feat: String escape sequence highlighting

CHANGELOG.md

@@ -17,6 +17,11 @@ Changelog structure reference:
 
 ## [Unreleased]
 
+### Added
+
+- Zig
+  - Syntax highlighting for escape sequences in strings
+
 ### Fixed
 
 - Zig

build.gradle.kts

@@ -2,6 +2,7 @@ import de.undercouch.gradle.tasks.download.Download
 import groovy.xml.XmlParser
 import org.jetbrains.changelog.Changelog
 import org.jetbrains.changelog.markdownToHTML
+import org.jetbrains.grammarkit.tasks.GenerateLexerTask
 import org.jetbrains.intellij.platform.gradle.IntelliJPlatformType
 import org.jetbrains.intellij.platform.gradle.tasks.PatchPluginXmlTask
 import org.jetbrains.intellij.platform.gradle.tasks.PublishPluginTask
@@ -204,11 +205,21 @@ project(":zig") {
             targetOutputDir = file("${grammarKitGenDir}/lexer/${rootPackagePath}/zig/lexer")
         }
 
+        register<GenerateLexerTask>("generateStringLexer") {
+            sourceFile = file("src/main/grammar/ZigString.flex")
+            targetOutputDir = file("${grammarKitGenDir}/lexer/${rootPackagePath}/zig/stringlexer")
+            purgeOldFiles = true
+        }
+
         generateParser {
             sourceFile = file("src/main/grammar/Zig.bnf")
             pathToParser = "${rootPackagePath}/zig/psi/ZigParser.java"
             pathToPsiRoot = "${rootPackagePath}/zig/psi"
         }
+
+        named("generateGrammars") {
+            dependsOn("generateStringLexer")
+        }
     }
 }
 

modules/zig/src/main/grammar/Zig.flex

@@ -90,8 +90,8 @@ char_char= {mb_utf8_literal}
          | {char_escape}
          | {ascii_char_not_nl_slash_squote}
 
-string_char= {char_escape}
+string_char= \\ .
-           | [^\\\"\n]
+           | [^\"\n]
 
 all_nl_wrap=[^\n]* [ \n]*
 all_nl_nowrap=[^\n]* \n

modules/zig/src/main/grammar/ZigString.flex

@@ -0,0 +1,60 @@
+/*
+ * Copyright 2023-2024 FalsePattern
+ *
+ * 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 com.falsepattern.zigbrains.zig.stringlexer;
+
+import com.intellij.lexer.FlexLexer;
+import com.intellij.psi.tree.IElementType;
+
+import static com.intellij.psi.TokenType.WHITE_SPACE;
+import static com.intellij.psi.TokenType.BAD_CHARACTER;
+import static com.falsepattern.zigbrains.zig.psi.ZigTypes.*;
+import static com.intellij.psi.StringEscapesTokenTypes.*;
+
+%%
+
+%public
+%class ZigStringLexer
+%implements FlexLexer
+%function advance
+%type IElementType
+
+hex=[0-9a-fA-F]
+
+char_escape_unicode= "\\x" {hex} {hex} | "\\u{" {hex}+ "}"
+char_escape_unicode_invalid= "\\x" | "\\u"
+
+char_escape_single_valid= "\\" [nr\\t'\"]
+char_escape_single_invalid= "\\" [^nr\\t'\"]
+
+non_escape= [^\\\"\n]
+
+
+%state STR
+%%
+
+
+<YYINITIAL> {
+      "\"" { yybegin(STR); return STRING_LITERAL_SINGLE; }
+      [^]  { return STRING_LITERAL_SINGLE; }
+}
+
+<STR> {
+      {char_escape_unicode} { return VALID_STRING_ESCAPE_TOKEN; }
+      {char_escape_unicode_invalid} { return INVALID_UNICODE_ESCAPE_TOKEN; }
+      {char_escape_single_valid} { return VALID_STRING_ESCAPE_TOKEN; }
+      {char_escape_single_invalid} { return INVALID_CHARACTER_ESCAPE_TOKEN; }
+      [^] { return STRING_LITERAL_SINGLE; }
+}

modules/zig/src/main/java/com/falsepattern/zigbrains/zig/highlighter/ZigColorSettingsPage.java

@@ -63,6 +63,9 @@ public class ZigColorSettingsPage implements ColorSettingsPage {
                     new AttributesDescriptor("Property//Declaration", ZigSyntaxHighlighter.PROPERTY_DECL),
                     new AttributesDescriptor("Property//Reference", ZigSyntaxHighlighter.PROPERTY_REF),
                     new AttributesDescriptor("String", ZigSyntaxHighlighter.STRING),
+                    new AttributesDescriptor("String//Escape", ZigSyntaxHighlighter.STRING_ESC_V),
+                    new AttributesDescriptor("String//Escape//Invalid char", ZigSyntaxHighlighter.STRING_ESC_I_C),
+                    new AttributesDescriptor("String//Escape//Invalid unicode", ZigSyntaxHighlighter.STRING_ESC_I_U),
                     new AttributesDescriptor("Struct//Declaration", ZigSyntaxHighlighter.STRUCT_DECL),
                     new AttributesDescriptor("Struct//Reference", ZigSyntaxHighlighter.STRUCT_REF),
                     new AttributesDescriptor("Type//Declaration", ZigSyntaxHighlighter.TYPE_DECL),

modules/zig/src/main/java/com/falsepattern/zigbrains/zig/highlighter/ZigSyntaxHighlighter.java

@@ -16,6 +16,7 @@
 
 package com.falsepattern.zigbrains.zig.highlighter;
 
+import com.falsepattern.zigbrains.zig.lexer.ZigHighlightingLexer;
 import com.falsepattern.zigbrains.zig.lexer.ZigLexerAdapter;
 import com.falsepattern.zigbrains.zig.psi.ZigTypes;
 import com.intellij.lexer.Lexer;
@@ -23,6 +24,7 @@ import com.intellij.openapi.editor.DefaultLanguageHighlighterColors;
 import com.intellij.openapi.editor.HighlighterColors;
 import com.intellij.openapi.editor.colors.TextAttributesKey;
 import com.intellij.openapi.fileTypes.SyntaxHighlighterBase;
+import com.intellij.psi.StringEscapesTokenTypes;
 import com.intellij.psi.TokenType;
 import com.intellij.psi.tree.IElementType;
 import com.redhat.devtools.lsp4ij.features.semanticTokens.SemanticTokensHighlightingColors;
@@ -48,7 +50,7 @@ public class ZigSyntaxHighlighter extends SyntaxHighlighterBase {
             ERROR_TAG_REF     = createKey("ERROR_TAG"          , ERROR_TAG_DECL                                         ),
             PROPERTY_DECL     = createKey("PROPERTY_DECL"      , SemanticTokensHighlightingColors.PROPERTY              ),
             PROPERTY_REF      = createKey("PROPERTY"           , PROPERTY_DECL                                          ),
-            FUNCTION_DECL     = createKey("FUNCTION_DECL"      , SemanticTokensHighlightingColors.FUNCTION_DECLARATION),
+            FUNCTION_DECL     = createKey("FUNCTION_DECL"      , SemanticTokensHighlightingColors.FUNCTION_DECLARATION  ),
             FUNCTION_DECL_GEN = createKey("FUNCTION_DECL_GEN"  , FUNCTION_DECL                                          ),
             FUNCTION_REF      = createKey("FUNCTION"           , SemanticTokensHighlightingColors.FUNCTION              ),
             FUNCTION_REF_GEN  = createKey("FUNCTION_GEN"       , FUNCTION_REF                                           ),
@@ -65,6 +67,9 @@ public class ZigSyntaxHighlighter extends SyntaxHighlighterBase {
             OPERATOR          = createKey("OPERATOR"           , SemanticTokensHighlightingColors.OPERATOR              ),
             PARAMETER         = createKey("PARAMETER"          , SemanticTokensHighlightingColors.PARAMETER             ),
             STRING            = createKey("STRING"             , SemanticTokensHighlightingColors.STRING                ),
+            STRING_ESC_V      = createKey("STRING_ESC_V"       , DefaultLanguageHighlighterColors.VALID_STRING_ESCAPE   ),
+            STRING_ESC_I_C    = createKey("STRING_ESC_I_C"     , DefaultLanguageHighlighterColors.INVALID_STRING_ESCAPE ),
+            STRING_ESC_I_U    = createKey("STRING_ESC_I_U"     , DefaultLanguageHighlighterColors.INVALID_STRING_ESCAPE ),
             STRUCT_DECL       = createKey("STRUCT_DECL"        , SemanticTokensHighlightingColors.CLASS_DECLARATION     ),
             STRUCT_REF        = createKey("STRUCT"             , SemanticTokensHighlightingColors.CLASS                 ),
             TYPE_DECL         = createKey("TYPE_DECL"          , SemanticTokensHighlightingColors.CLASS_DECLARATION     ),
@@ -102,6 +107,9 @@ public class ZigSyntaxHighlighter extends SyntaxHighlighterBase {
         }
         addMapping(BUILTIN, ZigTypes.BUILTINIDENTIFIER);
         addMapping(STRING, ZigTypes.STRING_LITERAL_SINGLE, ZigTypes.STRING_LITERAL_MULTI);
+        addMapping(STRING_ESC_V, StringEscapesTokenTypes.VALID_STRING_ESCAPE_TOKEN);
+        addMapping(STRING_ESC_I_C, StringEscapesTokenTypes.INVALID_CHARACTER_ESCAPE_TOKEN);
+        addMapping(STRING_ESC_I_U, StringEscapesTokenTypes.INVALID_UNICODE_ESCAPE_TOKEN);
         addMapping(BAD_CHAR, TokenType.BAD_CHARACTER);
         addMapping(NUMBER, ZigTypes.INTEGER, ZigTypes.FLOAT);
         addMapping(CHAR, ZigTypes.CHAR_LITERAL);
@@ -120,7 +128,7 @@ public class ZigSyntaxHighlighter extends SyntaxHighlighterBase {
 
     @Override
     public @NotNull Lexer getHighlightingLexer() {
-        return new ZigLexerAdapter();
+        return new ZigHighlightingLexer();
     }
 
     @Override

modules/zig/src/main/java/com/falsepattern/zigbrains/zig/lexer/ZigHighlightingLexer.java

@@ -0,0 +1,18 @@
+package com.falsepattern.zigbrains.zig.lexer;
+
+import com.falsepattern.zigbrains.zig.psi.ZigTypes;
+import com.intellij.lexer.FlexAdapter;
+import com.intellij.lexer.LayeredLexer;
+import com.intellij.lexer.MergingLexerAdapter;
+import com.intellij.psi.tree.IElementType;
+import com.intellij.psi.tree.TokenSet;
+import lombok.val;
+
+public class ZigHighlightingLexer extends LayeredLexer {
+    public ZigHighlightingLexer() {
+        super(new ZigLexerAdapter());
+        val stringLexer = new MergingLexerAdapter(new FlexAdapter(new com.falsepattern.zigbrains.zig.stringlexer.ZigStringLexer(null)), TokenSet.create(
+                ZigTypes.STRING_LITERAL_SINGLE));
+        registerSelfStoppingLayer(stringLexer, new IElementType[]{ZigTypes.STRING_LITERAL_SINGLE}, IElementType.EMPTY_ARRAY);
+    }
+}