Difference: PUSHPOPILFStatements (12 vs. 13)

Revision 132008-10-01 - SteveFrizzell

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META TOPICPARENT	name="APPX500Features"

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New ILF Statements

Application designers gain more control through these new ILF statements.

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POP --- OPTION FIELD

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Also related to this new statement is a new Pre-Defined Field called --- ACCESS PATH. As one might assume, the field contains the value of the current access path for the Process Control File. The field may be viewed, but not changed via ILF code (that is to say, an ILF statement to SET --- ACCESS PATH to a specified value will be ignored).

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Open Issues, Bugs, Suggestions

OPEN - Note that PUSHing a field after PUSHing a record containing that field will not cause the field value on the PUSHed record to change. The stack for the RECORD is independent from that of the field. This is a different behavior than designers may be used to from the STORE/RESTORE statements.

OPEN - It appears that fields with multiple occurrences ARE NOT supported by multiple stacks. For example, PUSH value 1 into field occurrence 1, then PUSH value 2 into field occurrence 2. If you then execute a POP on the field occurrence 1, it will retrieve the last value PUSHED into the field stack, ignoring occurrence, thus returning the value 2. However, that POP statement will place that value of 2 into occurrence 1. So the occurrence value is relevant for the source field and the destination field, but a single field name will support only one merged stack.

Some enhanced functionality that might be considered for down the road would be the following statements:

POPCLEAR - Empty the stack for the specified field or record
POPFIFO - Have the specified field or record get POPped in a FIFO (first in, first out) manner, rather than LIFO
POPLIFO - Reverse the above, and return to standard defined behavior

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Limitations:

Fields with multiple occurrences ARE NOT supported by multiple stacks. For example, PUSH value 1 into field occurrence 1, then PUSH value 2 into field occurrence 2. If you then execute a POP on the field occurrence 1, it will retrieve the last value PUSHED into the field stack, ignoring occurrence, thus returning the value 2. However, that POP statement will place that value of 2 into occurrence 1. So the occurrence value is relevant for the source field and the destination field, but a single field name will support only one merged stack.

Comments:

Read what other users have said about this page or add your own comments.

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Here are a couple of ideas for additional related statements:

POP ALL - Empty the stack for the specified field or record
POP FIFO - POP the specified field or record from the bottom of the stack - FIFO (first in, first out) manner, rather than LIFO

-- SteveFrizzell - 01 Oct 2008

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-- AlKalter - 04 Apr 2008 \ No newline at end of file

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