Ask HN: What's your most-used function that you wrote yourself?

Example:

    let n be an int
    n.Becomes("2") //returns 2
    n.Becomes("sdfsd") //returns n

    0.Becomes("12") returns 12
    0.Becomes("sdssdf") returns 0

    var person = Person.Get(0.Becomes(Request.QueryString["id"]));

    n.Becomes(SOME_STRING)

More technically, `Becomes` returns a `ParseAttemptResult<T>` that is implicitly convertible to `T`. It also has `true` and `false` operators so that it can be used in an expression expecting a `Boolean` (e.g. `if` and the ternary operator`?:`).

Github Repo: https://github.com/noblethrasher/Parser-Helpers/blob/master/...

   function plural(count, itemName, pluralWord, singLead, plurLead, singFollow, plurFollow) {
      if (((typeof pluralWord != 'undefined') && (typeof pluralWord.valueOf() == 'string')) && (pluralWord.length > 0))
         var outP = count + ' ' + ((count == 1) ? itemName : pluralWord);
      else
         var outP = count + ' ' + itemName + ((count == 1) ? '' : 's');
      
      var follow = (count == 1) ? singFollow : plurFollow;
      outP += (((typeof follow != 'undefined') && (typeof follow.valueOf() == 'string')) && (follow.length > 0) ? ' ' + follow : '');

      var lead = (count == 1) ? singLead : plurLead;
      return (((typeof lead != 'undefined') && (typeof lead.valueOf() == 'string')) && (lead.length > 0) ? lead + ' ' : '') + outP;
   }

  alert('There ' + plural(c,'dog','','is','are') + ' in my house');
  c = 1 --> There is 1 dog in my house.
  c <> 1 --> There are 2 dogs in my house.

  alert(plural(c,'dog','','','','is','are') + ' in my house');
  c = 1 --> 1 dog is in my house.
  c <> 1 --> 2 dogs are in my house.

  alert('There ' + plural(c,'company','companies','is','are') + ' on the list');
  c = 1 --> There is 1 company on the list.
  c <> 1 --> There are 2 companies on the list.

  alert(plural(c,'company','companies','','','is','are') + ' on the list');
  c = 1 --> 1 company is on the list.
  c <> 1 --> 2 companies are on the list.

  #define check(A, M, ...)                       \
      if(!(A)) {                                 \
        fprintf(stderr, M "\n", ##__VA_ARGS__);  \
        goto error;                              \
      }                                          \
    }

  FooClass *create_foo_class()
  {
    FooClass *fc = NULL;
    int rc;
    fc = malloc(sizeof(*fc));
    check(fc != NULL, "allocation failed");

    rc = do_something_to_foo_class(fc);
    check(rc == 0, "do_something_to_foo_class(...) failed");
    
    return fc;
  error:
    if(fc != NULL) free(fc);
    /* Other cleanup */
    return NULL;
  }

  #Non-destructive.  Returns the input array/list in randomized order.  Uses approximately O(n) time and O(n) space.
  def self.shuffle_array(array)
    shallow_copy = array.map {|a| a}
    shallow_copy.size.downto(1) {|n| shallow_copy.push(shallow_copy.delete_at(rand(n)))
    shallow_copy
  end

   def history(num=100)
     h = Readline::HISTORY.to_a
     start = [0,h.size-num-1].max
     h.zip((0..h.size).to_a)[start...h.size].each do |cmd,i|         
       puts " #{(i).to_s.rjust(4)}  #{cmd}"
     end
   end

    function becho($value, $key = NULL)
    {
        echo '<br /><span style="background: #FFFFFF; color: #000000;">' . (NULL != $key ? $key . ' = ' : '') . $value . '</span>';
    }

    function s($num)
    {
         return $num == 1 ? '' : 's';
    }

    echo 'Showing ' . $results . ' result' . s($results) . '.';

    (defun my-rename-symbol-at-point ()
      (interactive)
      (let* ((curword (thing-at-point 'symbol))
        (to-word nil))
      (if (null curword)
        (message "No symbol at point!")
        (progn
          (setq to-word (read-string (concat "Replace " curword " with: ")))
          (save-excursion
            (goto-char (point-min))
            (replace-regexp re-curword to-word))))))

    (\>) x f = f x

    [1..10]
        \> map (*2)
        \> filter (<5)

Should emit a small sound when run, useful when running long running tasks so you dont have to pop back to the console window all the time to check if its done.

   $some_var = isset($array[$key]) ? $array[$key] : $default;

  // Synchronizes asynchronous calls: sync(functions..., completionHandler)
  var sync = function() {
    var argLength = arguments.length - 1
      , completed = 0
      , callback  = arguments[argLength]
    
    for (var i = 0; i < argLength; i++) {
      arguments[i](function() {
        completed++;
        (completed == argLength) && callback && callback();
      });
    }
  };

  var pageData = null;
  sync
    ( function(cb) { $('#pageContainer').fadeOut('slow', cb); }
    , function(cb) {
        $.ajax(
          { url: 'page.html'
          , success: function(msg) {
              pageData = msg;
              cb();
            }
          }
        );
      }
    , function() {
        $('#pageContainer').html(pageData).fadeIn('slow');
      }
    );

In SCSS I use a very simple mixin for rounded corners, something I use frequently when designing sites.

  @mixin radius($dist) {
    border-radius:$dist;
    -moz-border-radius:$dist;
    -webkit-border-radius:$dist;
    -khtml-border-radius:$dist;
    -webkit-background-clip:padding-box;
  }

  @include radius(5px);

All throughout the platform, there are many points at which the ANI/caller ID and the dialed digits (the user part of the request URI) must be "translated", which is a fancy phone switch term for stripping one or more digits and then prepending one or more digits. It was such a common operation that it was genericised into our most oft-used PL/PgSQL utility function:

  -- Character stripping and prefix prepending transformation, which is applied
  -- to the ANI and DNIS at virtually all entry and exit points in the call
  -- processing machine.
  
  CREATE OR REPLACE FUNCTION strip_prepend_transform(_token varchar,
  						   _strip_digits integer,
  						   _prepend_prefix varchar)
  RETURNS varchar
  AS $$
    DECLARE 
      _strip_len		smallint := 0; 
    BEGIN
      IF _strip_digits > 0 THEN
  	-- If the strip length given for some reason exceeds the 
  	-- actual string length, trim it down so that those digits
  	-- that do exist are still trimmed.
  
        IF _strip_digits > LENGTH(_token) THEN
          _strip_len = LENGTH(_token);
        ELSE
  	  _strip_len = LENGTH(_token) - _strip_digits;
        END IF;
  
        _token := SUBSTRING(_token FROM (_strip_digits + 1) FOR _strip_len);
      END IF;
  
      IF LENGTH(_prepend_prefix) > 0 AND _prepend_prefix <> '' THEN
        _token := (_prepend_prefix || _token);
      END IF;
  
      RETURN _token;
    END
  $$ LANGUAGE 'plpgsql';

  def random():
    return 4

That way if I change the html structure I don't have to to change a million jquery selectors, I can just change the from function in one place.

    // Access one particular element from another.
    function from(start, end) {
      start = $(start)
      if(start.parent().hasClass('headline') && end == 'node')
        return start.parent().parent()
      if(end == 'nodes')  return start.children('.node')
      if(end == 'headline')  return start.children('.headline')
      if(end.indexOf('.') != 0)  end = '.' + end
      if(start.hasClass('headline'))  return $(start.children(end))
      return start.find('> .headline > ' + end)
    }

  arc> src.src
  From: /Users/waterhouse/Dropbox/arc3.1/a
  (mac src (name (o strict t))
    `(src-fn ',name
             ',strict))
  Found 1 results in 1 different files.

  arc> aps.mat-
  (fermat-prime mat-add mat-add-mod mat-det mat-det2 mat-expt mat-id
  mat-mod-expt mat-mul mat-mul-mod mat-order mat-trans)

    def call(cmd):
	args = shlex.split(str(cmd))
	p = Popen(args, stdout=PIPE, stderr=PIPE)
	text = p.stdout.read()
	if not text:
		text = p.stderr.read()
	return text

  // PHP error_log() wrapper
  function el($var, $die = true) {
     error_log(var_export($var, true));
  
     if ($die) {
        die();
     }
  }

  // Javascript console.log() wrapper
  window.log = function() {
     log.history = log.history || [];
     log.history.push(arguments);
  
     if (this.console) {
        console.log(Array.prototype.slice.call(arguments));
     }
  };

Also, in haskell I use these frequently to have monadic versions of some common flow control functions (some nonstandard libraries have similar functions to these but it's easier to write my own):

  whenM c a = c >>= flip when a
  unlessM c a = c >>= flip unless a
  (>>?) = whenM
  (>>!) = unlessM
  -- low fixity allows eg, foo bar >>! error $ "failed " ++ meep
  infixr 0 >>?
  infixr 0 >>!

Mathematica code. Sets the CWD for file operations for a notebook to the same directory the current file is in. This is not default for Mac OSX.

    // PHP example
    function lowerTrim($t) {
      return strtolower(trim($t));
    }

My most-used function during debug-phase is pR:

   // especially useful when dealing with PHP arrays/objects
   function pR($a)
   {
     echo '<pre>';
     print_r($a);
     exit;
   }

function render($data, $templateFile) {

    extract( $data );
    ob_start();
    require $templateFile;
    echo ob_get_clean();

It turns an array (or DTO object using get_object_vars) into global variables in the template, so this code in a controller

$data->foo = "bar";

Is accessed in the template like this:

<?= $foo ?>

  function echo(text)
  {
  	if(!window.console)
  	{
  		alert(text);
  	}
  	else
  	{
  		console.log(text);
  	}
  }

PHP: Printing arrays

  function A( $array)
  {
    echo "<pre>"; print_r($array); echo "</pre>"; 
  }

  // php function for getting an array of filenames for a given directory...

  function dirscan($directory)
  {
    $fileset = array();
    if ($handle = opendir($directory))
    {
      while (false !== ($file = readdir($handle)))
      {
        if (($file != ".") && ($file != ".."))
        {
          $fileset[] = $file;
        }
      }
      closedir($handle);
    }
    return $fileset;
  }

    //sanitize and return url vars
    function get($fields) {
        if(is_array($fields)) {
            $info = array();
    
            foreach($fields as $field) {
                if(get($field) !== false) {
                    $info[$field] = get($field);
                }
            }
        
            return $info;
        } else {
            //Single Value
            $field = $fields;
        
            if(isset($_POST[$field])) {
                return trim(addslashes(strip_tags($_POST[$field])));
            }
        }
    
        return false;
    }

    function json_header() {
        header("Expires:" . gmdate( "D, d M Y H:i:s", strtotime("+2 minutes")) . "GMT"); 
        header("Last-Modified: " . gmdate( "D, d M Y H:i:s" ) . "GMT"); 
        header("Cache-Control: no-cache, must-revalidate" ); 
        header("Pragma: no-cache" );
        header("Content-type: application/json");
    }

I particularly like an alternate version I wrote of that which returns an associative array keyed by a given database field instead of a regular linear array. I don't need it as much, though.

(If this is still active on Monday, I'll post my real code)

    public static bool CheckedRaise<T>(this EventHandler<T> eh, object sender, T e)
        where T : EventArgs
    {
        bool check = eh != null;

        if (check)
            eh(sender, e);

        return check;
    }

  def run( command ):
    process = subprocess.Popen(
      command, 
      stdout=subprocess.PIPE,
      stderr=subprocess.PIPE
    )
    return process.communicate()

    <?php
    echo str_replace('    ', '&nbsp;&nbsp;&nbsp;&nbsp;', nl2br(htmlentities(iconv('utf-8', 'utf-8//IGNORE', print_r($data, TRUE)), ENT_QUOTES, 'UTF-8')));
    ?>

    public int echo(int x, String name)
    {
        System.out.println(name + ":\t" + x);
        return x;
    }

In use:

    this.setPreferredSize(new Dimension(getPreferredSize.getWidth(), echo(getViewportHeight(itemCount), "Viewport"));

    # encoding: utf-8
    import random

    CHARACTER_SETS = {
        'alpha':                                                'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ',             # 52
        'alpha_lowercase':                                      'abcdefghijklmnopqrstuvwxyz',                                       # 26
        'alpha_uppercase':                                      'ABCDEFGHIJKLMNOPQRSTUVWXYZ',                                       # 26
    
        'alpha_numeric':                                        'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789',   # 62
        'alpha_numeric_lowercase':                              'abcdefghijklmnopqrstuvwxyz0123456789',                             # 36
        'alpha_numeric_uppercase':                              'ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789',                             # 36
    
        'alpha_hardtoconfuse':                                  'abcdefghjkmnpqrstuvwxyzABCDEFGHJKLMNPQRSTUVWXYZ',                  # 47 --- Omits: i, l, o, I, O
        'alpha_hardtoconfuse_lowercase':                        'abcdefghjkmnpqrstuvwxyz',                                          # 23 --- Omits: i, l, o
        'alpha_hardtoconfuse_uppercase':                        'ABCDEFGHJKLMNPQRSTUVWXYZ',                                         # 24 --- Omits: I, O
    
        'alpha_numeric_hardtoconfuse':                          'abcdefghjkmnpqrstuvwxyzABCDEFGHJKLMNPQRSTUVWXYZ23456789',          # 55 --- Omits: i, l, o, I, O, 0, 1
        'alpha_numeric_hardtoconfuse_lowercase':                'abcdefghjkmnpqrstuvwxyz23456789',                                  # 31 --- Omits: i, l, o, 0, 1
        'alpha_numeric_hardtoconfuse_uppercase':                'ABCDEFGHJKLMNPQRSTUVWXYZ23456789',                                 # 32 --- Omits: I, O, 0, 1
    
        'alpha_consonants':                                     'bcdfghjklmnpqrstvwxyzBCDFGHJKLMNPQRSTVWXYZ',                       # 42 --- Omits: a, e, i, o, u, A, E, I, O, U
        'alpha_consonants_lowercase':                           'bcdfghjklmnpqrstvwxyz',                                            # 21 --- Omits: a, e, i, o, u
        'alpha_consonants_uppercase':                           'BCDFGHJKLMNPQRSTVWXYZ',                                            # 21 --- Omits: A, E, I, O, U
    
        'alpha_numeric_consonants':                             'bcdfghjklmnpqrstvwxyzBCDFGHJKLMNPQRSTVWXYZ0123456789',             # 52 --- Omits: a, e, i, o, u, A, E, I, O, U
        'alpha_numeric_consonants_lowercase':                   'bcdfghjklmnpqrstvwxyz0123456789',                                  # 31 --- Omits: a, e, i, o, u
        'alpha_numeric_consonants_uppercase':                   'BCDFGHJKLMNPQRSTVWXYZ0123456789',                                  # 31 --- Omits: A, E, I, O, U
    
        'alpha_consonants_hardtoconfuse':                       'bcdfghjkmnpqrstvwxyzBCDFGHJKLMNPQRSTVWXYZ',                        # 41 --- Omits: a, e, i, l, o, u, A, E, I, O, U
        'alpha_consonants_hardtoconfuse_lowercase':             'bcdfghjkmnpqrstvwxyz',                                             # 20 --- Omits: a, e, i, l, o, u
        'alpha_consonants_hardtoconfuse_uppercase':             'BCDFGHJKLMNPQRSTVWXYZ',                                            # 21 --- Omits: A, E, I, O, U
    
        'alpha_numeric_consonants_hardtoconfuse':               'bcdfghjkmnpqrstvwxyzBCDFGHJKLMNPQRSTVWXYZ23456789',                # 49 --- Omits: a, e, i, l, o, u, A, E, I, O, U, 0, 1
        'alpha_numeric_consonants_hardtoconfuse_lowercase':     'bcdfghjkmnpqrstvwxyz23456789',                                     # 28 --- Omits: a, e, i, l, o, u, 0, 1
        'alpha_numeric_consonants_hardtoconfuse_uppercase':     'BCDFGHJKLMNPQRSTVWXYZ23456789',                                    # 29 --- Omits: A, E, I, O, U, 0, 1
    
        'binary':                                               '01',                                                               # 2  --- Base-2
        'decimal':                                              '0123456789',                                                       # 10 --- Base-10
        'hexadecimal_upper':                                    '0123456789ABCDEF',                                                 # 16 --- Base-16
        'hexadecimal_lower':                                    '0123456789abcdef',                                                 # 16 --- Base-16
        'octal':                                                '01234567',                                                         # 8  --- Base-8
    }

    def random_string(length=32, characters=CHARACTER_SETS['alpha_numeric']):
        random.seed()
        return ''.join(random.choice(characters) for x in range(length))