That's a great analogy and I think often missed by many people. Spelling and arithmetic seem obvious as limitations in more complex fields (where communication and mathematics are involved). No one would say: "I can spell 'journalist' so I should be the editor-in-chief of the Washington Post." or "I can add 2 and 2 so you should hire me as an electrical engineer." (certainly not once they've grown up a bit, at least)
You have to advance to grammar, geometry, algebra, and more to find success in those fields.
But with programming, many people seem to stop at the point where they can program, and don't realize how much more there is to it (or not until much later). Programming is just the spelling/arithmetic level. Being able to design systems, select between different data structures and algorithms, understanding what a state machine is and how to structure your program using that concept, etc. These are the algebra and calculus of the field.
I don't really understand this when people say it. My first instinct is that you're talking about keeping functions as pure as possible.
The other thing I think of is simply understanding all (Or most) of the possible states in your program, which seems like common sense.
ok_to_change = var1 && !var2 && var3 < 10;
if(ok_to_change && ...) ...
else if(ok_to_change && ...) ...
else if(!ok_to_change && ...) ...
...
ok_to_change was added after someone realized how much redundancy was in the tests. But the whole thing was a state machine and could've been expressed better as such. There are lots of ways to do it. You could make a more explicit state variable (or function that returns the current state from a set of variables), use lookup tables, or have functions that call each other to represent the current state of the system (mutual recursion is nice). But by making it an explicit part of the system design it usually leads to clearer, more concise, and more consistent code (IME).Love this analogy for programming...
It also reminds me that English and Public Speaking are very important skills I picked up in college which are easily neglected in a DIY program.
Perhaps I've just forgotten about how much I've actually learnt though.
If you have great English/ Public speaking skills this isn't so important. But I know a lot of people have really mediocre communications skills.
I spent years struggling to write quality code, and I couldn't figure out why: I knew syntax inside and out, but still struggled with tasks my peers could do while watching YouTube videos and chatting with their friends.
It's like I could spell but didn't know the first thing about grammar.
I eventually went back and took some classes online to fill in the gaps, but I feel like I would be much further in my career had I just went ahead and done it in the first place.