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Algebraic.isNULL - check if the current Algebraic represents the Maple NULL expression
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Calling Sequence
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boolean isNULL() throws MapleException
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Description
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The isNULL function returns true if the current Algebraic object represents the Maple NULL expression (an expression sequence of length 1) and false otherwise.
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Examples
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import com.maplesoft.openmaple.*;
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import com.maplesoft.externalcall.MapleException;
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class Example
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{
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public static void main( String notused[] ) throws MapleException
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{
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String mapleArgs[];
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Engine engine;
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Algebraic a1, a2;
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mapleArgs = new String[1];
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mapleArgs[0] = "java";
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engine = new Engine( mapleArgs, new EngineCallBacksDefault(),
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null, null );
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a1 = engine.evaluate( "1:" );
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if ( a1.isNULL() )
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{
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System.out.println( "NULL" );
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}
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else
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{
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System.out.println( "Not NULL" );
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}
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a1 = engine.evaluate( "NULL:" );
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if ( a1.isNULL() )
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{
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System.out.println( "NULL" );
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}
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else
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{
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System.out.println( "Not NULL" );
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}
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}
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}
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Executing this code should produce the following output.
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