PARAMETER: Pass Arguments to a Procedure

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PARAMETER evaluate parameters passed to a procedure. An example will show best how PARAMETER works. Suppose the following command was typed:
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The parameter list portion of the command line is saved, i.e. '2 X IMAGEFILE'. The procedure TEST.PRO is then called. TEST has in it the command
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BUFNUM and FACTOR are taken to be variable names and are associated with the first two parameters from the parameter list. In effect it does the command SET BUFNUM=2 FACTOR=X. Note that '2' and 'X' could have been any arithmetic expression.

The STRING= keyword means that the third parameter is used as a literal string and the string variable name FILENAME is given the string value IMAGENAME, in effect doing the command:
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If there are fewer parameters in the CALL than required in the PARAMETER command, the missing parameters are taken to be 0 or blank, as appropriate.

Note that there is only one area in VISTA for saving the list of passed parameters, so the PARAMETER command should be executed before calling another procedure.