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Posting-Version: version B 2.10.2 9/18/84; site utflis.UUCP
Path: utzoo!utcsri!utai!utflis!chai
From: chai@utflis.UUCP (Henry Chai)
Newsgroups: net.lang
Subject: Re: Snobol -> Icon translation
Message-ID: <543@utflis.UUCP>
Date: Thu, 24-Oct-85 20:54:25 EDT
Article-I.D.: utflis.543
Posted: Thu Oct 24 20:54:25 1985
Date-Received: Fri, 25-Oct-85 01:35:02 EDT
References: <45000004@hpcnof.UUCP>
Reply-To: chai@utflis.UUCP (Henry Chai)
Organization: FLIS, University of Toronto
Lines: 65
Summary: 

In article <45000004@hpcnof.UUCP> dat@hpcnof.UUCP writes:
>
>	&ANCHOR = 1
>	&TRIM   = 1
>TOP	OUTPUT = "WHAT IS YOUR NAME?"
>	STRING = INPUT
>	STRING   "DAVE"  RTAB(0)		:F(OTHER)
>	OUTPUT = "HELLO DAVE!"			:(END)
>OTHER	OUTPUT = "I DON'T KNOW YOU!"		:(TOP)
>END 
>
# Here is a translation into a one-liner Icon program 
procedure main()
  while ( write("What is your name?") ,
          String := trim(read()) ,
          not( if String[1:0] == "DAVE" then write("Hello Dave!"))
        ) do
	      write("I don't know you!")
end
# but it's very bad style.
#
# Explanation:
# while (x1, x2, x3) is just the same as while (x1 & x2 & x3).
# The reason why this can be done here is that all expressions either
# suceed or fail.  Thus the while will stop only on the third part
# (i.e. when the string "DAVE" is matched with the complete line)
# Since the write and read statements will always suceed.
# String[1:0] will take the place of &ANCHOR and RTAB(0) i.e. from the
# first char to the last (if I've remembered my SNOBOL correctly!)
# ("string" is a reserved word)
#
# For clarity, you can have
#
procedure main()
   while /done do
   {
       write("What is your name?")
       String := trim(read())
       if String[1:0] == "DAVE" then
       {
          write("Hello Dave!")
          done := 0                    # or any value
       }
       else
          write("I don't know you")
   }
end
#
# Explanation:
# The operation "/done" tests whether "done" is a null variable
# (i.e. whether it's defined or not). Once you assigned a value
# to "done", "/done" fails.

----------------------------------------------------------------------------

In general Icon is syntactically similar to Pascal, but the structure
is like C (i.e. no nested blocks).

I trust you have the book "The Icon Programming Language" by Griswold
& Griswold ?? (Prentice Hall, 1983)

-- 
Henry Chai, just a humble student at the 
Faculty of Library and Information Science, U of Toronto
{watmath,ihnp4,allegra}!utzoo!utflis!chai