Re: Problem with a small program

[Paul Haahr <haahr@netcom.com>]

> I was trying a small program from the paper
> 	"Es: A shell with higher-order functions" - Haahr and Rakitzis
> 
> on my system  "dgux asterix 5.4R3.10 generic AViiON" (asterix is my system's
> pet name). The program is as follows ..
> 
> ;fn hello-world {
> return 'hello, world'
> }
> ;echo <>{hello-world}
> ... At this point instead of getting the result as "hello, world", i get the
> following error 
> 	"bad /dev/fd redirection"

That's something which changed after the paper was published.  The <>
syntax was replaced with <=.  <> now means open for reading and writing.

Using the new syntax, it works:

  ; fn hello-world {
    return 'hello, world'
  }
  ; echo <= { hello-world }
  hello, world
  ; echo <= hello-world
  hello, world
  ; 

See http://www.webcom.com/haahr/es/es-usenix-winter93.html#erratum2.

> another question i have, is --
> 
> 	how to execute es programs from a file??
> 	i typed in above function and the following echo statement in a file,
> 	changed it's permissions to "a+x". But when i typed the name of this
> 	file on es prompt, it gave me "Bad Exec format error".

Try putting

  #! /usr/local/bin/es

(or whatever the right path is) as the first line of your file.

--p