Fall-Through Functions

When embracing functional programming principles in languages that aren’t designed specifically for functional programming, dealing with side effects requires great care and discipline. For those who can’t remember what side effects are, side effects are attempts to modify the state of the world (at least in terms of the scope of your program’s environment) through a means other than the return value of a function (e.g., performing a SQL insert, printing text to the standard output device, sending an email, etc.) Hopefully you noticed the word “attempts.” The problem with trying to directly modify the state of the world is that you don’t know what state the world is in: sometimes we’re caught by surprise.

I try to compartmentalize side effects in functions that lack branching constructs (e.g., if/then, switch, etc.) I refer to this type of function as a fall-through function because the function proceeds line-by-line until it reaches the last line and returns the status or result. Here’s a simple example of a fall-through function in PHP that sends an email:


$mail = function($to, $subject, $message){
    // handle longer lines
    $message = wordwrap($message, 70, "\r\n");
    // send message, returning status
    return mail($to, $subject, $message);


Fall-through functions provide clean separation of the logic we want to test from the world-dependent states that are unpredictable (i.e., code containing side effects), and as we know, clear boundaries are a good thing.

My Dream of Mom

A Long Year

Mom and dad and Matthew and me in front of Grandpa and Grandma's home.

I normally reserve this blog for technology-related posts, but I felt it was fitting to preserve these particular personal memories.

My mom passed away last October. In January my maternal grandmother passed away. And, since January, my father has been living at our house on hospice for end-stage prostate cancer. Long year.

My father’s presence has been a blessing in many ways. My family lived the farthest from my parents’ house, and phone calls a few times a week only went so far to bridge the gap. I’d often longed for the opportunity for my parents to be more integrated into my children’s lives, and having my father here to interact with, enjoy, and love my daughters is something for which I’ll always be thankful. Sarah (my little 2 year old) has gotten the biggest kick out of walking to grandpa’s room and showing him the activity that currently holds her attention (broadcasting her voice at progressively higher volumes if necessary to gain his attention.)

That said, I must confess there are things that I haven’t considered blessings. I haven’t been a fan of catheter care, bathroom breaks, and a host of other things related personal grooming tasks that don’t involve me grooming myself (although I’ve gained great respect for the work of nurses and CNA’s in the process.) I haven’t enjoyed becoming “THE POLICEMAN” who tries to regulate the unfathomable combinations of food my father wanted to “enjoy” (he knew he’d pay for a hot dog dressed with onions and peanut butter, but his perseverance  eventually caused me to cave.) And, most of all, I haven’t enjoyed seeing his capabilities and appearance diminish.

I know what you’re wondering: What’s all of this have to do with a dream about my mom? We’ll get there, just keep reading so I can provide a bit more backstory.

When Can We Leave?

There were things I didn’t enjoy that were especially associated with my mom. At church my mom was involved with many different tasks and responsibilities. She taught Sunday School, junior church, sang in the choir, hosted and scheduled coffee hours, directed Christmas pageants… well, I could go on, but you get the idea.

Now, her being involved in all of these tasks, that didn’t bother me a bit. What bothered me was having to wait for what seemed like an eternity to leave church every Sunday (and every other time we were there.) There was always something to work on, and this always meant that we (the “I” component here is what proved most painful) had to help out on many tasks if we wanted to attempt to get out of church before the service started for next week. These tasks often involved craft preparation of some sort, and let’s just say that to this day you’re not going to ever find my at Michaels.  DIDN’T MY MOM REALIZE I WAS MISSING THE ONLY NBA BASKETBALL I COULD WATCH ON TV!!! Things were so dire in terms of our departure time from church, that I was given the responsibility of locking up the church, something successively passed down to the oldest Richardson not away at college (except for then-rebel Kathleen.)

The Dream

About three weeks ago, there was a day where I felt especially drained because of all of the tasks required to care for my father. I wasn’t proud of it, but I must confess I resented doing the work. I was short with my dad that evening, and I went to bed that night carrying a heart full of frustration. A couple nights later, I had a dream about mom, one I’ve not described to anyone until now.

I remember being in one of the classrooms of my old church. I remember the fluorescent lighting, the basement smell, the rough texture on the walls, and I even noticed the old carpet pattern. It was a Sunday, and my family was the only one left at church. Out of the corner of my eye, I could see someone turned away from me quietly standing at a table and working. It was mom! I felt a rush of excitement overcome me and I ran as fast as I could to her side. She turned to see me with her smile of contentment, and I truly can’t describe the feelings I had at this moment. It really felt like I was in my mom’s presence again, and I couldn’t wait to hear her first words to me. I, with the utmost of eagerness, exclaimed, “Mom, how can I help!” I truly longed to work beside her, whatever the task might be.

Before she could utter one word in response, I felt the dream start to unwind. I pleaded with God in my heart for the dream to continue. In that moment I can honestly say that it had seemed so real and I had been so hopeful for even the smallest interaction, that it felt like I was losing her all over again. I woke balling uncontrollably, and I’m crying now as I remember this emotively overwhelming memory.

God granted me a wonderful truth through this experience that has greatly impacted me these past few weeks:

There will come a time for each of us when once-detested tasks would be counted as treasures if we could spend one more moment with the one we love. Cherish every moment.

My moments with my wonderful father are fleeting fast.

XSS Prevention in Four Simple Steps

Preventing Cross Site Scripting (XSS) attacks is a daunting task for developers. In short, XSS attacks are an injection attack in which data that is structurally significant in the current context changes the intended semantics and/or functionality. While there are great resources online that walk you through prevention techniques (one of the best security resources is The Open Web Application Security Project, or OWASP, website), it’s easy to get confused when you try to implement all of the necessary safeguards.

Below, I’ve outlined four simple steps that significantly lower the risk of XSS attacks against your website. By being a bit more restrictive, we can simplify our approach to preventing XSS Continue reading XSS Prevention in Four Simple Steps

Structurally compatible type checking in JavaScript with haven.js

JavaScript has come a long way since the early days of the web, a time when the language was utilized to add a quick pop-up to a page, make some gaudy graphic move across the screen, or, if you were really fancy, error check a few fields in a web form. Today, javascript dominates the world of web development (both in the browser and on the server through technologies such as node.js), speeds through tasks with performance that makes other languages envious, and proves to be a very capable language in terms of implementing a broad range of programming paradigms.

Many online tutorials demonstrate how to implement Object Oriented Programming (OOP) patterns in JavaScript, and, I must confess, the language proves very capable in this respect. However, it’s JavaScript’s ability to implement Functional Programming (FP) patterns that has benefited Continue reading Structurally compatible type checking in JavaScript with haven.js