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Sometimes programmers have a need to "save" the current values of fields and then restore then at some later time.

For instance a user may need to save the values of fields #A -> #C, and to do this you often code fields like this:      define #sava reffld

     define #sava reffld(#a)

...

     define #savb reffld(#b)

...

     define #savc reffld(#c)

and later .... (to save the values)      change #sava #a
      change #savb #b
      change #savc #c

     change #sava #a
     change #savb #b
     change #savc #c

and still later .... (to restore the values)

...

  change #a #sava
     change #b #savb
     change #c #savc

An easier way to do this is to use a "working" list as a "stack" like this:

               def_list #stack (#a #b #c) type(*working) entrys(1)

to save the current values, "stack" them like this:

               inz_list #stack

to restore the values, "unstack" them like this:

               get_entry 1 #stack

Some other points about this technique are:

...