rakulang

Raku 中的 IO 操作

Sun Jul 11, 2021

Io in Raku

文件存在、文件的时间戳、文件的修改时间等等

批量插入文本 #

my @filenames = dir '.',  test => any(/\.md$/, /\.markdown/);

for @filenames -> $filePath {
    my $path = $filePath.path();
    $path ~~ s/.md//;
    $path ~~ s/.markdown//;

    my $date = DateTime.new(now);
    my $head =
qq:heredoc 'EOT';
title:  $path.IO.basename()
date: $date
tags: Raku
categories: Raku

---

<blockquote class="blockquote-center">这城市有太多风景都在提醒那过去！</blockquote>

[TOC]

EOT

   my @content   = slurp $filePath;
   spurt($filePath.path, "$head\n@content[]");
}

在当前目录中查找所有以 .md (.markdown)结尾的文件（即markdown文件）, 并在文件最前面插入一段文本，形如：

title:  Raku
date: 2015-08-20T23:19:13Z
tags: Raku
categories: Raku

---

<blockquote class="blockquote-center">我站在天桥上念你, 有点狼狈</blockquote>

类 IO::Path 提供了 basename, path, parts, 等方法供使用, 具体用法请看文档:

rakudoc IO::Path

一些例子：

say IO::Path.new("/etc/passwd").basename;   # passwd
say IO::Path.new("docs/README.pod").extension;   # pod
say IO::Path.new("/etc/passwd").dirname;    # /etc
say IO::Path::Win32.new("C:\\Windows\\registry.ini").volume;    # C:
say IO::Path.new("/etc/passwd").parts.perl # ("dirname" => "/etc", "volume"  => "", "basename" => "passwd").hash

例子:

# To iterate over the contents of the current directory: for dir() -> $file
{
    say $file;
}

# As before, but include even '.' and '..' which are filtered out by # the
default :test matcher: for dir(test => *) -> $file {
    say $file;
}

# To get the names of all .jpg and .jpeg files in ~/Downloads: my @jpegs =
"%*ENV<HOME>/Downloads".IO.dir(test => /:i '.' jpe?g $/)».Str;

# An example program that lists all files and directories recursively:

sub MAIN($dir = '.') {
    my @todo = $dir.IO; while @todo {
        for @todo.pop.dir -> $path {
            say $path.Str; @todo.push: $path if $path.d;
        }
    }
}

文件测试操作符 #

# If you have a string - a path to something in the filesystem:

if "path/to/file".IO ~~ :e {
    say 'file exists';
}

my $file = "path/to/file"; if $file.IO ~~ :e {
    say 'file exists';
}

# Instead of the colonpair syntax, you can use method calls too:

if 'path/to/file'.IO.e {
    say 'file exists';
}

# If you already have an IO object in $file, either by creating one yourself, or
# by getting it from another subroutine, such as dir, you can write this:

my $file = "path/to/file".IO; if $file ~~ :e {
    say 'file exists';
}

文件时间戳 #

say "path/to/file".IO.modified;                # e.g. Instant:1424089165
say DateTime.new("path/to/file".IO.modified);  # e.g. 2015-02-16T12:18:50Z

my $modification_instant = "path/to/file".IO.modified;
my $modification_time    = DateTime.new($modification_instant);
say $modification_time;  # e.g. 2015-02-16T12:18:50Z

say "path/to/file".IO.accessed;                # e.g. Instant:1424353577
say DateTime.new("path/to/file".IO.accessed);  # e.g. 2015-02-19T13:45:42Z

my $access_instant = "path/to/file".IO.accessed;
my $access_time    =  DateTime.new($access_instant);
say $access_time;  # e.g. 2015-02-19T13:45:42Z

say "path/to/file".IO.changed;                # e.g. Instant:1424089165
say DateTime.new("path/to/file".IO.changed);  # e.g. 2015-02-16T12:18:50Z

my $change_instant = "path/to/file".IO.changed;
my $change_time    =  DateTime.new($chnge_instant);
say $change_time;  # e.g. 2015-02-16T12:18:50Z