Let ret: Number
If(someCondition){
<a lot of expensive calculations>
ret = resultOfOperations
} else {
<a lot of other different expensive operations>
ret = resultOfOtherOperations
}
return ret
letret = if some_condition {
<a lot of expensive calculations>
result_of_operations
} else {
<a lot of other different expensive calculations>
result_of_other_operations
};
Now you don’t have to declare it inside the blocks.
Yes, and no, sir, you missed the point. The procedure here is to allocate then give away, not reading a fixed-length returned value.
Say you can only afford to have ten bytes in the stack. You allocate char s[10]; then give it to a library to parse something. Also telling it to abort if it’s going to be longer than ten bytes, of course.
To be honest I always disliked variable declaration without value assignment, so to me both options suck. :)
What about
Let ret: Number If (someCondition) { <a lot of expensive calculations> ret = resultOfOperations } else { <a lot of other different expensive operations> ret = resultOfOtherOperations } return retYou can’t declare ret inside the brackets
Rust would allow you to
let ret = if some_condition { <a lot of expensive calculations> result_of_operations } else { <a lot of other different expensive calculations> result_of_other_operations };Now you don’t have to declare it inside the blocks.
Similarly, Perl lets you say
my $ret = do { if (...) { ... } else { ... }};That’s… Disgusting
What’s disgusting about it? The only thing I can think of is the implicit return, which felt a bit icky at first.
Also, as the if expression is an expression, you can call methods on it like so:
if 1 > 2 { 3 } else { 4 }.min(5)(the above is still an expression, so it could be used, for example, as part of a condition for another if)
Of course, you can write horrible code in any language, but the ability to use blocks where expressions are expected can be great sometimes.
let ret = someCondition ? expensiveOperation() : otherOperation()?
Yeah. That works.
What about you declare (then it gets allocated in stack) it and pass it to a different context for assignment?
Well, I don’t know your use case well enough, but I guess you might have perfect reason for that behavior.
One thing that comes to my mind is the old Try in C#
bool parsedSuccessfully = int.TryParse("123", out int result);But I guess more popular approach would be to use Error as Values, right?
E.g. something like this
Outcome<Exception, Int> result = int.TotallyNewParse("123");char c; scanf("%c", &c);Great example.
Wouldn’t
getchar()be more appropriate here? Last time I used C it was 16 years ago.Yes, and no, sir, you missed the point. The procedure here is to allocate then give away, not reading a fixed-length returned value.
Say you can only afford to have ten bytes in the stack. You allocate
char s[10];then give it to a library to parse something. Also telling it to abort if it’s going to be longer than ten bytes, of course.