For loop linguistic abstraction (usage)

[Filip Konvička]

Uh, sorry....

      {Dictionary.condExchange D X 0 O N}


F.
> Hi Craig,
>> Hello,
>>
>>    The following code calculates the frequency of elements in a 
>> list.  How
>> would the second function be written using the for loop linguistic
>> abstraction for lists if possible?  Thanks - Craig.
>>
>>
>> declare
>>
>> fun {IncMapForFeature FreqMap X}
>>   if {HasFeature FreqMap X} == false then
>>      {AdjoinAt FreqMap X 1}
>>   else
>>      {AdjoinAt FreqMap X FreqMap.X+1}
>>   end
>> end
> You can use {CondSelect FreqMap X 1} here.
>> fun {CalcFreqMap List}
>>   local
>>      fun {CalcFreqMap2 List FreqMap}
>>  case List of nil then FreqMap
>>  [] X|Xr then {CalcFreqMap2 Xr {IncMapForFeature FreqMap X}}
>>  end
>>      end
>>   in
>>      {CalcFreqMap2 List freqmap()}
>>   end
>> end
> Beware - you are using List as a local variable name, but it is a 
> builtin module name. I suggest you turn on the "variable shadowing" 
> compiler flag.
>
> You can do this like this
>
> fun {CalcFreqMap L}
>   D={NewDictionary}
> in
>   fun X in L do
>       O N
>   in
>       {Dictionary.condExchange D X O N}
>       N=O+1
>   end
>   {Dictionary.toRecord freqmap D}
> end