From 5338a361c6fd8c42e8bd47a637c21c128b122418 Mon Sep 17 00:00:00 2001 From: Michael Williamson Date: Sat, 14 Nov 2015 16:52:37 +0000 Subject: Implement while loops in backends --- .../backends/python/PythonCodeGenerator.java | 5 ++- .../couscous/backends/python/PythonSerializer.java | 36 ++++++++-------------- .../backends/python/ast/PythonWhileNode.java | 34 ++++++++++++++++++++ .../python/ast/visitors/PythonNodeVisitor.java | 20 ++---------- .../org/zwobble/couscous/interpreter/Executor.java | 34 ++++++++++++-------- 5 files changed, 75 insertions(+), 54 deletions(-) create mode 100644 src/main/java/org/zwobble/couscous/backends/python/ast/PythonWhileNode.java (limited to 'src/main/java/org') diff --git a/src/main/java/org/zwobble/couscous/backends/python/PythonCodeGenerator.java b/src/main/java/org/zwobble/couscous/backends/python/PythonCodeGenerator.java index ca1c706..5f6fefb 100644 --- a/src/main/java/org/zwobble/couscous/backends/python/PythonCodeGenerator.java +++ b/src/main/java/org/zwobble/couscous/backends/python/PythonCodeGenerator.java @@ -53,6 +53,7 @@ import static org.zwobble.couscous.backends.python.ast.PythonModuleNode.pythonMo import static org.zwobble.couscous.backends.python.ast.PythonReturnNode.pythonReturn; import static org.zwobble.couscous.backends.python.ast.PythonStringLiteralNode.pythonStringLiteral; import static org.zwobble.couscous.backends.python.ast.PythonVariableReferenceNode.pythonVariableReference; +import static org.zwobble.couscous.backends.python.ast.PythonWhileNode.pythonWhile; public class PythonCodeGenerator { public static PythonModuleNode generateCode(ClassNode classNode) { @@ -199,7 +200,9 @@ public class PythonCodeGenerator { @Override public PythonStatementNode visit(WhileNode whileLoop) { - throw new UnsupportedOperationException(); + return pythonWhile( + generateExpression(whileLoop.getCondition()), + generateStatements(whileLoop.getBody())); } } diff --git a/src/main/java/org/zwobble/couscous/backends/python/PythonSerializer.java b/src/main/java/org/zwobble/couscous/backends/python/PythonSerializer.java index 4eea760..6501d1b 100644 --- a/src/main/java/org/zwobble/couscous/backends/python/PythonSerializer.java +++ b/src/main/java/org/zwobble/couscous/backends/python/PythonSerializer.java @@ -2,28 +2,8 @@ package org.zwobble.couscous.backends.python; import java.util.List; import java.util.function.Consumer; -import org.zwobble.couscous.backends.python.ast.PythonAssignmentNode; -import org.zwobble.couscous.backends.python.ast.PythonAttributeAccessNode; -import org.zwobble.couscous.backends.python.ast.PythonBinaryOperation; -import org.zwobble.couscous.backends.python.ast.PythonBlock; -import org.zwobble.couscous.backends.python.ast.PythonBooleanLiteralNode; -import org.zwobble.couscous.backends.python.ast.PythonCallNode; -import org.zwobble.couscous.backends.python.ast.PythonClassNode; -import org.zwobble.couscous.backends.python.ast.PythonConditionalExpressionNode; -import org.zwobble.couscous.backends.python.ast.PythonExpressionNode; -import org.zwobble.couscous.backends.python.ast.PythonFunctionDefinitionNode; -import org.zwobble.couscous.backends.python.ast.PythonGetSliceNode; -import org.zwobble.couscous.backends.python.ast.PythonIfStatementNode; -import org.zwobble.couscous.backends.python.ast.PythonImportNode; -import org.zwobble.couscous.backends.python.ast.PythonIntegerLiteralNode; -import org.zwobble.couscous.backends.python.ast.PythonModuleNode; -import org.zwobble.couscous.backends.python.ast.PythonNode; -import org.zwobble.couscous.backends.python.ast.PythonNotNode; -import org.zwobble.couscous.backends.python.ast.PythonPassNode; -import org.zwobble.couscous.backends.python.ast.PythonReturnNode; -import org.zwobble.couscous.backends.python.ast.PythonStatementNode; -import org.zwobble.couscous.backends.python.ast.PythonStringLiteralNode; -import org.zwobble.couscous.backends.python.ast.PythonVariableReferenceNode; + +import org.zwobble.couscous.backends.python.ast.*; import org.zwobble.couscous.backends.python.ast.visitors.PythonNodeVisitor; import org.zwobble.couscous.util.Action; import static com.google.common.collect.Iterables.skip; @@ -207,7 +187,17 @@ public class PythonSerializer implements PythonNodeVisitor { writeBlock(ifStatement.getFalseBranch()); }); } - + + @Override + public void visit(PythonWhileNode whileLoop) { + writer.writeStatement(() -> { + writer.writeKeyword("while"); + writer.writeSpace(); + write(whileLoop.getCondition()); + writeBlock(whileLoop.getBody()); + }); + } + private void writeParenthesised(PythonExpressionNode expression) { writer.writeSymbol("("); write(expression); diff --git a/src/main/java/org/zwobble/couscous/backends/python/ast/PythonWhileNode.java b/src/main/java/org/zwobble/couscous/backends/python/ast/PythonWhileNode.java new file mode 100644 index 0000000..fa373e6 --- /dev/null +++ b/src/main/java/org/zwobble/couscous/backends/python/ast/PythonWhileNode.java @@ -0,0 +1,34 @@ +package org.zwobble.couscous.backends.python.ast; + +import org.zwobble.couscous.backends.python.ast.visitors.PythonNodeVisitor; + +import java.util.List; + +public class PythonWhileNode implements PythonStatementNode { + public static PythonWhileNode pythonWhile( + PythonExpressionNode condition, + List body) { + return new PythonWhileNode(condition, new PythonBlock(body)); + } + + private final PythonExpressionNode condition; + private final PythonBlock body; + + private PythonWhileNode(PythonExpressionNode condition, PythonBlock body) { + this.condition = condition; + this.body = body; + } + + public PythonExpressionNode getCondition() { + return condition; + } + + public PythonBlock getBody() { + return body; + } + + @Override + public void accept(PythonNodeVisitor visitor) { + visitor.visit(this); + } +} diff --git a/src/main/java/org/zwobble/couscous/backends/python/ast/visitors/PythonNodeVisitor.java b/src/main/java/org/zwobble/couscous/backends/python/ast/visitors/PythonNodeVisitor.java index fb8fa71..8f04787 100644 --- a/src/main/java/org/zwobble/couscous/backends/python/ast/visitors/PythonNodeVisitor.java +++ b/src/main/java/org/zwobble/couscous/backends/python/ast/visitors/PythonNodeVisitor.java @@ -1,23 +1,6 @@ package org.zwobble.couscous.backends.python.ast.visitors; -import org.zwobble.couscous.backends.python.ast.PythonAssignmentNode; -import org.zwobble.couscous.backends.python.ast.PythonAttributeAccessNode; -import org.zwobble.couscous.backends.python.ast.PythonBinaryOperation; -import org.zwobble.couscous.backends.python.ast.PythonBooleanLiteralNode; -import org.zwobble.couscous.backends.python.ast.PythonCallNode; -import org.zwobble.couscous.backends.python.ast.PythonClassNode; -import org.zwobble.couscous.backends.python.ast.PythonConditionalExpressionNode; -import org.zwobble.couscous.backends.python.ast.PythonFunctionDefinitionNode; -import org.zwobble.couscous.backends.python.ast.PythonGetSliceNode; -import org.zwobble.couscous.backends.python.ast.PythonIfStatementNode; -import org.zwobble.couscous.backends.python.ast.PythonImportNode; -import org.zwobble.couscous.backends.python.ast.PythonIntegerLiteralNode; -import org.zwobble.couscous.backends.python.ast.PythonModuleNode; -import org.zwobble.couscous.backends.python.ast.PythonNotNode; -import org.zwobble.couscous.backends.python.ast.PythonPassNode; -import org.zwobble.couscous.backends.python.ast.PythonReturnNode; -import org.zwobble.couscous.backends.python.ast.PythonStringLiteralNode; -import org.zwobble.couscous.backends.python.ast.PythonVariableReferenceNode; +import org.zwobble.couscous.backends.python.ast.*; public interface PythonNodeVisitor { void visit(PythonIntegerLiteralNode integerLiteral); @@ -38,6 +21,7 @@ public interface PythonNodeVisitor { void visit(PythonAssignmentNode assignment); void visit(PythonImportNode importNode); void visit(PythonIfStatementNode ifStatement); + void visit(PythonWhileNode whileLoop); void visit(PythonModuleNode module); diff --git a/src/main/java/org/zwobble/couscous/interpreter/Executor.java b/src/main/java/org/zwobble/couscous/interpreter/Executor.java index 1d9a327..8909acc 100644 --- a/src/main/java/org/zwobble/couscous/interpreter/Executor.java +++ b/src/main/java/org/zwobble/couscous/interpreter/Executor.java @@ -23,7 +23,7 @@ public class Executor implements StatementNodeMapper> } return UnitInterpreterValue.UNIT; } - + private static Environment buildEnvironment(final Environment environment, final CallableNode method, Optional thisValue, PositionalArguments arguments) { final org.zwobble.couscous.interpreter.StackFrameBuilder stackFrame = new StackFrameBuilder(); for (int index = 0; index < method.getArguments().size(); index++) { @@ -32,19 +32,19 @@ public class Executor implements StatementNodeMapper> findDeclarations(method.getBody()).forEach(declaration -> stackFrame.declare(declaration)); return environment.withStackFrame(thisValue, stackFrame.build()); } - + private static Stream findDeclarations(List body) { return body.stream().flatMap(statement -> statement.accept(new StatementNodeMapper>(){ @Override public Stream visit(ReturnNode returnNode) { return Stream.empty(); } - + @Override public Stream visit(ExpressionStatementNode expressionStatement) { return Stream.empty(); } - + @Override public Stream visit(LocalVariableDeclarationNode localVariableDeclaration) { return Stream.of(localVariableDeclaration); @@ -63,27 +63,27 @@ public class Executor implements StatementNodeMapper> } })); } - + public static Optional exec(Environment environment, StatementNode statement) { return statement.accept(new Executor(environment)); } private final Environment environment; - + private Executor(Environment environment) { this.environment = environment; } - + @Override public Optional visit(ReturnNode returnNode) { return Optional.of(eval(environment, returnNode.getValue())); } - + @Override public Optional visit(ExpressionStatementNode expressionStatement) { eval(environment, expressionStatement.getExpression()); return Optional.empty(); } - + @Override public Optional visit(LocalVariableDeclarationNode localVariableDeclaration) { final org.zwobble.couscous.interpreter.values.InterpreterValue value = eval(environment, localVariableDeclaration.getInitialValue()); @@ -93,8 +93,7 @@ public class Executor implements StatementNodeMapper> @Override public Optional visit(IfStatementNode ifStatement) { - BooleanInterpreterValue condition = (BooleanInterpreterValue) eval(environment, ifStatement.getCondition()); - List body = condition.getValue() + List body = evalCondition(ifStatement.getCondition()) ? ifStatement.getTrueBranch() : ifStatement.getFalseBranch(); return exec(body); @@ -102,7 +101,18 @@ public class Executor implements StatementNodeMapper> @Override public Optional visit(WhileNode whileLoop) { - throw new UnsupportedOperationException(); + while (evalCondition(whileLoop.getCondition())) { + Optional result = exec(whileLoop.getBody()); + if (result.isPresent()) { + return result; + } + } + return Optional.empty(); + } + + private boolean evalCondition(ExpressionNode conditionExpression) { + BooleanInterpreterValue condition = (BooleanInterpreterValue) eval(environment, conditionExpression); + return condition.getValue(); } private Optional exec(List statements) { -- cgit v1.2.3