Programming Leftovers

posted by Roy Schestowitz on Apr 06, 2023

• Using TLA⁺ at Work

  Here’s a short report of a time I used TLA⁺ at work, with interesting results. TLA⁺ is a formal specification language that is particularly effective when applied to concurrent & distributed systems. TLA⁺ made it tractable for an ordinary software engineer to reason about a tricky distributed systems problem, and it found a bug introduced by an “optimization” I tried to add (classic). The bug required 12 sequential steps to occur and would not have been uncovered by ordinary testing.

• BASIC vs. FORTRAN 77: Comparing programming blasts from the past

  If you grew up with computers in the 1970s and 1980s, as I did, you probably learned a common programming language for personal computers called BASIC, or the Beginner's All-purpose Symbolic Instruction Code. You could find BASIC implementations on every personal computer of the era, including the TRS-80, Apple II, and the IBM PC. Back then, I was a self-taught BASIC programmer, experimenting with AppleSoft BASIC on the Apple II before moving to GW-BASIC on the IBM PC and, later, to QuickBASIC on DOS.

  But once upon a time, a popular language for scientific programming was FORTRAN, short for FORmula TRANslation. Although since the 1990 specification of the language, the name is more commonly stylized as "Fortran."

  When I studied physics as a university undergraduate student in the early 1990s, I leveraged my experience in BASIC to learn FORTRAN 77. That was when I realized that BASIC derived many of its concepts from FORTRAN. To be clear, FORTRAN and BASIC differ in lots of other ways, but I found that knowing a little BASIC helped me to learn FORTRAN programming quickly.

  I want to show some similarities between the two languages by writing the same program in both. I'll explore the FOR loop in BASIC and FORTRAN 77 by writing a sample program to add a list of numbers from 1 to 10.

• Our favorite fonts for the Linux terminal

  Terminal emulators came up as a topic for me recently, and it got me thinking: What's everyone's favorite terminal font?

  So I asked Opensource.com contributors to share what font they like to use. Here are their answers.

• Exposing Field Errors

  This post is about exposing field errors programmatically. I have already shared some opinions (such as a caution about displaying messages below fields or avoiding default browser field validation), but this post dives into using ARIA to convey them to screen reader users.

  With fields that produce error messages on blur, I compare two types of live regions along with aria-describedby and aria-errormessage. This post does not address whether or not it is ideal to validate fields on blur. You can find plenty of opinions elsewhere.