When you reference a column name using As Name(), and Names Default To Here( 1 ) is set, JMP returns a variable reference. That reference is then processed using the standard reference rules.
In the following example, there is no height variable in the Here: scope, so JMP returns an error.
Names Default To Here( 1 );
Open( "$SAMPLE_DATA/Big Class.jmp" );
As Name( "height" )[3];
As Name( "height" )[/*###*/3];
Use As Column() instead of As Name():
Names Default To Here( 1 );
Open( "$SAMPLE_DATA/Big Class.jmp" );
As Column( "height" )[3];
Explicitly scope height with As Name():
Names Default To Here( 1 );
dt = Open( "$SAMPLE_DATA/Big Class.jmp" );
dt:( As Name( "height" ) )[3];
These scripts return 55, the value of height in the third row of Big Class.jmp.

Help created on 9/19/2017