first cut of XML::Tags

diff --git a/lib/XML/Tags.pm b/lib/XML/Tags.pm
new file mode 100644 (file)
index 0000000..f469070
--- /dev/null
+++ b/lib/XML/Tags.pm
@@ -0,0 +1,81 @@
+package XML::Tags;
+
+use strict;
+use warnings FATAL => 'all';
+
+my $IN_SCOPE = 0;
+
+sub import {
+  die "Can't import XML::Tags into a scope when already compiling one that uses it"
+    if $IN_SCOPE;
+  my ($class, @args) = @_;
+  my $opts = shift(@args) if ref($args[0]) eq 'HASH';
+  my $target = $class->_find_target(0, $opts);
+  my @tags = $class->_find_tags(@args);
+  my $unex = $class->_export_tags_into($target => @tags);
+  $class->_install_unexporter($unex);
+  $IN_SCOPE = 1;
+}
+
+sub _find_tags { shift; @_ }
+
+sub _find_target {
+  my ($class, $extra_levels, $opts) = @_;
+  return $opts->{into} if defined($opts->{into});
+  my $level = ($opts->{into_level} || 1) + $extra_levels;
+  return (caller($level))[0];
+}
+
+{
+  my $setup;
+
+  sub _setup_glob_override {
+    return if $setup;
+    $setup = 1;
+    no warnings 'redefine';
+    *CORE::GLOBAL::glob = sub {
+      for ($_[0]) {
+        # unless it smells like </foo> or <foo bar="baz">
+        return CORE::glob($_[0]) unless (/^\/\w+$/ || /^\w+\s+\w+="/);
+      }
+      return '<'.$_[0].'>';
+    };
+  }
+}
+
+sub _export_tags_into {
+  my ($class, $into, @tags) = @_;
+  foreach my $tag (@tags) {
+    no strict 'refs';
+    tie *{"${into}::${tag}"}, 'XML::Tags::TIEHANDLE', "<${tag}>";
+  }
+  my $orig = \&CORE::GLOBAL::glob || sub { CORE::glob($_[0]) };
+  {
+    no warnings 'redefine';
+    *CORE::GLOBAL::glob = sub { '<'.$_[0].'>' };
+  }
+  return sub {
+    foreach my $tag (@tags) {
+      no strict 'refs';
+      delete ${"${into}::"}{$tag}
+    }
+    $IN_SCOPE = 0;
+  };
+}
+
+sub _install_unexporter {
+  my ($class, $unex) = @_;
+  $^H |= 0x120000; # localize %^H
+  $^H{'XML::Tags::Unex'} = bless($unex, 'XML::Tags::Unex');
+}
+
+package XML::Tags::TIEHANDLE;
+
+sub TIEHANDLE { my $str = $_[1]; bless \$str, $_[0] }
+sub READLINE { ${$_[0]} }
+
+package XML::Tags::Unex;
+
+sub DESTROY { local $@; eval { $_[0]->(); 1 } || warn "ARGH: $@" }
+
+1;

diff --git a/t/tags.t b/t/tags.t
new file mode 100644 (file)
index 0000000..b7857ca
--- /dev/null
+++ b/t/tags.t
@@ -0,0 +1,36 @@
+use strict; use warnings FATAL => 'all';
+use Test::More qw(no_plan);
+
+{
+
+  package Foo;
+
+  sub foo {
+    use XML::Tags qw(one two three);
+    <one>, <two>, <three>;
+  }
+
+  sub bar {
+    no warnings 'once'; # this is supposed to warn, it's broken
+    <one>
+  }
+
+  sub baz {
+    use XML::Tags qw(bar);
+    </bar>;
+  }
+}
+
+is(
+  join(', ', Foo::foo()),
+  '<one>, <two>, <three>',
+  'open tags ok'
+);
+
+ok(!eval { Foo::bar(); 1 }, 'Death on use of unimported tag');
+
+is(
+  join(', ', Foo::baz()),
+  '</bar>',
+  'close tag ok'
+);