MENUSELECT
Copyright (C) 2005-2006, Digium, Inc.
Russell Bryant <russell@digium.com>
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ABOUT

Menuselect is a tool designed to be used in conjunction with GNU make. It
allows for an XML specification of Makefile variables and optional space
delimited values of these variables. These values can then be used in the
Makefile to make various decisions during the build process.

Menuselect also provides a mechanism for dependency checking for each possible
member (value) of each category (Makefile variable). These dependencies are
generally checked by using autoconf and the results provided to menuselect. If
dependencies for a member are not met, the user will not be allowed to make
that selection. In the same way the menuselect does dependency checking, it
also does conflict checking. If a listed conflict for a member is met, then
the user will not be allowed to select it.

For use with automated builds or when the user has no desire to make selections
different than the defined defaults, menuselect can generate a default output
file for use in the build.

Menuselect can also do a sanity check on existing input files. If any member
has been selected that has conflicts or unmet dependencies, then menuselect
will exit with an error and output to notify the user of the situation. This is
typically done at the beginning of the build process to ensure that given all
of the known information, the build is going to be successful.


MENUSELECT DEPENDENCIES

libncurses -- This is needed for the curses frontend.
libnewt -- This is needed for the newt frontend (optional).
libmxml -- This library, Mini-XML, is used for XML parsing. 
           (http://www.easysw.com/~mike/mxml/)
	   (Asterisk uses the code in http://svn.digium.com/svn/mxml/ )


ENVIRONMENT SETUP

The file menuselect.h contains a couple of defines which specify locations for
various files.  These locations are relative to the directory from which
menuselect will be executed.

#define OUTPUT_MAKEOPTS_DEFAULT "menuselect.makeopts"
This is the location where the menuselect output will be saved.

#define MENUSELECT_DEPS         "build_tools/menuselect-deps"
This is the location where menuselect will expect to find the input file that
provides dependency and conflict information. More information on the format of
this file can be found in the section about dependency and conflict checking.


DEPENDENCY AND CONFLICT CHECKING

Members may have as many conflicts and dependencies specified as needed. An
example of the MENUSELECT_DEPS file would look like this:

DEPENDENCY1=1
DEPENDENCY2=0
CONFLICT1=0

In this case, "DEPENDENCY1" has been met, "DEPENDENCY2" has not been met, and
"CONFLICT1" is not present.

To ask menuselect to do a background sanity check on dependencies and
conflicts, it can be called like this:

./menuselect --check-deps <input_file1> [input_file2] [...]

The format of the input files must be of the same format menuselect uses to
create the OUPUT_MAKEOPTS_DEFAULT.


SETTING UP AVAILABLE OPTIONS

The XML specification for the menu lives in the file "menuselect-tree" and should
be in the same directory that menuselect will be executed from. An example
menuselect-tree file as used in the Asterisk project (http://www.asterisk.org) is
provided in example_menuselect-tree

Menu:
   The top level tag in menuselect-tree is the <menu> tag. All of the categories
   reside inside of the <menu> ... </menu> block.

Menu Attributes:
   name="Asterisk Module Selection"
   This specifies the title of the menu. It is displayed at the top of the
   screen when using the curses frontend

Categories:
   A <category> contains members. The category tag can contain a number of
   different attributes to specify different behavior.

Category Attributes:
   name="MENUSELECT_APPS"
   The name attribute is required. This is the name of the variable that will
   be in the output from menuselect.
	
   displayname="Applications"
   If this is specfied, this is what will be shown in the menu to the user.

   positive_output="yes"
   The default for menuselect is to output all of the members of a category
   that are *not* selected. This is because it is often convenient to be able
   to define a full list in the Makefile and then filter out the results from
   menuselect. Using GNU make, an example of this would be:
   APPS:=$(filter-out $(MENUSELECT_APPS),$(APPS)) 

   remove_on_change=".lastclean"
   This attribute can contain a space delimited list of files to be deleted
   when it is time to build an output file if any of the members of this
   category have changed values from their values for existing input when the
   application was started.

Members:
   A <member> contains conflicts and dependencies. The member tag can contain a
   number of different attributes to specify different behavior.

Member Attributes:
   name="app_meetme"
   The name attribute is required. This is the value that will be added to the 
   variable specified by the category when selected (or not selected) depending
   on the setting of the positive_output attribute of the category.
	
   displayname="Call Conferencing Application"
   If this is specified, this will be provided as a description of this member
   when the cursor is on it in the menu.

   remove_on_change="apps/app_meetme.o apps/app_meetme.so"
   This attribute can contain a space delimeted list of files to be deleted
   when it is time to build an output file if the value of this member has
   changed from its value in any existing input when the application was
   started.

Dependencies:
   A dependency for a <member> is specified using a <depend> tag. The name of
   the dependency corresponds to names in the MENUSELECT_DEPS file. This is an
   example of specifying a dependency for a member:
      <member name="app_meetme">
         <depend>zaptel</depend>
      </member>   

Conflicts:
   A conflict for a <member> is specified using a <conflict> tag. The name of
   the conflict corresponds to names in the MENUSELECT_DEPS file. This is an
   example of specifying a dependency for a member:
      <member name="res_musiconhold">
         <conflict>win32</conflict>
      </member>


REPORTING BUGS

Any bug reports or feature enhancement submissions to menuselect should be
submitted at https://issues.asterisk.org/

Thank you!
