# Rules without side effects.

# Vanilla Jam compatibility
if ! $(INVOCATION_SUBDIR_SET) {
	rule FIsPrefix
	{
		# FIsPrefix <a> : <b> ;
		# Returns true, if list <a> is a prefix (a proper one or equal) of
		# list <b>, an empty list otherwise.
		local a = $(1) ;
		local b = $(2) ;
		while $(a) && $(a[1]) = $(b[1]) {
			a = $(a[2-]) ;
			b = $(b[2-]) ;
		}

		if $(a) {
			return ;
		} else {
			return true ;
		}
	}

	rule LocalClean { Clean $(1) : $(2) ; }

	rule LocalDepends { Depends $(1) : $(2) ; }

} # vanilla Jam compatibility

rule FFilter
{
	# FFilter <list> : <excludes> ;
	# Removes all occurrences of <excludes> in <list>.

	local list = $(1) ;
	local excludes = $(2) ;
	local newList ;
	local item ;
	for item in $(list) {
		local skip ;
		local exclude ;
		for exclude in $(excludes) {
			if $(item) = $(exclude) {
				skip = true ;
			}
		}
		if ! $(skip) {
			newList += $(item) ;
		}
	}
	return $(newList) ;
}

rule FGetGrist
{
	# FGetGrist <target> ;
	#
	# Returns the grist of a target, not including leading "<" and trailing ">".

	local grist = $(1[1]:G) ;
	if ! $(grist) {
		return ;
	}

	return [ Match <(.*)> : $(grist) ] ;
}

rule FSplitString string : delimiterChar
{
	local result ;

	while $(string) {
		local split = [ Match $(delimiterChar)*([^$(delimiterChar)]+)(.*)
			: $(string) ] ;
		result += $(split[1]) ;
		string = $(split[2-]) ;
	}

	return $(result) ;
}

rule FSplitPath
{
	# SplitPath <path> ;
	# Decomposes a path into its components.
	local path = $(1:G=) ;
	local components ;
	# $(path:D) for "/" is "/". Therefore the second condition.
	while $(path:D) && $(path:D) != $(path)
	{
		# Note: $(path:B) returns "." for "..", but $(path:D=) is fine.
		components = $(path:D=) $(components) ;
		path = $(path:D) ;
	}
	components = $(path) $(components) ;
	return $(components) ;
}


rule FConditionsHold conditions : predicate
{
	# FConditionsHold <conditions> : <predicate> ;
	# Checks whether the conditions <conditions> are satisfied by the predicate
	# rule <predicate> and returns a respective result (if so: "1", if not:
	# empty list). The conditions are satisfied when <conditions> is not empty
	# and
	# * none of the negative conditions it contains hold and
	# * if <conditions> contains any positive conditions, at least one of those
	#   holds.
	# A positive condition is an element not starting with a "!". It holds when
	# the predicate rule <predicate> returns true for the element.
	# A negative condition is an element that starts with a "!". It holds when
	# the predicate rule <predicate> returns true for the string resulting from
	# removing the leading "!".
	#
	# <conditions> - The list of conditions.
	# <predicate> - The predicate rule invoked to test the elements.
	#
	# Examples:
	# For a predicate that holds for the elements of the set { a b c } the
	# following conditions hold:
	# { a }, { a d }, { !d }, { !d !e }, { a !d }, { b !e !f }
	# The following conditions don't hold:
	# { }, { d }, { d e }, { !a }, { !a b }, { !d e } { a b !c !d }

	local hasPositive ;
	local hasNegative ;
	local positiveMatch ;
	local condition ;
	for condition in $(conditions) {
		switch $(condition) {
			case !* :
			{
				hasNegative = 1 ;
				condition = [ Match "!(.*)" : $(condition) ] ;
				if [ $(predicate) $(condition) ] {
					return ;
				}
			}
			case * :
			{
				hasPositive = 1 ;
				if [ $(predicate) $(condition) ] {
					positiveMatch = 1 ;
				}
			}
		}
	}

	if $(hasPositive) {
		return $(positiveMatch) ;
	}
	return $(hasNegative) ;
}


rule SetPlatformCompatibilityFlagVariables
{
	# SetPlatformCompatibilityFlagVariables <platform var> : <var prefix>
	#	: <platform kind> [ : other platforms ] ;

	local platformVar = $(1) ;
	local platform = $($(platformVar)) ;
	local varPrefix = $(2) ;
	local platformKind = $(3) ;
	local otherPlatforms = $(4) ;

	if ! $(platform) {
		ECHO "Variable $(platformVar) not set. Please run ./configure or" ;
		EXIT "specify it manually." ;
	}

	# special case: Haiku libbe.so built for testing under Haiku
	if $(platform) = libbe_test {
		platform = $(HOST_PLATFORM) ;
	}

	# unset variables first
	$(varPrefix)_PLATFORM_HAIKU_COMPATIBLE = ;

	switch $(platform)
	{
		case haiku_host :
		{
			$(varPrefix)_PLATFORM_HAIKU_COMPATIBLE = true ;
		}

		case haiku :
		{
			$(varPrefix)_PLATFORM_HAIKU_COMPATIBLE = true ;
		}

		case host :
			# not compatible to anything

		case * :
		{
			if ! ( $(platform) in $(otherPlatforms) ) {
				Exit Unsupported $(platformKind) platform: $(platform) ;
			}
		}
	}

	# set the machine friendly flags
	$(varPrefix)_PLATFORM_(haiku)_COMPATIBLE
		?= $($(varPrefix)_PLATFORM_HAIKU_COMPATIBLE) ;
	$(varPrefix)_PLATFORM_(haiku_host)_COMPATIBLE
		?= $($(varPrefix)_PLATFORM_HAIKU_COMPATIBLE) ;
}

rule SetIncludePropertiesVariables prefix : suffix
{
	# SetIncludePropertiesVariables <prefix> : <suffix> ;
	#
	suffix = $(suffix:E=) ;
	if $($(prefix)_CC_IS_LEGACY_GCC$(suffix)) = 1 {
		$(prefix)_INCLUDES_SEPARATOR$(suffix) = -I- ;
		$(prefix)_LOCAL_INCLUDES_OPTION$(suffix) = -I ;
		$(prefix)_SYSTEM_INCLUDES_OPTION$(suffix) = -I ;
	} else {
		$(prefix)_INCLUDES_SEPARATOR$(suffix) = ;
		$(prefix)_LOCAL_INCLUDES_OPTION$(suffix) = "-iquote " ;
		$(prefix)_SYSTEM_INCLUDES_OPTION$(suffix) = "-I " ;
	}
}


#pragma mark -

rule SetPlatformForTarget
{
	# SetPlatformForTarget <target> : <platform> ;

	PLATFORM on $(1) = $(2) ;
}

rule SetSubDirPlatform
{
	# SetSubDirPlatform <platform> ;

	PLATFORM = $(1) ;
}

rule SetSupportedPlatformsForTarget
{
	# SetSupportedPlatformsForTarget <target> : <platforms> ;

	SUPPORTED_PLATFORMS on $(1) = $(2) ;
}

rule SetSubDirSupportedPlatforms
{
	# SetSubDirSupportedPlatforms <platforms> ;

	SUPPORTED_PLATFORMS = $(1) ;
}

rule AddSubDirSupportedPlatforms
{
	# AddSubDirSupportedPlatforms <platforms> ;

	SUPPORTED_PLATFORMS += $(1) ;
}

rule IsPlatformSupportedForTarget
{
	# IsPlatformSupportedForTarget <target> [ : <platform> ]
	#

	on $(1) {
		if $(PLATFORM) in $(SUPPORTED_PLATFORMS) {
			return true ;
		} else {
			return ;
		}
	}
}

rule InheritPlatform
{
	# InheritPlatform <children> : <parent> ;
	# PLATFORM and SUPPORTED_PLATFORMS are set on <children> to their value
	# on <parent>.
	#
	local children = $(1) ;
	local parent = $(2) ;

	on $(parent) {
		PLATFORM on $(children) = $(PLATFORM) ;
		SUPPORTED_PLATFORMS on $(children) = $(SUPPORTED_PLATFORMS) ;
	}
}

rule SubDirAsFlags
{
	SUBDIRASFLAGS += $(<) ;
}