### Command Line Considerations

The command line parser supports abbreviation of keywords depending on the unique first characters. This is only useful if you work in dialog. If the command is specified in a persistent way (e.g. in a script) writing the complete keyword is recommended, to ensure that the script must not be changed to work with a later version of the program. For example:

Version X supports only one keyword starting with V (VERSION). Version X+1, supports the keywords VERSION and VERIFY. If you use version X with VER=4711 anything is fine but with with version X+1 it will fail, because one more character is required (VERS=4711) for the keyword to be unique.

The same is valid for the required string support. The CLP supports strings without enclosing. These strings depend on the keywords used in a name space. If new key words are added in future version, the string could cause errors and must be enclosed. Concerning this it is recommended to enclose strings if the command is defined in a script. For example:

    Version X:
        STRING=my/data/Name NUMBER=42

    Version X+1 supports the new keyword NAME, this requires:
        STRING='my/data/Name' NUMBER=42 NAME='Hugo'

The last item which could result in a damaged command syntax after a program update is the use of implicit array definitions after an assignment, because the end of such an array might change, for example if an array of numbers defined an a switch is the end. In a new version such a switch could be a number with a default value, if only the keyword is defined. In this case the defined number referenced by this keyword is then part of the number array and the parameter is lost. Concerning this it is recommended to use enclosed array definitions. For example:

    instead of:
       FLOATARRAY=1,2,3,PI
    use:
       FLOATARRAY[1,2,3,PI]

All these capabilities are implemented to be compatible with several existing command lines syntaxes and to limit the effort to port old commands or to simplify the interactive use. But in certain cases, the command interpretation could fail, if not the unique/enclosed variant of keywords, strings and arrays are used.