KT-584 Convert C-style for statement more correctly

src/org/jetbrains/jet/j2k/ast/ForeachWithRangeStatement.java

@@ -0,0 +1,29 @@
+package org.jetbrains.jet.j2k.ast;
+
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * @author ignatov
+ */
+public class ForeachWithRangeStatement extends Statement {
+  private Expression myStart;
+  private IdentifierImpl myIdentifier;
+  private Expression myEnd;
+  private Statement myBody;
+
+  public ForeachWithRangeStatement(IdentifierImpl identifier, Expression start, Expression end, Statement body) {
+    myStart = start;
+    myIdentifier = identifier;
+    myEnd = end;
+    myBody = body;
+  }
+
+  @NotNull
+  @Override
+  public String toKotlin() {
+    return "for" + SPACE + "(" +
+      myIdentifier.toKotlin() + SPACE + "in" + SPACE + myStart.toKotlin() + ".." + myEnd.toKotlin() +
+      ")" + SPACE +
+      myBody.toKotlin();
+  }
+}

src/org/jetbrains/jet/j2k/visitors/StatementVisitor.java

@@ -1,6 +1,9 @@
 package org.jetbrains.jet.j2k.visitors;
 
 import com.intellij.psi.*;
+import com.intellij.psi.search.searches.ReferencesSearch;
+import com.intellij.psi.tree.IElementType;
+import com.intellij.psi.util.PsiUtil;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.jet.j2k.ast.*;
 
@@ -93,17 +96,66 @@ public class StatementVisitor extends ElementVisitor {
   }
 
   @Override
-  public void visitForStatement(PsiForStatement statement) {
+  public void visitForStatement(@NotNull PsiForStatement statement) {
     super.visitForStatement(statement);
 
-    List<Statement> forStatements = new LinkedList<Statement>();
-    forStatements.add(statementToStatement(statement.getInitialization()));
-    forStatements.add(new WhileStatement(
-      expressionToExpression(statement.getCondition()),
-      new Block(
-        Arrays.asList(statementToStatement(statement.getBody()),
-          new Block(Arrays.asList(statementToStatement(statement.getUpdate())))))));
-    myResult = new Block(forStatements);
+    final PsiStatement initialization = statement.getInitialization();
+    final PsiStatement update = statement.getUpdate();
+    final PsiExpression condition = statement.getCondition();
+    final PsiLocalVariable firstChild = initialization != null && initialization.getFirstChild() instanceof PsiLocalVariable ?
+      (PsiLocalVariable) initialization.getFirstChild() : null;
+
+    final IElementType operationTokenType = condition != null && condition instanceof PsiBinaryExpression ?
+      ((PsiBinaryExpression) condition).getOperationTokenType() : null;
+    if (
+      initialization != null &&
+        initialization instanceof PsiDeclarationStatement
+        && initialization.getFirstChild() == initialization.getLastChild()
+        && condition != null
+        && update != null
+        && update.getChildren().length == 1
+        && update.getChildren()[0] instanceof PsiPostfixExpression
+        && ((PsiPostfixExpression) update.getChildren()[0]).getOperationTokenType() == JavaTokenType.PLUSPLUS
+        && operationTokenType != null
+        && (operationTokenType == JavaTokenType.LT || operationTokenType == JavaTokenType.LE)
+        && initialization.getFirstChild() != null
+        && initialization.getFirstChild() instanceof PsiLocalVariable
+        && firstChild != null
+        && firstChild.getNameIdentifier() != null
+        && isOnceWritableIterator(firstChild)
+      ) {
+      final Expression end = expressionToExpression(((PsiBinaryExpression) condition).getROperand());
+      final Expression endExpression = operationTokenType == JavaTokenType.LT ?
+        new BinaryExpression(end, new IdentifierImpl("1"), "-"):
+        end;
+      myResult = new ForeachWithRangeStatement(
+        new IdentifierImpl(firstChild.getName()),
+        expressionToExpression(firstChild.getInitializer()),
+        endExpression,
+        statementToStatement(statement.getBody())
+      );
+    } else { // common case: while loop instead of for loop
+      List<Statement> forStatements = new LinkedList<Statement>();
+      forStatements.add(statementToStatement(initialization));
+      forStatements.add(new WhileStatement(
+        expressionToExpression(condition),
+        new Block(
+          Arrays.asList(statementToStatement(statement.getBody()),
+            new Block(Arrays.asList(statementToStatement(update)))))));
+      myResult = new Block(forStatements);
+    }
+  }
+
+  private static boolean isOnceWritableIterator(PsiLocalVariable firstChild) {
+    int counter = 0;
+    if (firstChild != null)
+      for (PsiReference r : (ReferencesSearch.search(firstChild))) {
+        if (r instanceof PsiExpression) {
+          if (PsiUtil.isAccessedForWriting((PsiExpression) r))
+            counter++;
+        }
+      }
+    return counter == 1; // only increment usage
   }
 
   @Override

testData/ast/for/statement/forRangeWithLE.jav

@@ -0,0 +1,2 @@
+int[] array = new int[10];
+for (int i = 0; i <= 10; i++) {array[i] = i;}

testData/ast/for/statement/forRangeWithLE.kt

@@ -0,0 +1,4 @@
+var array : IntArray? = IntArray?(10, {null})
+for (i in 0..10) {
+array[i] = i
+}

testData/ast/for/statement/forRangeWithLT.jav

@@ -0,0 +1,2 @@
+int[] array = new int[10];
+for (int i = 0; i < 10; i++) {array[i] = i;}

testData/ast/for/statement/forRangeWithLT.kt

@@ -0,0 +1,4 @@
+var array : IntArray? = IntArray?(10, {null})
+for (i in 0..(10 - 1)) {
+array[i] = i
+}

testData/ast/for/statement/forWithBlock.jav

@@ -1 +1,2 @@
-for (int i = 0; i < 0; i++) {int i = 1; i++;}
+int[] array = new int[10];
+for (int i = 0; i < 10; i++) {array[i] = i;}

testData/ast/for/statement/forWithBlock.kt

@@ -1,13 +1,4 @@
-{
-var i : Int = 0
-while ((i < 0))
-{
-{
-var i : Int = 1
-(i++)
-}
-{
-(i++)
-}
-}
+var array : IntArray? = IntArray?(10, {null})
+for (i in 0..(10 - 1)) {
+array[i] = i
 }

testData/ast/for/statement/forWithExpression.kt

@@ -1,10 +1 @@
-{
-var i : Int = 0
-while ((i < 0))
-{
-(t++)
-{
-(i++)
-}
-}
-}
+for (i in 0..(0 - 1)) (t++)

testData/ast/labelStatement/statement/complicatedExampleFromJavaTutorial.kt

@@ -1,8 +1,4 @@
-@test {
-var i : Int = 0
-while ((i <= max))
-{
-{
+@test for (i in 0..max) {
 var n : Int = substring.length()
 var j : Int = i
 var k : Int = 0
@@ -16,11 +12,6 @@ continue@test
 foundIt = true
 break@test
 }
-{
-(i++)
-}
-}
-}
 System.out?.println((if (foundIt)
 "Found it"
 else