In this letter, Dijkstra talks about readability and maintainability in a time where those topics were rarely talked about (1968). This letter was one of the main causes why modern programmers don’t have to trouble themselves with goto statements. Older languages like Java and C# still have a (discouraged) goto statement, because they (mindlessly) copied it from C, which (mindlessly) copied it from Assembly, but more modern languages like Swift and Kotlin don’t even have a goto statement anymore.
TIL that C# and Java have a goto statement.
Forget about goto, the latest version of C# introduced what’s essentially comefrom.
To be fair,
awaitis a bit more likecomefrom, and it’s been around for a few releases now.async/await was introduced in version 4.5, released 2012. More than a few releases at this point!
How is
awaitlikecomefrom, any more than threading is likecomefrom? The variable context is preserved and you have no control over what is executed before theawaitreturns.What…? That is a terrible idea.
It’s scary as fuck, yeah, but, to be fair, it’s only intended to be used by code generators, and it’s quite awkward to use outside of them.
Java doesn’t. Well, it’s a reserved keyword but it’s not implemented.
Yeah but we got labels with continue and break, so we can pseudo goto.
Following that logic
if,elseandwhileare also “pseudo goto” statements.There’s nothing wrong with conditional jumps - we couldn’t program without them. The problem with goto specifically is that you can goto “anywhere”.
If pretty much gets compiled to a goto statement. Well more a jumpif but same principle
In C# at least,
gotocan take you between case labels in a switch statement (rather than using fallthrough), which I don’t view as being nearly as bad. For example, you can dogoto case 1orgoto defaultto jump to another case.The only other use of
gotoI find remotely tolerable is when paired with a labelled loop statement (like putting a label right before aforloop), but honestly Rust handles that far better with labelled loops (and labelled block expressions).I’ve programmed C# for nearly 15 years, and have used
gototwice . Once to simplify an early break from a nested loop, essentially a nestedcontinue. The second was to refactor a giant switch statement in a parser, essentially removing convolutedwhileloops, and just did agotothe start.It’s one of those things that almost should never be used, but the times it’s been needed, it removed a lot of silliness.