feat: initial package draft

This commit is contained in:
2026-08-05 23:18:16 -04:00
parent 66291ba545
commit 09c3222f8d
36 changed files with 21604 additions and 0 deletions
+686
View File
@@ -0,0 +1,686 @@
//! Exporting an assessment as a Canvas-importable QTI 1.2 package.
//!
//! QTI 1.2 is a fussy, half-abandoned standard, and Canvas reads a particular
//! dialect of it. Two details are worth recording because they are easy to get
//! wrong and produce silent misbehavior rather than an import error.
//!
//! First, question HTML lives inside `<mattext texttype="text/html">` as
//! character data, which means it is escaped once on the way in and unescaped
//! once by Canvas. So `&rarr;` is written as `&amp;rarr;`. Skipping that step
//! produces XML that parses and renders as literal `&rarr;` to students.
//!
//! Second, identifiers must be stable. Canvas keys re-imports and question banks
//! off them, so a package regenerated after a typo fix should carry the same ids
//! as the original. Every id here is derived by hashing the assessment id
//! together with the item's global id, never from a clock or a counter.
//!
//! Option order comes from the form, so exporting form A and form B of the same
//! assessment gives two packages that ask the same questions in different orders,
//! and the answer keys are guaranteed to agree with what was printed.
use crate::assessment::{AssessmentFile, Form, ScoringPolicy};
use crate::catalog::Catalog;
use crate::error::{Error, Result};
use crate::hash::{hex, sha256};
use crate::item::Item;
use crate::markup;
use crate::select;
use crate::taxonomy::Format;
use crate::zipfile::ZipBuilder;
/// The QTI 1.2 namespace.
const QTI_NS: &str = "http://www.imsglobal.org/xsd/ims_qtiasiv1p2";
/// The schema location Canvas expects alongside it.
const QTI_SCHEMA: &str = "http://www.imsglobal.org/xsd/ims_qtiasiv1p2 \
http://www.imsglobal.org/xsd/ims_qtiasiv1p2p1.xsd";
/// The XML Schema instance namespace.
const XSI_NS: &str = "http://www.w3.org/2001/XMLSchema-instance";
/// The IMS content packaging namespace.
const IMSCP_NS: &str = "http://www.imsglobal.org/xsd/imscp_v1p1";
/// The IMS metadata namespace.
const IMSMD_NS: &str = "http://www.imsglobal.org/xsd/imsmd_v1p2";
/// The content packaging schema location.
const IMSCP_SCHEMA: &str = "http://www.imsglobal.org/xsd/imscp_v1p1 imscp_v1p1.xsd \
http://www.imsglobal.org/xsd/imsmd_v1p2 imsmd_v1p2p2.xsd";
// ---------------------------------------------------------------------------
// A very small XML tree
// ---------------------------------------------------------------------------
/// One XML element.
#[derive(Debug, Clone)]
struct Node {
tag: String,
attrs: Vec<(String, String)>,
text: Option<String>,
children: Vec<Node>,
}
impl Node {
/// Creates an element with no attributes, text, or children.
fn new(tag: &str) -> Node {
Node {
tag: tag.to_string(),
attrs: Vec::new(),
text: None,
children: Vec::new(),
}
}
/// Adds an attribute, returning self for chaining.
fn attr(mut self, k: &str, v: impl Into<String>) -> Node {
self.attrs.push((k.to_string(), v.into()));
self
}
/// Sets the element text, returning self for chaining.
fn text(mut self, t: impl Into<String>) -> Node {
self.text = Some(t.into());
self
}
/// Appends a child, returning self for chaining.
fn child(mut self, c: Node) -> Node {
self.children.push(c);
self
}
/// Appends several children, returning self for chaining.
fn children(mut self, cs: Vec<Node>) -> Node {
self.children.extend(cs);
self
}
/// Renders the element and its subtree.
///
/// # Arguments
///
/// * `depth` - the indentation level.
///
/// # Returns
///
/// Indented XML, newline-terminated.
fn render(&self, depth: usize) -> String {
let pad = " ".repeat(depth);
let mut attrs = String::new();
for (k, v) in &self.attrs {
attrs.push_str(&format!(" {k}=\"{}\"", escape_attr(v)));
}
if self.children.is_empty() {
match &self.text {
None => format!("{pad}<{}{attrs}/>\n", self.tag),
Some(t) => format!(
"{pad}<{}{attrs}>{}</{}>\n",
self.tag,
escape_text(t),
self.tag
),
}
} else {
let mut out = format!("{pad}<{}{attrs}>\n", self.tag);
if let Some(t) = &self.text {
out.push_str(&format!("{pad} {}\n", escape_text(t)));
}
for c in &self.children {
out.push_str(&c.render(depth + 1));
}
out.push_str(&format!("{pad}</{}>\n", self.tag));
out
}
}
/// Renders a complete document with an XML declaration.
fn document(&self) -> String {
format!(
"<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n{}",
self.render(0)
)
}
}
/// Escapes text content.
fn escape_text(s: &str) -> String {
s.replace('&', "&amp;")
.replace('<', "&lt;")
.replace('>', "&gt;")
}
/// Escapes an attribute value.
fn escape_attr(s: &str) -> String {
escape_text(s).replace('"', "&quot;")
}
// ---------------------------------------------------------------------------
// Package construction
// ---------------------------------------------------------------------------
/// Options for a QTI export.
#[derive(Debug, Clone)]
pub struct QtiOptions {
/// Which form's option order to use.
pub form: Form,
/// Whether to include per-option feedback. Turn it off for a practice quiz
/// you intend to reuse as a graded one, since Canvas shows this feedback
/// immediately.
pub include_feedback: bool,
/// Whether to let Canvas shuffle answers on top of the form's own order.
pub shuffle_in_canvas: bool,
/// Maximum attempts; `-1` for unlimited.
pub attempts: i64,
/// How repeated attempts are scored.
pub scoring_policy: ScoringPolicy,
}
impl Default for QtiOptions {
fn default() -> QtiOptions {
QtiOptions {
form: Form {
id: "A".to_string(),
seed: 0,
shuffle_items: false,
shuffle_options: false,
},
include_feedback: true,
shuffle_in_canvas: false,
attempts: 1,
scoring_policy: ScoringPolicy::KeepHighest,
}
}
}
/// A rendered QTI package, ready to write.
#[derive(Debug, Clone)]
pub struct Package {
/// The name of the quiz XML file inside the archive.
pub quiz_filename: String,
/// The quiz XML.
pub quiz_xml: String,
/// The manifest XML.
pub manifest_xml: String,
}
impl Package {
/// Writes the package as a Canvas-importable zip.
///
/// # Arguments
///
/// * `path` - the destination `.zip` path.
///
/// # Errors
///
/// Returns [`Error::Io`] on a write failure.
pub fn write_zip(&self, path: &std::path::Path) -> Result<()> {
let mut z = ZipBuilder::new();
// Canvas only recognizes the archive as QTI when the manifest sits at the
// root rather than inside a directory.
z.add_text("imsmanifest.xml", &self.manifest_xml);
z.add_text(&self.quiz_filename, &self.quiz_xml);
z.write_to(path)
}
}
/// Builds a QTI package for an assessment.
///
/// # Arguments
///
/// * `catalog` - the loaded course, for resolving items.
/// * `record` - the assessment record.
/// * `opts` - export options.
///
/// # Returns
///
/// The rendered package.
///
/// # Errors
///
/// Returns [`Error::Unresolved`] when a placement references a missing item, and
/// [`Error::Invalid`] when an item cannot be represented in QTI, such as one with
/// no keyed option.
pub fn build(catalog: &Catalog, record: &AssessmentFile, opts: &QtiOptions) -> Result<Package> {
let assessment_id = qti_id(&format!("{}/assessment", record.assessment.id));
let default_points = catalog.course.policy.points_per_item;
let mut problems = Vec::new();
let mut items = Vec::new();
for placement in select::layout(record, &opts.form) {
let entry = catalog.require(&placement.item)?;
let item = &entry.item;
if item.key_indices().is_empty() {
problems.push(format!(
"question {} ({}) has no keyed option, so Canvas cannot score it",
placement.number, placement.item
));
continue;
}
let points = placement
.points
.unwrap_or_else(|| item.points(default_points));
items.push(build_item(
&record.assessment.id,
&placement.item,
item,
points,
opts,
));
}
if !problems.is_empty() {
return Err(Error::Invalid(problems));
}
let metadata = vec![
metadata_field("cc_maxattempts", &opts.attempts.to_string()),
metadata_field("cc_quiz_scoring_policy", opts.scoring_policy.as_str()),
metadata_field(
"cc_shuffle_answers",
if opts.shuffle_in_canvas {
"true"
} else {
"false"
},
),
];
let title = if record.forms.len() > 1 {
format!("{} (form {})", record.assessment.title, opts.form.id)
} else {
record.assessment.title.clone()
};
let assessment = Node::new("assessment")
.attr("ident", assessment_id.clone())
.attr("title", title.clone())
.child(Node::new("qtimetadata").children(metadata))
.child(
Node::new("section")
.attr("ident", "root_section")
.children(items),
);
let root = Node::new("questestinterop")
.attr("xmlns", QTI_NS)
.attr("xmlns:xsi", XSI_NS)
.attr("xsi:schemaLocation", QTI_SCHEMA)
.child(assessment);
let quiz_filename = format!("{}.xml", slug_filename(&record.assessment.id));
let manifest = build_manifest(
&quiz_filename,
&assessment_id,
&title,
&record.assessment.id,
);
Ok(Package {
quiz_filename,
quiz_xml: root.document(),
manifest_xml: manifest.document(),
})
}
/// Builds one `<item>` element.
///
/// # Arguments
///
/// * `assessment_id` - salts the generated ids.
/// * `uid` - the item's global id.
/// * `item` - the item.
/// * `points` - points as administered.
/// * `opts` - export options.
///
/// # Returns
///
/// The element.
fn build_item(assessment_id: &str, uid: &str, item: &Item, points: f64, opts: &QtiOptions) -> Node {
let order = select::option_order(&opts.form, uid, item.options.len());
let ordered: Vec<&crate::item::Choice> = order.iter().map(|i| &item.options[*i]).collect();
// Option identifiers are numeric, mirroring Canvas's own exports, and are
// derived from the item id so they survive regeneration.
let opt_ids: Vec<String> = ordered
.iter()
.map(|o| short_id(&format!("{assessment_id}/{uid}/{}", o.id)))
.collect();
let item_meta = Node::new("itemmetadata").child(Node::new("qtimetadata").children(vec![
metadata_field("question_type", item.format.qti_type()),
metadata_field("points_possible", &format!("{points:.2}")),
metadata_field("original_answer_ids", &opt_ids.join(",")),
metadata_field("assessment_question_identifierref", &qti_id(uid)),
]));
let cardinality = if item.format == Format::MultipleResponse {
"Multiple"
} else {
"Single"
};
let labels: Vec<Node> = ordered
.iter()
.zip(opt_ids.iter())
.map(|(o, id)| {
Node::new("response_label")
.attr("ident", id.clone())
.child(mattext(&markup::to_html(&o.text)))
})
.collect();
let presentation = Node::new("presentation")
.child(mattext(&format!(
"<div>{}</div>",
markup::to_html(&item.stem)
)))
.child(
Node::new("response_lid")
.attr("ident", "response1")
.attr("rcardinality", cardinality)
.child(Node::new("render_choice").children(labels)),
);
// --- response processing ---
let mut resprocessing = Node::new("resprocessing").child(
Node::new("outcomes").child(
Node::new("decvar")
.attr("maxvalue", "100")
.attr("minvalue", "0")
.attr("varname", "SCORE")
.attr("vartype", "Decimal"),
),
);
// A pass-through condition per option, so choosing anything triggers its
// feedback. `continue="Yes"` is what allows scoring to be evaluated after.
if opts.include_feedback {
for (o, id) in ordered.iter().zip(opt_ids.iter()) {
if o.student_text().is_none() {
continue;
}
resprocessing = resprocessing.child(
Node::new("respcondition")
.attr("continue", "Yes")
.child(
Node::new("conditionvar").child(
Node::new("varequal")
.attr("respident", "response1")
.text(id.clone()),
),
)
.child(
Node::new("displayfeedback")
.attr("feedbacktype", "Response")
.attr("linkrefid", format!("{id}_fb")),
),
);
}
}
let correct: Vec<&String> = ordered
.iter()
.zip(opt_ids.iter())
.filter(|(o, _)| o.correct)
.map(|(_, id)| id)
.collect();
let incorrect: Vec<&String> = ordered
.iter()
.zip(opt_ids.iter())
.filter(|(o, _)| !o.correct)
.map(|(_, id)| id)
.collect();
let condition = if item.format == Format::MultipleResponse {
// Full credit only for the exact set: every keyed option chosen and no
// unkeyed one. Without the negations, checking every box scores 100.
let mut and = Node::new("and");
for id in &correct {
and = and.child(
Node::new("varequal")
.attr("respident", "response1")
.text((*id).clone()),
);
}
for id in &incorrect {
and = and.child(
Node::new("not").child(
Node::new("varequal")
.attr("respident", "response1")
.text((*id).clone()),
),
);
}
Node::new("conditionvar").child(and)
} else {
Node::new("conditionvar").child(
Node::new("varequal")
.attr("respident", "response1")
.text(correct.first().map(|s| (*s).clone()).unwrap_or_default()),
)
};
resprocessing = resprocessing.child(
Node::new("respcondition")
.attr("continue", "No")
.child(condition)
.child(
Node::new("setvar")
.attr("action", "Set")
.attr("varname", "SCORE")
.text("100"),
),
);
let mut node = Node::new("item")
.attr("ident", qti_id(&format!("{assessment_id}/{uid}")))
.attr("title", item.display_title())
.child(item_meta)
.child(presentation)
.child(resprocessing);
if opts.include_feedback {
for (o, id) in ordered.iter().zip(opt_ids.iter()) {
if let Some(text) = o.student_text() {
node = node.child(
Node::new("itemfeedback")
.attr("ident", format!("{id}_fb"))
.child(
Node::new("flow_mat")
.child(mattext(&format!("<div>{}</div>", markup::to_html(text)))),
),
);
}
}
}
node
}
/// A `<material><mattext texttype="text/html">` pair.
///
/// # Arguments
///
/// * `html` - the HTML fragment, which is escaped on the way in.
///
/// # Returns
///
/// The element.
fn mattext(html: &str) -> Node {
Node::new("material").child(
Node::new("mattext")
.attr("texttype", "text/html")
.text(html),
)
}
/// A `<qtimetadatafield>` pair.
fn metadata_field(label: &str, entry: &str) -> Node {
Node::new("qtimetadatafield")
.child(Node::new("fieldlabel").text(label))
.child(Node::new("fieldentry").text(entry))
}
/// Builds the IMS content package manifest.
///
/// # Arguments
///
/// * `quiz_filename` - the quiz XML file name.
/// * `assessment_id` - the assessment identifier, reused as the resource id.
/// * `title` - the human title.
/// * `salt` - salts the manifest identifier.
///
/// # Returns
///
/// The manifest element.
fn build_manifest(quiz_filename: &str, assessment_id: &str, title: &str, salt: &str) -> Node {
let lom = Node::new("imsmd:lom").child(
Node::new("imsmd:general").child(
Node::new("imsmd:title").child(
Node::new("imsmd:langstring")
.attr("xml:lang", "en-US")
.text(title),
),
),
);
Node::new("manifest")
.attr("identifier", format!("man{}", qti_id(salt)))
.attr("xmlns", IMSCP_NS)
.attr("xmlns:imsmd", IMSMD_NS)
.attr("xmlns:xsi", XSI_NS)
.attr("xsi:schemaLocation", IMSCP_SCHEMA)
.child(
Node::new("metadata")
.child(Node::new("schema").text("IMS Content"))
.child(Node::new("schemaversion").text("1.1.3"))
.child(lom),
)
.child(
Node::new("organizations").attr("default", "root").child(
Node::new("organization")
.attr("identifier", "root")
.attr("structure", "rooted"),
),
)
.child(
Node::new("resources").child(
Node::new("resource")
.attr("identifier", assessment_id)
.attr("type", "imsqti_xmlv1p2")
.attr("href", quiz_filename)
.child(Node::new("file").attr("href", quiz_filename)),
),
)
}
/// A deterministic QTI identifier: `g` followed by 32 hex characters.
///
/// # Arguments
///
/// * `key` - the stable string to derive from.
///
/// # Returns
///
/// The identifier.
fn qti_id(key: &str) -> String {
let digest = hex(&sha256(key.as_bytes()));
format!("g{}", &digest[..32])
}
/// A deterministic short numeric identifier, as Canvas uses for answers.
///
/// # Arguments
///
/// * `key` - the stable string to derive from.
///
/// # Returns
///
/// A four-digit numeric string.
fn short_id(key: &str) -> String {
let d = sha256(key.as_bytes());
let n = u32::from_be_bytes([d[0], d[1], d[2], d[3]]);
// 1000..9999 keeps the width fixed, which some Canvas importers prefer.
format!("{}", 1000 + (n % 9000))
}
/// Makes a file-name-safe slug.
fn slug_filename(s: &str) -> String {
let mut out = String::new();
for ch in s.chars() {
if ch.is_ascii_alphanumeric() || ch == '-' || ch == '_' {
out.push(ch);
} else {
out.push('_');
}
}
if out.is_empty() {
"quiz".to_string()
} else {
out
}
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn escapes_html_once_inside_mattext() {
let n = mattext("<p>a &rarr; b</p>");
let xml = n.render(0);
// The HTML is character data, so its markup is escaped.
assert!(xml.contains("&lt;p&gt;a &amp;rarr; b&lt;/p&gt;"), "{xml}");
assert!(!xml.contains("<p>"));
}
#[test]
fn attributes_are_escaped() {
let xml = Node::new("item")
.attr("title", "a \"quoted\" & <angled>")
.render(0);
assert!(xml.contains("&quot;quoted&quot;"));
assert!(xml.contains("&amp;"));
assert!(!xml.contains("<angled>"));
}
#[test]
fn ids_are_deterministic_and_well_formed() {
assert_eq!(qti_id("a"), qti_id("a"));
assert_ne!(qti_id("a"), qti_id("b"));
let id = qti_id("exam-4/assessment");
assert_eq!(id.len(), 33);
assert!(id.starts_with('g'));
assert!(id[1..].chars().all(|c| c.is_ascii_hexdigit()));
let s = short_id("x");
assert_eq!(s.len(), 4);
assert!(s.parse::<u32>().unwrap() >= 1000);
}
#[test]
fn empty_element_renders_self_closing() {
assert_eq!(
Node::new("file").attr("href", "q.xml").render(0),
"<file href=\"q.xml\"/>\n"
);
}
#[test]
fn document_has_a_declaration() {
let doc = Node::new("root").document();
assert!(doc.starts_with("<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n"));
}
#[test]
fn manifest_points_at_the_quiz_file() {
let m = build_manifest("exam-4.xml", "gabc", "Exam 4", "exam-4").render(0);
assert!(m.contains("imsqti_xmlv1p2"));
assert!(m.contains("href=\"exam-4.xml\""));
assert!(m.contains("Exam 4"));
}
#[test]
fn slug_filename_is_safe() {
assert_eq!(slug_filename("exam-4 2026s"), "exam-4_2026s");
assert_eq!(slug_filename(""), "quiz");
}
}
+1084
View File
File diff suppressed because it is too large Load Diff
+518
View File
@@ -0,0 +1,518 @@
//! Rendering a printed exam with Typst.
//!
//! Typst rather than LaTeX because the toolchain is one binary with no package
//! manager, the error messages point at a line, and the compile is fast enough to
//! iterate on. `pixi run -e docs typst compile` turns the output of this module
//! into a PDF.
//!
//! The emitted document is deliberately plain and self-contained: no imports, no
//! template packages, nothing that can break because a package version moved. It
//! is also meant to be edited. A generated exam is a starting point, and the
//! output is formatted so that a human can reasonably open it and adjust spacing
//! before printing.
//!
//! Every export takes a form, so form B's answer key is generated from the same
//! permutation that produced form B's question paper. Keeping the key and the
//! paper in one code path is the only way to be sure they agree — a mismatch is
//! discovered by twenty-five students at once.
use crate::assessment::{AssessmentFile, Form};
use crate::catalog::Catalog;
use crate::course::CourseFile;
use crate::error::{Error, Result};
use crate::markup;
use crate::select;
/// Options for a printed exam.
#[derive(Debug, Clone)]
pub struct Options {
/// Which form to render.
pub form: Form,
/// Whether to leave a name and student-id block at the top.
pub name_block: bool,
/// Whether to show the points each question is worth.
pub show_points: bool,
/// Whether to start each question on a new page. Occasionally worth it for an
/// exam with long stimuli.
pub page_per_item: bool,
/// Paper size, as Typst names it.
pub paper: String,
/// Base font size.
pub font_size: String,
}
impl Default for Options {
fn default() -> Options {
Options {
form: Form {
id: "A".to_string(),
seed: 0,
shuffle_items: false,
shuffle_options: false,
},
name_block: true,
show_points: true,
page_per_item: false,
paper: "us-letter".to_string(),
font_size: "11pt".to_string(),
}
}
}
/// Renders the question paper.
///
/// # Arguments
///
/// * `catalog` - the loaded course.
/// * `record` - the assessment record.
/// * `opts` - rendering options.
///
/// # Returns
///
/// A complete Typst document.
///
/// # Errors
///
/// Returns [`Error::Unresolved`] when a placement references a missing item.
pub fn exam(catalog: &Catalog, record: &AssessmentFile, opts: &Options) -> Result<String> {
let course = &catalog.course;
let mut out = String::new();
out.push_str(&preamble(course, record, opts));
if opts.name_block {
out.push_str(
"#block(above: 1em, below: 1.5em)[\n \
#grid(columns: (auto, 1fr, auto, 1fr), gutter: 0.6em,\n \
[*Name*], [#box(width: 100%, repeat[.])],\n \
[*Student ID*], [#box(width: 100%, repeat[.])],\n )\n]\n\n",
);
}
if let Some(instructions) = &record.assessment.instructions {
out.push_str(&format!(
"#block(fill: luma(245), inset: 8pt, radius: 3pt, width: 100%)[\n {}\n]\n\n",
markup::to_typst(instructions)
));
}
let default_points = course.policy.points_per_item;
let mut printed = 0usize;
for placement in select::layout(record, &opts.form) {
if placement.dropped {
continue;
}
let entry = catalog.require(&placement.item)?;
let item = &entry.item;
printed += 1;
if opts.page_per_item && printed > 1 {
out.push_str("#pagebreak()\n\n");
}
// A stimulus shared by several items is printed with each of them. That
// repeats material, but a student should never have to flip pages to find
// the passage a question refers to.
if let Some(id) = &item.stimulus {
if let Some(stimulus) = course.stimuli.get(id) {
out.push_str(&format!(
"#block(stroke: 0.5pt + luma(180), inset: 8pt, radius: 3pt, width: 100%)[\n \
{}\n]\n",
markup::to_typst(&stimulus.body)
));
if let Some(caption) = &stimulus.caption {
out.push_str(&format!(
"#block(above: 0.3em)[#text(size: 0.85em, style: \"italic\")[{}]]\n",
markup::to_typst(caption)
));
}
}
}
let points = placement
.points
.unwrap_or_else(|| item.points(default_points));
let label = if placement.bonus {
if opts.show_points {
format!(
" #text(fill: rgb(\"#666666\"))[(bonus, {})]",
plural_points(points)
)
} else {
" #text(fill: rgb(\"#666666\"))[(bonus)]".to_string()
}
} else if opts.show_points {
format!(
" #text(fill: rgb(\"#666666\"))[({})]",
plural_points(points)
)
} else {
String::new()
};
// The question number is the recorded one, not the printed position, so a
// scanned answer sheet still joins to the assessment record.
out.push_str(&format!(
"#block(above: 1.2em, below: 0.5em)[*{}.*{label} {}]\n",
placement.number,
markup::to_typst(&item.stem)
));
if item.is_multi_key() {
out.push_str(
"#block(below: 0.4em)[#text(size: 0.9em, style: \"italic\")[Select all that \
apply.]]\n",
);
}
let order = select::option_order(&opts.form, &placement.item, item.options.len());
out.push_str("#block(inset: (left: 1.2em))[\n");
for (position, source_index) in order.iter().enumerate() {
let choice = &item.options[*source_index];
// Options are relabeled by printed position, so a shuffled form still
// reads A, B, C, D.
let letter = (b'A' + position as u8) as char;
out.push_str(&format!(
" #grid(columns: (1.4em, 1fr), gutter: 0.2em)[{letter}.][{}]\n",
markup::to_typst(&choice.text)
));
}
out.push_str("]\n\n");
}
if printed == 0 {
return Err(Error::Invalid(vec![
"this assessment has no printable items; every placement is marked dropped".to_string(),
]));
}
Ok(out)
}
/// Renders the answer key.
///
/// # Arguments
///
/// * `catalog` - the loaded course.
/// * `record` - the assessment record.
/// * `opts` - rendering options, whose form determines the letters.
///
/// # Returns
///
/// A complete Typst document.
///
/// # Errors
///
/// Returns [`Error::Unresolved`] when a placement references a missing item.
pub fn answer_key(catalog: &Catalog, record: &AssessmentFile, opts: &Options) -> Result<String> {
let mut out = String::new();
out.push_str(&format!(
"#set page(paper: \"{}\", margin: 2cm)\n#set text(size: 10pt)\n\n\
= {} — answer key (form {})\n\n",
opts.paper,
escape(&record.assessment.title),
opts.form.id
));
out.push_str(
"#text(size: 0.9em, style: \"italic\")[Letters below are the letters *as printed on this \
form*. Do not use this key on another form.]\n\n",
);
out.push_str(
"#table(\n columns: (auto, auto, auto, 1fr),\n align: (right, center, center, left),\n \
table.header([*\\#*], [*Key*], [*Level*], [*Objectives*]),\n",
);
for placement in select::layout(record, &opts.form) {
if placement.dropped {
continue;
}
let entry = catalog.require(&placement.item)?;
let item = &entry.item;
let order = select::option_order(&opts.form, &placement.item, item.options.len());
// Map the source option index to the letter it was printed as.
let mut printed_letters = Vec::new();
for (position, source_index) in order.iter().enumerate() {
if item.options[*source_index].correct {
printed_letters.push(((b'A' + position as u8) as char).to_string());
}
}
let objectives = if placement.learning_objectives.is_empty() {
item.learning_objectives.join(", ")
} else {
placement.learning_objectives.join(", ")
};
out.push_str(&format!(
" [{}], [*{}*], [{}], [{}],\n",
placement.number,
printed_letters.join(""),
placement
.level
.map(|l| l.code().to_string())
.unwrap_or_else(|| "-".into()),
escape(&objectives)
));
}
out.push_str(")\n\n");
// Partial credit decisions belong on the key, where the grader will see them.
let overrides: Vec<String> = record
.items
.iter()
.filter(|p| !p.credit_overrides.is_empty())
.map(|p| {
let list: Vec<String> = p
.credit_overrides
.iter()
.map(|(letter, credit)| format!("{letter} = {:.0}%", credit * 100.0))
.collect();
format!("Question {}: {}", p.number, list.join(", "))
})
.collect();
if !overrides.is_empty() {
out.push_str("== Partial credit\n\n");
for line in overrides {
out.push_str(&format!("- {}\n", escape(&line)));
}
out.push('\n');
}
let dropped: Vec<String> = record
.items
.iter()
.filter(|p| p.dropped)
.map(|p| p.number.to_string())
.collect();
if !dropped.is_empty() {
out.push_str(&format!(
"== Dropped\n\nQuestion(s) {} were dropped and are not printed.\n\n",
dropped.join(", ")
));
}
Ok(out)
}
/// Renders a bubble sheet matching the form.
///
/// # Arguments
///
/// * `catalog` - the loaded course, for option counts.
/// * `record` - the assessment record.
/// * `opts` - rendering options.
///
/// # Returns
///
/// A complete Typst document.
///
/// # Errors
///
/// Returns [`Error::Unresolved`] when a placement references a missing item.
pub fn bubble_sheet(catalog: &Catalog, record: &AssessmentFile, opts: &Options) -> Result<String> {
let mut out = format!(
"#set page(paper: \"{}\", margin: 1.5cm)\n#set text(size: 10pt)\n\n\
= {} — answer sheet (form {})\n\n\
#grid(columns: (auto, 1fr, auto, 1fr), gutter: 0.6em,\n \
[*Name*], [#box(width: 100%, repeat[.])],\n \
[*Student ID*], [#box(width: 100%, repeat[.])],\n)\n\n\
#v(1em)\n",
opts.paper,
escape(&record.assessment.title),
opts.form.id
);
out.push_str("#columns(2)[\n");
for placement in select::layout(record, &opts.form) {
if placement.dropped {
continue;
}
let entry = catalog.require(&placement.item)?;
let count = entry.item.options.len();
let bubbles: Vec<String> = (0..count)
.map(|i| {
let letter = (b'A' + i as u8) as char;
format!("#circle(radius: 0.42em, stroke: 0.5pt)[#align(center + horizon)[#text(size: 0.7em)[{letter}]]]")
})
.collect();
out.push_str(&format!(
" #block(below: 0.45em)[#box(width: 2em)[{}.] {}]\n",
placement.number,
bubbles.join(" ")
));
}
out.push_str("]\n");
Ok(out)
}
/// Builds the document preamble.
///
/// # Arguments
///
/// * `course` - the course.
/// * `record` - the assessment record.
/// * `opts` - rendering options.
///
/// # Returns
///
/// Typst setup and a title block.
fn preamble(course: &CourseFile, record: &AssessmentFile, opts: &Options) -> String {
let form_note = if record.forms.len() > 1 {
format!(" · Form {}", opts.form.id)
} else {
String::new()
};
let date = record
.assessment
.date
.map(|d| d.to_string())
.unwrap_or_default();
let minutes = record
.assessment
.minutes_allowed
.map(|m| format!(" · {m:.0} minutes"))
.unwrap_or_default();
format!(
"#set page(\n paper: \"{paper}\",\n margin: 2cm,\n \
header: [#text(size: 0.85em)[{code} · {title}{form_note}]],\n \
footer: context [#text(size: 0.85em)[Page #counter(page).display() of \
#counter(page).final().first()]],\n)\n\
#set text(size: {size})\n\
#set par(justify: false, leading: 0.65em)\n\n\
#align(center)[\n #text(size: 1.4em, weight: \"bold\")[{title}]\n \\\n \
#text(size: 0.95em)[{code}{course_title} · {term}]\n \\\n \
#text(size: 0.9em)[{date}{minutes}]\n]\n\n",
paper = opts.paper,
size = opts.font_size,
code = escape(&course.course.code),
course_title = escape(&course.course.title),
term = escape(
record
.assessment
.term
.as_deref()
.unwrap_or(&course.course.term)
),
title = escape(&record.assessment.title),
form_note = form_note,
date = date,
minutes = minutes,
)
}
/// Formats a point value with the right plural.
fn plural_points(points: f64) -> String {
if (points - 1.0).abs() < 1e-9 {
"1 point".to_string()
} else if (points.fract()).abs() < 1e-9 {
format!("{points:.0} points")
} else {
format!("{points} points")
}
}
/// Escapes text for Typst content mode.
fn escape(s: &str) -> String {
markup::to_typst(s)
}
#[cfg(test)]
mod tests {
use super::*;
use crate::assessment::Placement;
#[test]
fn point_labels_are_pluralized() {
assert_eq!(plural_points(1.0), "1 point");
assert_eq!(plural_points(2.0), "2 points");
assert_eq!(plural_points(1.5), "1.5 points");
}
#[test]
fn escaping_protects_typst_syntax() {
assert_eq!(escape("email me @ home"), "email me \\@ home");
assert_eq!(escape("a < b"), "a \\< b");
}
#[test]
fn the_key_reports_letters_as_printed() {
// Shuffling must relabel the key: if the correct option moves to the third
// printed position, the key says C.
let form = Form {
id: "B".into(),
seed: 99,
shuffle_items: false,
shuffle_options: true,
};
let order = select::option_order(&form, "bank::q-1", 4);
let correct_source = 0usize;
let printed_position = order.iter().position(|i| *i == correct_source).unwrap();
let letter = (b'A' + printed_position as u8) as char;
assert!(('A'..='D').contains(&letter));
// And it is reproducible.
let again = select::option_order(&form, "bank::q-1", 4);
assert_eq!(order, again);
}
#[test]
fn dropped_items_are_not_printed() {
let record = AssessmentFile {
schema_version: "1.0".into(),
assessment: crate::assessment::Assessment {
id: "e1".into(),
title: "Exam 1".into(),
term: None,
kind: crate::assessment::Kind::Exam,
date: None,
platform: crate::assessment::Platform::Paper,
minutes_allowed: None,
attempts: None,
shuffle: None,
scoring_policy: None,
instructions: None,
notes: None,
},
blueprint: None,
forms: Vec::new(),
items: vec![
Placement {
number: 1,
item: "b::q-1".into(),
version: None,
fingerprint: None,
points: None,
bonus: false,
key: vec!["A".into()],
level: None,
learning_objectives: Vec::new(),
credit_overrides: Default::default(),
dropped: true,
},
Placement {
number: 2,
item: "b::q-2".into(),
version: None,
fingerprint: None,
points: None,
bonus: false,
key: vec!["B".into()],
level: None,
learning_objectives: Vec::new(),
credit_overrides: Default::default(),
dropped: false,
},
],
};
let printable: Vec<u32> = select::layout(&record, &Options::default().form)
.into_iter()
.filter(|p| !p.dropped)
.map(|p| p.number)
.collect();
assert_eq!(printable, vec![2]);
}
}