Line length in programming

    match Error /\%81v.\+/

Not necessarily.

Most lines are below 80 characters, but there are good reasons (for readability!) to use longer lines from time to time: vertical space is more precious than horizontal on modern screens, and the more content I can fit into each vertical page, the faster I'll understand what I'm looking at.

The main reason I like the ability to occasionally have a 150 or 180 character line is akin to code folding, which some editors have as a feature. The feature allows you to hide a function or class by collapsing it into one line, because you want an overview of the code around it or calling it, and for the moment the implementation details aren't relevant. Now, I don't actually use the code folding feature in practice, mainly because I find that the times I would want to use it are times when I nearly always want to fold the code, and in a case like that, it's nice to be able to "pre-fold" it by putting it all on one line.

For example, if not using an ORM, I might want to use SQL to grab some results from a db (in a model, say), and I almost never want to think about my SQL and my surrounding code in the same context. Now, you might say, "Just put that SQL in its own method with a reasonably short name, and call it where you would otherwise have a long SQL string, and in the function that returns it, you can break each line at 70-80 characters," but that seems like a "solution" which improves nothing in my typical reading of the code, and requires me to jump around to find the SQL in the rare case I need to pay attention to it. It breaks up something which is naturally local and specific to this place in the code.

Another example which happens somewhat more frequently for me is when I want to use a literal object in JS. If I want to keep the definition local -- because, perhaps, nothing outside of this function ever needs it -- my choices are to put each key/value pair on its own line (easy to find a given key, but consumes lots of vertical space), to put multiple key/value pairs on each line to fit ~80 characters (both moderately difficult to find a given key, and still eats moderate amounts of vertical space), or to "fold" it all to one line (consumes the minimum vertical space, with the trade-off that it's difficult to find a given key). The most common case of this is where I have the choice between using 4-6 lines, or one line, and it's an easy choice for me to pick one line, though I've never encountered a coding standard that agreed with me.

    class Engineer(Person):
        __tablename__ = 'engineers'
        __mapper_args__ = {'polymorphic_identity': 'engineer'}
        engineer_id = Column('id', Integer, ForeignKey('people.id'), primary_key=True)
        primary_language = Column(String(50))

    12345678901234567890123456789012345678901234567890123456789012345678901234567890
    ^^ Line length marker

Guess perhaps I should rename my columns with more obscure names like engnr_id instead.

Seriously; you see this in python all the time; people not wanting to break the line because its only a character or two off, and then stupidly renaming a variable to some obscure abbreviation instead.

We won't go into the 2-character indents argument, or the push for the 100 character limit that the BDFL veto'd for the PEP8 revision; but... safe to say, I think a fair number of people hit this as an issue.

I don't think 'you can just refactor that to be shorter' is really a solution in all circumstances.