Autocomplete for packages

src/file.rs

@@ -290,6 +290,8 @@ impl PackageManifest {
 }
 
 /// The `package` key in the manifest.
+///
+/// More fields are specified, but they are not relevant to the compiler.
 #[derive(Debug, Clone, Eq, PartialEq, Hash, Serialize, Deserialize)]
 pub struct PackageInfo {
     /// The name of the package within its namespace.

src/ide/complete.rs

@@ -7,7 +7,7 @@ use unscanny::Scanner;
 use super::analyze::analyze_labels;
 use super::{analyze_expr, analyze_import, plain_docs_sentence, summarize_font_family};
 use crate::doc::Frame;
-use crate::eval::{methods_on, CastInfo, Library, Scope, Value};
+use crate::eval::{format_str, methods_on, CastInfo, Library, Scope, Value};
 use crate::syntax::{
     ast, is_id_continue, is_id_start, is_ident, LinkedNode, Source, SyntaxKind,
 };
@@ -402,6 +402,22 @@ fn field_access_completions(ctx: &mut CompletionContext, value: &Value) {
 
 /// Complete imports.
 fn complete_imports(ctx: &mut CompletionContext) -> bool {
+    // In an import path for a package:
+    // "#import "@|",
+    if_chain! {
+        if matches!(
+            ctx.leaf.parent_kind(),
+            Some(SyntaxKind::ModuleImport | SyntaxKind::ModuleInclude)
+        );
+        if let Some(ast::Expr::Str(str)) = ctx.leaf.cast();
+        if str.get().starts_with('@');
+        then {
+            ctx.from = ctx.leaf.offset();
+            ctx.package_completions();
+            return true;
+        }
+    }
+
     // Behind an import list:
     // "#import "path.typ": |",
     // "#import "path.typ": a, b, |".
@@ -413,7 +429,7 @@ fn complete_imports(ctx: &mut CompletionContext) -> bool {
         if let Some(value) = analyze_expr(ctx.world, &source).into_iter().next();
         then {
             ctx.from = ctx.cursor;
-            import_completions(ctx, &items, &value);
+            import_item_completions(ctx, &items, &value);
             return true;
         }
     }
@@ -431,7 +447,7 @@ fn complete_imports(ctx: &mut CompletionContext) -> bool {
         if let Some(value) = analyze_expr(ctx.world, &source).into_iter().next();
         then {
             ctx.from = ctx.leaf.offset();
-            import_completions(ctx, &items, &value);
+            import_item_completions(ctx, &items, &value);
             return true;
         }
     }
@@ -440,7 +456,7 @@ fn complete_imports(ctx: &mut CompletionContext) -> bool {
 }
 
 /// Add completions for all exports of a module.
-fn import_completions(
+fn import_item_completions(
     ctx: &mut CompletionContext,
     existing: &[ast::Ident],
     value: &Value,
@@ -839,14 +855,26 @@ fn code_completions(ctx: &mut CompletionContext, hashtag: bool) {
     );
 
     ctx.snippet_completion(
-        "import",
-        "import \"${file.typ}\": ${items}",
+        "import (file)",
+        "import \"${file}.typ\": ${items}",
         "Imports variables from another file.",
     );
 
     ctx.snippet_completion(
-        "include",
-        "include \"${file.typ}\"",
+        "import (package)",
+        "import \"@${}\": ${items}",
+        "Imports variables from another file.",
+    );
+
+    ctx.snippet_completion(
+        "include (file)",
+        "include \"${file}.typ\"",
+        "Includes content from another file.",
+    );
+
+    ctx.snippet_completion(
+        "include (package)",
+        "include \"@${}\"",
         "Includes content from another file.",
     );
 
@@ -960,6 +988,18 @@ impl<'a> CompletionContext<'a> {
         }
     }
 
+    /// Add completions for all available packages.
+    fn package_completions(&mut self) {
+        for (package, description) in self.world.packages() {
+            self.value_completion(
+                None,
+                &Value::Str(format_str!("{package}")),
+                false,
+                description.as_deref(),
+            );
+        }
+    }
+
     /// Add completions for raw block tags.
     fn raw_completions(&mut self) {
         for (name, mut tags) in (self.library.items.raw_languages)() {
@@ -1014,7 +1054,10 @@ impl<'a> CompletionContext<'a> {
         let detail = docs.map(Into::into).or_else(|| match value {
             Value::Symbol(_) => None,
             Value::Func(func) => func.info().map(|info| plain_docs_sentence(info.docs)),
-            v => Some(v.repr().into()),
+            v => {
+                let repr = v.repr();
+                (repr.as_str() != label).then(|| repr.into())
+            }
         });
 
         if parens && matches!(value, Value::Func(_)) {

src/lib.rs

@@ -54,11 +54,12 @@ pub mod model;
 pub mod syntax;
 
 use comemo::{Prehashed, Track, TrackedMut};
+use ecow::EcoString;
 
 use crate::diag::{FileResult, SourceResult};
 use crate::doc::Document;
 use crate::eval::{Datetime, Library, Route, Tracer};
-use crate::file::FileId;
+use crate::file::{FileId, PackageSpec};
 use crate::font::{Font, FontBook};
 use crate::syntax::Source;
 use crate::util::Bytes;
@@ -112,6 +113,11 @@ pub trait World {
     fn main(&self) -> Source;
 
     /// Try to access the specified source file.
+    ///
+    /// The returned `Source` file's [id](Source::id) does not have to match the
+    /// given `id`. Due to symlinks, two different file id's can point to the
+    /// same on-disk file. Implementors can deduplicate and return the same
+    /// `Source` if they want to, but do not have to.
     fn source(&self, id: FileId) -> FileResult<Source>;
 
     /// Try to access the specified file.
@@ -124,5 +130,18 @@ pub trait World {
     ///
     /// If no offset is specified, the local date should be chosen. Otherwise,
     /// the UTC date should be chosen with the corresponding offset in hours.
+    ///
+    /// If this function returns `None`, Typst's `datetime` function will
+    /// return an error.
     fn today(&self, offset: Option<i64>) -> Option<Datetime>;
+
+    /// A list of all available packages and optionally descriptions for them.
+    ///
+    /// This function is optional to implement. It enhances the user experience
+    /// by enabling autocompletion for packages. Details about packages from the
+    /// `@preview` namespace are available from
+    /// `https://packages.typst.org/preview/index.json`.
+    fn packages(&self) -> &[(PackageSpec, Option<EcoString>)] {
+        &[]
+    }
 }

src/syntax/source.rs

@@ -34,9 +34,6 @@ struct Repr {
 
 impl Source {
     /// Create a new source file.
-    ///
-    /// The path must be canonical, so that the same source file has the same
-    /// id even if accessed through different paths.
     #[tracing::instrument(skip_all)]
     pub fn new(id: FileId, text: String) -> Self {
         let mut root = parse(&text);