From 22ba6825db3b82e0b0f83ef6052f17289893e385 Mon Sep 17 00:00:00 2001
From: Laurenz <ritters_werth@outlook.com>
Date: Mon, 18 Dec 2023 12:18:41 +0100
Subject: [PATCH] Key/Value data from CLI (#2894)

---
 crates/typst-cli/src/args.rs        | 26 ++++++++++++++++++
 crates/typst-cli/src/world.rs       | 17 +++++++++---
 crates/typst-docs/src/lib.rs        |  2 +-
 crates/typst/src/foundations/mod.rs |  4 +--
 crates/typst/src/foundations/sys.rs |  5 ++--
 crates/typst/src/lib.rs             | 41 ++++++++++++++++++++++-------
 docs/reference/groups.yml           | 16 ++++++++---
 tests/fuzz/src/compile.rs           |  2 +-
 tests/src/benches.rs                |  2 +-
 tests/src/tests.rs                  |  2 +-
 10 files changed, 94 insertions(+), 23 deletions(-)

diff --git a/crates/typst-cli/src/args.rs b/crates/typst-cli/src/args.rs
index 075412cd2..8f0261f1d 100644
--- a/crates/typst-cli/src/args.rs
+++ b/crates/typst-cli/src/args.rs
@@ -1,6 +1,7 @@
 use std::fmt::{self, Display, Formatter};
 use std::path::PathBuf;
 
+use clap::builder::ValueParser;
 use clap::{ArgAction, Args, Parser, Subcommand, ValueEnum};
 use semver::Version;
 
@@ -116,6 +117,15 @@ pub struct SharedArgs {
     #[clap(long = "root", env = "TYPST_ROOT", value_name = "DIR")]
     pub root: Option<PathBuf>,
 
+    /// Add a string key-value pair visible through `sys.inputs`
+    #[clap(
+        long = "input",
+        value_name = "key=value",
+        action = ArgAction::Append,
+        value_parser = ValueParser::new(parse_input_pair),
+    )]
+    pub inputs: Vec<(String, String)>,
+
     /// Adds additional directories to search for fonts
     #[clap(
         long = "font-path",
@@ -134,6 +144,22 @@ pub struct SharedArgs {
     pub diagnostic_format: DiagnosticFormat,
 }
 
+/// Parses key/value pairs split by the first equal sign.
+///
+/// This function will return an error if the argument contains no equals sign
+/// or contains the key (before the equals sign) is empty.
+fn parse_input_pair(raw: &str) -> Result<(String, String), String> {
+    let (key, val) = raw
+        .split_once('=')
+        .ok_or("input must be a key and a value separated by an equal sign")?;
+    let key = key.trim().to_owned();
+    if key.is_empty() {
+        return Err("the key was missing or empty".to_owned());
+    }
+    let val = val.trim().to_owned();
+    Ok((key, val))
+}
+
 /// Lists all discovered fonts in system and custom font paths
 #[derive(Debug, Clone, Parser)]
 pub struct FontsCommand {
diff --git a/crates/typst-cli/src/world.rs b/crates/typst-cli/src/world.rs
index 8f8a7e5c0..cd4244fcd 100644
--- a/crates/typst-cli/src/world.rs
+++ b/crates/typst-cli/src/world.rs
@@ -7,7 +7,7 @@ use chrono::{DateTime, Datelike, Local};
 use comemo::Prehashed;
 use ecow::eco_format;
 use typst::diag::{FileError, FileResult, StrResult};
-use typst::foundations::{Bytes, Datetime};
+use typst::foundations::{Bytes, Datetime, Dict, IntoValue};
 use typst::syntax::{FileId, Source, VirtualPath};
 use typst::text::{Font, FontBook};
 use typst::{Library, World};
@@ -68,14 +68,25 @@ impl SystemWorld {
 
         // Resolve the virtual path of the main file within the project root.
         let main_path = VirtualPath::within_root(&input, &root)
-            .ok_or("input file must be contained in project root")?;
+            .ok_or("source file must be contained in project root")?;
+
+        let library = {
+            // Convert the input pairs to a dictionary.
+            let inputs: Dict = command
+                .inputs
+                .iter()
+                .map(|(k, v)| (k.as_str().into(), v.as_str().into_value()))
+                .collect();
+
+            Library::builder().with_inputs(inputs).build()
+        };
 
         Ok(Self {
             workdir: std::env::current_dir().ok(),
             input,
             root,
             main: FileId::new(None, main_path),
-            library: Prehashed::new(Library::build()),
+            library: Prehashed::new(library),
             book: Prehashed::new(searcher.book),
             fonts: searcher.fonts,
             slots: RwLock::new(HashMap::new()),
diff --git a/crates/typst-docs/src/lib.rs b/crates/typst-docs/src/lib.rs
index 444dda32c..ad40b9879 100644
--- a/crates/typst-docs/src/lib.rs
+++ b/crates/typst-docs/src/lib.rs
@@ -55,7 +55,7 @@ static GROUPS: Lazy<Vec<GroupData>> = Lazy::new(|| {
 });
 
 static LIBRARY: Lazy<Prehashed<Library>> = Lazy::new(|| {
-    let mut lib = Library::build();
+    let mut lib = Library::default();
     lib.styles
         .set(PageElem::set_width(Smart::Custom(Abs::pt(240.0).into())));
     lib.styles.set(PageElem::set_height(Smart::Auto));
diff --git a/crates/typst/src/foundations/mod.rs b/crates/typst/src/foundations/mod.rs
index 4ddc2162e..04380beef 100644
--- a/crates/typst/src/foundations/mod.rs
+++ b/crates/typst/src/foundations/mod.rs
@@ -83,7 +83,7 @@ use crate::syntax::Spanned;
 pub static FOUNDATIONS: Category;
 
 /// Hook up all `foundations` definitions.
-pub(super) fn define(global: &mut Scope) {
+pub(super) fn define(global: &mut Scope, inputs: Dict) {
     global.category(FOUNDATIONS);
     global.define_type::<bool>();
     global.define_type::<i64>();
@@ -110,7 +110,7 @@ pub(super) fn define(global: &mut Scope) {
     global.define_func::<eval>();
     global.define_func::<style>();
     global.define_module(calc::module());
-    global.define_module(sys::module());
+    global.define_module(sys::module(inputs));
 }
 
 /// Fails with an error.
diff --git a/crates/typst/src/foundations/sys.rs b/crates/typst/src/foundations/sys.rs
index 3561842e5..7c1281047 100644
--- a/crates/typst/src/foundations/sys.rs
+++ b/crates/typst/src/foundations/sys.rs
@@ -1,9 +1,9 @@
 //! System-related things.
 
-use crate::foundations::{Module, Scope, Version};
+use crate::foundations::{Dict, Module, Scope, Version};
 
 /// A module with system-related things.
-pub fn module() -> Module {
+pub fn module(inputs: Dict) -> Module {
     let mut scope = Scope::deduplicating();
     scope.define(
         "version",
@@ -13,5 +13,6 @@ pub fn module() -> Module {
             env!("CARGO_PKG_VERSION_PATCH").parse::<u32>().unwrap(),
         ]),
     );
+    scope.define("inputs", inputs);
     Module::new("sys", scope)
 }
diff --git a/crates/typst/src/lib.rs b/crates/typst/src/lib.rs
index 303d51836..ffe550408 100644
--- a/crates/typst/src/lib.rs
+++ b/crates/typst/src/lib.rs
@@ -66,7 +66,7 @@ use crate::diag::{warning, FileResult, SourceDiagnostic, SourceResult};
 use crate::engine::{Engine, Route};
 use crate::eval::Tracer;
 use crate::foundations::{
-    Array, Bytes, Content, Datetime, Module, Scope, StyleChain, Styles,
+    Array, Bytes, Content, Datetime, Dict, Module, Scope, StyleChain, Styles,
 };
 use crate::introspection::{Introspector, Locator};
 use crate::layout::{Align, Dir, LayoutRoot};
@@ -252,25 +252,48 @@ pub struct Library {
 }
 
 impl Library {
-    /// Construct the standard library.
-    pub fn build() -> Self {
-        let math = math::module();
-        let global = global(math.clone());
-        Self { global, math, styles: Styles::new() }
+    /// 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::build()
+        Self::builder().build()
+    }
+}
+
+/// Configurable builder for the standard library.
+///
+/// This struct is created by [`Library::builder`].
+#[derive(Debug, Clone, Default)]
+pub struct LibraryBuilder {
+    inputs: Option<Dict>,
+}
+
+impl LibraryBuilder {
+    /// Configure the inputs visible through `sys.inputs`.
+    pub fn with_inputs(mut self, inputs: Dict) -> Self {
+        self.inputs = Some(inputs);
+        self
+    }
+
+    /// Consumes the builder and returns a `Library`.
+    pub fn build(self) -> Library {
+        let math = math::module();
+        let inputs = self.inputs.unwrap_or_default();
+        let global = global(math.clone(), inputs);
+        Library { global, math, styles: Styles::new() }
     }
 }
 
 /// Construct the module with global definitions.
 #[tracing::instrument(skip_all)]
-fn global(math: Module) -> Module {
+fn global(math: Module, inputs: Dict) -> Module {
     let mut global = Scope::deduplicating();
-    self::foundations::define(&mut global);
+    self::foundations::define(&mut global, inputs);
     self::model::define(&mut global);
     self::text::define(&mut global);
     global.reset_category();
diff --git a/docs/reference/groups.yml b/docs/reference/groups.yml
index 5ae564b24..16ded6979 100644
--- a/docs/reference/groups.yml
+++ b/docs/reference/groups.yml
@@ -129,9 +129,19 @@
   details: |
     Module for system interactions.
 
-    Currently, this module defines a single item: The `sys.version` constant
-    (of type [`version`]($version)), that specifies the currently active
-    Typst compiler version.
+    This module defines the following items:
+
+    - The `sys.version` constant (of type [`version`]($version)) that specifies
+      the currently active Typst compiler version.
+
+    - The `sys.inputs` [dictionary]($dictionary), which makes external inputs
+      available to the project. An input specified in the command line as
+      `--input key=value` becomes available under `sys.inputs.key` as
+      `{"value"}`. To include spaces in the value, it may be enclosed with
+      single or double quotes.
+
+      The value is always of type [string]($str). More complex data
+      may be parsed manually using functions like [`json.decode`]($json.decode).
 
 - name: sym
   title: General
diff --git a/tests/fuzz/src/compile.rs b/tests/fuzz/src/compile.rs
index deb717789..c6345051a 100644
--- a/tests/fuzz/src/compile.rs
+++ b/tests/fuzz/src/compile.rs
@@ -24,7 +24,7 @@ impl FuzzWorld {
         let font = Font::new(FONT.into(), 0).unwrap();
         let book = FontBook::from_fonts([&font]);
         Self {
-            library: Prehashed::new(Library::build()),
+            library: Prehashed::new(Library::default()),
             book: Prehashed::new(book),
             font,
             source: Source::detached(text),
diff --git a/tests/src/benches.rs b/tests/src/benches.rs
index 5ec0be610..6d5f31335 100644
--- a/tests/src/benches.rs
+++ b/tests/src/benches.rs
@@ -91,7 +91,7 @@ impl BenchWorld {
         let book = FontBook::from_fonts([&font]);
 
         Self {
-            library: Prehashed::new(Library::build()),
+            library: Prehashed::new(Library::default()),
             book: Prehashed::new(book),
             font,
             source: Source::detached(TEXT),
diff --git a/tests/src/tests.rs b/tests/src/tests.rs
index f06783097..5e6b7b401 100644
--- a/tests/src/tests.rs
+++ b/tests/src/tests.rs
@@ -192,7 +192,7 @@ fn library() -> Library {
     // Set page width to 120pt with 10pt margins, so that the inner page is
     // exactly 100pt wide. Page height is unbounded and font size is 10pt so
     // that it multiplies to nice round numbers.
-    let mut lib = Library::build();
+    let mut lib = Library::default();
     lib.styles
         .set(PageElem::set_width(Smart::Custom(Abs::pt(120.0).into())));
     lib.styles.set(PageElem::set_height(Smart::Auto));