Basic functions I tend to re-create on a project by project basis, consolidated and documented for easy use.

Functions.inc.php

<?php
 /**     1         2         3         4         5         6         7         8
  * 5678901234567890123456789012345678901234567890123456789012345678901234567890
  * 
  * Standardized Function Include file, v.0.0.2
  * 	Johnathan McKnight (akoimeexx@gmail.com)
  * 
  * 
  * This functions are basic activities I find myself writing over and over 
  * again from project to project, on a nearly constant basis. They have been 
  * collected and re-written in a more standardized way so I no longer have to 
  * re-invent the wheel, but rather include this file.
  * 
  * The only non-standard function thus far in this include is usage(), which 
  * provides development information on each function that has a $__usage__ 
  * nowdoc string, outputting to error_log via debug() the contents therein.
  * 
  * Writing these usage nowdoc strings forces me to think through how a 
  * function will be used and how it should perform. This leads to writing 
  * cleaner, more concise functions, which seems to me to be a 
  * "Very Good Thing" (TM).
  */


	function debug($s, $show_path=false) {
$__usage__ = <<<'USAGE'
DEBUG(STRING[, BOOLEAN]);
Description:
    (void)      debug( (string) $s )
                Writes out a string to to error_log, formatting it to include 
                details like the line number and file that the message was 
                logged from.

Parameters:
    (string)    s
                Passed in string to write out to error_log

    (boolean)   show_path
                Prints out full file path of calling script if set to true, 
                basename of script if false. Defaults to false.

Returns:
    (void)      No value is returned.
USAGE;
		$dbg = array_pop(debug_backtrace(DEBUG_BACKTRACE_IGNORE_ARGS, 1));
		error_log(sprintf(
			"[%s: Line %s] %s", 
			($show_path === true) ? $dbg['file'] : basename($dbg['file']), 
			$dbg['line'], 
			$s
		));
	}

	function is_assoc($arr) {
$__usage__ = <<<'USAGE'
IS_ASSOC(ARRAY);
Description:
    (boolean)   is_assoc( (array) $arr )
                Checks a variable to see if it is an associative array by 
                evaluating is_int() on array keys.

Parameters:
    (array)     arr
                Passed in array to check

Returns:
    (boolean)   True if variable is an associative array, false if otherwise.
USAGE;
		if(is_array($arr) && count($arr) > 0) {
			foreach(array_keys($arr) as $key) {
				if(!is_int($key)) return true;
			}
		}
		return false;
	}

	function print_rr($mixed, $return=false) {
$__usage__ = <<<'USAGE'
PRINT_RR(MIXED[, BOOLEAN]);
Description:
    (string)    print_rr( (mixed) $mixed[, (boolean) $return] )
                Prints a print_r'ed string to output buffer, wrapped with html 
                <pre> tags.

Parameters:
    (mixed)     mixed
                Mixed data to print out.

    (boolean)   return
                Returns results as a string if set to true, outputs to buffer 
                if false. Defaults to false.

Returns:
    (string)    String of print_r'ed data with <pre> tags if $return is set to 
                true, otherwise outputs to buffer and returns nothing.
USAGE;
		$output = sprintf('<pre>%s</pre>', print_r($mixed, true));
		if($return) {
			return $output;
		}
		echo $output;
	}

	function salt($min=8) {
$__usage__ = <<<'USAGE'
SALT([INTEGER]);
Description:
    (string)    salt( (integer) $min )
                Generates a salt string from shuffle'd md5'ed microtime, 
                between $min and 32 characters in length.

Parameters:
    (integer)   min
                Minimum salt length to accept. Default is 8 characters.

Returns:
    (string)    String of random characters between $min & 32 characters.
USAGE;
		if($min > 31) { $min = 8; }
		return substr(str_shuffle(md5(microtime())), 0, rand($min, 31));
	}

	function usage($f, $return=false) {
$__usage__ = <<<'USAGE'
USAGE(STRING[, BOOLEAN]);
Description:
    (string)    usage( (string $f[, (boolean) $return )
                Prints function usage details out to error_log via debug().

Parameters:
    (string)    f
                function name to look up usage details for.

    (boolean)   return
                Returns results as a string if set to true, outputs to 
                error_log via debug() if false. Defaults to false.

Returns:
    (string)    String of function usage details if $return is set to true, 
                otherwise outputs to error_log via debug() and returns nothing.
USAGE;
		try {
			$func = new ReflectionFunction($f);
			$srcfile = $func->getFileName();
			$func_start = $func->getStartLine() - 1;
			$func_end = $func->getEndLine();
			$arr_func_body = array_slice(file($srcfile), $func_start, ($func_end - $func_start));
			$usage_start = array_search("\$__usage__ = <<<'USAGE'" . PHP_EOL, $arr_func_body);
			$usage_end = array_search("USAGE;" . PHP_EOL, $arr_func_body);
			if($usage_start === false) {
				throw new Exception('No $__usage__ variable found.');
			}
			if($usage_end === false) {
				throw new Exception('No ending usage marker found.');
			}
			$usage = implode('', array_slice($arr_func_body, $usage_start + 1, ($usage_end - $usage_start - 1)));
			if($return) {
				return $usage;
			}
			debug("Usage details: \n$usage");
		} catch (Exception $e) {
			debug($e->getMessage());
		}
	}
?>