On Friday, 13 March 2015 at 17:31:09 UTC, Andrei Alexandrescu
wrote:
For example the expression (assuming s is e.g. a string)
File("/tmp/a").byChunk(4096).joiner.startsWith(s)
opens a file, progressively reads chunks of 4KB, stitches them
together at no cost, compares against a prefix until it makes a
decision, then closes the file and returns the result. A
putative Go user wouldn't even dream of using HasPrefix
directly on a stream coming from a file; the whole endeavor
would be a function that painstakingly takes all of these steps
by hand.
I personally, would have no idea what this piece of code is doing
upon first sight. I'll have to look at the documentation of
at least two functions to understand that, and I'll have to
think carefully about what and who would throw in case of an
error.
Something like
while (n != EOF) {
n = read(fd, buf, sizeof(buf));
if (n==-1) throw(...);
if (strcmp(buf, PREFIX) == 0) {
return buf;
}
}
return NULL;
Requires no prior knowledge, and have similar effect.
I'd rather have a loop written by hand in my production code any
day,
so that when debugging it, and reading it I'll have easier time
to understand it, even though it would cost me a few more lines
when writing the code.
What if this pattern repeats a few times in the code?
I'd rather have a single function that have the explicit loop than
having this pattern in slight variations spread in the code.
Writing code is easy, maintaining it afterwards is costly.
