Soy to Python CL #8. Design Doc: []

Support for IfNodes as traditional conditionals and ternary expressions where possible. ------------- Created by MOE: http://code.google.com/p/moe-java MOE_MIGRATED_REVID=86653446
bolinfest · Feb 20, 2015 · 52647e7 · 52647e7
1 parent 5d3a12e
commit 52647e7
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Showing 7 changed files with 300 additions and 12 deletions.
diff --git a/java/src/com/google/template/soy/pysrc/internal/GenPyCodeVisitor.java b/java/src/com/google/template/soy/pysrc/internal/GenPyCodeVisitor.java
@@ -22,6 +22,7 @@
 import com.google.template.soy.internal.base.Pair;
 import com.google.template.soy.internal.i18n.SoyBidiUtils;
 import com.google.template.soy.pysrc.internal.GenPyExprsVisitor.GenPyExprsVisitorFactory;
+import com.google.template.soy.pysrc.internal.TranslateToPyExprVisitor.TranslateToPyExprVisitorFactory;
 import com.google.template.soy.pysrc.restricted.PyExpr;
 import com.google.template.soy.pysrc.restricted.PyExprUtils;
 import com.google.template.soy.shared.internal.FindCalleesNotInFileVisitor;
@@ -30,6 +31,9 @@
 import com.google.template.soy.shared.restricted.ApiCallScopeBindingAnnotations.TranslationPyModuleName;
 import com.google.template.soy.sharedpasses.ShouldEnsureDataIsDefinedVisitor;
 import com.google.template.soy.soytree.AbstractSoyNodeVisitor;
+import com.google.template.soy.soytree.IfCondNode;
+import com.google.template.soy.soytree.IfElseNode;
+import com.google.template.soy.soytree.IfNode;
 import com.google.template.soy.soytree.PrintNode;
 import com.google.template.soy.soytree.SoyFileNode;
 import com.google.template.soy.soytree.SoyFileSetNode;
@@ -75,10 +79,10 @@ final class GenPyCodeVisitor extends AbstractSoyNodeVisitor<List<String>> {
 
   @VisibleForTesting protected GenPyExprsVisitor genPyExprsVisitor;
 
+  private final TranslateToPyExprVisitorFactory translateToPyExprVisitorFactory;
+
   /**
    * @param runtimePath The module path for the runtime libraries.
-   * @param isComputableAsPyExprVisitor The IsComputableAsPyExprVisitor to use.
-   * @param genPyExprsVisitorFactory Factory for creating an instance of GenPyExprsVisitor.
    * @param translationPyModuleName Python module name used in python runtime to instantiate
    *        translation.
    */
@@ -87,12 +91,14 @@ final class GenPyCodeVisitor extends AbstractSoyNodeVisitor<List<String>> {
       @BidiIsRtlFn String bidiIsRtlFn,
       @TranslationPyModuleName String translationPyModuleName,
       IsComputableAsPyExprVisitor isComputableAsPyExprVisitor,
-      GenPyExprsVisitorFactory genPyExprsVisitorFactory) {
+      GenPyExprsVisitorFactory genPyExprsVisitorFactory,
+      TranslateToPyExprVisitorFactory translateToPyExprVisitorFactory) {
     this.runtimePath = runtimePath;
     this.bidiIsRtlFn = bidiIsRtlFn;
     this.translationPyModuleName = translationPyModuleName;
     this.isComputableAsPyExprVisitor = isComputableAsPyExprVisitor;
     this.genPyExprsVisitorFactory = genPyExprsVisitorFactory;
+    this.translateToPyExprVisitorFactory = translateToPyExprVisitorFactory;
   }
 
 
@@ -246,6 +252,56 @@ final class GenPyCodeVisitor extends AbstractSoyNodeVisitor<List<String>> {
     pyCodeBuilder.addToOutputVar(genPyExprsVisitor.exec(node));
   }
 
+  /**
+   * Visit an IfNode and generate a full conditional statement, or an inline ternary conditional
+   * expression if all the children are computable as expressions.
+   *
+   * <p>Example:
+   * <pre>
+   *   {if $boo > 0}
+   *     ...
+   *   {/if}
+   * </pre>
+   * might generate
+   * <pre>
+   *   if opt_data.get('boo') > 0:
+   *     ...
+   * </pre>
+   */
+  @Override protected void visitIfNode(IfNode node) {
+    if (isComputableAsPyExprVisitor.exec(node)) {
+      pyCodeBuilder.addToOutputVar(genPyExprsVisitor.exec(node));
+      return;
+    }
+
+    // Not computable as Python expressions, so generate full code.
+    TranslateToPyExprVisitor translator = translateToPyExprVisitorFactory.create();
+    for (SoyNode child : node.getChildren()) {
+      if (child instanceof IfCondNode) {
+        IfCondNode icn = (IfCondNode) child;
+        PyExpr condPyExpr = translator.exec(icn.getExprUnion().getExpr());
+
+        if (icn.getCommandName().equals("if")) {
+          pyCodeBuilder.appendLine("if ", condPyExpr.getText(), ":");
+        } else {
+          pyCodeBuilder.appendLine("elif ", condPyExpr.getText(), ":");
+        }
+
+        pyCodeBuilder.increaseIndent();
+        visit(icn);
+        pyCodeBuilder.decreaseIndent();
+
+      } else if (child instanceof IfElseNode) {
+        pyCodeBuilder.appendLine("else:");
+        pyCodeBuilder.increaseIndent();
+        visit(child);
+        pyCodeBuilder.decreaseIndent();
+      } else {
+        throw new AssertionError("Unexpected if child node type. Child: " + child);
+      }
+    }
+  }
+
 
   // -----------------------------------------------------------------------------------------------
   // Fallback implementation.

diff --git a/java/src/com/google/template/soy/pysrc/internal/GenPyExprsVisitor.java b/java/src/com/google/template/soy/pysrc/internal/GenPyExprsVisitor.java
@@ -29,6 +29,9 @@
 import com.google.template.soy.pysrc.restricted.PyStringExpr;
 import com.google.template.soy.pysrc.restricted.SoyPySrcPrintDirective;
 import com.google.template.soy.soytree.AbstractSoyNodeVisitor;
+import com.google.template.soy.soytree.IfCondNode;
+import com.google.template.soy.soytree.IfElseNode;
+import com.google.template.soy.soytree.IfNode;
 import com.google.template.soy.soytree.MsgFallbackGroupNode;
 import com.google.template.soy.soytree.MsgNode;
 import com.google.template.soy.soytree.PrintDirectiveNode;
@@ -207,4 +210,62 @@ public static interface GenPyExprsVisitorFactory {
     MsgFuncGenerator msgFuncGenerator = msgFuncGeneratorFactory.create(node);
     pyExprs.add(msgFuncGenerator.getPyExpr());
   }
+
+  /**
+   * If all the children are computable as expressions, the IfNode can be written as a ternary
+   * conditional expression.
+   */
+  @Override protected void visitIfNode(IfNode node) {
+    // Create another instance of this visitor for generating Python expressions from children.
+    GenPyExprsVisitor genPyExprsVisitor = genPyExprsVisitorFactory.create();
+    TranslateToPyExprVisitor translator = translateToPyExprVisitorFactory.create();
+
+    StringBuilder pyExprTextSb = new StringBuilder();
+
+    boolean hasElse = false;
+    for (SoyNode child : node.getChildren()) {
+
+      if (child instanceof IfCondNode) {
+        IfCondNode icn = (IfCondNode) child;
+
+        // Python ternary conditional expressions modify the order of the conditional from
+        // <conditional> ? <true> : <false> to
+        // <true> if <conditional> else <false>
+        PyExpr condBlock = PyExprUtils.concatPyExprs(genPyExprsVisitor.exec(icn)).toPyString();
+        condBlock = PyExprUtils.maybeProtect(condBlock,
+            PyExprUtils.pyPrecedenceForOperator(Operator.CONDITIONAL));
+        pyExprTextSb.append(condBlock.getText());
+
+        // Append the conditional and if/else syntax.
+        PyExpr condPyExpr = translator.exec(icn.getExprUnion().getExpr());
+        pyExprTextSb.append(" if ").append(condPyExpr.getText()).append(" else ");
+
+      } else if (child instanceof IfElseNode) {
+        hasElse = true;
+        IfElseNode ien = (IfElseNode) child;
+
+        PyExpr elseBlock = PyExprUtils.concatPyExprs(genPyExprsVisitor.exec(ien)).toPyString();
+        pyExprTextSb.append(elseBlock.getText());
+      } else {
+        throw new AssertionError("Unexpected if child node type. Child: " + child);
+      }
+    }
+
+    if (!hasElse) {
+      pyExprTextSb.append("''");
+    }
+
+    // By their nature, inline'd conditionals can only contain output strings, so they can be
+    // treated as a string type with a conditional precedence.
+    pyExprs.add(new PyStringExpr(pyExprTextSb.toString(),
+        PyExprUtils.pyPrecedenceForOperator(Operator.CONDITIONAL)));
+  }
+
+  @Override protected void visitIfCondNode(IfCondNode node) {
+    visitChildren(node);
+  }
+
+  @Override protected void visitIfElseNode(IfElseNode node) {
+    visitChildren(node);
+  }
 }
diff --git a/java/src/com/google/template/soy/pysrc/internal/TranslateToPyExprVisitor.java b/java/src/com/google/template/soy/pysrc/internal/TranslateToPyExprVisitor.java
@@ -216,7 +216,7 @@ private String visitNullSafeNodeRecurse(ExprNode node, StringBuilder nullSafetyP
 
       default: {
         PyExpr value = visit(node);
-        return genMaybeProtect(value, Integer.MAX_VALUE);
+        return PyExprUtils.maybeProtect(value, Integer.MAX_VALUE).getText();
       }
     }
   }
@@ -260,6 +260,7 @@ private String visitNullSafeNodeRecurse(ExprNode node, StringBuilder nullSafetyP
   @Override protected PyExpr visitConditionalOpNode(ConditionalOpNode node) {
     // Retrieve the operands.
     Operator op = Operator.CONDITIONAL;
+    int conditionalPrecedence = PyExprUtils.pyPrecedenceForOperator(op);
     List<SyntaxElement> syntax = op.getSyntax();
     List<PyExpr> operandExprs = visitChildren(node);
 
@@ -273,13 +274,13 @@ private String visitNullSafeNodeRecurse(ExprNode node, StringBuilder nullSafetyP
     // Python's ternary operator switches the order from <conditional> ? <true> : <false> to
     // <true> if <conditional> else <false>.
     StringBuilder exprSb = new StringBuilder();
-    exprSb.append(genMaybeProtect(trueExpr, PyExprUtils.pyPrecedenceForOperator(op)));
+    exprSb.append(PyExprUtils.maybeProtect(trueExpr, conditionalPrecedence).getText());
     exprSb.append(" if ");
-    exprSb.append(genMaybeProtect(conditionalExpr, PyExprUtils.pyPrecedenceForOperator(op)));
+    exprSb.append(PyExprUtils.maybeProtect(conditionalExpr, conditionalPrecedence).getText());
     exprSb.append(" else ");
-    exprSb.append(genMaybeProtect(falseExpr, PyExprUtils.pyPrecedenceForOperator(op)));
+    exprSb.append(PyExprUtils.maybeProtect(falseExpr, conditionalPrecedence).getText());
 
-    return new PyExpr(exprSb.toString(), PyExprUtils.pyPrecedenceForOperator(op));
+    return new PyExpr(exprSb.toString(), conditionalPrecedence);
   }
 
   @Override protected PyExpr visitFunctionNode(FunctionNode node) {
@@ -367,8 +368,4 @@ private PyExpr genPyExprUsingSoySyntax(OperatorNode opNode) {
 
     return new PyExpr(newExpr, PyExprUtils.pyPrecedenceForOperator(opNode.getOperator()));
   }
-
-  private static String genMaybeProtect(PyExpr expr, int minSafePrecedence) {
-    return (expr.getPrecedence() > minSafePrecedence) ? expr.getText() : "(" + expr.getText() + ")";
-  }
 }
diff --git a/java/src/com/google/template/soy/pysrc/restricted/PyExprUtils.java b/java/src/com/google/template/soy/pysrc/restricted/PyExprUtils.java
@@ -123,6 +123,24 @@ public static PyExpr genPyNotNullCheck(PyExpr pyExpr) {
     return new PyExpr(conditionalExpr, PyExprUtils.pyPrecedenceForOperator(Operator.NOT_EQUAL));
   }
 
+  /**
+   * Wraps an expression with parenthesis if it's not above the minimum safe precedence.
+   *
+   * <p>NOTE: For the sake of brevity, this implementation loses typing information in the
+   * expressions.
+   *
+   * @param expr The expression to wrap.
+   * @param minSafePrecedence The minimum safe precedence (not inclusive).
+   * @return The PyExpr potentially wrapped in parenthesis.
+   */
+  public static PyExpr maybeProtect(PyExpr expr, int minSafePrecedence) {
+    if (expr.getPrecedence() > minSafePrecedence) {
+      return expr;
+    } else {
+      return new PyExpr("(" + expr.getText() + ")", Integer.MAX_VALUE);
+    }
+  }
+
   /**
    * Wraps an expression with the proper SanitizedContent constructor if contentKind is non-null.
    *

diff --git a/java/tests/com/google/template/soy/pysrc/internal/GenPyCodeVisitorTest.java b/java/tests/com/google/template/soy/pysrc/internal/GenPyCodeVisitorTest.java
@@ -37,6 +37,8 @@
 /**
  * Unit tests for GenPyCodeVisitor.
  *
+ * <p>TODO(dcphillips): Add non-inlined 'if' test after adding LetNode support.
+ *
  */
 public final class GenPyCodeVisitorTest extends TestCase {
 
@@ -68,6 +70,7 @@ public final class GenPyCodeVisitorTest extends TestCase {
 
   private GenPyCodeVisitor genPyCodeVisitor;
 
+
   @Override protected void setUp() {
     // Default to empty values for the bidi and translation configs.
     setupGenPyCodeVisitor("", "");
@@ -173,6 +176,7 @@ public void testMsg() {
   // -----------------------------------------------------------------------------------------------
   // Test Utilities.
 
+
   private void assertGeneratedPyFile(String soyCode, String expectedPyCode) {
     assertThat(getGeneratedPyFile(soyCode)).isEqualTo(expectedPyCode);
   }

diff --git a/java/tests/com/google/template/soy/pysrc/internal/GenPyExprsVisitorTest.java b/java/tests/com/google/template/soy/pysrc/internal/GenPyExprsVisitorTest.java
@@ -0,0 +1,72 @@
+/*
+ * Copyright 2015 Google Inc.
+ *
+ * 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.google.template.soy.pysrc.internal;
+
+import static com.google.template.soy.pysrc.internal.PyCodeSubject.assertThatSoyCode;
+
+import com.google.common.collect.ImmutableList;
+import com.google.template.soy.exprtree.Operator;
+import com.google.template.soy.pysrc.restricted.PyExpr;
+import com.google.template.soy.pysrc.restricted.PyExprUtils;
+
+import junit.framework.TestCase;
+
+/**
+ * Unit tests for GenPyExprsVisitor.
+ *
+ */
+public final class GenPyExprsVisitorTest extends TestCase {
+
+  public void testRawText() {
+    assertThatSoyCode("I'm feeling lucky!").compilesTo(
+        ImmutableList.of(new PyExpr("'I\\'m feeling lucky!'", Integer.MAX_VALUE)));
+  }
+
+  public void testIf() {
+    String soyNodeCode =
+        "{if $boo}\n" +
+        "  Blah\n" +
+        "{elseif not $goo}\n" +
+        "  Bleh\n" +
+        "{else}\n" +
+        "  Bluh\n" +
+        "{/if}\n";
+    String expectedPyExprText =
+        "'Blah' if opt_data.get('boo') else 'Bleh' if not opt_data.get('goo') else 'Bluh'";
+
+    assertThatSoyCode(soyNodeCode).compilesTo(
+        ImmutableList.of(new PyExpr(expectedPyExprText,
+            PyExprUtils.pyPrecedenceForOperator(Operator.CONDITIONAL))));
+  }
+
+  public void testIf_nested() {
+    String soyNodeCode =
+        "{if $boo}\n" +
+        "  {if $goo}\n" +
+        "    Blah\n" +
+        "  {/if}\n" +
+        "{else}\n" +
+        "  Bleh\n" +
+        "{/if}\n";
+    String expectedPyExprText =
+        "('Blah' if opt_data.get('goo') else '') if opt_data.get('boo') else 'Bleh'";
+
+    assertThatSoyCode(soyNodeCode).compilesTo(
+        ImmutableList.of(new PyExpr(expectedPyExprText,
+            PyExprUtils.pyPrecedenceForOperator(Operator.CONDITIONAL))));
+  }
+}