1 files changed, 67 insertions, 0 deletions
diff --git a/yaksh/hook_evaluator.py b/yaksh/hook_evaluator.py
new file mode 100644
index 0000000..3956da1
--- /dev/null
+++ b/yaksh/hook_evaluator.py
@@ -0,0 +1,67 @@
+#!/usr/bin/env python
+from __future__ import unicode_literals
+import sys
+import traceback
+import os
+
+# Local imports
+from .file_utils import copy_files, delete_files
+from .base_evaluator import BaseEvaluator
+from .grader import TimeoutException
+
+
+class HookEvaluator(BaseEvaluator):
+    def __init__(self, metadata, test_case_data):
+        self.files = []
+
+        # Set metadata values
+        self.user_answer = metadata.get('user_answer')
+        self.file_paths = metadata.get('file_paths')
+        self.partial_grading = metadata.get('partial_grading')
+
+        # Set test case data values
+        self.hook_code = test_case_data.get('hook_code')
+        self.weight = test_case_data.get('weight')
+
+    def teardown(self):
+        # Delete the created file.
+        if self.files:
+            delete_files(self.files)
+
+    def check_code(self):
+        """ Function evaluates user answer by running a python based hook code
+        against it.
+        Returns
+        --------
+        Returns a tuple (success, error, test_case_weight)
+
+        success - Boolean, indicating if code was executed successfully, correctly
+        mark_fraction - Float, indicating fraction of the weight to a test case
+        error - String, error message if success is false
+
+        returns (True, "Correct answer", 1.0) : If the student script passes all
+        test cases/have same output, when compared to the instructor script
+
+        returns (False, error_msg, 0.0): If the student script fails a single
+        test/have dissimilar output, when compared to the instructor script.
+
+        Returns (False, error_msg, 0.0): If mandatory arguments are not files or if
+        the required permissions are not given to the file(s).
+        """
+        success = False
+        mark_fraction = 0.0
+        try:
+            tb = None
+            _tests = compile(self.hook_code, '<string>', mode='exec')
+            hook_scope = {}
+            exec(_tests, hook_scope)
+            check = hook_scope["check_answer"]
+            success, err, mark_fraction = check(self.user_answer)
+        except TimeoutException:
+            raise
+        except Exception:
+            msg = traceback.format_exc(limit=0)
+            err = "Error in Hook code: {0}".format(msg)
+        del tb
+        return success, err, mark_fraction
+ 
+\ No newline at end of file