HPlogo MPE/iX Commands Reference Manual > Chapter 2 Command Structure Defined

Commands and Parameters

MPE documents

Complete PDF
Table of Contents
Index

MPE/iX commands tell the computer to perform a specific function. The parameters you enter for each command tell the computer to perform the function in a specific way. MPE/iX uses four classifications of parameters:

  • Required parameters.

  • Optional parameters.

  • Keyword parameters.

  • Positional parameters.

These four classifications of parameters are briefly defined below. To understand the command syntax diagrams, refer to the Conventions pages in the front of this manual.

Required Parameters

If a command has any required parameters, they must be entered or MPE/iX displays an error message. In the syntax diagrams for each command in this chapter, required parameters are either surrounded by no other marks or by braces { }. In the following example, since myfile is not surrounded by any marks, it is a required parameter: 

  BUILD myfile
In some cases, you must select one parameter from a list of two or more parameters. In the following example, you must provide either a job number or a session number since these parameters are surrounded by braces: 

  ALTJOB {#Jnnn | #Snnn}

Optional Parameters

If a command has any optional parameters, you can either specify or ignore them, depending upon how you want the command to execute. In the syntax diagrams for each command in this chapter, optional parameters are surrounded by brackets [ ]. If you ignore optional parameters, MPE/iX uses the system-defined default values for each parameter. In the following example, [;PASS] is an optional parameter since it is surrounded by brackets: 

  NEWGROUP groupname [;PASS=[password]]

Positional Parameters

The meaning of a positional parameter depends upon its position (location) in the parameter list. In the syntax diagrams for each command in this chapter, positional parameters are separated from each other by a comma (,). If you omit a positional parameter from the list, you must provide the comma placeholder that would normally precede that parameter. In the following example, the subparameters of the REC parameter of the BUILD command can be treated as positional parameters: 

  BUILD filename;REC=128,1,F,ASCII
If you choose to use the system-defined default value F, you need not specify it, but you must hold the position with a comma: 

  BUILD filename;REC=128,1,,ASCII

Keyword Parameters

A keyword parameter denotes the meaning or value of a given parameter. In the syntax diagrams for each command in this chapter, keyword parameters appear in uppercase (CAPITAL) letters (although you may enter them in either uppercase or lowercase) and are preceded by a semicolon (;). In the following example, REC is a keyword parameter: 

  BUILD filename;REC=128,1,F,ASCII
Refer to the section "Combining Positional/Keyword Parameters," below, for additional information.



Chapter 2 Command Structure Defined

Native Mode Command Structure