Thanks, I tried your fusedAppend template but it didn't work (compiled, but
didn't change anything). I think for whatever reason it isn't getting used
because I added echo a as a 2nd line and nothing was displayed.
It may be true that no one uses s = s + t (I doubt that), but if a 2-line
template can change this into s &= t, I'd suggest it's worth adding that to the
compiler for a 250x speed increase. This was a very unexpected speed bump to me.
Here's a test comparing s.add('x') with s &= 'x'. It seems like these should
have identical performance, but:
ms:nim jim$ cat str1.nim
var
s: string
for i in 0..100_000_000:
s.add('x')
echo len(s)
ms:nim jim$ /usr/bin/time -l ./str1
100000001
0.88 real 0.73 user 0.14 sys
440184832 maximum resident set size
107485 page reclaims
1 block output operations
3 involuntary context switches
ms:nim jim$ cat str1c.nim
proc main() =
var
s: string
for i in 0..100_000_000:
s &= 'x'
echo len(s)
main()
ms:nim jim$ nim c -d:danger str1c
Hint: 14213 LOC; 0.587 sec; 16.016MiB peakmem; Dangerous Release build;
proj: /Users/jim/nim/str1c; out: /User\
s/jim/nim/str1c [SuccessX]
ms:nim jim$ /usr/bin/time -l ./str1c
100000001
0.54 real 0.42 user 0.11 sys
326619136 maximum resident set size
79751 page reclaims
8 page faults
1 voluntary context switches
5 involuntary context switches
Run
