Change JSON grammar to allow usage of any literals and identifiers as property keys

json/gen/com/intellij/json/JsonParser.java

@@ -297,14 +297,13 @@ public class JsonParser implements PsiParser {
   }
 
   /* ********************************************************** */
-  // string_literal (':' value)
+  // property_name (':' value)
   public static boolean property(PsiBuilder builder_, int level_) {
     if (!recursion_guard_(builder_, level_, "property")) return false;
-    if (!nextTokenIs(builder_, "<property>", DOUBLE_QUOTED_STRING, SINGLE_QUOTED_STRING)) return false;
     boolean result_;
     boolean pinned_;
     Marker marker_ = enter_section_(builder_, level_, _NONE_, "<property>");
-    result_ = string_literal(builder_, level_ + 1);
+    result_ = property_name(builder_, level_ + 1);
     pinned_ = result_; // pin = 1
     result_ = result_ && property_1(builder_, level_ + 1);
     exit_section_(builder_, level_, marker_, PROPERTY, result_, pinned_, null);
@@ -324,6 +323,18 @@ public class JsonParser implements PsiParser {
     return result_ || pinned_;
   }
 
+  /* ********************************************************** */
+  // literal | reference_expression
+  static boolean property_name(PsiBuilder builder_, int level_) {
+    if (!recursion_guard_(builder_, level_, "property_name")) return false;
+    boolean result_;
+    Marker marker_ = enter_section_(builder_);
+    result_ = literal(builder_, level_ + 1);
+    if (!result_) result_ = reference_expression(builder_, level_ + 1);
+    exit_section_(builder_, marker_, null, result_);
+    return result_;
+  }
+
   /* ********************************************************** */
   // INDENTIFIER
   public static boolean reference_expression(PsiBuilder builder_, int level_) {

json/gen/com/intellij/json/psi/JsonProperty.java

@@ -12,7 +12,7 @@ public interface JsonProperty extends JsonElement, PsiNamedElement {
   String getName();
 
   @NotNull
-  JsonStringLiteral getNameElement();
+  JsonValue getNameElement();
 
   @Nullable
   JsonValue getValue();

json/gen/com/intellij/json/psi/impl/JsonPropertyImpl.java

@@ -27,7 +27,7 @@ public class JsonPropertyImpl extends JsonPropertyMixin implements JsonProperty
   }
 
   @NotNull
-  public JsonStringLiteral getNameElement() {
+  public JsonValue getNameElement() {
     return JsonPsiImplUtils.getNameElement(this);
   }
 

json/src/com/intellij/json/editor/smartEnter/JsonSmartEnterProcessor.java

@@ -1,6 +1,9 @@
 package com.intellij.json.editor.smartEnter;
 
-import com.intellij.json.psi.*;
+import com.intellij.json.psi.JsonArray;
+import com.intellij.json.psi.JsonFile;
+import com.intellij.json.psi.JsonProperty;
+import com.intellij.json.psi.JsonValue;
 import com.intellij.lang.SmartEnterProcessorWithFixers;
 import com.intellij.openapi.diagnostic.Logger;
 import com.intellij.openapi.editor.Document;
@@ -91,7 +94,7 @@ public class JsonSmartEnterProcessor extends SmartEnterProcessorWithFixers {
           }
         }
         else {
-          final JsonStringLiteral propertyKey = ((JsonProperty)element).getNameElement();
+          final JsonValue propertyKey = ((JsonProperty)element).getNameElement();
           final int keyEndOffset = propertyKey.getTextRange().getEndOffset();
           //processor.myFirstErrorOffset = keyEndOffset;
           if (terminatedOnCurrentLine(editor, propertyKey) && !isFollowedByTerminal(propertyKey, COLON)) {

json/src/com/intellij/json/psi/JsonElementGenerator.java

@@ -36,7 +36,7 @@ public class JsonElementGenerator {
    * @param <T>     type of the JSON value desired
    * @return element created from given text
    *
-   * @see {@link com.intellij.json.psi.JsonElementGenerator#createStringLiteral(String)}
+   * @see #createStringLiteral(String)
    */
   @NotNull
   public <T extends JsonValue> T createValue(@NotNull String content) {

json/src/com/intellij/json/psi/impl/JsonPsiImplUtils.java

@@ -4,6 +4,7 @@ import com.intellij.json.JsonParserDefinition;
 import com.intellij.json.psi.*;
 import com.intellij.lang.ASTNode;
 import com.intellij.openapi.util.text.StringUtil;
+import com.intellij.psi.PsiElement;
 import com.intellij.psi.util.PsiTreeUtil;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
@@ -16,9 +17,18 @@ public class JsonPsiImplUtils {
     return StringUtil.stripQuotesAroundValue(property.getNameElement().getText());
   }
 
+  /**
+   * Actually only JSON string literal should be accepted as valid name of property according to standard,
+   * but for compatibility with JavaScript integration any JSON literals as well as identifiers (unquoted words)
+   * are possible and highlighted as error later.
+   *
+   * @see com.intellij.json.codeinsight.JsonStandardComplianceAnnotator
+   */
   @NotNull
-  public static JsonStringLiteral getNameElement(@NotNull JsonProperty property) {
-    return (JsonStringLiteral)property.getFirstChild();
+  public static JsonValue getNameElement(@NotNull JsonProperty property) {
+    final PsiElement firstChild = property.getFirstChild();
+    assert firstChild instanceof JsonLiteral || firstChild instanceof JsonReferenceExpression;
+    return (JsonValue)firstChild;
   }
 
   @Nullable

json/src/json.bnf

@@ -69,7 +69,7 @@ private object_element ::= property (','|&'}') {
   pin = 1
 }
 
-property ::= string_literal (':' value) {
+property ::= property_name (':' value) {
   methods=[
     getName
     getNameElement
@@ -81,6 +81,8 @@ property ::= string_literal (':' value) {
   pin(".*")=1
 }
 
+private property_name ::= literal | reference_expression
+
 array ::= '[' array_element* ']' { pin=1 }
 
 private array_element ::= value (','|&']') {

json/tests/test/com/intellij/json/JsonParsingTest.java

@@ -58,6 +58,10 @@ public class JsonParsingTest extends ParsingTestCase {
     doTest();
   }
 
+  public void testNonStandardPropertyKeyValues() {
+    doTest();
+  }
+
   // Moved from JavaScript
 
   public void testSimple1() {

json/tests/testData/psi/NonStandardPropertyKeyValues.json

@@ -0,0 +1,7 @@
+{
+  42: null,
+  null: null,
+  false: null,
+  true: null,
+  identifier: null
+}

json/tests/testData/psi/NonStandardPropertyKeyValues.txt

@@ -0,0 +1,49 @@
+JsonFile: NonStandardPropertyKeyValues.json
+  JsonObject
+    PsiElement({)('{')
+    PsiWhiteSpace('\n  ')
+    JsonProperty
+      JsonNumberLiteral
+        PsiElement(NUMBER)('42')
+      PsiElement(:)(':')
+      PsiWhiteSpace(' ')
+      JsonNullLiteral
+        PsiElement(null)('null')
+    PsiElement(,)(',')
+    PsiWhiteSpace('\n  ')
+    JsonProperty
+      JsonNullLiteral
+        PsiElement(null)('null')
+      PsiElement(:)(':')
+      PsiWhiteSpace(' ')
+      JsonNullLiteral
+        PsiElement(null)('null')
+    PsiElement(,)(',')
+    PsiWhiteSpace('\n  ')
+    JsonProperty
+      JsonBooleanLiteral
+        PsiElement(false)('false')
+      PsiElement(:)(':')
+      PsiWhiteSpace(' ')
+      JsonNullLiteral
+        PsiElement(null)('null')
+    PsiElement(,)(',')
+    PsiWhiteSpace('\n  ')
+    JsonProperty
+      JsonBooleanLiteral
+        PsiElement(true)('true')
+      PsiElement(:)(':')
+      PsiWhiteSpace(' ')
+      JsonNullLiteral
+        PsiElement(null)('null')
+    PsiElement(,)(',')
+    PsiWhiteSpace('\n  ')
+    JsonProperty
+      JsonReferenceExpression
+        PsiElement(INDENTIFIER)('identifier')
+      PsiElement(:)(':')
+      PsiWhiteSpace(' ')
+      JsonNullLiteral
+        PsiElement(null)('null')
+    PsiWhiteSpace('\n')
+    PsiElement(})('}')