JS backend: improve js readability which generated in the Dangerous translator -- initialize temporary vars in declaration.

(cherry picked from commit 4d8355c)

js/js.translator/src/org/jetbrains/k2js/translate/context/AliasingContext.java

@@ -16,7 +16,6 @@
 
 package org.jetbrains.k2js.translate.context;
 
-import com.google.common.collect.Maps;
 import com.google.dart.compiler.backend.js.ast.JsExpression;
 import com.google.dart.compiler.backend.js.ast.JsName;
 import org.jetbrains.annotations.NotNull;
@@ -24,7 +23,9 @@ import org.jetbrains.annotations.Nullable;
 import org.jetbrains.jet.lang.descriptors.DeclarationDescriptor;
 import org.jetbrains.jet.lang.psi.JetExpression;
 
-import java.util.*;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.Map;
 
 public class AliasingContext {
     private static final AliasingContext ROOT = new AliasingContext(null) {
@@ -46,36 +47,39 @@ public class AliasingContext {
     @Nullable
     private Map<DeclarationDescriptor, JsExpression> aliasesForDescriptors;
 
-    @NotNull
-    private final Map<JetExpression, JsName> aliasesForExpressions = Maps.newHashMap();
+    @Nullable
+    private final Map<JetExpression, JsName> aliasesForExpressions;
 
     @Nullable
     private final AliasingContext parent;
 
     private AliasingContext(@Nullable AliasingContext parent) {
-        this(parent, null);
+        this(parent, null, null);
     }
 
-    private AliasingContext(@Nullable AliasingContext parent, @Nullable Map<DeclarationDescriptor, JsExpression> aliasesForDescriptors) {
+    private AliasingContext(
+            @Nullable AliasingContext parent,
+            @Nullable Map<DeclarationDescriptor, JsExpression> aliasesForDescriptors,
+            @Nullable Map<JetExpression, JsName> aliasesForExpressions
+    ) {
         this.parent = parent;
         this.aliasesForDescriptors = aliasesForDescriptors;
+        this.aliasesForExpressions = aliasesForExpressions;
     }
 
     @NotNull
     public AliasingContext inner(@NotNull DeclarationDescriptor descriptor, @NotNull JsExpression alias) {
-        return new AliasingContext(this, Collections.singletonMap(descriptor, alias));
+        return new AliasingContext(this, Collections.singletonMap(descriptor, alias), null);
     }
 
     @NotNull
-    public AliasingContext withAliasesForExpressions(@NotNull Map<JetExpression, JsName> aliasesForExpressions) {
-        AliasingContext newContext = new AliasingContext(this);
-        newContext.aliasesForExpressions.putAll(aliasesForExpressions);
-        return newContext;
+    public AliasingContext withExpressionsAliased(@NotNull Map<JetExpression, JsName> aliasesForExpressions) {
+        return new AliasingContext(this, null, aliasesForExpressions);
     }
 
     @NotNull
     public AliasingContext withDescriptorsAliased(@NotNull Map<DeclarationDescriptor, JsExpression> aliases) {
-        return new AliasingContext(this, aliases);
+        return new AliasingContext(this, aliases, null);
     }
 
     @Nullable
@@ -89,13 +93,17 @@ public class AliasingContext {
             return alias;
         }
 
+        if (parent == null) {
+            return null;
+        }
+
         return parent.getAliasForDescriptor(descriptor);
     }
 
     @Nullable
     public JsName getAliasForExpression(@NotNull JetExpression element) {
-        JsName alias = aliasesForExpressions.get(element);
-        return alias != null ? alias : parent.getAliasForExpression(element);
+        JsName alias = aliasesForExpressions == null ? null : aliasesForExpressions.get(element);
+        return alias != null || parent == null ? alias : parent.getAliasForExpression(element);
     }
 
     public void registerAlias(@NotNull DeclarationDescriptor descriptor, @NotNull JsExpression alias) {

js/js.translator/src/org/jetbrains/k2js/translate/context/DynamicContext.java

@@ -73,6 +73,11 @@ public final class DynamicContext {
         return Pair.create(var, (JsExpression) new JsNameRef(var.getName()));
     }
 
+    @NotNull
+    public JsVar createTemporaryVar(@NotNull JsExpression initExpression) {
+        return new JsVar(currentScope.declareTemporary(), initExpression);
+    }
+
     @NotNull
     public JsScope getScope() {
         return currentScope;

js/js.translator/src/org/jetbrains/k2js/translate/context/TranslationContext.java

@@ -121,7 +121,7 @@ public class TranslationContext {
 
     @NotNull
     public TranslationContext innerContextWithAliasesForExpressions(@NotNull Map<JetExpression, JsName> aliases) {
-        return new TranslationContext(this, aliasingContext.withAliasesForExpressions(aliases));
+        return new TranslationContext(this, aliasingContext.withExpressionsAliased(aliases));
     }
 
     @NotNull

js/js.translator/src/org/jetbrains/k2js/translate/utils/dangerous/DangerousTranslator.java

@@ -16,17 +16,18 @@
 
 package org.jetbrains.k2js.translate.utils.dangerous;
 
-import com.google.common.collect.Maps;
 import com.google.dart.compiler.backend.js.ast.JsExpression;
 import com.google.dart.compiler.backend.js.ast.JsName;
 import com.google.dart.compiler.backend.js.ast.JsNode;
+import com.google.dart.compiler.backend.js.ast.JsVars;
+import gnu.trove.THashMap;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.jet.lang.psi.JetExpression;
-import org.jetbrains.k2js.translate.context.TemporaryVariable;
 import org.jetbrains.k2js.translate.context.TranslationContext;
 import org.jetbrains.k2js.translate.general.AbstractTranslator;
 import org.jetbrains.k2js.translate.general.Translation;
 
+import java.util.ArrayList;
 import java.util.List;
 import java.util.Map;
 
@@ -55,13 +56,15 @@ public final class DangerousTranslator extends AbstractTranslator {
 
     @NotNull
     private Map<JetExpression, JsName> translateAllExpressionsAndCreateAliasesForThem(@NotNull List<JetExpression> expressions) {
-        Map<JetExpression, JsName> aliasesForExpressions = Maps.newHashMap();
+        Map<JetExpression, JsName> aliasesForExpressions = new THashMap<JetExpression, JsName>(expressions.size());
+        List<JsVars.JsVar> vars = new ArrayList<JsVars.JsVar>(expressions.size());
         for (JetExpression expression : expressions) {
             JsExpression translatedExpression = Translation.translateAsExpression(expression, context());
-            TemporaryVariable aliasForExpression = context().declareTemporary(translatedExpression);
-            context().addStatementToCurrentBlock(aliasForExpression.assignmentExpression().makeStmt());
-            aliasesForExpressions.put(expression, aliasForExpression.name());
+            JsVars.JsVar aliasForExpression = context().dynamicContext().createTemporaryVar(translatedExpression);
+            vars.add(aliasForExpression);
+            aliasesForExpressions.put(expression, aliasForExpression.getName());
         }
+        context().addStatementToCurrentBlock(new JsVars(vars, true));
         return aliasesForExpressions;
     }
 }