path/PATH function

path/PATH function

[Sweth Chandramouli]

	i long time ago, i wrote a quick function to take a list of
space-delimited dirs, check to see if each one was currently in my path, and if 
not, add it.  i was just trying to make some changes to it, when i noticed in my 
.zshrc (modified from one that i got from someone else) a line saying 

cdpath=(. .. ~)

	i hadn't declared $CDPATH anywhere in my .z* files, but echoing $CDPATH 
after login returned
	
.:..:/home/sweth/sweth

	i'm assuming that this is some sort of zsh path-addition option, along 
the lines of what i had created; i couldn't find any reference to it in the FAQ, 
however, other than a note in the wish-list for users to "be able to create 
their own foopath/FOOPATH array/path combinations."  does anyone know anything 
more about this feature?

Re: path/PATH function

[Bruce Stephens]

[I'm reading from zsh-3.1.2, but I think this is the same in 3.0.5]

sweth@astaroth.nit.gwu.edu said:
> cdpath=(. .. ~)
> 	i hadn't declared $CDPATH anywhere in my .z* files, but echoing
> $CDPATH  after login returned
> 	 .:..:/home/sweth/sweth 

sweth@astaroth.nit.gwu.edu said:
> i'm assuming that this is some sort of zsh path-addition option, along
>  the lines of what i had created; i couldn't find any reference to it
> in the FAQ,  however, other than a note in the wish-list for users to
> "be able to create  their own foopath/FOOPATH array/path
> combinations."  does anyone know anything  more about this feature? 

Look at the zshparam manpage.  cdpath and CDPATH are linked in the same way as 
path and PATH.  typeset -U may also be relevant: it tells zsh to keep only the 
first element of identical copies, and comments that this also works with 
special variables like PATH and CDPATH.

Note that there's a typo in the description: should be "For arrays keep only 
the first element of each duplication.", not "...duplications".  I think, 
anyway, perhaps there's a better way to phrase it.

Re: path/PATH function

[Bart Schaefer]

On Nov 19, 10:37am, Sweth Chandramouli wrote:
} Subject: path/PATH function
}
} 	i long time ago, i wrote a quick function to take a list of
} space-delimited dirs, check to see if each one was currently in my path,
} and if  not, add it.
} 
[describes cdpath mapping onto CDPATH]
} 
} 	i'm assuming that this is some sort of zsh path-addition option, along 
} the lines of what i had created; i couldn't find any reference to it in the
} FAQ,  however, other than a note in the wish-list for users to "be able to
} create  their own foopath/FOOPATH array/path combinations."  does anyone
} know anything  more about this feature?

This "feature" is restricted at present to a few pairs of variables that are
hardwired at compile time.  They include:

CDPATH		cdpath
FPATH		fpath
MAILPATH	mailpath
MANPATH		manpath
PATH		path

These are documented in `man zshparam` and in the info files.  The remark
in the FAQ refers to the desire to provide arbitrary user-defined pairs
of variables that behave this way.

You might also wish to look into `typeset -U` which causes an array to
remove all non-unique elements from itself.  A function to test whether
any given directory is already in your path shouldn't be necessary.

-- 
Bart Schaefer                                 Brass Lantern Enterprises
http://www.well.com/user/barts              http://www.brasslantern.com

Re: path/PATH function

[Sweth Chandramouli]

On Wed, Nov 19, 1997 at 08:27:51AM -0800, Bart Schaefer wrote:

> This "feature" is restricted at present to a few pairs of variables that are
> hardwired at compile time.  They include:
> 
> CDPATH		cdpath
> FPATH		fpath
> MAILPATH	mailpath
> MANPATH		manpath
> PATH		path
	maybe the documentation i have isn't that complete, but all i could find 
in the manpage for zshparam is the fact that the variables like cdpath and path 
exist and are "special" varaibles; there isn't any mention of how they are 
mapped on to their capitalized counterparts.  my next question, then, is if 
these do, in fact, work the way i surmised (that is, they remove redundancies 
and map their colon-delimited versions onto the capitalized equivalent 
variable).  also, what exactly is the format for defining them?  is it just 
paren-enclosed, space-delimited lists?

> You might also wish to look into `typeset -U` which causes an array to
> remove all non-unique elements from itself.  A function to test whether
> any given directory is already in your path shouldn't be necessary.
	the version of typeset on my system doesn't seem to support this option 
(or at least, the man page doesn't mention it).  typeset doesn't return an error 
if i try to use the -U switch, however; could someone summarize the syntax so i 
could see if it is, in fact, implemented?
	
	tia,
	sweth.

Re: path/PATH function

[Bruce Stephens]

sweth@astaroth.nit.gwu.edu said:
> my next question, then, is if  these do, in fact, work the way i
> surmised (that is, they remove redundancies  and map their
> colon-delimited versions onto the capitalized equivalent  variable).

Yes, but there's no removing of redundancies.  There's back-mapping too, if you set CDPATH then cdpath gets set.

sweth@astaroth.nit.gwu.edu said:
> also, what exactly is the format for defining them?  is it just
> paren-enclosed, space-delimited lists? 

Yes, standard array syntax.

sweth@astaroth.nit.gwu.edu said:
> the version of typeset on my system doesn't seem to support this
> option  (or at least, the man page doesn't mention it).  typeset
> doesn't return an error  if i try to use the -U switch, however; could
> someone summarize the syntax so i  could see if it is, in fact,
> implemented?

Try:

cdpath=(.. ..)
echo $cdpath	;# Should give ".. .."
typeset -U cdpath
echo $cdpath	;# Should give ".."

Works in my 3.1.2 beta, anyway.  I don't know whether typeset -U is in 3.0.5.