Re: How to change environment from a module

["Mark Hessling" <m.hessling@qut.edu.au>]

> On Dec 22,  3:24pm, Mark Hessling wrote:
> }
> } So, from within the module I have, I need to be able to do the
> following: } 1) Get the current value of an environment variable
> } 2) Set the value of an enviornment variable
> } 3) Get the value of the current working directory
> } 4) Set the value of the current working directory
> } 
> } I thought I might be able to use bin_cd() and bin_typeset()
> 
> In general you shouldn't call bin_ functions directly.  They
> should almost always be called only via the command execution
> code.

Why should these functions not be called directly ? See below for more
explanation.

> 
> } 2) How does one get the values of an environment variable and
> current } working directory from within a module ?
> 
> Most likely you want these functions:
> 
>     createparam(variablename, PM_EXPORTED);
>     getsparam(variablename);
>     setsparam(variablename, valuestring);
> 
>     struct dirsave ds;
>     dir = zgetdir(&ds);
>     restoredir(&ds);
> 
> It's very likely that your module should call zgetdir(&ds) before
> running the Rexx program and call restoredir(&ds) after it.  That
> is, the Rexx program should not permanently change the shell's
> current directory. Within the Rexx program, the usual chdir()
> system call can be used (but the values of the PWD and OLDPWD
> variables cannot be relied upon).  In this sense the Rexx program
> would behave as if it is an external command.

But this is the only reason for running a Rexx interpreter within the
current process of the shell; to change the environment permanently.

Based on this premise, then calling routines like zchdir() doesn't go the
whole way. ie if you have a chpwd() function in .zshrc, then zchdir()
doesn't call it. It seems that only a call to bin_cd() will result in a
call to chpwd().

So again, how should one call the bin_*() functions directly from a module
as though a "cd" command or "export" command were executed directly by the
user ?

Cheers, Mark.

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