1 files changed, 168 insertions, 0 deletions
diff --git a/crates/typst-ide/src/utils.rs b/crates/typst-ide/src/utils.rs
new file mode 100644
index 00000000..9ea058b9
--- /dev/null
+++ b/crates/typst-ide/src/utils.rs
@@ -0,0 +1,168 @@
+use std::fmt::Write;
+use std::ops::ControlFlow;
+
+use ecow::{eco_format, EcoString};
+use typst::foundations::{Scope, Value};
+use typst::syntax::{LinkedNode, SyntaxKind};
+use typst::text::{FontInfo, FontStyle};
+
+use crate::IdeWorld;
+
+/// Extract the first sentence of plain text of a piece of documentation.
+///
+/// Removes Markdown formatting.
+pub fn plain_docs_sentence(docs: &str) -> EcoString {
+    let mut s = unscanny::Scanner::new(docs);
+    let mut output = EcoString::new();
+    let mut link = false;
+    while let Some(c) = s.eat() {
+        match c {
+            '`' => {
+                let mut raw = s.eat_until('`');
+                if (raw.starts_with('{') && raw.ends_with('}'))
+                    || (raw.starts_with('[') && raw.ends_with(']'))
+                {
+                    raw = &raw[1..raw.len() - 1];
+                }
+
+                s.eat();
+                output.push('`');
+                output.push_str(raw);
+                output.push('`');
+            }
+            '[' => link = true,
+            ']' if link => {
+                if s.eat_if('(') {
+                    s.eat_until(')');
+                    s.eat();
+                } else if s.eat_if('[') {
+                    s.eat_until(']');
+                    s.eat();
+                }
+                link = false
+            }
+            '*' | '_' => {}
+            '.' => {
+                output.push('.');
+                break;
+            }
+            _ => output.push(c),
+        }
+    }
+
+    output
+}
+
+/// Create a short description of a font family.
+pub fn summarize_font_family<'a>(
+    variants: impl Iterator<Item = &'a FontInfo>,
+) -> EcoString {
+    let mut infos: Vec<_> = variants.collect();
+    infos.sort_by_key(|info| info.variant);
+
+    let mut has_italic = false;
+    let mut min_weight = u16::MAX;
+    let mut max_weight = 0;
+    for info in &infos {
+        let weight = info.variant.weight.to_number();
+        has_italic |= info.variant.style == FontStyle::Italic;
+        min_weight = min_weight.min(weight);
+        max_weight = min_weight.max(weight);
+    }
+
+    let count = infos.len();
+    let mut detail = eco_format!("{count} variant{}.", if count == 1 { "" } else { "s" });
+
+    if min_weight == max_weight {
+        write!(detail, " Weight {min_weight}.").unwrap();
+    } else {
+        write!(detail, " Weights {min_weight}–{max_weight}.").unwrap();
+    }
+
+    if has_italic {
+        detail.push_str(" Has italics.");
+    }
+
+    detail
+}
+
+/// The global definitions at the given node.
+pub fn globals<'a>(world: &'a dyn IdeWorld, leaf: &LinkedNode) -> &'a Scope {
+    let in_math = matches!(
+        leaf.parent_kind(),
+        Some(SyntaxKind::Equation)
+            | Some(SyntaxKind::Math)
+            | Some(SyntaxKind::MathFrac)
+            | Some(SyntaxKind::MathAttach)
+    );
+
+    let library = world.library();
+    if in_math {
+        library.math.scope()
+    } else {
+        library.global.scope()
+    }
+}
+
+/// Checks whether the given value or any of its constituent parts satisfy the
+/// predicate.
+pub fn check_value_recursively(
+    value: &Value,
+    predicate: impl Fn(&Value) -> bool,
+) -> bool {
+    let mut searcher = Searcher { steps: 0, predicate, max_steps: 1000 };
+    match searcher.find(value) {
+        ControlFlow::Break(matching) => matching,
+        ControlFlow::Continue(_) => false,
+    }
+}
+
+/// Recursively searches for a value that passes the filter, but without
+/// exceeding a maximum number of search steps.
+struct Searcher<F> {
+    max_steps: usize,
+    steps: usize,
+    predicate: F,
+}
+
+impl<F> Searcher<F>
+where
+    F: Fn(&Value) -> bool,
+{
+    fn find(&mut self, value: &Value) -> ControlFlow<bool> {
+        if (self.predicate)(value) {
+            return ControlFlow::Break(true);
+        }
+
+        if self.steps > self.max_steps {
+            return ControlFlow::Break(false);
+        }
+
+        self.steps += 1;
+
+        match value {
+            Value::Dict(dict) => {
+                self.find_iter(dict.iter().map(|(_, v)| v))?;
+            }
+            Value::Content(content) => {
+                self.find_iter(content.fields().iter().map(|(_, v)| v))?;
+            }
+            Value::Module(module) => {
+                self.find_iter(module.scope().iter().map(|(_, v, _)| v))?;
+            }
+            _ => {}
+        }
+
+        ControlFlow::Continue(())
+    }
+
+    fn find_iter<'a>(
+        &mut self,
+        iter: impl Iterator<Item = &'a Value>,
+    ) -> ControlFlow<bool> {
+        for item in iter {
+            self.find(item)?;
+        }
+        ControlFlow::Continue(())
+    }
+}