switch-case in python

Python is a great language if you’re coding to IoT (Internet of Things) like small devices. If you’re coming from another language though you might be surprised that it doesn’t include the classic switch-case statement construct like you’d find in JavaScript, for example.

Fortunately, I just managed to create something that seems to work and the syntax isn’t too far off from the expected.

def switch(key, default):
    case = {
        0.0: 'zero-point-zero',
        0.1: 'zero-point-one',
        0.2: 'zero-point-two',
        0.3: 'zero-point-three',
        0.4: 'zero-point-four'
    }
    return case.get(key, default)

print switch(0.1, 'Unknown')
Running this would produce “zero-point-one”. This isn’t as robust as JavaScript’s or C’s implementation but this can be adjusted for lambda functions in a similar fashion.

 

python

the zen of source code formatting

 

Source code—assuming for a moment that you didn’t already know this—is a collection of (often English) words and symbols for humans which usually is turned into something more meaningful for a computer to understand when the program is running. Each computer language has its own rules about how you order the words and symbols but most allow for a fair amount of leeway with respect to whitespace, the “rests within the melody”, if-you-will.

“most [computer languages] allow for a fair amount of leeway with respect to whitespace, the rests within the melody…”

“Source code formatting is the task of using that whitespace to maximize… something.”

Source code formatting is the task of using that whitespace to maximize… something. This of course means different things to different people. For some, they believe that source code formatting can be done only one way. To format code using any other method, in their mind, would be the equivalent of breaking some sort of law.

Others believe that your text editor knows best and should be the authoritarian on the matter. There’s usually a feature to “format document” which they believe always gets this right.

As someone who’s been coding now for almost forty years, I’d like to share what I’ve learned and to permission you to completely ignore those first two camps who would say that you must do it their way.

The Virus

In my humble opinion, nearly all of the source code formatting as seen in the world’s collection of code suffers from poor readability. And this is so because of the attitudes surrounding the topic as well as the self-imposed “leaders” and big players who believe their way is better, demanding adherence to their own opinions.

In many software development firms, this is a hot topic for debate. Coders feel strongly about how all this plays out. Outspoken individuals like Douglas Crockford (author of jslint) have even developed tools to enforce their own (wrong) ideas about how code must be formatted.

As large corporations like Google publish more in the open source area, they bring with them this kind of Draconian mindset. If you bring in their code, you’re very likely also bringing in format-enforcing restrictions which come along for the ride.

“If we think of jslint as a virus that self-propagates, then cloning a Google-published project has now infected your project.”

I have personally been held hostage for days trying to make the jslint build tool happy when I’ve been forced to use it. It’s one of the worst anti-patterns I’ve seen in this industry, to be honest.

An Innovative & Meaningful Method of Formatting Your Source Code

For me, I choose to maximize whitespace instead so that I may understand the code instantly. The more I understand the code, the less likely it is that I will later introduce a bug into this code. The faster I can speed-read the code, the more productive and happier I’ll be.

“Code Complete” by Steve McConnell

The genesis of this new method comes in part from my having read this excellent book at least twenty years ago. At the time, this was ground-breaking in its revelations of coding statistics with respect to bugs and the impact of good source code formatting to minimize their presence in code.

My method goes beyond the author’s original suggestions and is the work of a couple decades in the making.

A Practical Example

Below, I show a pair of examples. It is the same code, just differently formatted. The code language is JavaScript and is written for NodeJS, more specifically. The other examples below also are written in JavaScript.

Before (classic jslint-like formatting)

Screen Shot 2018-11-29 at 12.20.13 PM
Figure 1

After (new, suggested method)

Screen Shot 2018-11-29 at 12.22.26 PM
Figure 2

Hopefully you will see the appeal to the second method. The spacing in Fig. 2 allows us to quickly see that this section includes the creation of several variables by pulling them in from separate files and modules. Additionally, they are alphabetized to make it easier to spot accidental double-inclusions.

Given the column-like behavior and the symmetry of those “require” functions, it’s now much easier to scan down the list. It’s now a pleasure to read.

Before (classic jslint-like formatting)

Screen Shot 2018-11-29 at 12.30.22 PM
Figure 3

After (new, suggested method)

Screen Shot 2018-11-29 at 12.17.01 PM
Figure 4

Here, by tightening up the first/third activities to become single-line events in Fig. 4, it’s easier to then see that we have what appears to be a sandwich-like construction:

  1. fs.closeSync() something
  2. create a variable
  3. fs.closeSync() with that variable

The second activity now has some pretty radical source code formatting. But it follows the column rule introduced from before:  columns make assignments easier to scan.

1) The Column Rule

To sum this up: use consistent whitespace to create columns out of assignments (storing a value into a variable). This applies to multi-line assignments as well as to assignments which take more than one line to accomplish.

Create columns: “…use consistent whitespace to create columns out of assignments…”

2) Squash for Readability

If it is possible to remove vertical space so that an entire function may be reviewed in one screenful in your editor, then consider doing so. Good candidates for this treatment are the open/close pairs of file functions seen in Fig. 4. The pairing makes sense to most coders so it’s a welcome form of abbreviation.

Squash: “If it is possible to remove vertical space so that an entire function may be reviewed in one screenful in your editor, then consider doing so.”

3) Comment the Breadcrumb Trail

When there are several levels of braces in one group at the end of something, clearly comment each with judiciously-provided whitespace so that they line up as a column as seen in Fig. 5.

Screen Shot 2018-11-29 at 12.45.00 PM
Figure 5

Breadcrumbs: “When there are several levels of braces in one group at the end of something, clearly comment each with judiciously-provided whitespace so that they line up as a column…”

4) Semicolons for Readability

Use line-ending punctuation to tell one type of scope/block from another. In Fig. 5 above, fs.readdir() and fs.unlink() as function calls are each terminated with a semicolon after the ending brace. Here, I’m omitting the terminal semicolons for both the sections in the if blocks and the for loop at their ending braces.

Semicolons: “Use line-ending punctuation to tell one type of scope/block from another.”

I’m sure this one will have its critics. I would argue that the introduction of chained functions and the concept of “Promises” have created some rather interesting “dogpiles” of code at times which are too difficult to follow without this strategy.

Applicability to Other Languages

The suggestions indicated also apply to other languages. One notable caution, though, goes out to Python-related code which is fairly picky about beginning indentation style. The beginning of each line of Python marks logical blocks of codes as you might see in a matching pair of braces in JavaScript. It’s therefore critical to first make Python happy in this regard before attempting to then adhere to these suggestions. The continuation line technique seen in Fig. 4 above would not work in Python for this reason.

to type or not to type…

that is the question.  Rather than a Shakespeare reference, I’m here referring to a term in software development which determines how a language deals with variables, for example.

Define: type

When you create a variable in a computer language, it’s usually something like this:

var someVarName = 1;

In a case like this, we might infer that someVarName stores a number (an integer).  We might say that the someVarName‘s type is integer.  Using a pet-ownership metaphor, it’s like purchasing a dog house first (“someVarName”) and then next buying a dog to put into it (“1”).  You wouldn’t buy a fish bowl to store a dog… although this seems to work out great if you own a cat.  JavaScript, e.g., is like this picture:  it doesn’t seemingly care if you want to store a cat in a fish bowl.

cat-in-a-bowl

Two Schools of Thought

There are two camps out there:  those who like languages which force the variable type and those who don’t.

A statically-typed language usually involves a step in which your code is converted into something else (compiling) and any type-related issues must be fixed before a program can be created.

A dynamically-typed language is run “as is” and the code is evaluated at the moment of truth—determinations about the type of a variable are made at this time.  If there is a type-related issue, your end-user could be the first person to see the error.

Statically-Typed Dynamically-Typed
Java JavaScript
C++ Python
C# PHP
C Objective-C

The Pendulum Swings

Over the past three decades, the popularity of either approach has waxed and waned.  It’s safe to suggest for the moment that the less-strict languages are gaining rapidly in popularity over their stricter counterparts.

most-popular

We have the world of open source to thank for the popularity and speed of development we’re currently seeing in these dynamically-typed languages like JavaScript and Python.

Seeing the Future

Honestly, though, there are too many people in that strict-is-better camp and their influence is felt within software development companies.  If I were to guess at the future of JavaScript, I’d probably have to say that TypeScript and Flow will gain in popularity as larger development teams look to lower the number of bugs in their code.

I don’t know, though.  Maybe it’s time that we just relax and let the cat hang out in the fish bowl.

 

the rise and fall of the microsoft empire

1975-1980

Our historical timeline begins in 1975 when an unlikely duo—Paul Allen as Batman and Bill Gates as his awkward “Boy Wonder”—started Microsoft Corporation.  I’m guessing that ro-sham-bo was involved in this decision but incredibly somehow Bill was made the CEO when the company got its start.  Maybe dropping out of Harvard gives you that kind of confidence.

1981BillPaul

1981-2000

Nothing really significant happened until they managed to modify an existing operating system for the IBM PC in 1981 from another company and rename this to MS-DOS. Significant sales of the IBM series of computers and those of their competitors then launched a thirty-year stretch of dominance in the business world in the area of operating systems, software and development platforms.

For most of us, we reasonably dismissed Apple’s hardware and the MacIntosh operating systems as nothing we could seriously use in business outside of the marketing department.

Consumers bought new versions of software and that license was good for life.  It could often be transferred from one computer to the next as long as the last one was de-registered first.  If you built software for Windows, you likely used a Microsoft compiler to do so and you paid for that.  In fact, the Microsoft Technet collection of CDs was quite expensive.

2001

About six years into the “Internet Tidal Wave” as Bill would call it, Microsoft was starting to lose its way.  They tried to dominate in the browser wars but never quite managed to quash the competition.  Others saw their efforts in this area as annoying.  Their software for creating programs, Visual Studio, first hit the scene about four years prior to this.

Google was founded some five years prior and was just beginning to get attention from an investor before they had anything real yet.  In 1999 they moved from their garage to an actual building in Palo Alto.  Yahoo’s popularity as a search engine from a decade ago was waning.  Google’s ad-based revenue from keywords was paying off; they’d planted a money tree which eventually created an entire forest of money trees for them.  It wouldn’t be long until Microsoft’s executives behind closed doors would consider Google their biggest threat.

About this time Apple created a very clever method of provisioning content for one-and-only-one device within the music-delivery space.  The iTunes store would turn out to be the goose that laid the golden egg, as seen in the following revenues.  And yet, it would take years for either Microsoft or Google to realize the beauty in this fulfillment model and to come up with their own versions.

showmethemoney

The “Internet of Things” concept started gaining in popularity at this time.

2009

Microsoft’s attempts at copying Google’s success (MSN Search, Windows Live Search, Live Search) now culminated in the introduction of Bing as their default search engine destination for all things Microsoft.

Apple introduced the first iPhone and the first iPad about this time, noting that the same provisioning model from iTunes was incorporated into both via iOS.  The subscription model of sofware licensing was born with this, if you think about it.  If you wanted to write a program for either, you needed to use Apple’s software to do so.

Google has just introduced Chrome as a browser and would begin their campaign to slowly break Internet Explorer.  The same was true of the Android phone and its related operating system.  It would take a few years for Microsoft to catch up to either the iPhone or the Android before releasing their own app-savvy smartphone offering.

Amazon some three years prior had introduced the beginning of what would be a full complement of cloud-based services to support web development.  It would take Microsoft two full years to realize that they needed to be in this space and they didn’t have their offering ready for a few years more, too late to effectively compete.

Github.com had just celebrated their first year online, hosting over 46,000 repositories by then.  The world of open source was the very antonym to the way that software had been developed prior to this.

The free Ubuntu operating system was released about four years prior to this, backed by the well-funded company Canonical.

2015

Microsoft releases Windows 10, “the last version of Windows” (they claimed).  Rumors suggested that Windows would eventually go from a version-based license model to an annual-subscription model with respect to pricing.  I think it’s safe to say that the market hasn’t really embraced either Windows 8 or Windows 10.

The subscription-based model for Office 365 was introduced four years prior to this so the writing was definitely on the wall:  Microsoft wanted to depart from their former methods of making money and to chase the monthly subscription model.

2015-popular-coding-languages

The world of open source was offering new programmers a wealth of free code.  All they had to do was to take it and make it their own.  Formerly, Microsoft-friendly coding languages like C, C++, C#, VB and .NET dominated the playing field but this graphic shows how the game had changed.

2017

And here we are, present-day.  That curious number 42 now describes the number of years that Microsoft has been around.

Yesterday evening, I attended a very geeky meetup of perhaps fifty or sixty coders and only saw one Windows-based laptop.  Almost everyone had a MacBook of some kind.

I just spent about two hours today installing the free Visual Studio Community 2017 software so that I could—in theory, anyway—alter a free copy of the source code for TightVNC software.  Out of the box, so-to-speak, Visual Studio doesn’t want me to build this project since it uses an earlier target platform (Windows 7 or 8, one would assume).

Microsoft only wants me to make things for Windows 10.

So rather than making it easy for me to build a program that will happily work with Windows 7, they’re forcing me to jump through hoops in order to add the necessary pieces for this to happen.

Add two more hours to this and I find that my installation does not want to download the earlier pieces to allow this to happen.  I’m forced to then upgrade the code to Windows 10 compatibility mode… only to find that the build fails with 528 errors.

The main crux of all these errors appear to be:  “we can’t find common files”.  It’s a very amateur sort of error from a company that’s been providing compilers for several decades now.

I have to think that Microsoft doesn’t want me to do anything with Visual Studio unless it benefits Microsoft.  And this is the core of the reason why I suggest that they’re doomed.

Every time a coder like myself runs into obstacles like these, the usual seed that’s planted inside their head is “this would be easier with another free compiler or another language from someone else”.

2022

Fast-forward another five years and Microsoft will have lost ground on many fronts.  New software development here, there and everywhere will be via some language which wasn’t popularized by Microsoft on computers which aren’t Windows and with browsers which aren’t Internet Explorer or Edge.  Our toasters and refrigerators and our cars will be powered by the Ubuntu operating system or perhaps Debian, a similar free Linux flavor.  These appliances will be connected to our wi-fi and even to the Internet but there won’t be a scrap of anything Microsoft about them.  They’ll be coded up with something that isn’t C#, doesn’t use .NET and doesn’t need Visual Studio in order to compile it.

The only thing with a Microsoft pedigree with some staying power could be some of the websites and services currently served up at Microsoft’s datacenters via Azure.  But Amazon or Google could kill that by simply lowering their own prices for cloud-based services.