Construct library via extension trait instead of default & inherent impl (#6576)

5 files changed, 48 insertions, 18 deletions

diff --git a/crates/typst-cli/src/world.rs b/crates/typst-cli/src/world.rs
index 95bee235..8ad766b1 100644
--- a/crates/typst-cli/src/world.rs
+++ b/crates/typst-cli/src/world.rs
@@ -12,7 +12,7 @@ use typst::foundations::{Bytes, Datetime, Dict, IntoValue};
 use typst::syntax::{FileId, Lines, Source, VirtualPath};
 use typst::text::{Font, FontBook};
 use typst::utils::LazyHash;
-use typst::{Library, World};
+use typst::{Library, LibraryExt, World};
 use typst_kit::fonts::{FontSlot, Fonts};
 use typst_kit::package::PackageStorage;
 use typst_timing::timed;
diff --git a/crates/typst-ide/src/tests.rs b/crates/typst-ide/src/tests.rs
index b3f368f2..168dfc9f 100644
--- a/crates/typst-ide/src/tests.rs
+++ b/crates/typst-ide/src/tests.rs
@@ -10,7 +10,7 @@ use typst::syntax::package::{PackageSpec, PackageVersion};
 use typst::syntax::{FileId, Source, VirtualPath};
 use typst::text::{Font, FontBook, TextElem, TextSize};
 use typst::utils::{singleton, LazyHash};
-use typst::{Feature, Library, World};
+use typst::{Feature, Library, LibraryExt, World};
 
 use crate::IdeWorld;
 
diff --git a/crates/typst-library/src/lib.rs b/crates/typst-library/src/lib.rs
index fa797788..3e2ce99e 100644
--- a/crates/typst-library/src/lib.rs
+++ b/crates/typst-library/src/lib.rs
@@ -36,6 +36,7 @@ use typst_utils::{LazyHash, SmallBitSet};
 use crate::diag::FileResult;
 use crate::foundations::{Array, Binding, Bytes, Datetime, Dict, Module, Scope, Styles};
 use crate::layout::{Alignment, Dir};
+use crate::routines::Routines;
 use crate::text::{Font, FontBook};
 use crate::visualize::Color;
 
@@ -139,6 +140,11 @@ impl<T: World + ?Sized> WorldExt for T {
 }
 
 /// Definition of Typst's standard library.
+///
+/// To create and configure the standard library, use the `LibraryExt` trait
+/// and call
+/// - `Library::default()` for a standard configuration
+/// - `Library::builder().build()` if you want to customize the library
 #[derive(Debug, Clone, Hash)]
 pub struct Library {
     /// The module that contains the definitions that are available everywhere.
@@ -154,30 +160,28 @@ pub struct Library {
     pub features: Features,
 }
 
-impl Library {
-    /// Create a new builder for a library.
-    pub fn builder() -> LibraryBuilder {
-        LibraryBuilder::default()
-    }
-}
-
-impl Default for Library {
-    /// Constructs the standard library with the default configuration.
-    fn default() -> Self {
-        Self::builder().build()
-    }
-}
-
 /// Configurable builder for the standard library.
 ///
-/// This struct is created by [`Library::builder`].
-#[derive(Debug, Clone, Default)]
+/// Constructed via the `LibraryExt` trait.
+#[derive(Debug, Clone)]
 pub struct LibraryBuilder {
+    #[expect(unused, reason = "will be used in the future")]
+    routines: &'static Routines,
     inputs: Option<Dict>,
     features: Features,
 }
 
 impl LibraryBuilder {
+    /// Creates a new builder.
+    #[doc(hidden)]
+    pub fn from_routines(routines: &'static Routines) -> Self {
+        Self {
+            routines,
+            inputs: None,
+            features: Features::default(),
+        }
+    }
+
     /// Configure the inputs visible through `sys.inputs`.
     pub fn with_inputs(mut self, inputs: Dict) -> Self {
         self.inputs = Some(inputs);
diff --git a/crates/typst-library/src/routines.rs b/crates/typst-library/src/routines.rs
index 4bf8d60c..6db99ba5 100644
--- a/crates/typst-library/src/routines.rs
+++ b/crates/typst-library/src/routines.rs
@@ -1,3 +1,4 @@
+use std::fmt::{self, Debug, Formatter};
 use std::hash::{Hash, Hasher};
 
 use comemo::{Tracked, TrackedMut};
@@ -38,6 +39,12 @@ macro_rules! routines {
         impl Hash for Routines {
             fn hash<H: Hasher>(&self, _: &mut H) {}
         }
+
+        impl Debug for Routines {
+            fn fmt(&self, f: &mut Formatter) -> fmt::Result {
+                f.pad("Routines(..)")
+            }
+        }
     };
 }
 
diff --git a/crates/typst/src/lib.rs b/crates/typst/src/lib.rs
index 0673c325..11d5c9e0 100644
--- a/crates/typst/src/lib.rs
+++ b/crates/typst/src/lib.rs
@@ -323,6 +323,25 @@ mod sealed {
     }
 }
 
+/// Provides ways to construct a [`Library`].
+pub trait LibraryExt {
+    /// Creates the default library.
+    fn default() -> Library;
+
+    /// Creates a builder for configuring a library.
+    fn builder() -> LibraryBuilder;
+}
+
+impl LibraryExt for Library {
+    fn default() -> Library {
+        Self::builder().build()
+    }
+
+    fn builder() -> LibraryBuilder {
+        LibraryBuilder::from_routines(&ROUTINES)
+    }
+}
+
 /// Defines implementation of various Typst compiler routines as a table of
 /// function pointers.
 ///