Why the need for metadata.xml?

Why the need for metadata.xml? @@ -115,9 +115,31 @@ <longdescription> This tag contains a description of the package. This is to augment the - DESCRIPTION field in the ebuilds themselves. + DESCRIPTION field in the ebuilds themselves. This tag has two optional + subtags: <pkg> and <cat>. + + <use> + + This tag contains descriptions of USE flags. + This tag is optional and, if specified, has one required subtag: + <flag>. + + + + <flag> + + This tag contains a description of how the named USE flag affects this + package. It is required if the <use> tag is specified. + It alos requires the USE flag to be named in the name attribute. + This tag has two optional subtags: <pkg> and + <cat>. + + + + <pkg>

@@ -256,5 +278,59 @@ + +Third Example + + +

+For the third example, we will describe the metadata.xml of +sys-apps/hal. This ebuild is maintained by the gentopia herd +and contains USE flag descriptions. +

+ +

+<?xml version="1.0" encoding="UTF-8">
+<!DOCTYPE pkgmetadata SYSTEM "http://www.gentoo.org/dtd/metadata.dtd">
+<pkgmetadata>
+<herd>gentopia</herd>
+<maintainer>
+	<email>compnerd@gentoo.org</email>
+</maintainer>
+<maintainer>
+	<email>steev@gentoo.org</email>
+</maintainer>
+<use>
+	<flag name='acpi'>Enables HAL to attempt to read from
+	/proc/acpi/event, if unavailable, HAL will read events from
+	<pkg>sys-power/acpid</pkg>. If you need multiple acpi
+	readers, ensure acpid is in your default runlevel along with HAL. This
+	will also enable HAL to read Toshia and IBM acpi events which do not
+	get sent via /proc/acpi/event</flag>
+	<flag name='crypt'>Allows HAL to mount volumes that are encrypted using
+	LUKS. <pkg>sys-fs/cryptsetup-luks</pkg> which has recently been renamed
+	to <pkg>sys-fs/cryptsetup</pkg> allows you to create such encrypted
+	volumes. HAL will be able to handle volumes that are removable or
+	fixed.</flag>
+	<flag name='dell'>Builds an installs the Dell addon, which reads data from
+	the Dell SM BIOS via <pkg>sys-libs/libsmbios</pkg>. It will read your
+	service tag information and your hardware backlight data as well as
+	allow you to modify the backlight settings on a Dell laptop.</flag>
+	<flag name='disk-partition'>Allows HAL to use libparted from
+	<pkg>sys-apps/parted</pkg> to read raw partition data from your disks
+	and process that data. Future versions of HAL (possibly 0.5.11 and
+	higher) will allow you to create, modify, delete and format partitions
+	from a GUI interface agnostic of your desktop environment.</flag>
+	<flag name='doc'>Generates documentation that describes HAL's fdi
+	format.</flag>
+	<flag name='pcmcia'>Allows HAL to process PCMCIA/CardBus slot data which
+	includes inserts and removals and act on these events.</flag>
+	<flag name='selinux'>Installs SELinux policies and links HAL to the SELinux
+	libraries.</flag>
+</use>
+</pkgmetadata>
+

+ + +