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Section 8.11.2.2:
TRI_STATE

immutable class TRI_STATE < $ENUMS{TRI_STATE}

$ENUMS{TRI_STATE} TRI_STATE
Inheritance Diagram

Formal Types

types

SAME = TRI_STATE ;
TRI_STATE = token ;

This enumeration class provides a three-state logic response to a question requiring a yes/no answer. The answer provided may, of course, be 'yes' or 'no', but may also be a response which is interpetable as neither - giving rise to the third value 'unknown'.


External specifications

The following feature is required to be implemented for this class in accordance with the specification given in $IS_EQ :-


The following feature is required to be implemented for this class in accordance with the specification given in $HASH :-


The following features are required to be implemented for this class in accordance with the specifications given in $BINARY :-


The following featuress are required to be implemented for this class in accordance with the specifications given in $STR :-


The following feature is required to be implemented for this class in accordance with the specification given in $TEXT which is a sub-type of the class $ENUMS{TRI_STATE} from which this class inherits :-


The following features are required to be implemented for this class in accordance with the specifications given in $ANCHORED_FMT :-


The following features are required to be implemented for this class in accordance with the specifications given in $ENUMS{T} :-


Enumeration Values

This enumeration provides three values which may be given the interpretation indicated :-


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Comments or enquiries should be made toKeith Hopper.
Page last modified: Friday, 1 June 2001.
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