Subject: IBIS standard inconsistency

From: Stephen Nolan <[email-masked]>
Date: Fri, 28 Jul 2000 21:51:42 -0500

In the IBIS standard, the keywords [IBIS Ver] and [File Rev] appear to the the
only keywords that have capitalized words other than the first word (the word
IBIS being completely capitalized accepted as an acronym). All other keyword
have the first word capitalized followed by the other words lower case. Eg.
[Comment char], [File name], [Voltage range]....

Why is there an inconsistency in the style of these keywords?

Also, some multiple-word keywords use an underscore between words instead of a
space. Eg. [GND_clamp], [POWER_clamp]. 

Again, why the inconsistency?
-- 
Regards,
Stephen M. Nolan

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From: Ian Dodd <[email-masked]>
Date: Mon, 31 Jul 2000 10:37:49 -0400

Stephen,

My reading of the spec suggests you are free to use any of these styles..... 

| 1)  The content of the files is case sensitive, except for reserved
|     words and keywords.

| 6)  Keywords must be enclosed in square brackets, [], and must start in
|     column 1 of the line.  No space or tab is allowed immediately after the
|     opening bracket '[' or immediately before the closing bracket ']'.  If
|     used, only one space (' ') or underscore ('_') character separates the
|     parts of a multi-word keyword.

Have you experimented with the golden parser to see what it will accept?

Ian Dodd
Cadence Design Systems
[email-masked]

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From: "Matthew Flora" <[email-masked]>
Date: Mon, 31 Jul 2000 07:46:20 -0700

Dear Stephen M. Nolan,

Section three of the specification does say:

and:

So both forms you mentioned are legal.  Why the text of the specification
mixes the two is anyone's guess.

Best regards,
Matthew Flora

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From: Mike LaBonte <[email-masked]>
Date: Tue, 01 Aug 2000 08:36:31 -0400

The IBIS spec distinguishes between keywords and subparameters. Keywords are
enclosed within square brackets. The spec examples of keywords have space
separators, even though the spec says that underscores are allowed. The use of
opening and closing brackets makes it easy to parse these, even though they
may appear as multiple words. The spec also says that underscores and spaces
are equivalent. So even though the spec examples use [GND clamp], parsers
are supposed to recognize [GND_clamp] as being equivalent.

Subparameters have no brackets. The spec states "Spaces are not allowed in
subparameter names". An example of a subparameter name is Model_type.
Although parsers certainly can handle multiple word sequences, it works out
better that subparameters are always a single word (no spaces).

Mike LaBonte
Cadence Design Systems