From: "Stu P. D'naim" <lists@...>
Date: 2013-02-16T01:32:01+09:00
Subject: [from BASIC to Ruby] so, what's the proper way to replace funcionality of GOTO ?

I need to make few scripts for tasks I do often manually, but last time
I programmed something was almost 20 years ago in high school, we used
some BASIC dialect. Since no one uses BASIC nowdays, I decided to give a
try to Ruby (I also tried Python, but it's strict indentation is driving
me insane).

I watched Ruby Essentials Video from Lynda.com (twice), and I pretty
much understand almost all of it, but still, I'm having trouble to adapt
how to structure my programs (without using of GOTO)


Here's a simple example written in FreeBASIC (it works)
---------------------------------------------------------------------
Dim As Integer strKeyPress

menu_00:

CLS
PRINT "what do you desire:"
PRINT
PRINT "1 - open menu_01"
PRINT "2 - open menu_02"
PRINT "3 - open menu_03"
PRINT "4 - open menu_04"
PRINT "q  - Quit"

REM is comment line, same as ' ... code for Q is 81, q = 113

Do
  strKeyPress = GetKey
Loop Until strKeyPress <> 0

'49 represents number 1 on a keybord, and so on

if strKeyPress = 49 THEN
  goto menu_01
elseif strKeyPress = 50 THEN
  goto menu_02
elseif strKeyPress = 51 THEN
  goto menu_03
elseif strKeyPress = 52 THEN
  goto menu_04
elseif strKeyPress = 81 or strKeyPress = 113 THEN
  goto programendshere
else
  print
  print "Wrong Choice, Try Again!"
  sleep 1000

menu_00_endif:
end if

goto menu_00

menu_01:
  cls
  print
  print "menu 01"
  sleep 1000
  goto menu_00_endif
menu_02:
  cls
  print
  print "menu 02"
  sleep 1000
  goto menu_00_endif
menu_03:
  cls
  print
  print "menu 03"
  sleep 1000
  goto menu_00_endif
menu_04:
  cls
  print
  print "menu 04"
  sleep 1000
  goto menu_00_endif

programendshere:

End 0
------------------------------------------------------------------

So, what would be the best practice to make this work in modern
languages, like Ruby ? Here are some ideas I have, would be nice to know
if it's good thinking or wrong:

1- make all menues part of a same Class, so I can use instance variables
(I will need to do some calculations)

2- define every menu as separate method, so you travel from root
menu_00 (method) --> menu_01 (which is separate method) --> ... etc go
back and forth ... #could this be memory demanding if there is too many
sub-menu branching ???

3- define every menu as separate method, but you DO NOT start new method
from INSIDE of other method. It goes something like this: menu_00
returns value to a loop, that value is name of sub-menu (menu_01,
separate method) ... I'd then have to use -->
method(name_of_returned_value).call()
This looks better than option #2, but my attempts to make it work so far
failed ... not sure if it is even possible to achieve at all

4- every menu is separate method, but they only have puts "enter choice"
lines, no other code, and a $global variable which I will use later in
IF loops to detect inside which menu (method) I am:

if $global == "00" and userInputChoice == "1"
  #if you are currently inside root menu 00, and user input is "1"
  menu_01()
  $global = "01"
  ... etc

I think this could easily work, though, might not look nice
.................................................................

So basically, I'd like to know which way should I go for, 2,3 or 4, or
there is maybe even something else? And, also is idea #1 ok ?

I hope this wasn't too long to read for my first question here, starting
something new is always hardest part for me

-- 
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