More precise math font autocomplete suggestions (#6316)

1 files changed, 41 insertions, 4 deletions

diff --git a/crates/typst-ide/src/complete.rs b/crates/typst-ide/src/complete.rs
index 91fa53f9..15b4296e 100644
--- a/crates/typst-ide/src/complete.rs
+++ b/crates/typst-ide/src/complete.rs
@@ -15,7 +15,7 @@ use typst::syntax::{
     ast, is_id_continue, is_id_start, is_ident, FileId, LinkedNode, Side, Source,
     SyntaxKind,
 };
-use typst::text::RawElem;
+use typst::text::{FontFlags, RawElem};
 use typst::visualize::Color;
 use unscanny::Scanner;
 
@@ -1081,6 +1081,24 @@ fn code_completions(ctx: &mut CompletionContext, hash: bool) {
     }
 }
 
+/// See if the AST node is somewhere within a show rule applying to equations
+fn is_in_equation_show_rule(leaf: &LinkedNode<'_>) -> bool {
+    let mut node = leaf;
+    while let Some(parent) = node.parent() {
+        if_chain! {
+            if let Some(expr) = parent.get().cast::<ast::Expr>();
+            if let ast::Expr::ShowRule(show) = expr;
+            if let Some(ast::Expr::FieldAccess(field)) = show.selector();
+            if field.field().as_str() == "equation";
+            then {
+                return true;
+            }
+        }
+        node = parent;
+    }
+    false
+}
+
 /// Context for autocompletion.
 struct CompletionContext<'a> {
     world: &'a (dyn IdeWorld + 'a),
@@ -1152,10 +1170,12 @@ impl<'a> CompletionContext<'a> {
 
     /// Add completions for all font families.
     fn font_completions(&mut self) {
-        let equation = self.before_window(25).contains("equation");
+        let equation = is_in_equation_show_rule(self.leaf);
         for (family, iter) in self.world.book().families() {
-            let detail = summarize_font_family(iter);
-            if !equation || family.contains("Math") {
+            let variants: Vec<_> = iter.collect();
+            let is_math = variants.iter().any(|f| f.flags.contains(FontFlags::MATH));
+            let detail = summarize_font_family(variants);
+            if !equation || is_math {
                 self.str_completion(
                     family,
                     Some(CompletionKind::Font),
@@ -1790,4 +1810,21 @@ mod tests {
             .must_include(["r", "dashed"])
             .must_exclude(["cases"]);
     }
+
+    #[test]
+    fn test_autocomplete_fonts() {
+        test("#text(font:)", -1)
+            .must_include(["\"Libertinus Serif\"", "\"New Computer Modern Math\""]);
+
+        test("#show link: set text(font: )", -1)
+            .must_include(["\"Libertinus Serif\"", "\"New Computer Modern Math\""]);
+
+        test("#show math.equation: set text(font: )", -1)
+            .must_include(["\"New Computer Modern Math\""])
+            .must_exclude(["\"Libertinus Serif\""]);
+
+        test("#show math.equation: it => { set text(font: )\nit }", -6)
+            .must_include(["\"New Computer Modern Math\""])
+            .must_exclude(["\"Libertinus Serif\""]);
+    }
 }