Imported Upstream version 20120701

[perltidy.git] / examples / filter_example.pl

diff --git a/examples/filter_example.pl b/examples/filter_example.pl
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+++ b/examples/filter_example.pl
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+#!/usr/bin/perl -w
+use Perl::Tidy;
+
+# Illustrate use of prefilter and postfilter parameters to perltidy.  
+# This example program uses a prefilter it to convert the 'method'
+# keyword to 'sub', and a postfilter to convert back, so that perltidy will
+# work for Method::Signature::Simple code.  
+# NOTE: This program illustrates the use of filters but has not been
+# extensively tested.  
+
+# usage:
+#   perl filter_example.pl filter_example.in
+#
+# How it works:
+# 1. First the prefilter changes lines beginning with 'method foo' to 'sub
+# METHOD_foo'
+# 2. Then perltidy formats the code
+# 3. Then the postfilter changes 'sub METHOD_' to 'method ' everywhere.
+# (This assumes that there are no methods named METHOD_*, and that the keyword
+# method always begins a line in the input file).  
+#
+# Debugging hints: 
+# 1. Try commenting out the postfilter and running with 
+# the --notidy option to see what the prefilter alone is doing.
+# 2. Then run with both pre- and post ters with --notidy to be sure
+# that the postfilter properly undoes the prefilter.
+
+my $arg_string = undef;
+Perl::Tidy::perltidy(
+    argv => $arg_string,
+    prefilter =>
+      sub { $_ = $_[0]; s/^\s*method\s+(\w.*)/sub METHOD_$1/gm; return $_ },
+    postfilter =>
+      sub { $_ = $_[0]; s/sub\s+METHOD_/method /gm; return $_ }
+);
+__END__
+
+# Try running on the following code (file filter_example.in):
+
+use Method::Signatures::Simple;
+
+ method foo { $self->bar }
+
+       # with signature
+    method foo($bar, %opts) { $self->bar(reverse $bar) if $opts{rev};
+    }
+
+    # attributes
+    method foo : lvalue { $self->{foo} 
+}
+
+ # change invocant name
+    method 
+foo ($class: $bar) { $class->bar($bar) }