Base classes for matcher and library

libs/caper/constraint.py

@@ -0,0 +1,134 @@
+# Copyright 2013 Dean Gardiner <gardiner91@gmail.com>
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+
+class CaptureConstraint(object):
+    def __init__(self, capture_group, constraint_type, comparisons=None, target=None, **kwargs):
+        """Capture constraint object
+
+        :type capture_group: CaptureGroup
+        """
+
+        self.capture_group = capture_group
+
+        self.constraint_type = constraint_type
+        self.target = target
+
+        self.comparisons = comparisons if comparisons else []
+        self.kwargs = {}
+
+        for orig_key, value in kwargs.items():
+            key = orig_key.split('__')
+            if len(key) != 2:
+                self.kwargs[orig_key] = value
+                continue
+            name, method = key
+
+            method = 'constraint_match_' + method
+            if not hasattr(self, method):
+                self.kwargs[orig_key] = value
+                continue
+
+            self.comparisons.append((name, getattr(self, method), value))
+
+    def execute(self, parent_node, node, **kwargs):
+        func_name = 'constraint_%s' % self.constraint_type
+
+        if hasattr(self, func_name):
+            return getattr(self, func_name)(parent_node, node, **kwargs)
+
+        raise ValueError('Unknown constraint type "%s"' % self.constraint_type)
+
+    #
+    # Node Matching
+    #
+
+    def constraint_match(self, parent_node, node):
+        results = []
+        total_weight = 0
+
+        for name, method, argument in self.comparisons:
+            weight, success = method(node, name, argument)
+            total_weight += weight
+            results.append(success)
+
+        return total_weight / (float(len(results)) or 1), all(results) if len(results) > 0 else False
+
+    def constraint_match_eq(self, node, name, expected):
+        if not hasattr(node, name):
+            return 1.0, False
+
+        return 1.0, getattr(node, name) == expected
+
+    def constraint_match_re(self, node, name, arg):
+        # Node match
+        if name == 'node':
+            group, minimum_weight = arg if type(arg) is tuple and len(arg) > 1 else (arg, 0)
+
+            weight, match, num_fragments = self.capture_group.parser.matcher.fragment_match(node, group)
+            return weight, weight > minimum_weight
+
+        # Regex match
+        if type(arg).__name__ == 'SRE_Pattern':
+            return 1.0, arg.match(getattr(node, name)) is not None
+
+        # Value match
+        if hasattr(node, name):
+            match = self.capture_group.parser.matcher.value_match(getattr(node, name), arg, single=True)
+            return 1.0, match is not None
+
+        raise ValueError("Unknown constraint match type '%s'" % name)
+
+    #
+    # Result
+    #
+
+    def constraint_result(self, parent_node, fragment):
+        ctag = self.kwargs.get('tag')
+        if not ctag:
+            return 0, False
+
+        ckey = self.kwargs.get('key')
+
+        for tag, result in parent_node.captured():
+            if tag != ctag:
+                continue
+
+            if not ckey or ckey in result.keys():
+                return 1.0, True
+
+        return 0.0, False
+
+    #
+    # Failure
+    #
+
+    def constraint_failure(self, parent_node, fragment, match):
+        if not match or not match.success:
+            return 1.0, True
+
+        return 0, False
+
+    #
+    # Success
+    #
+
+    def constraint_success(self, parent_node, fragment, match):
+        if match and match.success:
+            return 1.0, True
+
+        return 0, False
+
+    def __repr__(self):
+        return "CaptureConstraint(comparisons=%s)" % repr(self.comparisons)