Semantic highlighting

library/src/main/kotlin/com/strumenta/kolasu/languageserver/KolasuServer.kt

@@ -81,6 +81,10 @@ import org.eclipse.lsp4j.services.LanguageClientAware
 import org.eclipse.lsp4j.services.LanguageServer
 import org.eclipse.lsp4j.services.TextDocumentService
 import org.eclipse.lsp4j.services.WorkspaceService
+import org.eclipse.lsp4j.SemanticTokensWithRegistrationOptions
+import org.eclipse.lsp4j.SemanticTokensLegend
+import org.eclipse.lsp4j.SemanticTokensParams
+import org.eclipse.lsp4j.SemanticTokens
 import java.io.File
 import java.io.InputStream
 import java.io.OutputStream
@@ -91,6 +95,10 @@ import java.nio.file.Paths
 import java.util.UUID
 import java.util.concurrent.CompletableFuture
 import kotlin.system.exitProcess
+import com.strumenta.kolasu.languageserver.semanticHighlighting.SemanticTokenType;
+import com.strumenta.kolasu.languageserver.semanticHighlighting.SemanticTokenModifier;
+import com.strumenta.kolasu.languageserver.semanticHighlighting.encode
+import com.strumenta.kolasu.languageserver.semanticHighlighting.SemanticToken
 
 open class KolasuServer<T : Node>(
     protected open val parser: ASTParser<T>?,
@@ -155,6 +163,11 @@ open class KolasuServer<T : Node>(
         capabilities.setDefinitionProvider(this.enableDefinitionCapability)
         capabilities.setReferencesProvider(this.enableReferencesCapability)
 
+        capabilities.semanticTokensProvider = SemanticTokensWithRegistrationOptions().apply {
+            legend = SemanticTokensLegend(SemanticTokenType.values().map { it.legendName }, SemanticTokenModifier.values().map { it.legendName });
+            full = Either.forLeft(true)
+        }
+
         return CompletableFuture.completedFuture(InitializeResult(capabilities))
     }
 
@@ -567,6 +580,15 @@ open class KolasuServer<T : Node>(
         val reader = DirectoryReader.open(FSDirectory.open(indexPath))
         indexSearcher = IndexSearcher(reader)
     }
+
+    override fun semanticTokensFull(params: SemanticTokensParams): CompletableFuture<SemanticTokens> {
+        val ast = files[params.textDocument.uri]?.root ?: return CompletableFuture.completedFuture(SemanticTokens())
+        val code = files[params.textDocument.uri]?.code ?: return CompletableFuture.completedFuture(SemanticTokens())
+        val tokens = semanticTokens(ast)
+        return CompletableFuture.completedFuture(encode(tokens, code))
+    }
+
+    open fun semanticTokens(ast: T): List<SemanticToken> = listOf()
 }
 
 interface CodeGenerator<T : Node> {

library/src/main/kotlin/com/strumenta/kolasu/languageserver/semanticHighlighting/SemanticToken.kt

@@ -0,0 +1,29 @@
+package com.strumenta.kolasu.languageserver.semanticHighlighting
+
+import com.strumenta.kolasu.model.Point
+import com.strumenta.kolasu.model.Position
+import org.eclipse.lsp4j.SemanticTokens
+
+data class SemanticToken(val position: Position, val type: SemanticTokenType, val modifiers: List<SemanticTokenModifier>)
+
+fun encode(tokens: List<SemanticToken>, code: String): SemanticTokens {
+    // Create synthetic token at start to compute relative positions from
+    var lastToken = SemanticToken(Position(Point(1, 0), Point(1, 0)), SemanticTokenType.TYPE, listOf())
+
+    val data = mutableListOf<Int>()
+    for (token in tokens) {
+        val deltaLine = token.position.start.line - (lastToken.position.start.line)
+        val deltaStart = if (token.position.start.line == lastToken.position.start.line) {
+            token.position.start.column - lastToken.position.start.column
+        } else {
+            token.position.start.column
+        }
+        val length = token.position.length(code)
+        val tokenType = token.type.ordinal
+        val tokenModifiers = token.modifiers.sumOf { it.bit }
+
+        data.addAll(listOf(deltaLine, deltaStart, length, tokenType, tokenModifiers))
+        lastToken = token
+    }
+    return SemanticTokens(data)
+}

library/src/main/kotlin/com/strumenta/kolasu/languageserver/semanticHighlighting/SemanticTokenModifier.kt

@@ -0,0 +1,14 @@
+package com.strumenta.kolasu.languageserver.semanticHighlighting
+
+enum class SemanticTokenModifier(val legendName: String, val bit: Int) {
+	DECLARATION("declaration", 1),
+	DEFINITION("definition", 2),
+	READ_ONLY("readonly", 4),
+	STATIC("static", 8),
+	DEPRECATED("deprecated", 16),
+	ABSTRACT("abstract", 32),
+	ASYNCHRONOUS("async", 64),
+	MODIFICATION("modification", 128),
+	DOCUMENTATION("documentation", 256),
+	DEFAULT_LIBRARY("defaultLibrary", 512)
+}

library/src/main/kotlin/com/strumenta/kolasu/languageserver/semanticHighlighting/SemanticTokenType.kt

@@ -0,0 +1,27 @@
+package com.strumenta.kolasu.languageserver.semanticHighlighting
+
+enum class SemanticTokenType (val legendName: String) {
+    NAMESPACE("namespace"),
+    CLASS("class"),
+    ENUM("enum"),
+    INTERFACE("interface"),
+    STRUCT("struct"),
+    TYPE_PARAMETER("typeParameter"),
+    TYPE("type"),
+    PARAMETER("parameter"),
+    VARIABLE("variable"),
+    PROPERTY("property"),
+    ENUM_MEMBER("enumMember"),
+    DECORATOR("decorator"),
+    EVENT("event"),
+    FUNCTION("function"),
+    METHOD("method"),
+    MACRO("macro"),
+    LABEL("label"),
+    COMMENT("comment"),
+    STRING("string"),
+    KEYWORD("keyword"),
+    NUMBER("number"),
+    REGULAR_EXPRESSION("regexp"),
+    OPERATOR("operator")
+}