Better value representations, type function 🌐

src/color.rs

@@ -1,6 +1,6 @@
 //! Color handling.
 
-use std::fmt::{self, Debug, Formatter};
+use std::fmt::{self, Debug, Display, Formatter};
 use std::str::FromStr;
 
 /// A color in a dynamic format.
@@ -10,10 +10,18 @@ pub enum Color {
     Rgba(RgbaColor),
 }
 
+impl Display for Color {
+    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
+        match self {
+            Self::Rgba(c) => Display::fmt(c, f),
+        }
+    }
+}
+
 impl Debug for Color {
     fn fmt(&self, f: &mut Formatter) -> fmt::Result {
         match self {
-            Self::Rgba(c) => c.fmt(f),
+            Self::Rgba(c) => Debug::fmt(c, f),
         }
     }
 }
@@ -76,6 +84,16 @@ impl FromStr for RgbaColor {
     }
 }
 
+impl Display for RgbaColor {
+    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
+        write!(f, "#{:02x}{:02x}{:02x}", self.r, self.g, self.b)?;
+        if self.a != 255 {
+            write!(f, "{:02x}", self.a)?;
+        }
+        Ok(())
+    }
+}
+
 impl Debug for RgbaColor {
     fn fmt(&self, f: &mut Formatter) -> fmt::Result {
         if f.alternate() {
@@ -83,14 +101,10 @@ impl Debug for RgbaColor {
                 f,
                 "rgba({:02}, {:02}, {:02}, {:02})",
                 self.r, self.g, self.b, self.a,
-            )?;
+            )
         } else {
-            write!(f, "#{:02x}{:02x}{:02x}", self.r, self.g, self.b)?;
-            if self.a != 255 {
-                write!(f, "{:02x}", self.a)?;
-            }
+            Display::fmt(self, f)
         }
-        Ok(())
     }
 }
 

src/eval/context.rs

@@ -119,15 +119,17 @@ impl EvalContext {
         if !children.is_empty() || keep_empty(group.softness) {
             self.runs.push(NodePages {
                 size: group.size,
-                child: Node::any(NodePad {
+                child: NodePad {
                     padding: group.padding,
-                    child: Node::any(NodeStack {
+                    child: NodeStack {
                         dirs: group.dirs,
                         align: group.align,
                         expansion: Gen::uniform(Expansion::Fill),
                         children,
-                    }),
-                }),
+                    }
+                    .into(),
+                }
+                .into(),
             })
         }
         group.softness

src/eval/state.rs

@@ -128,7 +128,22 @@ impl StateFont {
 impl Default for StateFont {
     fn default() -> Self {
         Self {
-            families: Rc::new(default_font_families()),
+            /// The default tree of font fallbacks.
+            families: Rc::new(fallback! {
+                list: ["sans-serif"],
+                classes: {
+                    "serif"      => ["source serif pro", "noto serif"],
+                    "sans-serif" => ["source sans pro", "noto sans"],
+                    "monospace"  => ["source code pro", "noto sans mono"],
+                },
+                base: [
+                    "source sans pro",
+                    "noto sans",
+                    "segoe ui emoji",
+                    "noto emoji",
+                    "latin modern math",
+                ],
+            }),
             variant: FontVariant {
                 style: FontStyle::Normal,
                 weight: FontWeight::REGULAR,
@@ -141,22 +156,3 @@ impl Default for StateFont {
         }
     }
 }
-
-/// The default tree of font fallbacks.
-fn default_font_families() -> FallbackTree {
-    fallback! {
-        list: ["sans-serif"],
-        classes: {
-            "serif"      => ["source serif pro", "noto serif"],
-            "sans-serif" => ["source sans pro", "noto sans"],
-            "monospace"  => ["source code pro", "noto sans mono"],
-        },
-        base: [
-            "source sans pro",
-            "noto sans",
-            "segoe ui emoji",
-            "noto emoji",
-            "latin modern math",
-        ],
-    }
-}

src/eval/value.rs

@@ -1,6 +1,6 @@
 use std::any::Any;
 use std::collections::HashMap;
-use std::fmt::{self, Debug, Formatter};
+use std::fmt::{self, Debug, Display, Formatter};
 use std::ops::Deref;
 use std::rc::Rc;
 
@@ -45,14 +45,6 @@ pub enum Value {
 }
 
 impl Value {
-    /// Create a new dynamic value.
-    pub fn any<T>(any: T) -> Self
-    where
-        T: Type + Debug + Clone + PartialEq + 'static,
-    {
-        Self::Any(ValueAny::new(any))
-    }
-
     /// Try to cast the value into a specific type.
     pub fn cast<T>(self) -> CastResult<T, Self>
     where
@@ -68,8 +60,8 @@ impl Value {
             Self::Bool(_) => bool::TYPE_NAME,
             Self::Int(_) => i64::TYPE_NAME,
             Self::Float(_) => f64::TYPE_NAME,
-            Self::Relative(_) => Relative::TYPE_NAME,
             Self::Length(_) => Length::TYPE_NAME,
+            Self::Relative(_) => Relative::TYPE_NAME,
             Self::Linear(_) => Linear::TYPE_NAME,
             Self::Color(_) => Color::TYPE_NAME,
             Self::Str(_) => String::TYPE_NAME,
@@ -88,16 +80,24 @@ impl Eval for &Value {
 
     /// Evaluate everything contained in this value.
     fn eval(self, ctx: &mut EvalContext) -> Self::Output {
-        match self {
-            // Don't print out none values.
-            Value::None => {}
-
-            // Pass through.
-            Value::Content(tree) => tree.eval(ctx),
-
-            // Format with debug.
-            val => ctx.push(ctx.make_text_node(format!("{:?}", val))),
-        }
+        ctx.push(ctx.make_text_node(match self {
+            Value::None => return,
+            Value::Bool(v) => v.to_string(),
+            Value::Int(v) => v.to_string(),
+            Value::Float(v) => v.to_string(),
+            Value::Length(v) => v.to_string(),
+            Value::Relative(v) => v.to_string(),
+            Value::Linear(v) => v.to_string(),
+            Value::Color(v) => v.to_string(),
+            Value::Str(v) => v.clone(),
+            // TODO: Find good representation for composite types.
+            Value::Array(_v) => "(array)".into(),
+            Value::Dict(_v) => "(dictionary)".into(),
+            Value::Content(tree) => return tree.eval(ctx),
+            Value::Func(v) => v.to_string(),
+            Value::Any(v) => v.to_string(),
+            Value::Error => "(error)".into(),
+        }));
     }
 }
 
@@ -110,21 +110,21 @@ impl Default for Value {
 impl Debug for Value {
     fn fmt(&self, f: &mut Formatter) -> fmt::Result {
         match self {
-            Self::None => f.pad("none"),
-            Self::Bool(v) => v.fmt(f),
-            Self::Int(v) => v.fmt(f),
-            Self::Float(v) => v.fmt(f),
-            Self::Length(v) => v.fmt(f),
-            Self::Relative(v) => v.fmt(f),
-            Self::Linear(v) => v.fmt(f),
-            Self::Color(v) => v.fmt(f),
-            Self::Str(v) => v.fmt(f),
-            Self::Array(v) => v.fmt(f),
-            Self::Dict(v) => v.fmt(f),
-            Self::Content(v) => v.fmt(f),
-            Self::Func(v) => v.fmt(f),
-            Self::Any(v) => v.fmt(f),
-            Self::Error => f.pad("<error>"),
+            Self::None => f.pad("None"),
+            Self::Bool(v) => Debug::fmt(v, f),
+            Self::Int(v) => Debug::fmt(v, f),
+            Self::Float(v) => Debug::fmt(v, f),
+            Self::Length(v) => Debug::fmt(v, f),
+            Self::Relative(v) => Debug::fmt(v, f),
+            Self::Linear(v) => Debug::fmt(v, f),
+            Self::Color(v) => Debug::fmt(v, f),
+            Self::Str(v) => Debug::fmt(v, f),
+            Self::Array(v) => Debug::fmt(v, f),
+            Self::Dict(v) => Debug::fmt(v, f),
+            Self::Content(v) => Debug::fmt(v, f),
+            Self::Func(v) => Debug::fmt(v, f),
+            Self::Any(v) => Debug::fmt(v, f),
+            Self::Error => f.pad("Error"),
         }
     }
 }
@@ -140,15 +140,18 @@ pub type ValueContent = Tree;
 
 /// A wrapper around a reference-counted executable function.
 #[derive(Clone)]
-pub struct ValueFunc(Rc<dyn Fn(&mut EvalContext, &mut Args) -> Value>);
+pub struct ValueFunc {
+    name: String,
+    f: Rc<dyn Fn(&mut EvalContext, &mut Args) -> Value>,
+}
 
 impl ValueFunc {
     /// Create a new function value from a rust function or closure.
-    pub fn new<F>(func: F) -> Self
+    pub fn new<F>(name: impl Into<String>, f: F) -> Self
     where
         F: Fn(&mut EvalContext, &mut Args) -> Value + 'static,
     {
-        Self(Rc::new(func))
+        Self { name: name.into(), f: Rc::new(f) }
     }
 }
 
@@ -162,13 +165,18 @@ impl Deref for ValueFunc {
     type Target = dyn Fn(&mut EvalContext, &mut Args) -> Value;
 
     fn deref(&self) -> &Self::Target {
-        self.0.as_ref()
+        self.f.as_ref()
     }
 }
 
+impl Display for ValueFunc {
+    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
+        write!(f, "<function {}>", self.name)
+    }
+}
 impl Debug for ValueFunc {
     fn fmt(&self, f: &mut Formatter) -> fmt::Result {
-        f.pad("<function>")
+        Display::fmt(self, f)
     }
 }
 
@@ -179,7 +187,7 @@ impl ValueAny {
     /// Create a new instance from any value that satisifies the required bounds.
     pub fn new<T>(any: T) -> Self
     where
-        T: Type + Debug + Clone + PartialEq + 'static,
+        T: Type + Debug + Display + Clone + PartialEq + 'static,
     {
         Self(Box::new(any))
     }
@@ -221,13 +229,19 @@ impl PartialEq for ValueAny {
     }
 }
 
-impl Debug for ValueAny {
+impl Display for ValueAny {
     fn fmt(&self, f: &mut Formatter) -> fmt::Result {
-        self.0.fmt(f)
+        Display::fmt(&self.0, f)
     }
 }
 
-trait Bounds: Debug + 'static {
+impl Debug for ValueAny {
+    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
+        Debug::fmt(&self.0, f)
+    }
+}
+
+trait Bounds: Debug + Display + 'static {
     fn as_any(&self) -> &dyn Any;
     fn into_any(self: Box<Self>) -> Box<dyn Any>;
     fn dyn_eq(&self, other: &ValueAny) -> bool;
@@ -237,7 +251,7 @@ trait Bounds: Debug + 'static {
 
 impl<T> Bounds for T
 where
-    T: Type + Debug + Clone + PartialEq + 'static,
+    T: Type + Debug + Display + Clone + PartialEq + 'static,
 {
     fn as_any(&self) -> &dyn Any {
         self
@@ -304,6 +318,16 @@ impl<T, V> CastResult<T, V> {
     }
 }
 
+impl Type for Value {
+    const TYPE_NAME: &'static str = "value";
+}
+
+impl Cast<Value> for Value {
+    fn cast(value: Value) -> CastResult<Self, Value> {
+        CastResult::Ok(value)
+    }
+}
+
 impl<T> Cast<Spanned<Value>> for T
 where
     T: Cast<Value>,
@@ -390,15 +414,6 @@ impl From<&str> for Value {
     }
 }
 
-impl<F> From<F> for Value
-where
-    F: Fn(&mut EvalContext, &mut Args) -> Value + 'static,
-{
-    fn from(func: F) -> Self {
-        Self::Func(ValueFunc::new(func))
-    }
-}
-
 impl From<ValueAny> for Value {
     fn from(v: ValueAny) -> Self {
         Self::Any(v)
@@ -407,9 +422,8 @@ impl From<ValueAny> for Value {
 
 /// Make a type usable as a [`Value`].
 ///
-/// Given a type `T`, this implements the following traits:
+/// Given a type `T`, this always implements the following traits:
 /// - [`Type`] for `T`,
-/// - [`From<T>`](From) for [`Value`],
 /// - [`Cast<Value>`](Cast) for `T`.
 #[macro_export]
 macro_rules! impl_type {
@@ -423,12 +437,6 @@ macro_rules! impl_type {
             const TYPE_NAME: &'static str = $type_name;
         }
 
-        impl From<$type> for $crate::eval::Value {
-            fn from(any: $type) -> Self {
-                $crate::eval::Value::any(any)
-            }
-        }
-
         impl $crate::eval::Cast<$crate::eval::Value> for $type {
             fn cast(
                 value: $crate::eval::Value,

src/geom/length.rs

@@ -90,7 +90,7 @@ impl Display for Length {
         } else {
             (self.to_cm(), Unit::Cm)
         };
-        write!(f, "{:.2}{}", val, unit)
+        write!(f, "{}{}", (val * 100.0).round() / 100.0, unit)
     }
 }
 
@@ -214,8 +214,8 @@ mod tests {
 
     #[test]
     fn test_length_formatting() {
-        assert_eq!(Length::pt(-28.34).to_string(), "-1.00cm".to_string());
-        assert_eq!(Length::pt(23.0).to_string(), "23.00pt".to_string());
+        assert_eq!(Length::pt(-28.34).to_string(), "-1cm".to_string());
+        assert_eq!(Length::pt(23.0).to_string(), "23pt".to_string());
         assert_eq!(Length::cm(12.728).to_string(), "12.73cm".to_string());
     }
 }

src/geom/relative.rs

@@ -32,7 +32,7 @@ impl Relative {
 
 impl Display for Relative {
     fn fmt(&self, f: &mut Formatter) -> fmt::Result {
-        write!(f, "{:.2}%", self.0)
+        write!(f, "{}%", (self.0 * 10000.0).round() / 100.0)
     }
 }
 

src/layout/fixed.rs

@@ -25,8 +25,8 @@ impl Layout for NodeFixed {
     }
 }
 
-impl From<NodeFixed> for Node {
+impl From<NodeFixed> for NodeAny {
     fn from(fixed: NodeFixed) -> Self {
-        Self::any(fixed)
+        Self::new(fixed)
     }
 }

src/layout/node.rs

@@ -14,16 +14,6 @@ pub enum Node {
     Any(NodeAny),
 }
 
-impl Node {
-    /// Create a new dynamic node.
-    pub fn any<T>(any: T) -> Self
-    where
-        T: Layout + Debug + Clone + PartialEq + 'static,
-    {
-        Self::Any(NodeAny::new(any))
-    }
-}
-
 impl Layout for Node {
     fn layout(&self, ctx: &mut LayoutContext, areas: &Areas) -> Layouted {
         match self {
@@ -81,9 +71,12 @@ impl Debug for NodeAny {
     }
 }
 
-impl From<NodeAny> for Node {
-    fn from(dynamic: NodeAny) -> Self {
-        Self::Any(dynamic)
+impl<T> From<T> for Node
+where
+    T: Into<NodeAny>,
+{
+    fn from(t: T) -> Self {
+        Self::Any(t.into())
     }
 }
 

src/layout/pad.rs

@@ -29,9 +29,9 @@ impl Layout for NodePad {
     }
 }
 
-impl From<NodePad> for Node {
+impl From<NodePad> for NodeAny {
     fn from(pad: NodePad) -> Self {
-        Self::any(pad)
+        Self::new(pad)
     }
 }
 

src/layout/par.rs

@@ -36,9 +36,9 @@ impl Layout for NodePar {
     }
 }
 
-impl From<NodePar> for Node {
+impl From<NodePar> for NodeAny {
     fn from(par: NodePar) -> Self {
-        Self::any(par)
+        Self::new(par)
     }
 }
 

src/layout/stack.rs

@@ -34,9 +34,9 @@ impl Layout for NodeStack {
     }
 }
 
-impl From<NodeStack> for Node {
+impl From<NodeStack> for NodeAny {
     fn from(stack: NodeStack) -> Self {
-        Self::any(stack)
+        Self::new(stack)
     }
 }
 

src/library/extend.rs

@@ -0,0 +1,16 @@
+use crate::prelude::*;
+
+/// `type`: Find out the name of a value's type.
+///
+/// # Positional arguments
+/// - Any value.
+///
+/// # Return value
+/// The name of the value's type as a string.
+pub fn type_(ctx: &mut EvalContext, args: &mut Args) -> Value {
+    if let Some(value) = args.require::<Value>(ctx, "value") {
+        value.type_name().into()
+    } else {
+        Value::Error
+    }
+}

src/library/insert.rs

@@ -83,8 +83,8 @@ impl Layout for NodeImage {
     }
 }
 
-impl From<NodeImage> for Node {
+impl From<NodeImage> for NodeAny {
     fn from(image: NodeImage) -> Self {
-        Self::any(image)
+        Self::new(image)
     }
 }

src/library/layout.rs

@@ -1,3 +1,5 @@
+use std::fmt::{self, Display, Formatter};
+
 use crate::eval::Softness;
 use crate::layout::{Expansion, NodeFixed, NodeSpacing, NodeStack};
 use crate::paper::{Paper, PaperClass};
@@ -153,7 +155,19 @@ impl Switch for Alignment {
 }
 
 impl_type! {
-    Alignment: "alignment"
+    Alignment: "alignment",
+}
+
+impl Display for Alignment {
+    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
+        f.pad(match self {
+            Self::Left => "left",
+            Self::Center => "center",
+            Self::Right => "right",
+            Self::Top => "top",
+            Self::Bottom => "bottom",
+        })
+    }
 }
 
 /// `box`: Layout content into a box.
@@ -161,7 +175,7 @@ impl_type! {
 /// # Named arguments
 /// - Width of the box:  `width`, of type `linear` relative to parent width.
 /// - Height of the box: `height`, of type `linear` relative to parent height.
-pub fn boxed(ctx: &mut EvalContext, args: &mut Args) -> Value {
+pub fn box_(ctx: &mut EvalContext, args: &mut Args) -> Value {
     let snapshot = ctx.state.clone();
 
     let width = args.get(ctx, "width");
@@ -189,7 +203,7 @@ pub fn boxed(ctx: &mut EvalContext, args: &mut Args) -> Value {
     ctx.push(NodeFixed {
         width,
         height,
-        child: Node::any(NodeStack { dirs, align, expansion, children }),
+        child: NodeStack { dirs, align, expansion, children }.into(),
     });
 
     ctx.state = snapshot;

src/library/mod.rs

@@ -1,67 +1,78 @@
 //! The standard library.
 
+mod extend;
 mod insert;
 mod layout;
 mod style;
 
+pub use extend::*;
 pub use insert::*;
 pub use layout::*;
 pub use style::*;
 
 use fontdock::{FontStretch, FontStyle, FontWeight};
 
-use crate::eval::Scope;
+use crate::eval::{Scope, ValueAny, ValueFunc};
 use crate::geom::Dir;
 
 /// The scope containing the standard library.
 pub fn _std() -> Scope {
     let mut std = Scope::new();
+    macro_rules! set {
+        (func: $name:expr, $func:expr) => {
+            std.set($name, ValueFunc::new($name, $func))
+        };
+        (any: $var:expr, $any:expr) => {
+            std.set($var, ValueAny::new($any))
+        };
+    }
 
     // Functions.
-    std.set("align", align);
-    std.set("box", boxed);
-    std.set("font", font);
-    std.set("h", h);
-    std.set("image", image);
-    std.set("page", page);
-    std.set("pagebreak", pagebreak);
-    std.set("rgb", rgb);
-    std.set("v", v);
+    set!(func: "align", align);
+    set!(func: "box", box_);
+    set!(func: "font", font);
+    set!(func: "h", h);
+    set!(func: "image", image);
+    set!(func: "page", page);
+    set!(func: "pagebreak", pagebreak);
+    set!(func: "rgb", rgb);
+    set!(func: "type", type_);
+    set!(func: "v", v);
 
     // Constants.
-    std.set("left", Alignment::Left);
-    std.set("center", Alignment::Center);
-    std.set("right", Alignment::Right);
-    std.set("top", Alignment::Top);
-    std.set("bottom", Alignment::Bottom);
-    std.set("ltr", Dir::LTR);
-    std.set("rtl", Dir::RTL);
-    std.set("ttb", Dir::TTB);
-    std.set("btt", Dir::BTT);
-    std.set("serif", FontFamily::Serif);
-    std.set("sans-serif", FontFamily::SansSerif);
-    std.set("monospace", FontFamily::Monospace);
-    std.set("normal", FontStyle::Normal);
-    std.set("italic", FontStyle::Italic);
-    std.set("oblique", FontStyle::Oblique);
-    std.set("thin", FontWeight::THIN);
-    std.set("extralight", FontWeight::EXTRALIGHT);
-    std.set("light", FontWeight::LIGHT);
-    std.set("regular", FontWeight::REGULAR);
-    std.set("medium", FontWeight::MEDIUM);
-    std.set("semibold", FontWeight::SEMIBOLD);
-    std.set("bold", FontWeight::BOLD);
-    std.set("extrabold", FontWeight::EXTRABOLD);
-    std.set("black", FontWeight::BLACK);
-    std.set("ultra-condensed", FontStretch::UltraCondensed);
-    std.set("extra-condensed", FontStretch::ExtraCondensed);
-    std.set("condensed", FontStretch::Condensed);
-    std.set("semi-condensed", FontStretch::SemiCondensed);
-    std.set("normal", FontStretch::Normal);
-    std.set("semi-expanded", FontStretch::SemiExpanded);
-    std.set("expanded", FontStretch::Expanded);
-    std.set("extra-expanded", FontStretch::ExtraExpanded);
-    std.set("ultra-expanded", FontStretch::UltraExpanded);
+    set!(any: "left", Alignment::Left);
+    set!(any: "center", Alignment::Center);
+    set!(any: "right", Alignment::Right);
+    set!(any: "top", Alignment::Top);
+    set!(any: "bottom", Alignment::Bottom);
+    set!(any: "ltr", Dir::LTR);
+    set!(any: "rtl", Dir::RTL);
+    set!(any: "ttb", Dir::TTB);
+    set!(any: "btt", Dir::BTT);
+    set!(any: "serif", FontFamily::Serif);
+    set!(any: "sans-serif", FontFamily::SansSerif);
+    set!(any: "monospace", FontFamily::Monospace);
+    set!(any: "normal", FontStyle::Normal);
+    set!(any: "italic", FontStyle::Italic);
+    set!(any: "oblique", FontStyle::Oblique);
+    set!(any: "thin", FontWeight::THIN);
+    set!(any: "extralight", FontWeight::EXTRALIGHT);
+    set!(any: "light", FontWeight::LIGHT);
+    set!(any: "regular", FontWeight::REGULAR);
+    set!(any: "medium", FontWeight::MEDIUM);
+    set!(any: "semibold", FontWeight::SEMIBOLD);
+    set!(any: "bold", FontWeight::BOLD);
+    set!(any: "extrabold", FontWeight::EXTRABOLD);
+    set!(any: "black", FontWeight::BLACK);
+    set!(any: "ultra-condensed", FontStretch::UltraCondensed);
+    set!(any: "extra-condensed", FontStretch::ExtraCondensed);
+    set!(any: "condensed", FontStretch::Condensed);
+    set!(any: "semi-condensed", FontStretch::SemiCondensed);
+    set!(any: "normal", FontStretch::Normal);
+    set!(any: "semi-expanded", FontStretch::SemiExpanded);
+    set!(any: "expanded", FontStretch::Expanded);
+    set!(any: "extra-expanded", FontStretch::ExtraExpanded);
+    set!(any: "ultra-expanded", FontStretch::UltraExpanded);
 
     std
 }

src/syntax/span.rs

@@ -269,14 +269,14 @@ impl Location {
     }
 }
 
-impl Debug for Location {
-    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
-        Display::fmt(self, f)
-    }
-}
-
 impl Display for Location {
     fn fmt(&self, f: &mut Formatter) -> fmt::Result {
         write!(f, "{}:{}", self.line, self.column)
     }
 }
+
+impl Debug for Location {
+    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
+        Display::fmt(self, f)
+    }
+}