Javascript-like for_each

[Paolo Redælli]

I may have been contaminated by _javascript_... :)

See https://developer.mozilla.org/en-US/docs/Web/_javascript_/Reference/Global_Objects/Array/forEach

// Arrow function
forEach((element) => { /* ... */ })
forEach((element, index) => { /* ... */ })
forEach((element, index, array) => { /* ... */ })

// Callback function
forEach(callbackFn)
forEach(callbackFn, thisArg)

// Inline callback function
forEach(function(element) { /* ... */ })
forEach(function(element, index) { /* ... */ })
forEach(function(element, index, array){ /* ... */ })
forEach(function(element, index, array) { /* ... */ }, thisArg)

one can call in [2,3,5,7,11].forEach( (e,i) => {console.log( i+"-nth prime is "+e);})


to get

0-nth prime is 2
1-nth prime is 3
2-nth prime is 5
3-nth prime is 7
4-nth prime is 11

Liberty Eiffel allows for an almost brief syntax:

class FOO
create make
feature
      make is
   do
      (<<2,3,5,7,11>>).do_all(agent (x: INTEGER_8) do
      print(x.out+" is prime%N");
      end)
   end
end



    Where the actual code equivalent is  (<<2,3,5,7,11>>).do_all(agent
      (x: INTEGER_8) do print(x.out+" is prime%N"); end)
    
    Which is a little more verbose. Since the index and the
      container is often useful in the called agent I think that we may
      evaluate to change the signature of for_each to
        for_each (action: PROCEDURE[TUPLE[AN_ITEM,INTEGER,ANY]]) 
    
    becuase TUPLE[AN_ITEM] and TUPLE[AN_ITEM,INTEGER] conform to TUPLE[AN_ITEM,INTEGER,ANY]