quasiquote for primitive lisp

I was searching for a basic quasiquote implementation in lisp which mentioned a paper by Alan Bawden. Anyway it was difficult to find via google so I figured I would type it up here for posterity. The original paper can be found: here.

(define (qq-expand x)
  (cond ((tag-comma? x)
         (tag-data x))
        ((tag-comma-atsign? x)
         (error "Illegal"))
        ((tag-backquote? x)
         (qq-expand (qq-expand (tag-data x))))
        ((pair? x)
         `(append ,(qq-expand-list (car x))
                  ,(qq-expand (cdr x))))
        (else '', x)))

(define (qq-expand-list x)
  (cond ((tag-comma? x)
         `(list ,(tag-data x)))
        ((tag-comma-atsign? x)
         (tag-data x))
        ((tag-backquote? x)
         (qq-expand-list (qq-expand (tag-data x))))
        ((pair? x)
         `(list (append ,(qq-expand-list (car x))
                        ,(qq-expand (cdr x)))))
        (else ''(,x))))

PHP to javascript fluent expressions

There are many times in Voltron views where I need to make a jquery/javascript call, initially I compromised and created the UI::ScriptSnippet in which I would put the typical "$(document).ready(function(){})" type deal in place. This was becoming increasingly more obnoxious particularly when the rest of the view code was so clean. So I give you the JSCallBuilder:

    UI::JSCall('object')->method(array('a' => 'b')); 
    // renders to object.method({'a': 'b'}); 

    UI::JSReady('object')->method(array('a' => 'b')); 
    //renders to <\script type="text/javascript">$(document).ready(function(){ object.method({'a', 'b'}) });<\/script> 
*/note the escaped script tags for bloggers sake? */

The source to make this happens is relatively trivial: http://code.google.com/p/phpviewadapter/source/browse/trunk/UI/JSCallBuilder.php

solving the word cube in voltron

In response to: http://programmingpraxis.com/2010/07/13/word-cube/

/* returns array of words found in the 9 letters provided */
function solveCube($letters) {
    $words = newType(TFile, 'words.txt')->splitBy("\n");

    return newType(TString, $letters)
        ->asArray
        ->powerSet('contains', $letters[4])
        ->map('permutations', I('asString')->in($words))
        ->map('join');
}

echo solveCube('ncbciune');

There are a few alternative ways that could be written and I am not sure if the idea of just having an optional filter as arguments to powerSet and permutations is entirely intuitive but the reality is that w/o the filter permutations will die on anything over 8 unless you crank the memory up in php.ini and thats just filthy.

Next post I will delve into iterative permutation and powerset internals on Array as that is obviously where the meat of that solution lies.

voltron model calculated fields

In the field definition of a voltron model you usually specify the field and the type as a key => val associative array. In the case that you have a calculated field the current practice is to specify field => array(Type::Calculated, 'methodNameOnRecord'). With fluent lambdas I have added a short cut:

class TimeRecord extends Voltron_Model
{
    protected $table = 'time_record';

    protected $fields = array(
        'id' => Type::Primary,
        'created' => Type::Timestamp,
        'created_hour' => Type::Calculated('created')->asDateTime->formatAs('H'));
}

The magic lies with in the created_hour type definition which can also be written as Type::Calculated(I()->created->asDateTime->formatAs('H')).

Because of the oo and fluent nature of Voltron the majority of calculated fields can be defined this way rather than requiring an actual method definition in the record class.