Re: Version 0.17.0 released!

[bpr]

> If you do, you may consider put some words into documentation what to do to 
> achieve similar behaviour because there is quite a lot of people that are 
> comfortable with that approach.

Agreed on documentation. The VTable section of the manual is short, and there's 
no tutorial. IMO it would make more sense to rework the tutorial part 2 when 
the feature is ready.

It would be interesting to have some numbers on the use of **method**. Can you 
point to some Nim where the multiple dispatch feature is being used in an 
essential way? I wrote some 'expression problem' type code to test it but I 
rarely use dynamic dispatch at all in Nim. Are multimethods widely used, like 
they are in Julia? You can already simulate single dispatch already without 
using **method**.

Re: Slow strings

[dataman]

Levenshtein distance, based on my old Pascal source. In some cases, faster than 
a implementation in strutils module by 10%.

(Enj|Destr)oy! 


import strutils, os
import nimbench

proc editDistance2*(a, b: string): int = #{.noSideEffect.} =
  ## Returns the edit distance between `a` and `b`.
  ##
  ## This uses the `Levenshtein`:idx: distance algorithm with only a linear
  ## memory overhead.  This implementation is highly optimized!
  var len1 = a.len
  var len2 = b.len
  if len1 > len2:
# make `b` the longer string
return editDistance(b, a)
  
  # strip common prefix:
  var s = 0
  while a[s] == b[s] and a[s] != '\0':
inc(s)
dec(len1)
dec(len2)
  
  # strip common suffix:
  while len1 > 0 and len2 > 0 and a[s+len1-1] == b[s+len2-1]:
dec(len1)
dec(len2)
  
  # trivial cases:
  if len1 == 0: return len2
  if len2 == 0: return len1
  
  # another special case:
  if len1 == 1:
for j in s..s+len2-1:
  if a[s] == b[j]: return len2 - 1

return len2
  
  inc(len1)
  inc(len2)
  var row: seq[int]
  newSeq(row, len2)
  
  for i in 0..len2 - 1: row[i] = i
  
  for i in 1 .. len1- 1:
var char1 = a[s + i - 1]
var prevCost = i - 1;
var newCost = i;

for j in 1 .. len2 - 1:
  var char2 = b[s + j - 1]
  
  if char1 == char2:
newCost = prevCost
  else:
newCost = min(newCost, min(prevCost, row[j])) + 1
  
  prevCost = row[j]
  row[j] = newCost
  
  result = row[len2 - 1]

var s1: string = "0123456789"
var s2: string = "0123455779"

if paramCount() > 1:
  if fileExists(paramStr(1)):
s1 = readFile(paramStr(1))
  else:
s1 = paramStr(1)
  
  if fileExists(paramStr(2)):
s2 = readFile(paramStr(2))
  else:
s2 = paramStr(2)

echo "editDistance:  ", editDistance(s1, s2)
echo "editDistance2: ", editDistance2(s1, s2)

bench(editDistance, m):
  var d = 0
  for i in 1..m:
d = editDistance(s1, s2)
  
  doNotOptimizeAway(d)

benchRelative(editDistance2, m):
  var d = 0
  
  for i in 1..m:
d = editDistance2(s1, s2)
  
  doNotOptimizeAway(d)


runBenchmarks()

Re: Nim Robot the Second

[dom96]

Awesome! I'd love to see an article on how you put all of this together. I can 
even let you publish it on nim-lang.org if you'd like.

Re: Please , can we stop spams?

[dom96]

**@dataman** there is no "attitude" we just miss new people sometimes (that's a 
forum issue that needs to be fixed), apologies.

Re: Nim Robot the Second

[xyz32]

Thanks,

No the white box is just a mini wireless router running openwrt that can act 
either as a WIFI hotspot or as a wifi client.

The computer is a BeagleBone Black on the left side of the robot, and it was 
developed using this library: 
[https://github.com/xyz32/boneGPIO](https://github.com/xyz32/boneGPIO)

Re: Nim Robot the Second

[matkuki]

Nice!

Is the white box the computer? Which one did you use?

Re: Please , can we stop spams?

[dataman]

Almost two days passed, and my first message is still moderated. I have never 
seen such an attitude to users at any forum.

Re: Version 0.17.0 released!

[mmierzwa]

First of all. Congratulations.

> But you're spot on, I hope this feature means we can remove method from the 
> language.

If you do, you may consider put some words into documentation what to do to 
achieve similar behaviour because there is quite a lot of people that are 
comfortable with that approach.

Re: Version 0.17.0 released!

[adrianv]

> Ahhh damn, I thought you'd go for the first option and add the feature soon

me too - normally documentation takes longer than implementation...

Re: Python3 extension help needed

[matkuki]

Thanks jlp765!

Tried **GC_disableMarkAndSweep()** at the beginning and 
**GC_enableMarkAndSweep()** at the end of the procedure, still it throws the 
segmentation fault.

Then I tried **GC_disable()** and **GC_enable()** \+ **GC_fullCollect()** and 
it works!

Re: Python3 extension help needed

[jlp765]

Try disabling 
[MarkAndSweep](https://nim-lang.org/docs/system.html#GC_disableMarkAndSweep) 
temporarily.