我在perl6中写了一个类似grep的程序,现在我把它编成了并行处理.但是我遇到了一些问题：即使使用相同的命令行,程序有时会成功,有时会失败.当它成功时,事情对我来说是正常的.当它失败时,我不知道为什么……
这是失败时的错误消息.
> grep6 perl * An operation first awaited: in sub MAIN at /Users/xxx/DropBox/bin/grep6 line 28 in block <unit> at /Users/xxx/DropBox/bin/grep6 line 30 Died with the exception: Cannot find method 'Any' on object of type Match in regex at /Users/xxx/DropBox/bin/grep6 line 34 in sub do_something at /Users/xxx/DropBox/bin/grep6 line 34 in block at /Users/xxx/DropBox/bin/grep6 line 24
代码是：
#!/usr/bin/env perl6
constant $color_red = "\e[31m";
constant $color_off = "\e[0m";
sub MAIN(Str $pattern,*@filenames){
my $channel = Channel.new();
$channel.send($_) for @filenames; # dir();
$channel.close;
my @workers;
for 1..3 -> $n {
push @workers,start {
while (my $file = $channel.poll) {
do_something($pattern,$file);
}
}
}
await(@workers);
}
sub do_something(Str $pattern,Str $filename) {
#say $filename;
for $filename.IO.lines -> $line {
my Str $temp = $line;
if $temp ~~ s:g/ (<$pattern>) /$color_red$0$color_off/ {
say $filename ~ ": " ~ $temp;
}
}
}
我的问题是它为什么有时会失败？
问候
鑫
解决方法
这个问题似乎与已知的
rakudo issue for the
race method基本相同.
我转自：
if $temp ~~ s:g/ (<$pattern>) /$color_red$0$color_off/ {
至：
if $temp ~~ s:g/ ($pattern) /$color_red$0$color_off/ {
问题似乎消失了.
正如后面提到的Xin Cheng以及同一文档中所描述的那样,更简单的插值在字面上符合文档示例所阐明.发行票修复了以下问题：
my $reg = regex { <$pattern> };
'' ~~ $reg;
导致更新的程序具有类似的解决方法：
#!/usr/bin/env perl6
constant $color_red = "\e[31m";
constant $color_off = "\e[0m";
sub MAIN(Str $pattern,*@filenames){
my $channel = Channel.new();
$channel.send($_) for @filenames; # dir();
$channel.close;
my @workers;
# match seems required for pre-compilation
'' ~~ (my regex pat_regex { <$pattern> });
for 1..3 -> $n {
push @workers,start {
while (my $file = $channel.poll) {
do_something(&pat_regex,$file);
}
}
}
await(@workers);
}
sub do_something(Regex $pat_regex,Str $filename) {
# say $filename;
for $filename.IO.lines -> $line {
my Str $temp = $line;
if $temp ~~ s:g/ ($pat_regex) /$color_red$0$color_off/ {
say $filename ~ ": " ~ $temp;
}
}
}