def parse_extern_modules(lpyfile):
""" Parse an lpyfile to retrieve its modules and expected extern parameters """
lines = list(open(lpyfile).readlines())
externs = set()
def f(**kwd):
nonlocal externs
externs = externs.union(set(kwd.keys()))
code = ''.join([l for l in lines if l.startswith('extern')])
n = {'extern' : f, 'externs' : externs}
exec(code, n, n)
code2 = ''.join([l for l in lines if l.startswith('module')])
from openalea.lpy import Lsystem
l = Lsystem()
l.setCode(code2)
l.makeCurrent()
modules = {}
for m in l.execContext().declaredModules():
modules[m.name] = m.parameterNames
l.done()
return externs, modules
