common code patterns

Mark Wieder ahsoftware at sonic.net
Fri Aug 11 11:26:46 EDT 2017


On 08/11/2017 02:24 AM, Mark Waddingham via use-livecode wrote:

> Not quite on topic for the thread, but this interested in me in terms of 
> - what are the use cases?

Somewhat similar to Ralph's use cases, this paradigm comes up quite 
often in my code. Probably the most common case is where I want the 
performance of a 'repeat for each' loop but don't have a proper iterator 
to use, so I have to use a doppelganger. Examples here from actual 
working code:

case 1:
setting up an array of constants:

put 0 into tCount
repeat for each item tConst in tConsts
   put tConst into tArray[tCount]
   add 1 to tCount
end repeat

case 2:
iterating through a cr-separated list and needing to modify lines
(note: this is even more extreme if I need to delete lines):

put tBreaks into tNewBreaks
put 1 into tLine
repeat for each line tBreak in tBreaks
   put item 1 of tBreak into tID
   put the long id of control id tID of the topstack into tObjectID
   put tObjectID into item 1 of line tLine of tNewBreaks
   add 1 to tLine
end repeat
return tNewBreaks

case 3:
parsing data and needing an iterator:

command SetVarFieldColors pFieldName
   local x

   put 1 into x
   set the itemdelimiter to tab
   repeat for each line tLine in field pFieldName
     switch item 3 of tLine
       case "C"
         set the forecolor of item 2 to 3 of line x of field pFieldName 
to sDebugColors["declarations"]
         break
       case "P"
         set the forecolor of item 2 to 3 of line x of field pFieldName 
to sDebugColors["parameters"]
         break
       default
         break
     end switch
     add 1 to x
   end repeat
end SetVarFieldColors


-- 
  Mark Wieder
  ahsoftware at gmail.com




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