"""Macro support for P65.

	P65 Macros are cached SequenceNodes with arguments
	set via .alias commands and prevented from escaping
	with .scope and .scend commands."""

import sys

import Ophis.IR as IR
import Ophis.CmdLine as Cmd
import Ophis.Errors as Err

macros = {}
currentname = None
currentbody = None

def newMacro(name):
	"Start creating a new macro with the specified name."
	global currentname
	global currentbody
	global macros
	if currentname is not None:
		Err.log("Internal error!  Nested macro attempt!")
	else:
		if name in macros:
			Err.log("Duplicate macro definition '%s'" % name)
		currentname = name
		currentbody = []

def registerNode(node):
	global currentbody
	currentbody.append(IR.Node(node.ppt, node.nodetype, *node.data))

def endMacro():
	global currentname
	global currentbody
	global macros
	if currentname is None:
		Err.log("Internal error!  Ended a non-existent macro!")
	else:
		macros[currentname] = currentbody
		currentname = None
		currentbody = None

def expandMacro(ppt, name, arglist):
	global macros
	if name not in macros:
		Err.log("Undefined macro '%s'" % name)
		return IR.NullNode
	argexprs = [IR.Node(ppt, "Label", "_*%d" % i, arg) for (i, arg) in zip(xrange(1, sys.maxint), arglist)]
	bindexprs = [IR.Node(ppt, "Label", "_%d" % i, IR.LabelExpr("_*%d" % i)) for i in range(1, len(arglist)+1)]
	body = [IR.Node("%s->%s" % (ppt, node.ppt), node.nodetype, *node.data) for node in macros[name]]
	invocation = [IR.Node(ppt, "ScopeBegin")] + argexprs + [IR.Node(ppt, "ScopeBegin")] + bindexprs + body + [IR.Node(ppt, "ScopeEnd"), IR.Node(ppt, "ScopeEnd")]
	return IR.SequenceNode(ppt, invocation)

def dump():
	global macros
	for mac in macros:
		body = macros[mac]
		print "Macro: "+mac
		for node in body: print node
		print ""