☜	Process-Stack 1990 Version of ANSI Standard					☞

2.2.2.4 Variable Contexts

The organization of multiple variable contexts requires the use of a PROCESS-STACK. This is a simple push-down stack, or last-in-first-out (LIFO) list, used to save and restore items which control the execution flow or variable environment. Five types of items, or frames, will be placed on the PROCESS-STACK, Do frames, exfunc frames, exvar frames, New frames, and parameter frames:

1. Do frames contain the execution level and the execution location of the doargument. In the case of the argumentless Do, the execution level, the execution location of the Do command and a saved value of $T are saved. The execution location of a MUMPS process is a descriptor of the location of the command and possible argument currently being executed. This descriptor includes, at minimum, the routinename and the character position following the current command or argument.
2. Exfunc and exvar frames contain saved values of $T, the execution level, and the execution location.
3. New frames contain a New argument (newargument) and a set of NAME-TABLE entries.
4. Parameter frames contain a formallist and a set of NAME-TABLE entries.

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Copyright © Examples: 1995-2024 Ed de Moel;
Copyright © Annotations: 2003-2008 Jacquard Systems Research
Copyright © Annotations: 2008-2024 Ed de Moel.

This page most recently updated on 28-Nov-2011, 21:03:45.

For comments, contact Ed de Moel (demoel@jacquardsystems.com)