[core] Still refactoring the core behaviour of bags, starting to be much simpler.

bonobo/util/resolvers.py

@@ -0,0 +1,61 @@
+"""
+This package is considered private, and should only be used within bonobo.
+
+"""
+
+import json
+
+import bonobo
+from bonobo.util.collections import tuplize
+from bonobo.util.python import WorkingDirectoryModulesRegistry
+
+
+def _parse_option(option):
+    """
+    Parse a 'key=val' option string into a python (key, val) pair
+
+    :param option: str
+    :return: tuple
+    """
+    try:
+        key, val = option.split('=', 1)
+    except ValueError:
+        return option, True
+
+    try:
+        val = json.loads(val)
+    except json.JSONDecodeError:
+        pass
+
+    return key, val
+
+
+def _resolve_options(options=None):
+    """
+    Resolve a collection of option strings (eventually coming from command line) into a python dictionary.
+
+    :param options: tuple[str]
+    :return: dict
+    """
+    if options:
+        return dict(map(_parse_option, options))
+    return dict()
+
+
+@tuplize
+def _resolve_transformations(transformations):
+    """
+    Resolve a collection of strings into the matching python objects, defaulting to bonobo namespace if no package is provided.
+
+    Syntax for each string is path.to.package:attribute
+
+    :param transformations: tuple(str)
+    :return: tuple(object)
+    """
+    registry = WorkingDirectoryModulesRegistry()
+    for t in transformations:
+        try:
+            mod, attr = t.split(':', 1)
+            yield getattr(registry.require(mod), attr)
+        except ValueError:
+            yield getattr(bonobo, t)