Keep4

This is another version of Keep, which allows a user to specify what variables are kept in the workspace of the calling routine. "Keep" compliments "Clear".

This version has been extended to match the command format of the "clear" command for clearing variables. Thus wildcards and regular expressions are allowed. The version also supports the "global" key word and Keep will not touch global variables unless the "global" key word is used.

Examples of supported formats:
keep var1 var2
keep var*
keep -regexp expr1
keep global
keep global var1
keep global -regexp expr1