SONARPY-916 Match / case statement: support class patterns (#990)

Author: andrea-guarino-sonarsource

python-frontend/src/main/java/org/sonar/plugins/python/api/tree/BaseTreeVisitor.java

@@ -530,4 +530,16 @@ public void visitWildcardPattern(WildcardPattern wildcardPattern) {
   public void visitGroupPattern(GroupPattern groupPattern) {
     scan(groupPattern.pattern());
   }
+
+  @Override
+  public void visitClassPattern(ClassPattern classPattern) {
+    scan(classPattern.targetClass());
+    scan(classPattern.arguments());
+  }
+
+  @Override
+  public void visitKeywordPattern(KeywordPattern keywordPattern) {
+    scan(keywordPattern.attributeName());
+    scan(keywordPattern.pattern());
+  }
 }

python-frontend/src/main/java/org/sonar/plugins/python/api/tree/ClassPattern.java

@@ -0,0 +1,43 @@
+/*
+ * SonarQube Python Plugin
+ * Copyright (C) 2011-2021 SonarSource SA
+ * mailto:info AT sonarsource DOT com
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 3 of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+package org.sonar.plugins.python.api.tree;
+
+import java.util.List;
+
+/**
+ * Class pattern
+ *  <pre>case Foo(x): ...</pre>
+ * See https://docs.python.org/3/reference/compound_stmts.html#class-patterns
+ */
+public interface ClassPattern extends Pattern {
+
+  /**
+   * Return type can only be {@link Name} or {@link QualifiedExpression}
+   */
+  Expression targetClass();
+
+  Token leftPar();
+
+  List<Pattern> arguments();
+
+  List<Token> argumentSeparators();
+
+  Token rightPar();
+}

python-frontend/src/main/java/org/sonar/plugins/python/api/tree/KeywordPattern.java

@@ -0,0 +1,41 @@
+/*
+ * SonarQube Python Plugin
+ * Copyright (C) 2011-2021 SonarSource SA
+ * mailto:info AT sonarsource DOT com
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 3 of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+package org.sonar.plugins.python.api.tree;
+
+
+/**
+ * Keyword pattern
+ * Used only inside Class pattern
+ *
+ * <pre>
+ *   case Foo({@link #attributeName()} = {@link #pattern()}):
+ *     ...
+ * </pre>
+ *
+ * See https://docs.python.org/3/reference/compound_stmts.html#grammar-token-python-grammar-keyword_pattern
+ */
+public interface KeywordPattern extends Pattern {
+
+  Name attributeName();
+
+  Token equalToken();
+
+  Pattern pattern();
+}

python-frontend/src/main/java/org/sonar/plugins/python/api/tree/Tree.java

@@ -64,6 +64,8 @@ enum Kind {
 
     CLASSDEF(ClassDef.class),
 
+    CLASS_PATTERN(ClassPattern.class),
+
     CONDITIONAL_EXPR(ConditionalExpression.class),
 
     CONTINUE_STMT(ContinueStatement.class),
@@ -112,6 +114,8 @@ enum Kind {
 
     IMPORT_STMT(DottedName.class),
 
+    KEYWORD_PATTERN(KeywordPattern.class),
+
     LAMBDA(LambdaExpression.class),
 
     LIST_LITERAL(ListLiteral.class),

python-frontend/src/main/java/org/sonar/plugins/python/api/tree/TreeVisitor.java

@@ -194,4 +194,8 @@ public interface TreeVisitor {
   void visitWildcardPattern(WildcardPattern wildcardPattern);
 
   void visitGroupPattern(GroupPattern groupPattern);
+
+  void visitClassPattern(ClassPattern classPattern);
+
+  void visitKeywordPattern(KeywordPattern keywordPattern);
 }

python-frontend/src/main/java/org/sonar/python/api/PythonGrammar.java

@@ -168,6 +168,11 @@ public enum PythonGrammar implements GrammarRuleKey {
   OPEN_SEQUENCE_PATTERN,
   WILDCARD_PATTERN,
   GROUP_PATTERN,
+  CLASS_PATTERN,
+  PATTERN_ARGS,
+  PATTERN_ARG,
+  KEYWORD_PATTERN,
+  NAME_OR_ATTR,
 
   SIGNED_NUMBER,
   COMPLEX_NUMBER,
@@ -469,7 +474,7 @@ public static void compoundStatements(LexerfulGrammarBuilder b) {
 
     b.rule(PATTERNS).is(b.firstOf(OPEN_SEQUENCE_PATTERN, PATTERN));
     b.rule(PATTERN).is(b.firstOf(AS_PATTERN, OR_PATTERN));
-    b.rule(CLOSED_PATTERN).is(b.firstOf(LITERAL_PATTERN, GROUP_PATTERN, WILDCARD_PATTERN, CAPTURE_PATTERN, SEQUENCE_PATTERN));
+    b.rule(CLOSED_PATTERN).is(b.firstOf(CLASS_PATTERN, LITERAL_PATTERN, GROUP_PATTERN, WILDCARD_PATTERN, CAPTURE_PATTERN, SEQUENCE_PATTERN));
     b.rule(AS_PATTERN).is(OR_PATTERN, "as", CAPTURE_PATTERN);
     b.rule(OR_PATTERN).is(CLOSED_PATTERN, b.zeroOrMore("|", CLOSED_PATTERN));
     b.rule(CAPTURE_PATTERN).is(NAME);
@@ -483,6 +488,12 @@ public static void compoundStatements(LexerfulGrammarBuilder b) {
     b.rule(MAYBE_STAR_PATTERN).is(b.firstOf(STAR_PATTERN, PATTERN));
     b.rule(STAR_PATTERN).is("*", b.firstOf(WILDCARD_PATTERN, CAPTURE_PATTERN));
 
+    b.rule(CLASS_PATTERN).is(NAME_OR_ATTR, "(", b.optional(PATTERN_ARGS), ")");
+    b.rule(NAME_OR_ATTR).is(NAME, b.zeroOrMore(".", NAME));
+    b.rule(PATTERN_ARGS).is(PATTERN_ARG, b.zeroOrMore(b.sequence(",", PATTERN_ARG)), b.optional(","));
+    b.rule(PATTERN_ARG).is(b.firstOf(KEYWORD_PATTERN, PATTERN));
+    b.rule(KEYWORD_PATTERN).is(NAME, "=", PATTERN);
+
     b.rule(LITERAL_PATTERN).is(b.firstOf(
       COMPLEX_NUMBER,
       SIGNED_NUMBER,

python-frontend/src/main/java/org/sonar/python/tree/ClassPatternImpl.java

@@ -0,0 +1,97 @@
+/*
+ * SonarQube Python Plugin
+ * Copyright (C) 2011-2021 SonarSource SA
+ * mailto:info AT sonarsource DOT com
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 3 of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+package org.sonar.python.tree;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+import org.sonar.plugins.python.api.tree.ClassPattern;
+import org.sonar.plugins.python.api.tree.Expression;
+import org.sonar.plugins.python.api.tree.Pattern;
+import org.sonar.plugins.python.api.tree.Token;
+import org.sonar.plugins.python.api.tree.Tree;
+import org.sonar.plugins.python.api.tree.TreeVisitor;
+
+public class ClassPatternImpl extends PyTree implements ClassPattern {
+
+  private final Expression targetClass;
+  private final Token leftPar;
+  private final List<Pattern> arguments;
+  private final List<Token> argumentSeparators;
+  private final Token rightPar;
+
+  public ClassPatternImpl(Expression targetClass, Token leftPar, List<Pattern> arguments, List<Token> argumentSeparators, Token rightPar) {
+    this.targetClass = targetClass;
+    this.leftPar = leftPar;
+    this.arguments = arguments;
+    this.argumentSeparators = argumentSeparators;
+    this.rightPar = rightPar;
+  }
+
+  @Override
+  public Expression targetClass() {
+    return targetClass;
+  }
+
+  @Override
+  public Token leftPar() {
+    return leftPar;
+  }
+
+  @Override
+  public List<Pattern> arguments() {
+    return arguments;
+  }
+
+  @Override
+  public List<Token> argumentSeparators() {
+    return argumentSeparators;
+  }
+
+  @Override
+  public Token rightPar() {
+    return rightPar;
+  }
+
+  @Override
+  public void accept(TreeVisitor visitor) {
+    visitor.visitClassPattern(this);
+  }
+
+  @Override
+  public Kind getKind() {
+    return Kind.CLASS_PATTERN;
+  }
+
+  @Override
+  List<Tree> computeChildren() {
+    List<Tree> children = new ArrayList<>(Arrays.asList(targetClass, leftPar));
+    int i = 0;
+    for (Pattern element : arguments) {
+      children.add(element);
+      if (i < argumentSeparators.size()) {
+        children.add(argumentSeparators.get(i));
+      }
+      i++;
+    }
+    children.add(rightPar);
+    return children;
+  }
+}

python-frontend/src/main/java/org/sonar/python/tree/KeywordPatternImpl.java

@@ -0,0 +1,71 @@
+/*
+ * SonarQube Python Plugin
+ * Copyright (C) 2011-2021 SonarSource SA
+ * mailto:info AT sonarsource DOT com
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 3 of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+package org.sonar.python.tree;
+
+import java.util.Arrays;
+import java.util.List;
+import org.sonar.plugins.python.api.tree.KeywordPattern;
+import org.sonar.plugins.python.api.tree.Name;
+import org.sonar.plugins.python.api.tree.Pattern;
+import org.sonar.plugins.python.api.tree.Token;
+import org.sonar.plugins.python.api.tree.Tree;
+import org.sonar.plugins.python.api.tree.TreeVisitor;
+
+public class KeywordPatternImpl extends PyTree implements KeywordPattern {
+  private final Name attributeName;
+  private final Token equalToken;
+  private final Pattern pattern;
+
+  public KeywordPatternImpl(Name attributeName, Token equalToken, Pattern pattern) {
+    this.attributeName = attributeName;
+    this.equalToken = equalToken;
+    this.pattern = pattern;
+  }
+
+  @Override
+  public Name attributeName() {
+    return attributeName;
+  }
+
+  @Override
+  public Token equalToken() {
+    return equalToken;
+  }
+
+  @Override
+  public Pattern pattern() {
+    return pattern;
+  }
+
+  @Override
+  public void accept(TreeVisitor visitor) {
+    visitor.visitKeywordPattern(this);
+  }
+
+  @Override
+  public Kind getKind() {
+    return Kind.KEYWORD_PATTERN;
+  }
+
+  @Override
+  List<Tree> computeChildren() {
+    return Arrays.asList(attributeName, equalToken, pattern);
+  }
+}