Adam

[Ruby] On Ugly ruby if statement.

2011-11-29T18:56:44-08:00

@topic = @parent.topic || @parent

[Ruby] On Refactor for table "generator"

2011-10-02T20:03:29-07:00

#customers
  %table#customerTable
    - @customers.each_slice(5) do |customers|
      %tr
        - customers.each do |customer|
          %td
            = image_tag(customer.logo.url(:thumb))

[Ruby] On is there a smart way to using "NOT IN" SQL with ActiveRecord?

2011-09-08T21:46:50-07:00

class Book < ActiveRecord::Base
  def self.excluding(ids)
    ids.blank? ? self : where('id NOT IN (?)', ids)
  end
end

Book.excluding(good_books_ids)

[Ruby] On Randomize case

2011-08-31T14:18:46-07:00

def randomize_case(string)
  string.gsub(/./) { |char| char.send(rand(2).zero? ? :downcase : :upcase) }
end

[Ruby] On Generate span elements for rating

2011-07-06T08:47:55-07:00

def rating_stars(rating)
  content_tag(:span, :title => "#{rating}-stars hotel") do
    5.times.map { |star| content_tag(:span, '★', :class => ('full' if star <= rating.round)) }
  end
end

[Ruby] On move a element of array to top

2011-07-06T08:43:01-07:00

If User happens to be an ActiveRecord class:

class User < ActiveRecord::Base
  def self.promote(id)
    # A bound variable would be preferred here, but doesn't seem to be supported by the MySQL adapter.
    # I would recommend sanitizing id for real-world usage.
    order("id = #{id} DESC")
  end
end

User.promote(user_id)

[PHP] On CSS compiler/parser nested sets

2011-07-06T00:48:49-07:00

Upon closer inspection, I misinterpreted the format you wanted to use. These modifications should fix that.

function selectors() {
	$selectors = preg_split('/\s*,\s*/', $this->selector);
	
	if ($this->parent) {
		$mergedSelectors = array();
		$parentSelectors = $this->parent->selectors();
		
		foreach ($parentSelectors as $parentSelector) {
			foreach ($selectors as $selector) {
				if ($selector[0] == '&') {
					$selector = substr($selector, 1);
				} else if ($selector[0] != ':') {
					$selector = " $selector";
				}
				
				array_push($mergedSelectors, "$parentSelector$selector");
			}
		}
		
		return $mergedSelectors;
	} else {
		return $selectors;
	}
}

function nextIdentifier() {
	if (preg_match('/\s*(:?.*?)\s*([\{\:\;\}])/', $this->css, &$matches, 0, $this->offset)) {
		$this->offset += strlen($matches[0]);		
		return $matches;
	} else {
		return NULL;
	}
}

[PHP] On CSS compiler/parser nested sets

2011-07-06T00:39:36-07:00

class Block {
	protected $parent;
	protected $selector;
	protected $properties;
	
	function Block($selector) {
		$this->selector = $selector;
		$this->children = array();
		$this->properties = array();
	}
	
	function parent() {
		return $this->parent;
	}
	
	function setParent($parent) {
		$this->parent = $parent;
	}
	
	function addChild($child) {
		$child->setParent($this);
		array_push($this->children, $child);
	}
	
	function setProperty($name, $value) {
		$this->properties[$name] = $value;
	}
	
	function selector() {
		return implode(", ", $this->selectors());
	}
	
	function selectors() {
		$selectors = preg_split('/\s*,\s*/', $this->selector);
		
		if ($this->parent) {
			$mergedSelectors = array();
			$parentSelectors = $this->parent->selectors();
			
			foreach ($parentSelectors as $parentSelector) {
				foreach ($selectors as $selector) {
					array_push($mergedSelectors, "$parentSelector$selector");
				}
			}
			
			return $mergedSelectors;
		} else {
			return $selectors;
		}
	}
	
	function toCSS() {
		$css = "{$this->selector()} {";
		
		foreach ($this->properties as $name => $value)
			$css .= " $name: $value;";
			
		$css .= " }\n";
		
		foreach ($this->children as $child)
			$css .= $child->toCSS();
		
		return $css;
	}
}

class Parser {
	protected $css;
	protected $current;
	protected $offset;
	protected $parents;
	
	function Parser($css) {
		$this->css = $css;
	}
	
	function reset() {
		$this->current = null;
		$this->offset = 0;
		$this->parents = array();
	}
	
	function parse() {
		$this->reset();
		
		while (list($unused_variable, $identifier, $action) = $this->nextIdentifier()) {
			switch ($action) {
				case '{':
					$block = new Block($identifier);
					
					if ($this->current)
						$this->current->addChild($block);
					else
						array_push($this->parents, $block);
						
					$this->current = $block;					
					break;
					
				case ':':
					$propertyName = $identifier;
					break;
					
				case ';':
					$this->current->setProperty($propertyName, $identifier);
					break;
					
				case '}':
					$this->current = $this->current->parent();
					break;
			}
		}
	}
	
	function nextIdentifier() {
		if (preg_match('/\s*(.*?)\s*([\{\:\;\}])/', $this->css, &$matches, 0, $this->offset)) {
			$this->offset += strlen($matches[0]);		
			return $matches;
		} else {
			return NULL;
		}
	}
	
	function toCSS() {
		$css = "";
		
		foreach ($this->parents as $parent) {
			$css .= $parent->toCSS();
		}
		
		return $css;
	}
}

// Example Usage
$parser = new Parser(CSS_DATA);
$parser->parse();
echo $parser->toCSS();

[JavaScript] On Remove duplicate declarations in jQuery callback

2011-07-01T12:26:18-07:00

function CategoryDescription(element)
{
	var div = $(element).find('.description');
	var dark = div.siblings('.darkdiv');
	var para = div.find('p');
	var h1 = div.find('h1');
	
	var animate = function(paraOpacity, darkOpacity, extras) {
		return function() {
			extras();
			para.animate({ 'opacity', paraOpacity }, 200);
			dark.animate({ 'opacity', darkOpacity }, 200);
		}
	}
	
	this.show = animate(1, 0, function() { div.animate({'margin-bottom': 0}, 300).animate({'margin-bottom': -3}, 100); });
	this.hide = animate(0, 0.4, function() { animate({'margin-bottom': 5 - div.height() - h1.height() }, 200); });
}

[Ruby] On find a horizontal line in an image, or consecutive array elements

2011-06-28T11:23:37-07:00

def find_8_9s(screen)
  match = screen.to_s.match(/9{8}/)
  [ match.offset(0).first / screen.first.size, match.offset(0).first % screen.first.size ] if match
end

[Ruby] On string concat

2011-06-24T08:42:46-07:00

Requires Rails 3.1, but there's really no reason to not be using it for development.

//= require jquery
//= require jquery_ujs
//= require jquery-ui

[Ruby] On rental_has_been_refunded?

2011-06-24T00:08:40-07:00

Not true. At least with 3.1, any? does the SELECT COUNT(*) internally. I suppose earlier versions may not.

[Ruby] On rental_has_been_refunded?

2011-06-23T18:43:28-07:00

def rental_has_been_refunded?
  refunds.where(:transaction_sub_type => 'rental').any?
end

[Ruby] On Can I compact multiple gsub calls

2011-06-22T10:43:05-07:00

@email.body.gsub!(/~(.+?)~/) { @person.send($1.downcase).to_s }

[Ruby] On Existence of ActiveRecord attribute

2011-06-19T17:28:52-07:00

When you're chaining that many objects together, you're probably approaching it from the wrong point of view. I believe you're trying to do something like this:

class User < ActiveRecord::Base
  has_many :orders
  has_many :stores, :through => :orders
  
  def has_store_url?
    store = stores.order('orders.created_at DESC').first
    store.url.present? if store
  end
end

# For backwards compatibility with your method
def has_store_url?(user)
  user.has_store_url? if user
end

[Ruby] On Parents

2011-06-14T20:50:10-07:00

Seems like a good place to use an enumerator.

class Node
  attr_reader :parent
  
  def ancestors(&block)
    if block_given?
      if parent
        block.call(parent)
        parent.ancestors(&block)
      end
    else
      Enumerable::Enumerator.new(self, :ancestors)
    end
  end
end

[ActionScript] On Combining certain attributes in an array into a single string

2011-06-03T14:16:22-07:00

summary.detentionComments = summary.detentionNotes.map(function(note) { return note.comments }).join("; ");

[PHP] On JSON Literals in PHP

2011-06-01T08:10:41-07:00

Good eye. It should have been set in the beginning, but I guess I was able to exploit the fact that switch handles an undefined value as 0 by default as it does work as written.

[PHP] JSON Literals in PHP

2011-05-31T22:13:16-07:00

On a forum I was reading, someone wanted to use JSON-style arrays instead of the more verbose PHP-style arrays in a PHP script. I spent a couple of minutes whipping up this PHP preprocessor to be silly, but it turned out to be kind of neat in the end and seemed like a prime target for some refactoring. Have at it!

<?php
/*
$foo = {
    "bar": [
        "baz",
        "refactor",
        {
            "my": "code"
        }
    ]
};

Becomes:

$foo = array (
   'bar' => array (
        0 => 'baz',
        1 => 'refactor',
        2 => array (
           'my' => 'code',
        )
    )
);
*/

$file = fopen($argv[1], "r");
$json = "";
$depth = 0;

while (!feof($file)) {
    $chr = fgetc($file);
    
    switch ($state) {
        case 0:
            echo $chr;
        
            if ($chr == '=' || $chr == '(' || $chr == ',') {
                $state = 1;
            }
            break;
            
        case 1:
            if ($chr == '[' || $chr == '{') {
                $json .= $chr;
                
                $depth = 1;
                $state = 2;
            } else if (preg_match("/\s/", $chr)) {
                echo $chr;
            } else {
                echo $chr;
                $state = 0;
            }
            break;
            
        case 2:
            $json .= $chr;
        
            if ($chr == '[' || $chr == '{') {
                $depth++;
            } else if ($chr == ']' || $chr == '}') {
                $depth--;
            }
            
            if ($depth == 0) {
                $code = var_export(json_decode($json), true);
                $code = str_replace("stdClass::__set_state", "", $code);
                echo $code;
                
                $json = "";
                $state = 0;
            }
            
            break;
    }
}
?>

[Ruby] On Test if array contains the same elements of given value

2011-05-25T07:35:20-07:00

Great questions. Unsure about the termination, however it worked in all of my tests. Definitely something you'd want to investigate more seriously if used beyond an exercise.

false in the C API is defined as 0, so it would fail. However, the constraints defined were to find 9 as fast as possible so we're not worried about false. :)

[Ruby] On Test if array contains the same elements of given value

2011-05-24T11:58:15-07:00

Okay, one more. This is more succinct.

Benchmarks (100,000 iterations of a 1,000 element array):

user system total real
fast_uniq 0.110000 0.000000 0.110000 ( 0.108271)
ants_is_all_the_same 0.140000 0.000000 0.140000 ( 0.147539)
adam_is_all_the_same 0.060000 0.000000 0.060000 ( 0.061935)

VALUE is_all_the_same(VALUE self)
{
	if (RARRAY_LEN(self) < 2)
		return Qtrue;
	
	VALUE *first = RARRAY_PTR(self);
	VALUE *element = first + 1;

	while (*element++ == *first);	
	return *element ? Qfalse : Qtrue;
}

[Ruby] On Test if array contains the same elements of given value

2011-05-24T11:50:17-07:00

How come edit doesn't work anymore? Anyway, you need to check that the array is empty if you want to return true in that case. I'll leave that as an exercise for the reader since I can't update it.

[Ruby] On Test if array contains the same elements of given value

2011-05-24T11:43:57-07:00

This is only slightly faster with short arrays, but the array length grows, this is quite a bit faster on my machine.

VALUE is_all_the_same(VALUE self)
{
	VALUE *first = RARRAY_PTR(self);
	VALUE *element = first + 1;

	while (*element++ == *first);	
	return (element - first - 1) == RARRAY_LEN(self) ? Qtrue : Qfalse;
}

[Ruby] On Test if array contains the same elements of given value

2011-05-23T16:41:44-07:00

input = [9,9,9,9,9,9,9,9,9,9,9,9]
input.fast_uniq(9)

## [C]

#include <ruby.h>

VALUE method_fast_uniq(VALUE self, VALUE num)
{
	int i;
	VALUE *element = RARRAY_PTR(self);
	
	for (i = 0; i < RARRAY_LEN(self); i++) {
		if (*element != num)
			return Qfalse;
		
		element++;
	}
	
	return Qtrue;
}

void Init_fast_uniq()
{
	VALUE array = rb_define_class("Array", rb_cObject);
	rb_define_method(array, "fast_uniq", method_fast_uniq, 1);
}

[C++] On String parsing in AVR-GCC

2011-05-04T22:28:03-07:00

Good points. Apparently I've been spending too much time in Objective-C where instance variables are initialized to zero. :)