How can the below code be changed to use the trampoline function? Thanks.  var count = function (n) {     if(typeof n !== 'number' || n % 1 !== 0) return null;     if(n &lt; 3) { return 1; }     console.log(n)     return count(n - 1) + count(n - 3) }
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During recent discussions at work, someone referred to a trampoline function.  I have read the description at .  It is enough to give a general idea of the functionality, but I would like something a bit more concrete.  Do you have a simple snippet of code that would illustrate a trampoline?
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I understand passing in a function to another function as a callback and having it execute, but I'm not understanding the best implementation to do that. I'm looking for a very basic example, like this:  var myCallBackExample = {     myFirstFunction : function( param1, param2, callback ) {         // Do something with param1 and param2.         if ( arguments.length == 3 ) {             // Execute callback function.             // What is the "best" way to do this?         }     },     mySecondFunction : function() {         myFirstFunction( false, true, function() {             // When this anonymous function is called, execute it.         });     } };   In myFirstFunction, if I do return new callback(), then it works and executes the anonymous function, but that doesn't seem like the correct approach to me.
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Find all functions $f$ that assign a real number $f(x)$ to every real number $x$ such that $$(x+y)f(x)+f(y^2)=(x+y)f(y)+f(x^2)$$  I've tried subbing in heaps of values but I keep getting things like $f(0)=f(0)$ and other such useless results.  Any help would be hugely appreciated.
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What is the best or most concise method for returning a string repeated an arbitrary amount of times?  The following is my best shot so far:  function repeat(s, n){     var a = [];     while(a.length &lt; n){         a.push(s);     }     return a.join(''); }
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I'm trying to figure out how to make a function that can take an array as a parameter and sort it. I think it is done with positional variables, but I'm not sure.
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Note that this function does not have a "{" and "}" body.  Just a try/catch block:  void func( void ) try {     ... } catch(...) {     ... }   Is this intentionally part of C++, or is this a g++ extension?  Is there any purpose to this other than bypass 1 level of {}?  I'd never heard of this until I ran into
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The following code works differently depending on which way Parse_Short_Switches() is called.  After calling the function 'Parse_Short_Switches' by using result=$(Parse_Short_Switches), the value of $error_flag is NOT set to -1 as I would expect.  After calling the function 'Parse_Short_Switches' by simply using Parse_Short_Switches, the the value of $error_flag is set to -1 as I would expect.  Any help would be greatly appreciated.  Thanks  #!/bin/bash  function Parse_Short_Switches() { echo "error_flag inside of the function= $error_flag" 1&gt;&amp;2 error_flag="-1" echo "blah blah ..." }  # --- MAIN --- error_flag="999" echo "error_flag= $error_flag" #result=$(Parse_Short_Switches) Parse_Short_Switches echo "error_flag= $error_flag"
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I have a Python function that takes a numeric argument that must be an integer in order for it behave correctly. What is the preferred way of verifying this in Python?  My first reaction is to do something like this:  def isInteger(n):     return int(n) == n   But I can't help thinking that this is 1) expensive 2) ugly and 3) subject to the tender mercies of machine epsilon.   Does Python provide any native means of type checking variables? Or is this considered to be a violation of the language's dynamically typed design?  EDIT: since a number of people have asked - the application in question works with IPv4 prefixes, sourcing data from flat text files. If any input is parsed into a float, that record should be viewed as malformed and ignored.
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I have the name of a function in JavaScript as a string. How do I convert that into a function pointer so I can call it later?  Depending on the circumstances, I may need to pass various arguments into the method too.  Some of the functions may take the form of namespace.namespace.function(args[...]).
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I have a function isoToScreen(x, y) that converts Isometric coordinates to Screen coordinates.  var tileW = 16; var tileH = 16;  var isoToScreen = function(x, y) {     var posX = (x - y) * tileW;     var posY = (x + y) * tileH / 2;      return [posX, posY]; };   But how would I make a function that converts screen coordinates back to Isometric coordinates?  var pos = screenToIso(16, 8);  pos[0] = 1; // Iso X pos[1] = 0; // Iso Y
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Is it like...  var obj = new Object();  obj.function1 = function(){     //code }   or something like that?
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First of all, I swear this is not homework, it's a question I was asked in an interview. I think I made a mess of it (though I did realise the solution requires recursion). Here is the question:  Implement the count() method which returns the number of nodes in a tree. If a node doesn't have either a left or right child, the relevant getXXChild() method will return null  class Tree {    Tree getRightChild() {     // Assume this is already implemented   }    Tree getLeftChild() {     // Assume this is already implemented   }    int count() {     // Implement me   } }   My reason for asking the question is simply curious to see the correct solution, and thereby measure how bad mine was.  Cheers, Tony
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I'd like to convert a float to a whole number in JavaScript. Actually, I'd like to know how to do BOTH of the standard conversions: by truncating and by rounding. And efficiently, not via converting to a string and parsing.
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I'm sure there's a simpler way of doing this that's just not occurring to me.  I'm calling a bunch of methods that return a list.  The list may be empty.  If the list is non-empty, I want to return the first item; otherwise, I want to return None.  This code works:  my_list = get_list() if len(my_list) &gt; 0: return my_list[0] return None   It seems to me that there should be a simple one-line idiom for doing this, but for the life of me I can't think of it.  Is there?  Edit:  The reason that I'm looking for a one-line expression here is not that I like incredibly terse code, but because I'm having to write a lot of code like this:  x = get_first_list() if x:     # do something with x[0]     # inevitably forget the [0] part, and have a bug to fix y = get_second_list() if y:     # do something with y[0]     # inevitably forget the [0] part AGAIN, and have another bug to fix   What I'd like to be doing can certainly be accomplished with a function (and probably will be):  def first_item(list_or_none):     if list_or_none: return list_or_none[0]  x = first_item(get_first_list()) if x:     # do something with x y = first_item(get_second_list()) if y:     # do something with y   I posted the question because I'm frequently surprised by what simple expressions in Python can do, and I thought that writing a function was a silly thing to do if there was a simple expression could do the trick.  But seeing these answers, it seems like a function is the simple solution.
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I've recently started maintaining someone else's JavaScript code. I'm fixing bugs, adding features and also trying to tidy up the code and make it more consistent.  The previous developer used two ways of declaring functions and I can't work out if there is a reason behind it or not.  The two ways are:  var functionOne = function() {     // Some code };     function functionTwo() {     // Some code }   What are the reasons for using these two different methods and what are the pros and cons of each? Is there anything that can be done with one method that can't be done with the other?
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Is there any function in Apex which could emulate functionality of the  formula function? I'm trying to get 18-char Id variant from the standard one.
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What does it mean to extend a function? Can someone please give an example?  Thanks in advance!