1 files changed, 99 insertions, 0 deletions
diff --git a/src/syntax/lit.rs b/src/syntax/lit.rs
new file mode 100644
index 00000000..e9807a17
--- /dev/null
+++ b/src/syntax/lit.rs
@@ -0,0 +1,99 @@
+//! Literals.
+
+use super::{Expr, Ident, SpanWith, Spanned, SynTree};
+use crate::color::RgbaColor;
+use crate::compute::dict::{DictKey, SpannedEntry};
+use crate::compute::value::{DictValue, Value};
+use crate::layout::LayoutContext;
+use crate::length::Length;
+use crate::{DynFuture, Feedback};
+
+/// A literal.
+#[derive(Debug, Clone, PartialEq)]
+pub enum Lit {
+    /// A identifier literal: `left`.
+    Ident(Ident),
+    /// A boolean literal: `true`, `false`.
+    Bool(bool),
+    /// An integer literal: `120`.
+    Int(i64),
+    /// A floating-point literal: `1.2`, `10e-4`.
+    Float(f64),
+    /// A percent literal: `50%`.
+    Percent(f64),
+    /// A length literal: `12pt`, `3cm`.
+    Length(Length),
+    /// A color literal: `#ffccee`.
+    Color(RgbaColor),
+    /// A string literal: `"hello!"`.
+    Str(String),
+    /// A dictionary literal: `(false, 12cm, greeting = "hi")`.
+    Dict(LitDict),
+    /// A content literal: `{*Hello* there!}`.
+    Content(SynTree),
+}
+
+impl Lit {
+    /// Evaluate the dictionary literal to a dictionary value.
+    pub async fn eval<'a>(
+        &'a self,
+        ctx: &'a LayoutContext<'a>,
+        f: &'a mut Feedback,
+    ) -> Value {
+        match *self {
+            Lit::Ident(ref i) => Value::Ident(i.clone()),
+            Lit::Bool(b) => Value::Bool(b),
+            Lit::Int(i) => Value::Number(i as f64),
+            Lit::Float(f) => Value::Number(f as f64),
+            Lit::Percent(p) => Value::Number(p as f64 / 100.0),
+            Lit::Length(l) => Value::Length(l),
+            Lit::Color(c) => Value::Color(c),
+            Lit::Str(ref s) => Value::Str(s.clone()),
+            Lit::Dict(ref d) => Value::Dict(d.eval(ctx, f).await),
+            Lit::Content(ref c) => Value::Tree(c.clone()),
+        }
+    }
+}
+
+/// A dictionary literal: `(false, 12cm, greeting = "hi")`.
+#[derive(Debug, Default, Clone, PartialEq)]
+pub struct LitDict(pub Vec<LitDictEntry>);
+
+impl LitDict {
+    /// Create an empty dict literal.
+    pub fn new() -> Self {
+        Self(vec![])
+    }
+
+    /// Evaluate the dictionary literal to a dictionary value.
+    pub fn eval<'a>(
+        &'a self,
+        ctx: &'a LayoutContext<'a>,
+        f: &'a mut Feedback,
+    ) -> DynFuture<'a, DictValue> {
+        Box::pin(async move {
+            let mut dict = DictValue::new();
+
+            for entry in &self.0 {
+                let val = entry.value.v.eval(ctx, f).await;
+                let spanned = val.span_with(entry.value.span);
+                if let Some(key) = &entry.key {
+                    dict.insert(&key.v, SpannedEntry::new(key.span, spanned));
+                } else {
+                    dict.push(SpannedEntry::val(spanned));
+                }
+            }
+
+            dict
+        })
+    }
+}
+
+/// An entry in a dictionary literal: `false` or `greeting = "hi"`.
+#[derive(Debug, Clone, PartialEq)]
+pub struct LitDictEntry {
+    /// The key of the entry if there was one: `greeting`.
+    pub key: Option<Spanned<DictKey>>,
+    /// The value of the entry: `"hi"`.
+    pub value: Spanned<Expr>,
+}