File I/O

File I/O

[Tim Johnson]

Hi:

Is it possible to do File I/O with elisp.
  (as opposed to reading it into a buffer)

IOWS: read a file
      process stream a line at a time
	  process programmatically

thanks
tim

-- 
Tim Johnson <tim@johnsons-web.com>
      http://www.alaska-internet-solutions.com

Re: File I/O

[Robert Thorpe]

Tim Johnson wrote:
> Hi:
>
> Is it possible to do File I/O with elisp.
>   (as opposed to reading it into a buffer)
>
> IOWS: read a file
>       process stream a line at a time
> 	  process programmatically

Not really.  The normal way of doing the above is to create a buffer
for the file first.

It might be better if you tell us what you're trying to do, that makes
it easier to suggest something.

Re: File I/O

[Tim Johnson]

On 2006-11-02, Robert Thorpe <rthorpe@realworldtech.com> wrote:
>> IOWS: read a file
>>       process stream a line at a time
>> 	  process programmatically
>
> Not really.  The normal way of doing the above is to create a buffer
> for the file first.
>
> It might be better if you tell us what you're trying to do, that makes
> it easier to suggest something.

 My hope was to read a file into an emacs data structure. 
 text delimited by an arbitrary line ( blank or all hyphens as an
 example)

 the data structure would be a list of lists.

 each internal list would have 3 elements.

 the first two would be strings, the last a list of strings.
 and the structure would be accessed via 'assoc.
 
 ( ;; begin parent structure
  ( ;; begin element
   "chop"  ;; key
   "Remove last member" ;; terse description
   ("Line one" "Line two" "Line three") ;; verbose description
   ) 
 )

 I've created such a structure using a General Purpose Programming
 Language, but had headaches with escaping. Thought using emacs
 might bypass that problem.

 thanks
 tim

-- 
Tim Johnson <tim@johnsons-web.com>
      http://www.alaska-internet-solutions.com

Re: File I/O

[Robert Thorpe]

Tim Johnson wrote:
> On 2006-11-02, Robert Thorpe <rthorpe@realworldtech.com> wrote:
> >> IOWS: read a file
> >>       process stream a line at a time
> >> 	  process programmatically
> >
> > Not really.  The normal way of doing the above is to create a buffer
> > for the file first.
> >
> > It might be better if you tell us what you're trying to do, that makes
> > it easier to suggest something.
>
>  My hope was to read a file into an emacs data structure.
>  text delimited by an arbitrary line ( blank or all hyphens as an
>  example)
>
>  the data structure would be a list of lists.
>
>  each internal list would have 3 elements.
>
>  the first two would be strings, the last a list of strings.
>  and the structure would be accessed via 'assoc.
>
>  ( ;; begin parent structure
>   ( ;; begin element
>    "chop"  ;; key
>    "Remove last member" ;; terse description
>    ("Line one" "Line two" "Line three") ;; verbose description
>    )
>  )
>

You could use the command David mentions below for this.

If you are defining the data file yourself there is no reason not to
use elisp read and print.
In elisp a set of lists can be printed by "print" and reconstructed by
reading with "read".

>  I've created such a structure using a General Purpose Programming
>  Language, but had headaches with escaping. Thought using emacs
>  might bypass that problem.

Escaping problems tend to be, erm, hard to escape.  Using elisp may not
help here.

Re: File I/O

[David Kastrup]

Tim Johnson <tim@johnsons-web.com> writes:

> Is it possible to do File I/O with elisp.
>   (as opposed to reading it into a buffer)
>
> IOWS: read a file
>       process stream a line at a time
> 	  process programmatically

See `insert-file-contents' which can extract just parts from a file
into a buffer.

-- 
David Kastrup, Kriemhildstr. 15, 44793 Bochum