LLFourn

This is a response I made to the thread that didn't make it into the archive (I think) :https://lists.linuxfoundation.org/pipermail/lightning-dev/2018-December/001752.html

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Happy new year lightning-dev!

This topic is my main area of research at moment so I'm really happy to see a thread about it. In general I agree with ZmnSCPxj's analysis and conclusions. I'd like to add a couple of ideas to this discussion and would greatly appreciate some early peer review on them :)

HTLCs as American call options

LLFourn

class Rakudo {

    constant File $:install-to;
    constant $:checkout = '2017.07';
    constant File $:clone-to = './rakudo';
    constant GitHub $:zef-repo = 'ugexe/zef';
    constant GitHub $:repo = 'rakudo/rakudo';
    constant Bool $:debug-moar;

    static method install-deps on {

LLFourn

# So you want to pipe shell scripts to docker. But docker runs the container's command as PID 1. 
# Linux doesn't set up signal handlers for PID 1.
# This gives you the following problems:
# 1. The script can't kill itself:
echo 'kill $$; echo "Still alive"' | docker run -i --rm alpine sh 
# 2. You can't kill the script from outside with a normal kill:
echo "sleep 1000" | docker run -i --rm alpine sh & sleep 1 && kill $!
docker ps # it didn't die

#==== Solving problem 1 ====

LLFourn

BEFORE:
A 9.0422700
C 10.6984718
B 10.3635278
a 17.9581401
b 21.61539652
c 27.7105599
HEAD:
A 4.126187
C 4.918153

LLFourn

for i in $(seq 1 5); do
    ./install/bin/perl6 -e '"a" x 1000000000 ~ "b" ~~ /b/; say now - INIT now;'
done | awk '{ v += $0; i++; }; END { print v/i }'

LLFourn

#!/usr/bin/env perl6

sub perl6-loop($n)
{
    my $sum = 0;
    for 1..$n -> $i {
        for 1..$i -> $j {
            $sum += $i+$j;
        }
    }

LLFourn

My top 10 p6 features

My brain did work so I wrote it down. This is more for my use cases than why I think the language will succeed in general.

1. containers
2. grammars
3. multi-dispatch (esp on type narrowness)
4. lexical $_
5. easy + sane defaults builtin OO
6. Types as first class citizens + MOP
7. lazy iterators

LLFourn

I've been getting segfaults in this area recently. The trace is a bit different but I guess it's related. It seems that flag_map in gc_mark is no longer allocated so I get segfault.

(lldb) r
There is a running process, kill it and restart?: [Y/n] y
Process 75673 exited with status = 9 (0x00000009) 
Process 75691 launched: '/Users/llfourn/src/rakudo/install/bin/moar' (x86_64)
Process 75691 stopped
* thread #1: tid = 0x23cfc68, 0x0000000100063ca4 libmoar.dylib`gc_mark(tc=0x0000000100500290, st=0x0000000101004f40, data=<unavailable>, worklist=0x000000010d27c1a0) + 84 at MVMCallCapture.c:55, queue = 'com.apple.main-thread', stop reason = EXC_BAD_ACCESS (code=1, address=0x10a72533)
    frame #0: 0x0000000100063ca4 libmoar.dylib`gc_mark(tc=0x0000000100500290, st=0x0000000101004f40, data=<unavailable>, worklist=0x000000010d27c1a0) + 84 at MVMCallCapture.c:55
   52  	        MVMuint16  count = ctx->arg_count;

LLFourn

#== WITH LLDB \o/
(lldb) run
Process 41869 launched: '/Users/llfourn/src/rakudo/install/bin/moar' (x86_64)
Process 41869 stopped
* thread #1: tid = 0x1a7644d, 0x0000000100063cf4 libmoar.dylib`gc_mark(tc=0x0000000100402a80, st=0x0000000100804b40, data=<unavailable>, worklist=0x000000010a0e61f0) + 84 at MVMCallCapture.c:55, queue = 'com.apple.main-thread', stop reason = EXC_BAD_ACCESS (code=EXC_I386_GPFLT)
    frame #0: 0x0000000100063cf4 libmoar.dylib`gc_mark(tc=0x0000000100402a80, st=0x0000000100804b40, data=<unavailable>, worklist=0x000000010a0e61f0) + 84 at MVMCallCapture.c:55
   52  	        MVMuint16  count = ctx->arg_count;
   53  	        MVMuint16  i, flag;
   54  	        for (i = 0, flag = 0; i < count; i++, flag++) {
-> 55  	            if (flag_map[flag] & MVM_CALLSITE_ARG_NAMED) {

LLFourn

use nqp;

my package EXPORTHOW {
    package SUPERSEDE {
        class subset is Metamodel::SubsetHOW {
            has @!ss-params;
            method parameterize($obj,*@params) {
                @!ss-params = @params;
                $obj;
            }