#  Copyright (C) Vladimir Prus 2003. Permission to copy, use, modify, sell and
#  distribute this software is granted provided this copyright notice appears in
#  all copies. This software is provided "as is" without express or implied
#  warranty, and with no claim as to its suitability for any purpose.

#  This module defines the 'alias' rule and associated class.
#
#  Alias is just a main target which returns its source targets without any 
#  processing. For example::
#
#    alias bin : hello test_hello ;
#    alias lib : helpers xml_parser ;
#
#  Another important use of 'alias' is to conveniently group source files::
#
#    alias platform-src : win.cpp : <os>NT ;
#    alias platform-src : linux.cpp : <os>LINUX ;
#    exe main : main.cpp platform-src ;
# 
#  Lastly, it's possible to create local alias for some target, with different
#  properties::
#
#    alias big_lib : : @/external_project/big_lib/<link>static ;
#

import targets ;
import "class" : new ;
import property ;
import errors : error ;
import type : type ;
import regex ;

class alias-target-class : basic-target 
{
    rule __init__ ( name : project : sources * : requirements * : default-build * )
    {
        basic-target.__init__ $(name) : $(project) : $(sources) : $(requirements) 
          : $(default-build) ;
    }
        
    rule construct ( source-targets * : property-set )
    {
        return $(source-targets) ;
    }   
}

# Declares the 'alias' target. It will build sources, and return them unaltered.
rule alias ( name : sources * : requirements * : default-build * )
{
    local project = [ CALLER_MODULE ] ;
    
    targets.main-target-alternative
      [ new alias-target-class $(name) : $(project) 
        : [ targets.main-target-sources $(sources) : $(name) ] 
        : [ targets.main-target-requirements $(requirements) : $(project) ] 
        : [ targets.main-target-default-build $(default-build) : $(project) ] 
      ] ;
}

IMPORT $(__name__) : alias : : alias ;