Add support for array default values

src/internal.rs

@@ -62,3 +62,19 @@ pub fn from_env_with<T>(
         }.into()),
     }
 }
+
+/// `serde` does not implement `IntoDeserializer` for fixed size arrays. This
+/// helper type is just used for this purpose.
+pub struct ArrayIntoDeserializer<T, const N: usize>(pub [T; N]);
+
+impl<'de, T, E, const N: usize> serde::de::IntoDeserializer<'de, E> for ArrayIntoDeserializer<T, N>
+where
+    T: serde::de::IntoDeserializer<'de, E>,
+    E: serde::de::Error,
+{
+    type Deserializer = serde::de::value::SeqDeserializer<std::array::IntoIter<T, N>, E>;
+
+    fn into_deserializer(self) -> Self::Deserializer {
+        serde::de::value::SeqDeserializer::new(self.0.into_iter())
+    }
+}

src/meta.rs

@@ -53,6 +53,7 @@ pub enum Expr {
     Float(Float),
     Integer(Integer),
     Bool(bool),
+    Array(&'static [Expr]),
 }
 
 #[derive(Debug, Clone, Copy, PartialEq)]

src/toml.rs

@@ -193,6 +193,18 @@ impl fmt::Display for PrintExpr {
             Expr::Float(v) => v.fmt(f),
             Expr::Integer(v) => v.fmt(f),
             Expr::Bool(v) => v.fmt(f),
+            Expr::Array(items) => {
+                // TODO: pretty printing of long arrays onto multiple lines?
+                f.write_char('[')?;
+                for (i, item) in items.iter().enumerate() {
+                    if i != 0 {
+                        f.write_str(", ")?;
+                    }
+                    PrintExpr(item).fmt(f)?;
+                }
+                f.write_char(']')?;
+                Ok(())
+            },
         }
     }
 }

src/yaml.rs

@@ -184,6 +184,18 @@ impl fmt::Display for PrintExpr {
             Expr::Float(v) => v.fmt(f),
             Expr::Integer(v) => v.fmt(f),
             Expr::Bool(v) => v.fmt(f),
+            Expr::Array(items) => {
+                // TODO: pretty printing of long arrays onto multiple lines?
+                f.write_char('[')?;
+                for (i, item) in items.iter().enumerate() {
+                    if i != 0 {
+                        f.write_str(", ")?;
+                    }
+                    PrintExpr(item).fmt(f)?;
+                }
+                f.write_char(']')?;
+                Ok(())
+            }
         }
     }
 }