategy.GrammarCheckingStrategy.TextDomain
+import com.intellij.ide.plugins.PluginManagerCore
+import com.intellij.openapi.diagnostic.Logger
+import com.intellij.openapi.extensions.PluginId
+import com.intellij.psi.PsiElement
+import net.sergeych.lyng.idea.highlight.LyngTokenTypes
+import net.sergeych.lyng.idea.settings.LyngFormatterSettings
+import net.sergeych.lyng.idea.spell.LyngSpellIndex
+
+/**
+ * Grazie/Natural Languages strategy for Lyng.
+ *
+ * - Comments: checked as natural language (TextDomain.COMMENTS)
+ * - String literals: optionally checked (setting), skipping printf-like specifiers via stealth ranges (TextDomain.LITERALS)
+ * - Identifiers (non-keywords): checked under TextDomain.CODE so "Process code" controls apply
+ * - Keywords: skipped
+ */
+class LyngGrazieStrategy : GrammarCheckingStrategy {
+
+    private val log = Logger.getInstance(LyngGrazieStrategy::class.java)
+    @Volatile private var loggedOnce = false
+    @Volatile private var loggedFirstMatch = false
+    private val seenTypes: MutableSet<String> = java.util.Collections.synchronizedSet(mutableSetOf())
+
+    private fun legacySpellcheckerInstalled(): Boolean =
+        PluginManagerCore.isPluginInstalled(PluginId.getId("com.intellij.spellchecker"))
+
+    // Regex for printf-style specifiers: %[flags][width][.precision][length]type
+    private val spec = Regex("%(?:[-+ #0]*(?:\\d+)?(?:\\.\\d+)?[a-zA-Z%])")
+
+    override fun isMyContextRoot(element: PsiElement): Boolean {
+        val type = element.node?.elementType
+        val settings = LyngFormatterSettings.getInstance(element.project)
+        val legacyPresent = legacySpellcheckerInstalled()
+        if (type != null && seenTypes.size < 10) {
+            val name = type.toString()
+            if (seenTypes.add(name)) {
+                log.info("LyngGrazieStrategy: saw PSI type=$name")
+            }
+        }
+        if (!loggedOnce) {
+            loggedOnce = true
+            log.info("LyngGrazieStrategy activated: legacyPresent=$legacyPresent, preferGrazieForCommentsAndLiterals=${settings.preferGrazieForCommentsAndLiterals}, spellCheckStringLiterals=${settings.spellCheckStringLiterals}, grazieChecksIdentifiers=${settings.grazieChecksIdentifiers}")
+        }
+
+        val file = element.containingFile ?: return false
+        val index = LyngSpellIndex.getUpToDate(file) ?: return false // Suspend until ready
+        // To ensure Grazie asks TextExtractor for all leafs, accept any Lyng element once index is ready.
+        // The extractor will decide per-range/domain what to actually provide.
+        if (!loggedFirstMatch) {
+            loggedFirstMatch = true
+            log.info("LyngGrazieStrategy: enabling Grazie on all Lyng elements (index ready)")
+        }
+        return true
+    }
+
+    override fun getContextRootTextDomain(root: PsiElement): TextDomain {
+        val type = root.node?.elementType
+        val settings = LyngFormatterSettings.getInstance(root.project)
+        val file = root.containingFile
+        val index = if (file != null) LyngSpellIndex.getUpToDate(file) else null
+        val r = root.textRange
+
+        return when (type) {
+            LyngTokenTypes.LINE_COMMENT, LyngTokenTypes.BLOCK_COMMENT -> TextDomain.COMMENTS
+            LyngTokenTypes.STRING -> if (settings.grazieTreatLiteralsAsComments) TextDomain.COMMENTS else TextDomain.LITERALS
+            LyngTokenTypes.IDENTIFIER -> {
+                // For Grazie-only reliability in 243+, route identifiers via COMMENTS when configured
+                if (settings.grazieTreatIdentifiersAsComments && index != null && r != null && index.identifiers.any { it.contains(r) })
+                    TextDomain.COMMENTS
+                else TextDomain.PLAIN_TEXT
+            }
+
+            else -> TextDomain.PLAIN_TEXT
+        }
+    }
+
+    // Note: do not override getLanguageSupport to keep compatibility with 243 API
+
+    override fun getStealthyRanges(root: PsiElement, text: CharSequence): java.util.LinkedHashSet<IntRange> {
+        val result = LinkedHashSet<IntRange>()
+        val type = root.node?.elementType
+        if (type == LyngTokenTypes.STRING) {
+            if (!shouldCheckLiterals(root)) {
+                // Hide the entire string when literals checking is disabled by settings
+                result += (0 until text.length)
+                return result
+            }
+            // Hide printf-like specifiers in strings
+            val (start, end) = stripQuotesBounds(text)
+            if (end > start) {
+                val content = text.subSequence(start, end)
+                for (m in spec.findAll(content)) {
+                    val ms = start + m.range.first
+                    val me = start + m.range.last
+                    result += (ms..me)
+                }
+                if (result.isNotEmpty()) {
+                    log.debug("LyngGrazieStrategy: hidden ${result.size} printf specifier ranges in string literal")
+                }
+            }
+        }
+        return result
+    }
+
+    override fun isEnabledByDefault(): Boolean = true
+
+    private fun shouldCheckLiterals(root: PsiElement): Boolean =
+        LyngFormatterSettings.getInstance(root.project).spellCheckStringLiterals
+
+    private fun stripQuotesBounds(text: CharSequence): Pair<Int, Int> {
+        if (text.length < 2) return 0 to text.length
+        val first = text.first()
+        val last = text.last()
+        return if ((first == '"' && last == '"') || (first == '\'' && last == '\''))
+            1 to (text.length - 1) else (0 to text.length)
+    }
+}

lyng-idea/src/main/kotlin/net/sergeych/lyng/idea/grazie/LyngTextExtractor.kt

@@ -19,29 +19,84 @@ package net.sergeych.lyng.idea.grazie
 import com.intellij.grazie.text.TextContent
 import com.intellij.grazie.text.TextContent.TextDomain
 import com.intellij.grazie.text.TextExtractor
+import com.intellij.openapi.diagnostic.Logger
 import com.intellij.psi.PsiElement
 import net.sergeych.lyng.idea.highlight.LyngTokenTypes
-import net.sergeych.lyng.idea.psi.LyngElementTypes
+import net.sergeych.lyng.idea.settings.LyngFormatterSettings
+import net.sergeych.lyng.idea.spell.LyngSpellIndex
 
 /**
- * Simplified TextExtractor for Lyng.
+ * Provides Grazie with extractable text for Lyng PSI elements.
- * Designates areas for Natural Languages (Grazie) to check.
+ * We return text for identifiers, comments, and (optionally) string literals.
+ * printf-like specifiers are filtered by the Grammar strategy via stealth ranges.
  */
 class LyngTextExtractor : TextExtractor() {
+    private val log = Logger.getInstance(LyngTextExtractor::class.java)
+    @Volatile private var loggedOnce = false
+    private val seen: MutableSet<String> = java.util.Collections.synchronizedSet(mutableSetOf())
+
     override fun buildTextContent(element: PsiElement, allowedDomains: Set<TextDomain>): TextContent? {
         val type = element.node?.elementType ?: return null
+        if (!loggedOnce) {
+            loggedOnce = true
+            log.info("LyngTextExtractor active; allowedDomains=${allowedDomains.joinToString()}")
+        }
+        val settings = LyngFormatterSettings.getInstance(element.project)
+        val file = element.containingFile
+        val index = if (file != null) LyngSpellIndex.getUpToDate(file) else null
+        val r = element.textRange
 
-        val domain = when (type) {
+        // Decide target domain by intersection with our MiniAst-driven index; prefer comments > strings > identifiers
+        var domain: TextDomain? = null
+        if (index != null && r != null) {
+            if (index.comments.any { it.intersects(r) }) domain = TextDomain.COMMENTS
+            else if (index.strings.any { it.intersects(r) } && settings.spellCheckStringLiterals) domain = TextDomain.LITERALS
+            else if (index.identifiers.any { it.contains(r) }) domain = if (settings.grazieTreatIdentifiersAsComments) TextDomain.COMMENTS else TextDomain.DOCUMENTATION
+        } else {
+            // Fallback to token type if index is not ready (rare timing), mostly for comments
+            domain = when (type) {
                 LyngTokenTypes.LINE_COMMENT, LyngTokenTypes.BLOCK_COMMENT -> TextDomain.COMMENTS
-            LyngTokenTypes.STRING -> TextDomain.LITERALS
+                else -> null
-            LyngElementTypes.NAME_IDENTIFIER,
-            LyngElementTypes.PARAMETER_NAME,
-            LyngElementTypes.ENUM_CONSTANT_NAME -> TextDomain.COMMENTS
-            else -> return null
             }
+        }
+        if (domain == null) return null
 
-        if (!allowedDomains.contains(domain)) return null
+        // If literals aren't requested but fallback is enabled, route strings as COMMENTS
-        
+        if (domain == TextDomain.LITERALS && !allowedDomains.contains(TextDomain.LITERALS) && settings.grazieTreatLiteralsAsComments) {
-        return TextContent.psiFragment(domain, element)
+            domain = TextDomain.COMMENTS
+        }
+        if (!allowedDomains.contains(domain)) {
+            if (seen.add("deny-${domain.name}")) {
+                log.info("LyngTextExtractor: domain ${domain.name} not in allowedDomains; skipping")
+            }
+            return null
+        }
+        return try {
+            // Try common factory names across versions
+            val methods = TextContent::class.java.methods.filter { it.name == "psiFragment" }
+            val built: TextContent? = when {
+                // Try psiFragment(PsiElement, TextDomain)
+                methods.any { it.parameterCount == 2 && it.parameterTypes[0].name.contains("PsiElement") } -> {
+                    val m = methods.first { it.parameterCount == 2 && it.parameterTypes[0].name.contains("PsiElement") }
+                    @Suppress("UNCHECKED_CAST")
+                    (m.invoke(null, element, domain) as? TextContent)?.also {
+                        if (seen.add("ok-${domain.name}")) log.info("LyngTextExtractor: provided ${domain.name} for ${type} via psiFragment(element, domain)")
+                    }
+                }
+                // Try psiFragment(TextDomain, PsiElement)
+                methods.any { it.parameterCount == 2 && it.parameterTypes[0].name.endsWith("TextDomain") } -> {
+                    val m = methods.first { it.parameterCount == 2 && it.parameterTypes[0].name.endsWith("TextDomain") }
+                    @Suppress("UNCHECKED_CAST")
+                    (m.invoke(null, domain, element) as? TextContent)?.also {
+                        if (seen.add("ok-${domain.name}")) log.info("LyngTextExtractor: provided ${domain.name} for ${type} via psiFragment(domain, element)")
+                    }
+                }
+                else -> null
+            }
+            built
+        } catch (e: Throwable) {
+            log.info("LyngTextExtractor: failed to build TextContent: ${e.javaClass.simpleName}: ${e.message}")
+            null
+        }
     }
 }

lyng-idea/src/main/kotlin/net/sergeych/lyng/idea/grazie/ReplaceWordFix.kt

@@ -0,0 +1,86 @@
+/*
+ * Copyright 2025 Sergey S. Chernov real.sergeych@gmail.com
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+package net.sergeych.lyng.idea.grazie
+
+import com.intellij.codeInsight.daemon.DaemonCodeAnalyzer
+import com.intellij.codeInsight.intention.IntentionAction
+import com.intellij.openapi.command.WriteCommandAction
+import com.intellij.openapi.editor.CaretModel
+import com.intellij.openapi.editor.Document
+import com.intellij.openapi.editor.Editor
+import com.intellij.openapi.project.Project
+import com.intellij.openapi.util.TextRange
+import com.intellij.psi.PsiFile
+
+/**
+ * Lightweight quick-fix to replace a misspelled word (subrange) with a suggested alternative.
+ * Works without the legacy Spell Checker. The replacement is applied directly to the file text.
+ */
+class ReplaceWordFix(
+    private val range: TextRange,
+    private val original: String,
+    private val replacementRaw: String
+) : IntentionAction {
+
+    override fun getText(): String = "Replace '$original' with '$replacementRaw'"
+    override fun getFamilyName(): String = "Lyng Spelling"
+    override fun isAvailable(project: Project, editor: Editor?, file: PsiFile?): Boolean =
+        editor != null && file != null && range.startOffset in 0..range.endOffset
+
+    override fun startInWriteAction(): Boolean = true
+
+    override fun invoke(project: Project, editor: Editor?, file: PsiFile?) {
+        if (editor == null) return
+        val doc: Document = editor.document
+        val safeRange = range.constrainTo(doc)
+        val current = doc.getText(safeRange)
+        // Preserve basic case style based on the original token
+        val replacement = adaptCaseStyle(current, replacementRaw)
+        WriteCommandAction.runWriteCommandAction(project, "Replace word", null, Runnable {
+            doc.replaceString(safeRange.startOffset, safeRange.endOffset, replacement)
+        }, file)
+        // Move caret to end of replacement for convenience
+        try {
+            val caret: CaretModel = editor.caretModel
+            caret.moveToOffset(safeRange.startOffset + replacement.length)
+        } catch (_: Throwable) {}
+        // Restart daemon to refresh highlights
+        if (file != null) DaemonCodeAnalyzer.getInstance(project).restart(file)
+    }
+
+    private fun TextRange.constrainTo(doc: Document): TextRange {
+        val start = startOffset.coerceIn(0, doc.textLength)
+        val end = endOffset.coerceIn(start, doc.textLength)
+        return TextRange(start, end)
+    }
+
+    private fun adaptCaseStyle(sample: String, suggestion: String): String {
+        if (suggestion.isEmpty()) return suggestion
+        return when {
+            sample.all { it.isUpperCase() } -> suggestion.uppercase()
+            // PascalCase / Capitalized single word
+            sample.firstOrNull()?.isUpperCase() == true && sample.drop(1).any { it.isLowerCase() } ->
+                suggestion.replaceFirstChar { if (it.isLowerCase()) it.titlecase() else it.toString() }
+            // snake_case -> lower
+            sample.contains('_') -> suggestion.lowercase()
+            // camelCase -> lower first
+            sample.firstOrNull()?.isLowerCase() == true && sample.any { it.isUpperCase() } ->
+                suggestion.replaceFirstChar { it.lowercase() }
+            else -> suggestion
+        }
+    }
+}

lyng-idea/src/main/kotlin/net/sergeych/lyng/idea/psi/LyngElementTypes.kt

@@ -1,27 +0,0 @@
-/*
- * Copyright 2026 Sergey S. Chernov real.sergeych@gmail.com
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- *
- */
-
-package net.sergeych.lyng.idea.psi
-
-import com.intellij.psi.tree.IElementType
-import net.sergeych.lyng.idea.LyngLanguage
-
-object LyngElementTypes {
-    val NAME_IDENTIFIER = IElementType("NAME_IDENTIFIER", LyngLanguage)
-    val PARAMETER_NAME = IElementType("PARAMETER_NAME", LyngLanguage)
-    val ENUM_CONSTANT_NAME = IElementType("ENUM_CONSTANT_NAME", LyngLanguage)
-}

lyng-idea/src/main/kotlin/net/sergeych/lyng/idea/psi/LyngParserDefinition.kt

@@ -1,5 +1,5 @@
 /*
- * Copyright 2026 Sergey S. Chernov real.sergeych@gmail.com
+ * Copyright 2025 Sergey S. Chernov real.sergeych@gmail.com
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -45,68 +45,7 @@ class LyngParserDefinition : ParserDefinition {
 
     override fun createParser(project: Project?): PsiParser = PsiParser { root, builder ->
         val mark: PsiBuilder.Marker = builder.mark()
-        var lastKeyword: String? = null
+        while (!builder.eof()) builder.advanceLexer()
-        var inEnum = false
-        var inParams = false
-        var parenDepth = 0
-        var braceDepth = 0
-
-        while (!builder.eof()) {
-            val type = builder.tokenType
-            val text = builder.tokenText
-
-            when (type) {
-                LyngTokenTypes.KEYWORD -> {
-                    lastKeyword = text
-                    if (text == "enum") inEnum = true
-                }
-                LyngTokenTypes.PUNCT -> {
-                    if (text == "(") {
-                        parenDepth++
-                        if (lastKeyword == "fun" || lastKeyword == "constructor" || lastKeyword == "init") inParams = true
-                    } else if (text == ")") {
-                        parenDepth--
-                        if (parenDepth == 0) inParams = false
-                    } else if (text == "{") {
-                        braceDepth++
-                    } else if (text == "}") {
-                        braceDepth--
-                        if (braceDepth == 0) inEnum = false
-                    }
-                    if (text != ".") lastKeyword = null
-                }
-                LyngTokenTypes.IDENTIFIER -> {
-                    val m = builder.mark()
-                    builder.advanceLexer()
-                    val nextType = builder.tokenType
-                    val isQualified = nextType == LyngTokenTypes.PUNCT && builder.tokenText == "."
-                    
-                    if (!isQualified) {
-                        when {
-                            lastKeyword in setOf("fun", "val", "var", "class", "enum", "object", "interface", "type", "property") -> {
-                                m.done(LyngElementTypes.NAME_IDENTIFIER)
-                            }
-                            inParams && parenDepth > 0 -> {
-                                m.done(LyngElementTypes.PARAMETER_NAME)
-                            }
-                            inEnum && braceDepth > 0 && parenDepth == 0 -> {
-                                m.done(LyngElementTypes.ENUM_CONSTANT_NAME)
-                            }
-                            else -> m.drop()
-                        }
-                    } else {
-                        m.drop()
-                    }
-                    lastKeyword = null
-                    continue
-                }
-                LyngTokenTypes.WHITESPACE, LyngTokenTypes.LINE_COMMENT, LyngTokenTypes.BLOCK_COMMENT -> {
-                    // keep lastKeyword
-                }
-                else -> lastKeyword = null
-            }
-            builder.advanceLexer()
-        }
         mark.done(root)
         builder.treeBuilt
     }

lyng-idea/src/main/kotlin/net/sergeych/lyng/idea/settings/LyngFormatterSettings.kt

@@ -1,5 +1,5 @@
 /*
- * Copyright 2026 Sergey S. Chernov real.sergeych@gmail.com
+ * Copyright 2025 Sergey S. Chernov real.sergeych@gmail.com
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -32,6 +32,24 @@ class LyngFormatterSettings(private val project: Project) : PersistentStateCompo
         var reindentClosedBlockOnEnter: Boolean = true,
         var reindentPastedBlocks: Boolean = true,
         var normalizeBlockCommentIndent: Boolean = false,
+        var spellCheckStringLiterals: Boolean = true,
+        // When Grazie/Natural Languages is present, prefer it for comments and literals (avoid legacy duplicates)
+        var preferGrazieForCommentsAndLiterals: Boolean = true,
+        // When Grazie is available, also check identifiers via Grazie.
+        // Default OFF because Grazie typically doesn't flag code identifiers; legacy Spellchecker is better for code.
+        var grazieChecksIdentifiers: Boolean = false,
+        // Grazie-only fallback: treat identifiers as comments domain so Grazie applies spelling rules
+        var grazieTreatIdentifiersAsComments: Boolean = true,
+        // Grazie-only fallback: treat string literals as comments domain when LITERALS domain is not requested
+        var grazieTreatLiteralsAsComments: Boolean = true,
+        // Debug helper: show the exact ranges we feed to Grazie/legacy as weak warnings
+        var debugShowSpellFeed: Boolean = false,
+        // Visuals: render Lyng typos using the standard Typo green underline styling
+        var showTyposWithGreenUnderline: Boolean = true,
+        // Enable lightweight quick-fixes (Replace..., Add to dictionary) without legacy Spell Checker
+        var offerLyngTypoQuickFixes: Boolean = true,
+        // Per-project learned words (do not flag again)
+        var learnedWords: MutableSet<String> = mutableSetOf(),
         // Experimental: enable Lyng autocompletion (can be disabled if needed)
         var enableLyngCompletionExperimental: Boolean = true,
     )
@@ -64,6 +82,42 @@ class LyngFormatterSettings(private val project: Project) : PersistentStateCompo
         get() = myState.normalizeBlockCommentIndent
         set(value) { myState.normalizeBlockCommentIndent = value }
 
+    var spellCheckStringLiterals: Boolean
+        get() = myState.spellCheckStringLiterals
+        set(value) { myState.spellCheckStringLiterals = value }
+
+    var preferGrazieForCommentsAndLiterals: Boolean
+        get() = myState.preferGrazieForCommentsAndLiterals
+        set(value) { myState.preferGrazieForCommentsAndLiterals = value }
+
+    var grazieChecksIdentifiers: Boolean
+        get() = myState.grazieChecksIdentifiers
+        set(value) { myState.grazieChecksIdentifiers = value }
+
+    var grazieTreatIdentifiersAsComments: Boolean
+        get() = myState.grazieTreatIdentifiersAsComments
+        set(value) { myState.grazieTreatIdentifiersAsComments = value }
+
+    var grazieTreatLiteralsAsComments: Boolean
+        get() = myState.grazieTreatLiteralsAsComments
+        set(value) { myState.grazieTreatLiteralsAsComments = value }
+
+    var debugShowSpellFeed: Boolean
+        get() = myState.debugShowSpellFeed
+        set(value) { myState.debugShowSpellFeed = value }
+
+    var showTyposWithGreenUnderline: Boolean
+        get() = myState.showTyposWithGreenUnderline
+        set(value) { myState.showTyposWithGreenUnderline = value }
+
+    var offerLyngTypoQuickFixes: Boolean
+        get() = myState.offerLyngTypoQuickFixes
+        set(value) { myState.offerLyngTypoQuickFixes = value }
+
+    var learnedWords: MutableSet<String>
+        get() = myState.learnedWords
+        set(value) { myState.learnedWords = value }
+
     var enableLyngCompletionExperimental: Boolean
         get() = myState.enableLyngCompletionExperimental
         set(value) { myState.enableLyngCompletionExperimental = value }

lyng-idea/src/main/kotlin/net/sergeych/lyng/idea/settings/LyngFormatterSettingsConfigurable.kt

@@ -1,5 +1,5 @@
 /*
- * Copyright 2026 Sergey S. Chernov real.sergeych@gmail.com
+ * Copyright 2025 Sergey S. Chernov real.sergeych@gmail.com
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -30,6 +30,14 @@ class LyngFormatterSettingsConfigurable(private val project: Project) : Configur
     private var reindentClosedBlockCb: JCheckBox? = null
     private var reindentPasteCb: JCheckBox? = null
     private var normalizeBlockCommentIndentCb: JCheckBox? = null
+    private var spellCheckLiteralsCb: JCheckBox? = null
+    private var preferGrazieCommentsLiteralsCb: JCheckBox? = null
+    private var grazieChecksIdentifiersCb: JCheckBox? = null
+    private var grazieIdsAsCommentsCb: JCheckBox? = null
+    private var grazieLiteralsAsCommentsCb: JCheckBox? = null
+    private var debugShowSpellFeedCb: JCheckBox? = null
+    private var showTyposGreenCb: JCheckBox? = null
+    private var offerQuickFixesCb: JCheckBox? = null
     private var enableCompletionCb: JCheckBox? = null
 
     override fun getDisplayName(): String = "Lyng Formatter"
@@ -42,6 +50,14 @@ class LyngFormatterSettingsConfigurable(private val project: Project) : Configur
         reindentClosedBlockCb = JCheckBox("Reindent enclosed block on Enter after '}'")
         reindentPasteCb = JCheckBox("Reindent pasted blocks (align pasted code to current indent)")
         normalizeBlockCommentIndentCb = JCheckBox("Normalize block comment indentation [experimental]")
+        spellCheckLiteralsCb = JCheckBox("Spell check string literals (skip % specifiers like %s, %d, %-12s)")
+        preferGrazieCommentsLiteralsCb = JCheckBox("Prefer Natural Languages/Grazie for comments and string literals (avoid duplicates)")
+        grazieChecksIdentifiersCb = JCheckBox("Check identifiers via Natural Languages/Grazie when available")
+        grazieIdsAsCommentsCb = JCheckBox("Natural Languages/Grazie: treat identifiers as comments (forces spelling checks in 2024.3)")
+        grazieLiteralsAsCommentsCb = JCheckBox("Natural Languages/Grazie: treat string literals as comments when literals are not processed")
+        debugShowSpellFeedCb = JCheckBox("Debug: show spell-feed ranges (weak warnings)")
+        showTyposGreenCb = JCheckBox("Show Lyng typos with green underline (TYPO styling)")
+        offerQuickFixesCb = JCheckBox("Offer Lyng typo quick fixes (Replace…, Add to dictionary) without Spell Checker")
         enableCompletionCb = JCheckBox("Enable Lyng autocompletion (experimental)")
 
         // Tooltips / short help
@@ -50,12 +66,27 @@ class LyngFormatterSettingsConfigurable(private val project: Project) : Configur
         reindentClosedBlockCb?.toolTipText = "On Enter after a closing '}', reindent the just-closed {…} block using formatter rules."
         reindentPasteCb?.toolTipText = "When caret is in leading whitespace, reindent the pasted text and align it to the caret's indent."
         normalizeBlockCommentIndentCb?.toolTipText = "Experimental: normalize indentation inside /* … */ comments (code is not modified)."
+        preferGrazieCommentsLiteralsCb?.toolTipText = "When ON and Natural Languages/Grazie is installed, comments and string literals are checked by Grazie. Turn OFF to force legacy Spellchecker to check them."
+        grazieChecksIdentifiersCb?.toolTipText = "When ON and Natural Languages/Grazie is installed, identifiers (non-keywords) are checked by Grazie too."
+        grazieIdsAsCommentsCb?.toolTipText = "Grazie-only fallback: route identifiers as COMMENTS domain so Grazie applies spelling in 2024.3."
+        grazieLiteralsAsCommentsCb?.toolTipText = "Grazie-only fallback: when Grammar doesn't process literals, route strings as COMMENTS so they are checked."
+        debugShowSpellFeedCb?.toolTipText = "Show the exact ranges we feed to spellcheckers (ids/comments/strings) as weak warnings."
+        showTyposGreenCb?.toolTipText = "Render Lyng typos using the platform's green TYPO underline instead of generic warnings."
+        offerQuickFixesCb?.toolTipText = "Provide lightweight Replace… and Add to dictionary quick-fixes without requiring the legacy Spell Checker."
         enableCompletionCb?.toolTipText = "Turn on/off the lightweight Lyng code completion (BASIC)."
         p.add(spacingCb)
         p.add(wrappingCb)
         p.add(reindentClosedBlockCb)
         p.add(reindentPasteCb)
         p.add(normalizeBlockCommentIndentCb)
+        p.add(spellCheckLiteralsCb)
+        p.add(preferGrazieCommentsLiteralsCb)
+        p.add(grazieChecksIdentifiersCb)
+        p.add(grazieIdsAsCommentsCb)
+        p.add(grazieLiteralsAsCommentsCb)
+        p.add(debugShowSpellFeedCb)
+        p.add(showTyposGreenCb)
+        p.add(offerQuickFixesCb)
         p.add(enableCompletionCb)
         panel = p
         reset()
@@ -69,6 +100,14 @@ class LyngFormatterSettingsConfigurable(private val project: Project) : Configur
                 reindentClosedBlockCb?.isSelected != s.reindentClosedBlockOnEnter ||
                 reindentPasteCb?.isSelected != s.reindentPastedBlocks ||
                 normalizeBlockCommentIndentCb?.isSelected != s.normalizeBlockCommentIndent ||
+                spellCheckLiteralsCb?.isSelected != s.spellCheckStringLiterals ||
+                preferGrazieCommentsLiteralsCb?.isSelected != s.preferGrazieForCommentsAndLiterals ||
+                grazieChecksIdentifiersCb?.isSelected != s.grazieChecksIdentifiers ||
+                grazieIdsAsCommentsCb?.isSelected != s.grazieTreatIdentifiersAsComments ||
+                grazieLiteralsAsCommentsCb?.isSelected != s.grazieTreatLiteralsAsComments ||
+                debugShowSpellFeedCb?.isSelected != s.debugShowSpellFeed ||
+                showTyposGreenCb?.isSelected != s.showTyposWithGreenUnderline ||
+                offerQuickFixesCb?.isSelected != s.offerLyngTypoQuickFixes ||
                 enableCompletionCb?.isSelected != s.enableLyngCompletionExperimental
     }
 
@@ -79,6 +118,14 @@ class LyngFormatterSettingsConfigurable(private val project: Project) : Configur
         s.reindentClosedBlockOnEnter = reindentClosedBlockCb?.isSelected == true
         s.reindentPastedBlocks = reindentPasteCb?.isSelected == true
         s.normalizeBlockCommentIndent = normalizeBlockCommentIndentCb?.isSelected == true
+        s.spellCheckStringLiterals = spellCheckLiteralsCb?.isSelected == true
+        s.preferGrazieForCommentsAndLiterals = preferGrazieCommentsLiteralsCb?.isSelected == true
+        s.grazieChecksIdentifiers = grazieChecksIdentifiersCb?.isSelected == true
+        s.grazieTreatIdentifiersAsComments = grazieIdsAsCommentsCb?.isSelected == true
+        s.grazieTreatLiteralsAsComments = grazieLiteralsAsCommentsCb?.isSelected == true
+        s.debugShowSpellFeed = debugShowSpellFeedCb?.isSelected == true
+        s.showTyposWithGreenUnderline = showTyposGreenCb?.isSelected == true
+        s.offerLyngTypoQuickFixes = offerQuickFixesCb?.isSelected == true
         s.enableLyngCompletionExperimental = enableCompletionCb?.isSelected == true
     }
 
@@ -89,6 +136,14 @@ class LyngFormatterSettingsConfigurable(private val project: Project) : Configur
         reindentClosedBlockCb?.isSelected = s.reindentClosedBlockOnEnter
         reindentPasteCb?.isSelected = s.reindentPastedBlocks
         normalizeBlockCommentIndentCb?.isSelected = s.normalizeBlockCommentIndent
+        spellCheckLiteralsCb?.isSelected = s.spellCheckStringLiterals
+        preferGrazieCommentsLiteralsCb?.isSelected = s.preferGrazieForCommentsAndLiterals
+        grazieChecksIdentifiersCb?.isSelected = s.grazieChecksIdentifiers
+        grazieIdsAsCommentsCb?.isSelected = s.grazieTreatIdentifiersAsComments
+        grazieLiteralsAsCommentsCb?.isSelected = s.grazieTreatLiteralsAsComments
+        debugShowSpellFeedCb?.isSelected = s.debugShowSpellFeed
+        showTyposGreenCb?.isSelected = s.showTyposWithGreenUnderline
+        offerQuickFixesCb?.isSelected = s.offerLyngTypoQuickFixes
         enableCompletionCb?.isSelected = s.enableLyngCompletionExperimental
     }
 }

lyng-idea/src/main/kotlin/net/sergeych/lyng/idea/spell/LyngSpellIndex.kt

@@ -0,0 +1,50 @@
+/*
+ * Copyright 2025 Sergey S. Chernov real.sergeych@gmail.com
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+package net.sergeych.lyng.idea.spell
+
+import com.intellij.openapi.diagnostic.Logger
+import com.intellij.openapi.util.Key
+import com.intellij.openapi.util.TextRange
+import com.intellij.psi.PsiFile
+
+/**
+ * Per-file cached spellcheck index built from MiniAst-based highlighting and the lynglib highlighter.
+ * It exposes identifier, comment, and string literal ranges. Strategies should suspend until data is ready.
+ */
+object LyngSpellIndex {
+    private val LOG = Logger.getInstance(LyngSpellIndex::class.java)
+
+    data class Data(
+        val modStamp: Long,
+        val identifiers: List<TextRange>,
+        val comments: List<TextRange>,
+        val strings: List<TextRange>,
+    )
+
+    private val KEY: Key<Data> = Key.create("LYNG_SPELL_INDEX")
+
+    fun getUpToDate(file: PsiFile): Data? {
+        val doc = file.viewProvider.document ?: return null
+        val d = file.getUserData(KEY) ?: return null
+        return if (d.modStamp == doc.modificationStamp) d else null
+    }
+
+    fun store(file: PsiFile, data: Data) {
+        file.putUserData(KEY, data)
+        LOG.info("LyngSpellIndex built: ids=${data.identifiers.size}, comments=${data.comments.size}, strings=${data.strings.size}")
+    }
+}

lyng-idea/src/main/kotlin/net/sergeych/lyng/idea/spell/LyngSpellcheckingStrategy.kt

@@ -20,11 +20,10 @@ import com.intellij.psi.PsiElement
 import com.intellij.spellchecker.tokenizer.SpellcheckingStrategy
 import com.intellij.spellchecker.tokenizer.Tokenizer
 import net.sergeych.lyng.idea.highlight.LyngTokenTypes
-import net.sergeych.lyng.idea.psi.LyngElementTypes
 
 /**
  * Standard IntelliJ spellchecking strategy for Lyng.
- * Uses the simplified PSI structure to identify declarations.
+ * It uses the MiniAst-driven [LyngSpellIndex] to limit identifier checks to declarations only.
  */
 class LyngSpellcheckingStrategy : SpellcheckingStrategy() {
     override fun getTokenizer(element: PsiElement?): Tokenizer<*> {
@@ -32,9 +31,21 @@ class LyngSpellcheckingStrategy : SpellcheckingStrategy() {
         return when (type) {
             LyngTokenTypes.LINE_COMMENT, LyngTokenTypes.BLOCK_COMMENT -> TEXT_TOKENIZER
             LyngTokenTypes.STRING -> TEXT_TOKENIZER
-            LyngElementTypes.NAME_IDENTIFIER,
+            LyngTokenTypes.IDENTIFIER -> {
-            LyngElementTypes.PARAMETER_NAME,
+                // We use standard NameIdentifierOwner/PsiNamedElement-based logic
-            LyngElementTypes.ENUM_CONSTANT_NAME -> TEXT_TOKENIZER
+                // if it's a declaration. Argument names, class names, etc. are PSI-based.
+                // However, our PSI is currently very minimal (ASTWrapperPsiElement).
+                // So we stick to the index but ensure it is robustly filled.
+                val file = element.containingFile
+                val index = LyngSpellIndex.getUpToDate(file)
+                if (index != null) {
+                    val range = element.textRange
+                    if (index.identifiers.any { it.contains(range) }) {
+                        return TEXT_TOKENIZER
+                    }
+                }
+                EMPTY_TOKENIZER
+            }
             else -> super.getTokenizer(element)
         }
     }

lyng-idea/src/main/resources/META-INF/grazie-bundled.xml

@@ -1,5 +1,5 @@
 <!--
-  ~ Copyright 2026 Sergey S. Chernov real.sergeych@gmail.com
+  ~ Copyright 2025 Sergey S. Chernov real.sergeych@gmail.com
   ~
   ~ Licensed under the Apache License, Version 2.0 (the "License");
   ~ you may not use this file except in compliance with the License.
@@ -20,6 +20,8 @@
 -->
 <idea-plugin>
     <extensions defaultExtensionNs="com.intellij">
+        <grazie.grammar.strategy language="Lyng"
+                                  implementationClass="net.sergeych.lyng.idea.grazie.LyngGrazieStrategy"/>
         <!-- Provide text extraction for Lyng PSI so Grazie (bundled Natural Languages) can check content -->
         <grazie.textExtractor language="Lyng"
                               implementationClass="net.sergeych.lyng.idea.grazie.LyngTextExtractor"/>

lyng-idea/src/main/resources/META-INF/grazie-lite.xml

@@ -1,5 +1,5 @@
 <!--
-  ~ Copyright 2026 Sergey S. Chernov real.sergeych@gmail.com
+  ~ Copyright 2025 Sergey S. Chernov real.sergeych@gmail.com
   ~
   ~ Licensed under the Apache License, Version 2.0 (the "License");
   ~ you may not use this file except in compliance with the License.
@@ -21,6 +21,8 @@
 -->
 <idea-plugin>
     <extensions defaultExtensionNs="com.intellij">
+        <grazie.grammar.strategy language="Lyng"
+                                  implementationClass="net.sergeych.lyng.idea.grazie.LyngGrazieStrategy"/>
         <!-- Provide text extraction for Lyng PSI so Grazie can actually check content -->
         <grazie.textExtractor language="Lyng"
                               implementationClass="net.sergeych.lyng.idea.grazie.LyngTextExtractor"/>

lynglib/src/commonMain/kotlin/net/sergeych/lyng/obj/ObjException.kt

@@ -112,7 +112,7 @@ open class ObjException(
                             )
                         } else {
                             // Fallback textual entry if StackTraceEntry class is not available in this scope
-                            result.list += ObjString("#${pos.source.objSourceName}:${pos.line+1}:${pos.column+1}: ${pos.currentLine}")
+                            result.list += ObjString("?${pos.source.objSourceName}:${pos.line+1}:${pos.column+1}: ${pos.currentLine}")
                         }
                         lastPos = pos
                     }

lynglib/stdlib/lyng/root.lyng

@@ -266,8 +266,12 @@ class StackTraceEntry(
 /* Print this exception and its stack trace to standard output. */
 fun Exception.printStackTrace() {
     println(this)
-    for( entry in stackTrace )
+    var lastEntry = null
+    for( entry in stackTrace ) {
+        if( lastEntry == null || lastEntry !is StackTraceEntry || lastEntry.line != entry.line )
             println("\tat "+entry.toString())
+        lastEntry = entry
+    }
 }
 
 /* Compile this string into a regular expression. */