import configure ;
import feature ;
import print ;
import property ;
import regex ;
import sequence ;

feature.feature config-define : : free ;

local rule format-define ( macro-def )
{
     local args = [ regex.match "([^=]*)=(.*)" : $(macro-def) ] ;
     return "#define $(args[1]) $(args[2])" ;
}

rule create-config-header ( target : : properties * )
{
    local macros = [ property.select <config-define> : $(properties) ] ;
    local include-guard = [ MD5 $(macros:J=) ] ;
    print.output $(target) ;
    print.text
        "#ifndef $(include-guard)"
        "#define $(include-guard)"
        [ sequence.transform format-define : $(macros:G=) ]
        "#endif"
      : overwrite
      ;
}

rule check-config-macro ( target name macro )
{
    return [ configure.check-target-builds $(target) $(name) :
        <config-define>$(macro)=1 : <config-define>$(macro)=0 ] ;
}

rule config-header ( target : requirements * )
{
    return [ make $(target) : : @create-config-header : $(requirements) ] ;
}


compile test.cpp ;
explicit test ;

config-header config.h : [ check-config-macro test "has test.h" HAS_TEST_H ] ;