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我想我遇到了 Unicode 和 IO::Handle 的问题。我很可能做错了什么。我想从 IO::Handle 获取和取消获取单个 unicode 字符（不是字节）。但我遇到了一个令人惊讶的错误。

#!/usr/local/bin/perl

use 5.016;
use utf8;
use strict;
use warnings;

binmode(STDIN,  ':encoding(utf-8)');
binmode(STDOUT, ':encoding(utf-8)');
binmode(STDERR, ':encoding(utf-8)');

my $string = qq[a Å];
my $fh = IO::File->new();

$fh->open(\$string, '<:encoding(UTF-8)');

say $fh->getc(); # a
say $fh->getc(); # SPACE
say $fh->getc(); # Å LATIN CAPITAL LETTER A WITH RING ABOVE (U+00C5)
$fh->ungetc(ord("Å"));
say $fh->getc(); # should be A RING again.

来自 ungetc() 行的错误消息是“在 unicode.pl 第 21 行中说的格式错误的 UTF-8 字符（字符串的意外结尾）。” \x{00c5}“未映射到 unicode.pl 第 21 行的 utf8。” 但这是字符的正确十六进制，它应该映射到字符。

我使用十六进制编辑器来确保 A-RING 的字节对于 UTF-8 是正确的。

这似乎是任何两字节字符的问题。

最后的输出'\xC5'（字面意思是四个字符：反斜杠，x，C，5）。

我已经通过从文件而不是标量变量中读取来测试了这一点。结果是一样的。

这是为 darwin-2level 构建的 perl 5，版本 16，subversion 2 (v5.16.2)

并且脚本以 UTF-8 保存。这是我检查的第一件事。

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2 回答 2

2

鉴于此输出，我很确定这证明存在严重的 Unicode 处理错误：

perl5.16.0 ungettest
ungettest 98896 @ Sun Jan  6 16:01:08 2013: sending normal line to kid
ungettest 98896 @ Sun Jan  6 16:01:08 2013: await()ing kid
ungettest 98897 @ Sun Jan  6 16:01:08 2013: ungetting litte z
ungettest 98897 @ Sun Jan  6 16:01:08 2013: ungetting big sigma
ungettest 98897 @ Sun Jan  6 16:01:08 2013: kid looping on parental input
98897: Unexpected fatalized warning: utf8 "\xA3" does not map to Unicode at ungettest line 40, <STDIN> line 1.
 at ungettest line 10, <STDIN> line 1.
    main::__ANON__('utf8 "\xA3" does not map to Unicode at ungettest line 40, <ST...') called at ungettest line 40
98896: parent pclose failed: 65280,  at ungettest line 28.
Exit 255

由这个程序产生：

#!/usr/bin/env perl

use v5.16;
use strict;
use warnings;
use open qw( :utf8    :std );

use Carp;

$SIG{__WARN__} = sub {  confess "$$: Unexpected fatalized warning: @_" };

sub ungetchar($) {
    my $char = shift();
    confess "$$: expected single character pushback, not <$char>" if length($char) != 1;
    STDIN->ungetc(ord $char);
}

sub debug {
    my $now = localtime(time());
    print STDERR "$0 $$ \@ $now: @_\n";
}

if (open(STDOUT, "|-")                          // confess "$$: cannot fork: $!") {
    $| = 1;
    debug("sending normal line to kid");
    say "From \N{greek:alpha} to \N{greek:omega}.";
    debug("await()ing kid");
    close(STDOUT)                               || confess "$$: parent pclose failed: $?, $!";
    debug("child finished, parent exiting normally");
    exit(0);
}

debug("ungetting litte z");
ungetchar("z")                                  || confess "$$: ASCII ungetchar failed: $!";

debug("ungetting big sigma");
ungetchar("\N{greek:Sigma}")                    || confess "$$: Unicode ungetchar failed: $!";

debug("kid looping on parental input");
while (<STDIN>) {
    chomp;
    debug("kid got $_");
}
close(STDIN)                                    || confess "$$: child pclose failed: $?, $!";
debug("parent closed pipe, child exiting normally");
exit 0;
于 2013-01-06T23:02:34.403 回答
1

ungetc在底层输入流中添加一个字节。要返回 U+00C5，流必须包含C3 A5（该字符的 UTF-8 编码），而不是C5( ord("Å"))。请改用IO:: Unread unread。

于 2013-01-06T06:17:32.343 回答