From savicky at cs.cas.cz  Mon May  7 16:20:13 2007
From: savicky at cs.cas.cz (Petr Savicky)
Date: Mon, 7 May 2007 16:20:13 +0200
Subject: [Rd] grep with fixed=TRUE and ignore.case=TRUE
In-Reply-To: <20070429135347.GA4690@cs.cas.cz>
References: <20070428114959.GA25723@cs.cas.cz>
	<46337DE1.5030607@statistik.uni-dortmund.de>
	<20070429135347.GA4690@cs.cas.cz>
Message-ID: <20070507142012.GF31253@cs.cas.cz>

Dear R developers,

I suggest to modify the behaviour of "grep" function with fixed=TRUE option.

Currently, fixed=TRUE implies ignore.case=FALSE (overrides ignore.case=TRUE,
if set by the user).

I suggest to keep ignore.case as set by the user even if fixed=TRUE. Since
the default of ignore.case is FALSE, this would not change the behaviour
of grep, if the user does not set ignore.case explicitly.

In my opinion, fixed=TRUE is most useful for suppressing meta-character
expansion. On the other hand, for a simple word search, ignoring
case is sometimes useful.

If for some reason, it is better to keep the current behavior of grep, then I
suggest to extend the documentation as follows:

ORIGINAL:
   fixed: logical.  If 'TRUE', 'pattern' is a string to be matched as
          is.  Overrides all conflicting arguments.

SUGGESTED:
   fixed: logical.  If 'TRUE', 'pattern' is a string to be matched as
          is.  Overrides all conflicting arguments including ignore.case.

All the best, Petr Savicky.



[Rd] grep with fixed=TRUE and ignore.case=TRUE
Petr Savicky