Demo of clang AST

courseInstances/Part4/assessments/DL4/infoAssessment.json

@@ -19,6 +19,7 @@
         { "id": "Gallery/PromotionalProduct", "points": 10 },
         { "id": "Gallery/Invoice", "points": 10 },
         { "id": "Gallery/RandomCProgram", "points": 10 },
+        { "id": "Gallery/AstOfCProgram", "points": 10 },
         { "id": "Gallery/LinkedListRemove", "points": 10 }
       ],
       "comment": "This zone contains questions demonstrating the basic functionality of external autograder, as well as official autograders for Java and C. For more info, contact: Jonatan Schroeder jonatan@yorku.ca"

questions/Gallery/AstOfCProgram/info.json

@@ -0,0 +1,15 @@
+{
+    "uuid": "34292487-5019-47ab-8175-49e9dada8790",
+    "title": "Sale Price",
+    "topic": "Variables",
+    "singleVariant": true,
+    "tags": [ "jgfoster" ],
+    "type": "v3",
+    "gradingMethod": "External",
+    "externalGradingOptions": {
+        "enabled": true,
+        "image": "prairielearn/grader-c",
+        "entrypoint": "/grade/tests/test.sh",
+        "serverFilesCourse": ["clang/"]
+    }
+}

questions/Gallery/AstOfCProgram/question.html

@@ -0,0 +1,25 @@
+<pl-question-panel>
+    <p>Jimmy is at Hollister and he wants to buy a hoodie. 
+        The hoodie costs $65, but it has a discount of 15%.</p> 
+    <p>Write a program to help Jimmy calculate the sale price of the hoodie. 
+        The program must ask Jimmy for the item price, and then it will display 
+        the sale price with a precision of 2 decimal places.</p>
+    <p>You <b>must</b> declare a double constant variable and assign it with the sale percentage.</p>
+    <p>You <b>must</b> declare the sale percentage using scientific notation.
+        (No, this isn't how you would normally write a program like this, but it is a convenient demo.)
+    </p>
+    <p>Below is an example of the program:</p>
+
+    <pl-code language="output">
+Enter an item price: $65.00
+The sale price is $55.25
+
+</pl-code>
+</pl-question-panel>
+
+<pl-file-editor source-file-name="source.cpp" file-name="student.cpp" ace-mode="ace/mode/c_cpp"></pl-file-editor>
+
+<pl-submission-panel>
+    <pl-external-grader-results></pl-external-grader-results>
+    <pl-file-preview></pl-file-preview>
+</pl-submission-panel>

questions/Gallery/AstOfCProgram/solution.cpp

@@ -0,0 +1,13 @@
+#include <iostream>
+#include <iomanip>
+using namespace std;
+
+int main() {
+    const double DISCOUNT = 1.5e-1;
+    double price;
+
+    cout << "Enter an item price: $";
+    cin >> price;
+    cout << fixed << setprecision(2) << price * (1.0 - DISCOUNT) << endl;
+    return 0;
+}

questions/Gallery/AstOfCProgram/source.cpp

@@ -0,0 +1,9 @@
+#include <iostream>
+using namespace std;
+
+int main() {
+
+    // Your solution goes here
+
+    return 0;
+}

questions/Gallery/AstOfCProgram/tests/test.py

@@ -0,0 +1,93 @@
+#! /usr/bin/python3
+
+import cgrader
+import clang.cindex
+
+clang.cindex.Config.set_library_path("/usr/lib/")
+
+def print_ast(node, indent=0):
+    print(" " * indent + str(node.spelling) + " (" + str(node.kind) + ")")
+    for child in node.get_children():
+        print_ast(child, indent + 2)
+
+def find_const_double(node):
+    if (
+        node.kind == clang.cindex.CursorKind.VAR_DECL
+        and "double" in node.type.spelling
+        and node.type.is_const_qualified()
+    ):
+        return node
+    for child in node.get_children():
+        found = find_const_double(child)
+        if found is not None:
+            return found
+    return None
+
+def var_name_is_valid(node):
+    return not any(c.islower() for c in node.spelling)
+
+def find_double_initializer(node):
+    child = list(node.get_children())[0]
+    return child if child.kind == clang.cindex.CursorKind.FLOATING_LITERAL else None
+
+def initializer_is_scientific_notation(node):
+    tokens = list(node.get_tokens())
+    if tokens:
+        literal = tokens[0].spelling
+        return "e" in literal or "E" in literal
+    return False
+
+class QuestionGrader(cgrader.CPPGrader):
+    def tests(self):
+        index = clang.cindex.Index.create()
+        translation_unit = index.parse("student.cpp", args=["-x", "c++"])
+        # print_ast(translation_unit.cursor) # Uncomment to print the AST (be sure to comment out includes!)
+        decl = find_const_double(translation_unit.cursor)
+        if decl is None:
+            self.add_test_result("const double not found", points=0, max_points=1)
+            return
+        self.add_test_result("const double found")
+        if not var_name_is_valid(decl):
+            self.add_test_result("variable name is not using the capitalization expected for a constant variable", points=0, max_points=1)
+            return
+        self.add_test_result("variable name is valid")
+        initializer = find_double_initializer(decl)
+        if initializer is None:
+            self.add_test_result("variable does not have a double initializer", points=0, max_points=1)
+            return
+        self.add_test_result("variable has a double initializer")
+        if not initializer_is_scientific_notation(initializer):
+            self.add_test_result("initializer is not in scientific notation", points=0, max_points=1)
+            return
+        self.add_test_result("initializer is in scientific notation")
+        self.test_compile_file(
+            "student.cpp", "student", flags="-Wall -Wextra -pedantic -Werror"
+        )
+        self.test_run(
+            "./student",
+            input="65.00\n",
+            exp_output="55.25",
+            must_match_all_outputs="partial",
+        )
+        self.test_run(
+            "./student",
+            input="35.00\n",
+            exp_output="29.75",
+            must_match_all_outputs="partial",
+        )
+        self.test_run(
+            "./student",
+            input="77.00\n",
+            exp_output="65.45",
+            must_match_all_outputs="partial",
+        )
+        self.test_run(
+            "./student",
+            input="48.00\n",
+            exp_output="40.8",
+            must_match_all_outputs="partial",
+        )
+        self.add_test_result("code runs correctly")
+
+g = QuestionGrader()
+g.start()

questions/Gallery/AstOfCProgram/tests/test.sh

@@ -0,0 +1,4 @@
+#! /bin/bash
+export PATH=/grade/serverFilesCourse:$PATH
+ln -s /usr/lib/llvm-18/lib/libclang.so.1 /usr/lib/libclang.so
+python3 /grade/tests/test.py