( ESNUG 360 Item 17 ) -------------------------------------------- [11/02/00]
From: Rajkumar Kadam <rkadam@asic.qntm.com>
Subject: Synopsys Tcl 'Collections' in DC Not Like Tcl 'Lists'! Why!???
Hi John!
I thought that this may be useful for people using Tcl as their scripting
language for DC. Synopsys has a new form of list equivalent in Tcl called
'collection'. I assumed that the 'collection' worked similar to 'list' with
their custom commands, but it did not turn out so.
Following is the example which I thought should have worked logically.
set in_list [all_inputs]
foreach_in_collection element [all_clocks] {
set in_list [remove_from_collection $in_list $clock_name]
}
I was trying to remove a collection item from an collection, but it does not
work. The following was the workaround to make it work, which I achieved
with the help of a Synopsys FAE.
set in_list [all_inputs]
foreach_in_collection element [all_clocks] {
set clock_name [get_port $element]
set in_list [remove_from_collection $in_list $clock_name]
}
Reasoning: You cannot remove a collection item from a collection which has
a different object class. When you run all_clocks it returns a collection
which has a object class as clock. When you run all_inputs it returns a
collection which has a object class as ports.
I understand this logic, but I really do not understand the need for having
such a limitation in Synopsys tools. I always wanted it to be like Tcl
'list'. Why not?
- Rajkumar Kadam
Quantum Corp.
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