xtc.parser
Class SemanticValue

java.lang.Object
  xtc.parser.Result
      xtc.parser.SemanticValue

public final class SemanticValue
extends Result

A semantic value.

Version:

$Revision: 1.23 $

Author:

Robert Grimm

Field Summary

ParseError	error The embedded parse error.
java.lang.Object	value The actual value.

Fields inherited from class xtc.parser.Result

index

Constructor Summary

SemanticValue(java.lang.Object value, int index)
Create a new semantic value.

SemanticValue(java.lang.Object value, int index, ParseError error)
Create a new semantic value.

Method Summary

SemanticValue	createValue(java.lang.Object value, ParseError error) Create a semantic value based on this result.
boolean	hasValue() Determine whether this result has a value.
boolean	hasValue(java.lang.String s) Determine whether this result has the specified string value.
boolean	hasValueIgnoreCase(java.lang.String s) Determine whether this result has the specified string value, ignoring case.
ParseError	parseError() Get the parse error for this result.
ParseError	select(ParseError error) Select the more specific parse error.
ParseError	select(ParseError error, int index) Select the more specific parse error.
<T> T	semanticValue() Get the semantic value for this result.

Methods inherited from class java.lang.Object

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

Field Detail

value

public final java.lang.Object value

The actual value.

error

public final ParseError error

The embedded parse error. An embedded parse error is the most specific parse error encountered during the parse leading to this semantic value (typically, returned by an unsuccessful option). It is used to possibly replace a less specific parse error generated while continuing to parse the input. This field must not be null; instead, a dummy parse error should be used.

Constructor Detail

SemanticValue

public SemanticValue(java.lang.Object value,
                     int index)

Create a new semantic value.

Parameters:

value - The value.

index - The index into the rest of the input.

SemanticValue

public SemanticValue(java.lang.Object value,
                     int index,
                     ParseError error)

Create a new semantic value.

Parameters:

value - The value.

index - The index into the rest of the input.

error - The embedded parse error.

Method Detail

hasValue

public boolean hasValue()

Description copied from class: Result

Determine whether this result has a value.

Specified by:

hasValue in class Result

Returns:

true if this result has a value.

hasValue

public boolean hasValue(java.lang.String s)

Description copied from class: Result

Determine whether this result has the specified string value. The specified value must not be null.

Specified by:

hasValue in class Result

Parameters:

s - The string value.

Returns:

true if this result has the specified string value.

hasValueIgnoreCase

public boolean hasValueIgnoreCase(java.lang.String s)

Description copied from class: Result

Determine whether this result has the specified string value, ignoring case. The specified value must not be null.

Specified by:

hasValueIgnoreCase in class Result

Parameters:

s - The string value.

Returns:

true if this result has the specified string value, ignoring case.

semanticValue

public <T> T semanticValue()

Description copied from class: Result

Get the semantic value for this result.

Specified by:

semanticValue in class Result

Returns:

The semantic value for this result.

parseError

public ParseError parseError()

Description copied from class: Result

Get the parse error for this result. If the result does not represent a parse error or does not have an embedded parse error, this method must return the dummy parse error.

Specified by:

parseError in class Result

Returns:

The parse error for this result.

select

public ParseError select(ParseError error)

Description copied from class: Result

Select the more specific parse error. This method compares this result (i.e., either the parse error or the embedded parse error) with the specified parse error and returns the one representing the longer parse.

Specified by:

select in class Result

Parameters:

error - The error.

Returns:

The more specific parse error.

select

public ParseError select(ParseError error,
                         int index)

Description copied from class: Result

Select the more specific parse error. This method comparse this result (i.e., either the parse error or embedded parse error) with specified error and index. If this result represents an error beyond the specified error and index, it returns this result's error. Otherwise, it returns the specified parse error.

Specified by:

select in class Result

Parameters:

error - The error.

index - The index.

Returns:

The more specific parse error.

createValue

public SemanticValue createValue(java.lang.Object value,
                                 ParseError error)

Description copied from class: Result

Create a semantic value based on this result. A straight-forward implementation of this method simply creates a new semantic value, using the specified actual value, this result's index, and the specified parse error:

   public SemanticValue value(Object value, ParseError error) {
     return new SemanticValue(value, index, error);
   }
 

However, for a result that already is a semantic value, a more sophisticated implementation can avoid creating a new semantic value if the specified actual value and parse error are identical to those for this result.

Specified by:

createValue in class Result

Parameters:

value - The actual value.

error - The embedded parse error.