Re: "case" or better? (2.6 suggestion mode)
- Posted by Eglenn4511 at aol.com
Apr 03, 2005
-------------------------------1112561998
Content-Type: text/plain; charset="US-ASCII"
Content-Transfer-Encoding: 7bit
In a message dated 4/3/2005 11:47:32 A.M. Mountain Standard Time,
guest at RapidEuphoria.com writes:
The programer does the evaluating when
> the program is written instead of the machine each time the program is
> executed.
>
Very interesting, please elaborate. I am having trouble understanding how
this would work if a decision had to be made at run-time.
This seems common in Forth:
http://pfe.sourceforge.net/4thtutor/4thl3-3.htm
However, Forth still has if-else.
Oh my :) I am brand new to Euphoria and have done most of my programming in
Forth. I once wrote a program to help learn Morse code. Originally, I used
an if/elsif sequence as follows
if c = 'e' or 'E' then
dit()
elsif c = 't' or 'T' then
dah()
elsif c = 'i' or 'I' then
di() dah()
... etc
Then I saved a little space and time by converting alpha characters to
uppercase.
This cut the program size and increased its speed a little
Next I decided to try vectored execution. I defined each letter, aa() = di
dah, bb() = da di di dit, ... etc. I then put aa() in position 65, bb() in
position 66, etc in a table. noop was placed in each location for which there
was no Morse code symbol. Sending the letter 'a' became code_table['a']
Finally, I got rid of the "aa() = di dah" etc statements. I converted them
to binary numbers that represented dits and dahs. A dit was a '0' and a dah was
a '1'. 'A' became 110, 'b' was 10001, 'e' was 10, 't' was 11, etc. I worked
out the numbers and stored them in a table. In Euphoria, they would be stored
as a sequence. This reduced the program size and kept the speed. (For the
curious, the numbers were read from right to left. The most significant bit
said that a code symbol was represented. The numbers were shifted left after
each read and when c / 2 = 0 conversion was completed.)
I then learned that the program read text files as easily as it read
keyboard input. I now wrote a program that I could use on Amateur Radio I hated
using a key to send Morse code but could type fairly well. The program sent
perfect code which could never be said about me.
-------------------------------1112561998
Content-Type: text/html; charset="US-ASCII"
Content-Transfer-Encoding: 8bit
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META http-equiv=Content-Type content="text/html; charset=US-ASCII">
<META content="MSHTML 6.00.2900.2604" name=GENERATOR></HEAD>
<BODY id=role_body style="FONT-SIZE: 10pt; COLOR: #000000; FONT-FAMILY: Arial"
bottomMargin=7 leftMargin=7 topMargin=7 rightMargin=7><FONT id=role_document
face=Arial color=#000000 size=2>
<DIV>
<DIV>In a message dated 4/3/2005 11:47:32 A.M. Mountain Standard Time,
guest at RapidEuphoria.com writes:</DIV>
<BLOCKQUOTE
style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: blue 2px solid"><FONT
style="BACKGROUND-COLOR: transparent" face=Arial color=#000000 size=2>The
programer does the evaluating when <BR>> the program is written
instead of the machine each time the program is<BR>> executed.<BR>>
<BR><BR>Very interesting, please elaborate. I am having trouble understanding
how<BR>this would work if a decision had to be made at run-time.<BR><BR>This
seems common in
Forth:<BR><BR>http://pfe.sourceforge.net/4thtutor/4thl3-3.htm<BR><BR>However,
Forth still has if-else.<BR></FONT></BLOCKQUOTE></DIV>
<DIV></DIV>
<DIV>Oh my :) I am brand new to Euphoria and have done most of my
programming in Forth. I once wrote a program to help learn Morse code.
Originally, I used an if/elsif sequence as follows </DIV>
<DIV>if c = 'e' or 'E' then</DIV>
<DIV> dit()</DIV>
<DIV>elsif c = 't' or 'T' then</DIV>
<DIV> dah()</DIV>
<DIV>elsif c = 'i' or 'I' then</DIV>
<DIV> di() dah()</DIV>
<DIV>... etc</DIV>
<DIV> </DIV>
<DIV>Then I saved a little space and time by converting alpha characters to
uppercase.</DIV>
<DIV>This cut the program size and increased its speed a little</DIV>
<DIV> </DIV>
<DIV>Next I decided to try vectored execution. I defined each letter, aa() = di
dah, bb() = da di di dit, ... etc. I then put aa() in position 65, bb() in
position 66, etc in a table. noop was placed in each location for which there
was no Morse code symbol. Sending the letter 'a' became code_table['a']</DIV>
<DIV> </DIV>
<DIV>Finally, I got rid of the "aa() = di dah" etc statements. I converted them
to binary numbers that represented dits and dahs. A dit was a '0' and a dah was
a '1'. 'A' became 110, 'b' was 10001, 'e' was 10, 't' was 11, etc. I worked out
the numbers and stored them in a table. In Euphoria, they would be stored as a
sequence. This reduced the program size and kept the speed. (For the curious,
the numbers were read from right to left. The most significant bit said that
a code symbol was represented. The numbers were shifted left after each
read and when c / 2 = 0 conversion was completed.)</DIV>
<DIV> </DIV>
<DIV>I then learned that the program read text files as easily as it read
keyboard input. I now wrote a program that I could use on Amateur Radio I hated
using a key to send Morse code but could type fairly well. The program sent
perfect code which could never be said about me.</DIV></FONT></BODY></HTML>
-------------------------------1112561998--
|
Not Categorized, Please Help
|
|
