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pl-external-grader-variables element

Displays variables that are given to the student, or expected for the student to define in externally-graded Python questions.

We advise against using this element for any question not using the prairielearn/grader-python Docker image, as the way this element stores parameters is specifically for use with that autograder. If you want to display a table of variables for a question using a different autograder, consider using a standard HTML <table> instead.

The list of variables can be defined in data["params"] or the question HTML itself (but not both!). If defined in the question HTML itself, the variable information is added to data["params"] for use by the external grader. If no descriptions are present, this column is hidden in the table shown to the student.

If stored in data["params"], the variables list has the following format:

data["params"]["names_for_user"] = [
    {"name": "var1", "description": "Human-readable description.", "type": "type"},
    {"name": "var2", "description": "...", "type": "..."}
]
data["params"]["names_from_user"] = [
    {"name": "result1", "description": "...", "type": "..."}
]

Sample element

Screenshot of the pl-external-grader-variables element

question.html
<p>The setup code gives the following variables:</p>
<pl-external-grader-variables params-name="names_for_user"></pl-external-grader-variables>

<p>Your code snippet should define the following variables:</p>
<pl-external-grader-variables params-name="names_from_user">
  <pl-variable name="x" type="numpy array (length $n$)">
    Solution to $\mathbf{Ax}=\mathbf{b}$.
  </pl-variable>
</pl-external-grader-variables>
server.py
def generate(data):
    data["params"]["names_for_user"] = [
        {"name": "n", "description": r"Dimensionality of $\mathbf{A}$ and $\mathbf{b}$.", "type": "integer"},
        {"name": "A", "description": r"Matrix $\mathbf{A}$.", "type": "numpy array"},
        {"name": "b", "description": r"Vector $\mathbf{b}$.", "type": "numpy array"}
    ]

Customizations

Attribute Type Default Description
empty boolean false Whether the entry for the given params-name should be set to empty. Will throw an error if variables are defined and this is set to true.
params-name string — Name of variable specification in data["params"] to display, the format for which is given above.

The HTML inside the inner pl-variable tag is used as the description. If the tag is empty, no description is used for the given variable. The inner pl-variable tag has the following attributes:

Attribute Type Default Description
name string — Name of the given variable. Required for all variables.
type string — Type of the given variable. Required for all variables.

Example implementations