[CWEP002] introduce RQLRelationRewriter
Refactor existing RQLRewriter for later reuse of rewriting relation as specified
by CWEP002. Work is different because we simply want to replace a relation by
another rql snippet and we don't have to bother with EXISTS, subqueries and all.
This rewriter is not yet plugged into the querier.
Depends on yams 0.40 API.
Related to #3546717
"""https://pastebin.logilab.fr/show/860/"""
from astroid import MANAGER, InferenceError, nodes, scoped_nodes
from astroid.builder import AstroidBuilder
def turn_function_to_class(node):
"""turn a Function node into a Class node (in-place)"""
node.__class__ = scoped_nodes.Class
node.bases = ()
# remove return nodes so that we don't get warned about 'return outside
# function' by pylint
for rnode in node.nodes_of_class(nodes.Return):
rnode.parent.body.remove(rnode)
# that seems to be enough :)
def cubicweb_transform(module):
# handle objectify_predicate decorator (and its former name until bw compat
# is kept). Only look at module level functions, should be enough.
for assnodes in module.locals.itervalues():
for node in assnodes:
if isinstance(node, scoped_nodes.Function) and node.decorators:
for decorator in node.decorators.nodes:
try:
for infered in decorator.infer():
if infered.name in ('objectify_predicate', 'objectify_selector'):
turn_function_to_class(node)
break
else:
continue
break
except InferenceError:
continue
# add yams base types into 'yams.buildobjs', astng doesn't grasp globals()
# magic in there
if module.name == 'yams.buildobjs':
from yams import BASE_TYPES
for etype in BASE_TYPES:
module.locals[etype] = [scoped_nodes.Class(etype, None)]
# add data() to uiprops module
if module.name.split('.')[-1] == 'uiprops':
fake = AstroidBuilder(MANAGER).string_build('''
def data(string):
return u''
''')
module.locals['data'] = fake.locals['data']
def register(linter):
"""called when loaded by pylint --load-plugins, nothing to do here"""
MANAGER.register_transform(nodes.Module, cubicweb_transform)