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from the depends-on-whether-you-code-using-emacs-or-vim? dept.
Are 80 Characters Per Line Still Reasonable In 2020?
[...] In case of the Linux kernel, that's of course [Linus Torvalds], who has recently shaken up the community with a mailing list response declaring an overly common, often even unwritten rule of code formatting as essentially obsolete: the 80-character line limitation. Considering the notoriety of his rants and crudeness, his response, which was initiated by a line break change in the submitted patch, seems downright diplomatic this time.
[Linus]' reasoning against a continuing enforcement of 80-char line limits is primarly the fact that screens are simply big enough today to comfortably fit longer lines, even with multiple terminals (or windows) next to each other. As he puts it, the only reason to stick to the limitation is using an actual VT100, which won't serve much use in kernel development anyway.
Allowing longer lines on the other hand would encourage the use of more verbose variable names and whitespace, which in turn would actually increase readability. Of course, all to a certain extent, and [Linus] obviously doesn't call for abolishing line breaks altogether. But he has a point; does it really make sense to stick to a decades old, nowadays rather arbitrary-seeming limitation in 2020?
The article then gives an overview of the history of how 80 columns became the de facto standard width. Though mentioned briefly in passing, it all really got started with the invention of the punched card dating back to 1804 when "Joseph Marie Jacquard demonstrated a mechanism to automate loom operation". The physical size of the punch card used in the 1890 United States Census was the same as US currency at that time. The cards were then known as "Hollerith cards" after the inventor Herman Hollerith. Later, IBM came to dominate the field.
As technology progressed, punch cards eventually gave way to computer terminals such at the IBM 3270 and "glass TTYs" like the DEC VT05 and Lear Siegler ADM-3A.
Computer languages were even designed around that common size. Both FORTRAN and COBOL had fixed line layouts with certain columns reserved for such things as sequence numbers, comment indicator, continuation marker, as well as the code itself.
Human factors play a role, too. A newspaper could, for example, have lines of text as long as the page is wide. It was found to be difficult to connect visually where the next line would start when one reached the end of a physical line. Hence multiple columns of text on a page. The same often holds for magazines, too.
Back to the question at hand.
I have personally used punch cards, FORTRAN, COBOL, and all of the computer terminals listed. I generally aim for 80-columns in the code I write, but I am flexible about it. Should I find that 90-100 columns better allows me to express and comprehend the code I've written, I'll err on the side of using more columns. A quick look through some code I've written revealed one case where I used 132 columns.
What about you? Hard and fast limit of 80 columns and not a single column more? 80-90? 100? Whatever it takes? Where and how do you draw the line?
(Score: 1, Interesting) by Anonymous Coward on Saturday June 20 2020, @04:58AM (1 child)
I don't understand the value of placing each parameter on its own line. People generally understand what buf and pos are, just like i and j are understood as counters in loops. In other cases when the variable's purpose is less obvious, I'd be all for avoiding abbreviations, though I don't think it's necessary in that instance. Extending a single function call across several lines reduces the amount of code visible on the screen at any particular time, which actually makes code less readable. If I want to understand what a block of code does, it's easier if I can see more of the block of code at once. Needlessly long function calls make that more difficult. The original function call with everything on one line is just fine with me. But yes, use more descriptive variable names when it's less obvious what the variables do.
I like the use of wide tabs for indenting code, something that Linus also mentions in his post. I prefer to just press tab once for each level of indentation. It's wide enough to make it readable. Plus it's quicker than having to press the space bar many times to achieve the same indentation, though some editors do this automatically. While I'm on the subject of indentation, the programmer should be able to decide how much indentation is needed for their particular use case. Indentation should not be used by compilers or interpreters to delineate the beginning and end of control structures. Python's use of indentation to define blocks of code is an absolute abomination.
(Score: 0) by Anonymous Coward on Sunday June 21 2020, @02:57AM
A lot of these conventions date back to when people exchanged diffs through mail and centralized systems like CVS. They make the code changes much cleaner while also making it easier to parse in your head. For example:
The closing brace aligned with the if statement shows what your closing scope is. Each parameter on its own line makes it more obvious what types and variables you are dealing with while making the actual changes easier to spot in the diff. And try parsing something like that in your head when the declarations are more complicated "int const * const x, int * const y, int const * z" or includes structs or other complicated types. Once you get the variables in your head, you don't really have to refer back to them; and when you do because there are too many or you lost your source reference it is easier to spot the one you are looking for when it is spread out rather than in a bunch so you can quickly get back to what you were doing.