Package ptolemy.data.expr

Class ParseTreeEvaluator

java.lang.Object

ptolemy.data.expr.AbstractParseTreeVisitor

ptolemy.data.expr.ParseTreeEvaluator

All Implemented Interfaces:

ParseTreeVisitor

Direct Known Subclasses:

ExpressionConceptFunctionParseTreeEvaluator, GTParameter.Evaluator, ParseTreeEvaluatorForGuardExpression

public class ParseTreeEvaluator
extends AbstractParseTreeVisitor

This class evaluates a parse tree given a reference to its root node. It implements a visitor that visits the parse tree in depth-first order, evaluating each node and storing the result as a token in the node. Two exceptions are logic nodes and the ternary if node (the ? : construct), which do not necessarily evaluate all children nodes.

Since:

Ptolemy II 2.1

Version:

$Id$

Author:

Steve Neuendorffer

See Also:

ASTPtRootNode

Pt.AcceptedRating:

Yellow (neuendor)

Pt.ProposedRating:

Green (neuendor)

Field Summary

Fields

Modifier and Type	Field	Description
protected Token	_evaluatedChildToken
protected ParseTreeTypeInference	_typeInference

Constructor Summary

Constructors

Constructor	Description
ParseTreeEvaluator()

Method Summary

Modifier and Type	Method	Description
protected void	_assert(boolean flag, ASTPtRootNode node, java.lang.String message)	Assert that the given boolean value, which describes the given parse tree node, is true.
protected Token[]	_evaluateAllChildren(ASTPtRootNode node)	Loop through all of the children of this node, visiting each one of them; this will cause their token value to be determined.
protected Token	_evaluateArrayIndex(ASTPtRootNode node, Token value, Token index)	Evaluate the array index operation represented by the given node.
protected Token	_evaluateChild(ASTPtRootNode node, int i)	Evaluate the child with the given index of the given node.
protected Token	_evaluateMatrixIndex(ASTPtRootNode node, Token value, Token rowIndex, Token columnIndex)	Evaluate the Matrix index operation represented by the given node.
protected Token	_functionCall(java.lang.String functionName, Type[] argTypes, java.lang.Object[] argValues)	Evaluate the specified function.
protected Token	_methodCall(java.lang.String methodName, Type[] argTypes, java.lang.Object[] argValues)	Evaluate the specified method.
protected void	_trace(java.lang.String string)	Add a record to the current trace corresponding to the given message.
protected void	_traceEnter(ASTPtRootNode node)	Add a record to the current trace corresponding to the start of the evaluation of the given node.
protected void	_traceLeave(ASTPtRootNode node)	Add a record to the current trace corresponding to the completion of the evaluation of the given node.
Token	evaluateParseTree(ASTPtRootNode node)	Evaluate the parse tree with the specified root node.
Token	evaluateParseTree(ASTPtRootNode node, ParserScope scope)	Evaluate the parse tree with the specified root node using the specified scope to resolve the values of variables.
java.lang.String	traceParseTreeEvaluation(ASTPtRootNode node, ParserScope scope)	Trace the evaluation of the parse tree with the specified root node using the specified scope to resolve the values of variables.
void	visitArrayConstructNode(ASTPtArrayConstructNode node)	Construct an ArrayToken that contains the tokens from the children of the specified node.
void	visitBitwiseNode(ASTPtBitwiseNode node)	Evaluate a bitwise operator on the children of the specified node, where the particular operator is property of the node.
void	visitFunctionalIfNode(ASTPtFunctionalIfNode node)	Evaluate the first child, and depending on its (boolean) result, evaluate either the second or the third child.
void	visitFunctionApplicationNode(ASTPtFunctionApplicationNode node)	Apply a function to the children of the specified node.
void	visitFunctionDefinitionNode(ASTPtFunctionDefinitionNode node)	Define a function, where the children specify the argument types and the expression.
void	visitLeafNode(ASTPtLeafNode node)	Evaluate a numeric constant or an identifier.
void	visitLogicalNode(ASTPtLogicalNode node)	Evaluate a logical AND or OR on the children of the specified node.
void	visitMatrixConstructNode(ASTPtMatrixConstructNode node)	Construct a matrix containing the children nodes.
void	visitMethodCallNode(ASTPtMethodCallNode node)	Apply a method to the children of the specified node, where the first child is the object on which the method is defined and the rest of the children are arguments.
void	visitPowerNode(ASTPtPowerNode node)	Evaluate the power operator on the children of the specified node.
void	visitProductNode(ASTPtProductNode node)	Multiply the children of the specified node.
void	visitRecordConstructNode(ASTPtRecordConstructNode node)	Construct a record by assigning the fields values given by the children nodes.
void	visitRelationalNode(ASTPtRelationalNode node)
void	visitShiftNode(ASTPtShiftNode node)	Apply a shift operator to the children of the specified node.
void	visitSumNode(ASTPtSumNode node)	Apply a sum operator to the children of the specified node.
void	visitUnaryNode(ASTPtUnaryNode node)	Apply a unary operator to the single child of the specified node.
void	visitUnionConstructNode(ASTPtUnionConstructNode node)	Construct a union by assigning the label value given by the children nodes.

Methods inherited from class ptolemy.data.expr.AbstractParseTreeVisitor

_unsupportedVisitException, _visitAllChildren, _visitChild, visitAssignmentNode

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

_evaluatedChildToken

protected Token _evaluatedChildToken

_typeInference

protected ParseTreeTypeInference _typeInference

Constructor Detail

ParseTreeEvaluator

public ParseTreeEvaluator()

Method Detail

evaluateParseTree

public Token evaluateParseTree(ASTPtRootNode node)
                        throws IllegalActionException

Evaluate the parse tree with the specified root node.

Parameters:

node - The root of the parse tree.

Returns:

The result of evaluation.

Throws:

IllegalActionException - If an evaluation error occurs.

evaluateParseTree

public Token evaluateParseTree(ASTPtRootNode node,
                               ParserScope scope)
                        throws IllegalActionException

Evaluate the parse tree with the specified root node using the specified scope to resolve the values of variables.

Parameters:

node - The root of the parse tree.

scope - The scope for evaluation.

Returns:

The result of evaluation.

Throws:

IllegalActionException - If an error occurs during evaluation.

traceParseTreeEvaluation

public java.lang.String traceParseTreeEvaluation(ASTPtRootNode node,
                                                 ParserScope scope)
                                          throws IllegalActionException

Trace the evaluation of the parse tree with the specified root node using the specified scope to resolve the values of variables.

Parameters:

node - The root of the parse tree.

scope - The scope for evaluation.

Returns:

The trace of the evaluation.

Throws:

IllegalActionException - If an error occurs during evaluation.

visitArrayConstructNode

public void visitArrayConstructNode(ASTPtArrayConstructNode node)
                             throws IllegalActionException

Construct an ArrayToken that contains the tokens from the children of the specified node.

Specified by:

visitArrayConstructNode in interface ParseTreeVisitor

Overrides:

visitArrayConstructNode in class AbstractParseTreeVisitor

Parameters:

node - The specified node.

Throws:

IllegalActionException - If an evaluation error occurs.

visitBitwiseNode

public void visitBitwiseNode(ASTPtBitwiseNode node)
                      throws IllegalActionException

Evaluate a bitwise operator on the children of the specified node, where the particular operator is property of the node.

Specified by:

visitBitwiseNode in interface ParseTreeVisitor

Overrides:

visitBitwiseNode in class AbstractParseTreeVisitor

Parameters:

node - The specified node.

Throws:

IllegalActionException - If an evaluation error occurs.

visitFunctionApplicationNode

public void visitFunctionApplicationNode(ASTPtFunctionApplicationNode node)
                                  throws IllegalActionException

Apply a function to the children of the specified node. This also handles indexing into matrices and arrays, which look like function calls. In the simplest cases, if the function is being applied to an expression that evaluated to a FunctionToken, an ArrayToken, or a MatrixToken, then the function application is simply applied to the available arguments. More complex is if the function is being applied to an expression that does not evaluate as above, resulting in three cases: Of primary interest is a function node that represents the invocation of a Java method registered with the expression parser. This method uses the reflection mechanism in the CachedMethod class to find the correct method, based on the types of the arguments and invoke it. See that class for information about how method arguments are matched. A second case is the eval() function, which is handled specially in this method. The argument to the function is evaluated, and the parsed as a string using the expression parser. The result is then evaluated *in this evaluator*. This has the effect that any identifiers are evaluated in the same scope as the original expression. A third case is the matlab() function, which is also handled specially in this method, allowing the evaluation of expressions in matlab if matlab is installed. The format of the function is covered in MatlabUtilities.evaluate(String, Set, ParserScope) .

Specified by:

visitFunctionApplicationNode in interface ParseTreeVisitor

Overrides:

visitFunctionApplicationNode in class AbstractParseTreeVisitor

Parameters:

node - The specified node.

Throws:

IllegalActionException - If an evaluation error occurs.

visitFunctionDefinitionNode

public void visitFunctionDefinitionNode(ASTPtFunctionDefinitionNode node)
                                 throws IllegalActionException

Define a function, where the children specify the argument types and the expression. The expression is not evaluated. The resulting token in the node is an instance of FunctionToken.

Specified by:

visitFunctionDefinitionNode in interface ParseTreeVisitor

Overrides:

visitFunctionDefinitionNode in class AbstractParseTreeVisitor

Parameters:

node - The specified node.

Throws:

IllegalActionException - If an evaluation error occurs.

visitFunctionalIfNode

public void visitFunctionalIfNode(ASTPtFunctionalIfNode node)
                           throws IllegalActionException

Evaluate the first child, and depending on its (boolean) result, evaluate either the second or the third child. The result of that evaluation becomes the result of the specified node.

Specified by:

visitFunctionalIfNode in interface ParseTreeVisitor

Overrides:

visitFunctionalIfNode in class AbstractParseTreeVisitor

Parameters:

node - The specified node.

Throws:

IllegalActionException - If an evaluation error occurs.

visitLeafNode

public void visitLeafNode(ASTPtLeafNode node)
                   throws IllegalActionException

Evaluate a numeric constant or an identifier. In the case of an identifier, its value is obtained from the scope or from the list of registered constants.

Specified by:

visitLeafNode in interface ParseTreeVisitor

Overrides:

visitLeafNode in class AbstractParseTreeVisitor

Parameters:

node - The specified node.

Throws:

IllegalActionException - If an evaluation error occurs.

visitLogicalNode

public void visitLogicalNode(ASTPtLogicalNode node)
                      throws IllegalActionException

Evaluate a logical AND or OR on the children of the specified node.

Specified by:

visitLogicalNode in interface ParseTreeVisitor

Overrides:

visitLogicalNode in class AbstractParseTreeVisitor

Parameters:

node - The specified node.

Throws:

IllegalActionException - If an evaluation error occurs.

visitMatrixConstructNode

public void visitMatrixConstructNode(ASTPtMatrixConstructNode node)
                              throws IllegalActionException

Construct a matrix containing the children nodes. The specified node ends up with a MatrixToken value.

Specified by:

visitMatrixConstructNode in interface ParseTreeVisitor

Overrides:

visitMatrixConstructNode in class AbstractParseTreeVisitor

Parameters:

node - The specified node.

Throws:

IllegalActionException - If an evaluation error occurs.

visitMethodCallNode

public void visitMethodCallNode(ASTPtMethodCallNode node)
                         throws IllegalActionException

Apply a method to the children of the specified node, where the first child is the object on which the method is defined and the rest of the children are arguments. This also handles indexing into a record, which looks the same.

Specified by:

visitMethodCallNode in interface ParseTreeVisitor

Overrides:

visitMethodCallNode in class AbstractParseTreeVisitor

Parameters:

node - The specified node.

Throws:

IllegalActionException - If an evaluation error occurs.

visitPowerNode

public void visitPowerNode(ASTPtPowerNode node)
                    throws IllegalActionException

Evaluate the power operator on the children of the specified node.

Specified by:

visitPowerNode in interface ParseTreeVisitor

Overrides:

visitPowerNode in class AbstractParseTreeVisitor

Parameters:

node - The specified node.

Throws:

IllegalActionException - If an evaluation error occurs.

visitProductNode

public void visitProductNode(ASTPtProductNode node)
                      throws IllegalActionException

Multiply the children of the specified node.

Specified by:

visitProductNode in interface ParseTreeVisitor

Overrides:

visitProductNode in class AbstractParseTreeVisitor

Parameters:

node - The specified node.

Throws:

IllegalActionException - If an evaluation error occurs.

visitRecordConstructNode

public void visitRecordConstructNode(ASTPtRecordConstructNode node)
                              throws IllegalActionException

Construct a record by assigning the fields values given by the children nodes.

Specified by:

visitRecordConstructNode in interface ParseTreeVisitor

Overrides:

visitRecordConstructNode in class AbstractParseTreeVisitor

Parameters:

node - The record constructor node.

Throws:

IllegalActionException - If an evaluation error occurs.

visitRelationalNode

public void visitRelationalNode(ASTPtRelationalNode node)
                         throws IllegalActionException

Specified by:

visitRelationalNode in interface ParseTreeVisitor

Overrides:

visitRelationalNode in class AbstractParseTreeVisitor

Throws:

IllegalActionException

visitShiftNode

public void visitShiftNode(ASTPtShiftNode node)
                    throws IllegalActionException

Apply a shift operator to the children of the specified node.

Specified by:

visitShiftNode in interface ParseTreeVisitor

Overrides:

visitShiftNode in class AbstractParseTreeVisitor

Parameters:

node - The specified node.

Throws:

IllegalActionException - If an evaluation error occurs.

visitSumNode

public void visitSumNode(ASTPtSumNode node)
                  throws IllegalActionException

Apply a sum operator to the children of the specified node.

Specified by:

visitSumNode in interface ParseTreeVisitor

Overrides:

visitSumNode in class AbstractParseTreeVisitor

Parameters:

node - The specified node.

Throws:

IllegalActionException - If an evaluation error occurs.

visitUnaryNode

public void visitUnaryNode(ASTPtUnaryNode node)
                    throws IllegalActionException

Apply a unary operator to the single child of the specified node.

Specified by:

visitUnaryNode in interface ParseTreeVisitor

Overrides:

visitUnaryNode in class AbstractParseTreeVisitor

Parameters:

node - The specified node.

Throws:

IllegalActionException

visitUnionConstructNode

public void visitUnionConstructNode(ASTPtUnionConstructNode node)
                             throws IllegalActionException

Construct a union by assigning the label value given by the children nodes.

Specified by:

visitUnionConstructNode in interface ParseTreeVisitor

Overrides:

visitUnionConstructNode in class AbstractParseTreeVisitor

Parameters:

node - The union constructor node.

Throws:

IllegalActionException - If an evaluation error occurs.

_assert

protected void _assert(boolean flag,
                       ASTPtRootNode node,
                       java.lang.String message)

Assert that the given boolean value, which describes the given parse tree node, is true. If it is false, then throw a new InternalErrorException that describes the node and includes the given message.

Parameters:

flag - The flag that is asserted to be true.

node - The node on which the assertion is asserted.

message - The message to include in the exception.

Throws:

InternalErrorException - If the assertion is violated. Note that this is a runtime exception, so it need not be declared explicitly.

_evaluateAllChildren

protected Token[] _evaluateAllChildren(ASTPtRootNode node)
                                throws IllegalActionException

Loop through all of the children of this node, visiting each one of them; this will cause their token value to be determined.

Parameters:

node - The node whose children are evaluated.

Returns:

The values of the children.

Throws:

IllegalActionException - If an evaluation error occurs.

_evaluateArrayIndex

protected Token _evaluateArrayIndex(ASTPtRootNode node,
                                    Token value,
                                    Token index)
                             throws IllegalActionException

Evaluate the array index operation represented by the given node.

Parameters:

node - The node that caused this method to be called.

value - The token that is being indexed into, which must be an ArrayToken.

index - The index, which must be an integer token.

Returns:

The element of the given token at the given index.

Throws:

IllegalActionException - If an evaluation error occurs.

_evaluateChild

protected Token _evaluateChild(ASTPtRootNode node,
                               int i)
                        throws IllegalActionException

Evaluate the child with the given index of the given node. This is usually called while visiting the given node.

Parameters:

node - The node

i - The index of the node

Returns:

The token

Throws:

IllegalActionException - If an evaluation error occurs.

_evaluateMatrixIndex

protected Token _evaluateMatrixIndex(ASTPtRootNode node,
                                     Token value,
                                     Token rowIndex,
                                     Token columnIndex)
                              throws IllegalActionException

Evaluate the Matrix index operation represented by the given node.

Parameters:

node - The node that caused this method to be called.

value - The token that is being indexed into, which must be a MatrixToken.

rowIndex - The row index, which must be an integer token.

columnIndex - The column index, which must be an integer token.

Returns:

The element of the given token at the given index.

Throws:

IllegalActionException - If an evaluation error occurs.

_functionCall

protected Token _functionCall(java.lang.String functionName,
                              Type[] argTypes,
                              java.lang.Object[] argValues)
                       throws IllegalActionException

Evaluate the specified function. The function must be defined as one of the registered functions with PtParser.

Parameters:

functionName - The function name.

argTypes - An array of argument types.

argValues - An array of argument values.

Returns:

The value of returned by the specified method.

Throws:

IllegalActionException - If an evaluation error occurs.

_methodCall

protected Token _methodCall(java.lang.String methodName,
                            Type[] argTypes,
                            java.lang.Object[] argValues)
                     throws IllegalActionException

Evaluate the specified method. The object on which the method is evaluated should be the first argument.

Parameters:

methodName - The method name.

argTypes - An array of argument types.

argValues - An array of argument values.

Returns:

The value of returned by the specified method.

Throws:

IllegalActionException - If an evaluation error occurs.

_trace

protected void _trace(java.lang.String string)

Add a record to the current trace corresponding to the given message. If the trace is null, do nothing.

Parameters:

string - The string

_traceEnter

protected void _traceEnter(ASTPtRootNode node)

Add a record to the current trace corresponding to the start of the evaluation of the given node. If the trace is null, then do nothing.

Parameters:

node - The node.

_traceLeave

protected void _traceLeave(ASTPtRootNode node)

Add a record to the current trace corresponding to the completion of the evaluation of the given node. If the trace is null, then do nothing.

Parameters:

node - The node.