Item252: Render is too aggressive converting ! to <nop>

look at http://foswiki.org/bin/rdiff/Tasks/Item244?render=sidebyside&type=history&rev1=3&rev2=2

!= gets rendered as simply =

perhaps ! should have a requirement to only NOP WikiWords?

-- WillNorris - 23 Nov 2008 - 00:59

The issue is that the "not equal" (=) string in the topic is rendered as "equal" (=) in the diff. Fails right here as well in plain render. The ! is removed from the not-equal in the parenthesis.

Note that this fails on both RDiff and CompareRevisionsAddOn.

-- GeorgeClark - 24 May 2011

Changing this to Urgent. Bad news to corrupt example code in a wiki: This example is written as a not-equals.

if ( $a = $b ) Do something

-- GeorgeClark - 04 Jan 2015

The root cause is use of ! to escape wiki markup in addition to wikiWords. The aggressive conversion of ! to also supports:

Escaped	Not escaped	Standalone
=Code=	Code	=
*Bold*	Bold	*
_Italics_	Italics	_
name@email.com	name@email.com	name

Any ! prefix is converted to nop.

-- GeorgeClark - 04 Jan 2015

And this is actually documented in WikiSyntax:

• To escape the exclamation mark escape, try prefixing a <nop>, e.g. write A <nop>!= B to get "A != B". Alternatively, use the HTML entity !, which renders as an exclamation mark, e.g. write A != B to get "A != B".

-- GeorgeClark - 04 Jan 2015

As much as this is annoying, it has worked this way since before Foswiki 1.0, No way this should be a blocker. It's working as documented. Changing this back to an enhancement. Changing something this fundamental to render this late in the release would be too risky.

-- GeorgeClark - 07 Jan 2015

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