Add Value type and replace dyn-nodes with call-exprs 🏗

- In addition to syntax trees there are now `Value`s, which syntax trees can be evaluated into (e.g. the tree is `5+5` and the value is `10`)
- Parsing is completely pure, function calls are not parsed into nodes, but into simple call expressions, which are resolved later
- Functions aren't dynamic nodes anymore, but simply functions which receive their arguments as a table and the layouting context
- Functions may return any `Value`
- Layouting is powered by functions which return the new `Commands` value, which informs the layouting engine what to do
- When a function returns a non-`Commands` value, the layouter simply dumps the value into the document in monospace

1 files changed, 0 insertions, 43 deletions

diff --git a/src/func.rs b/src/func.rs
deleted file mode 100644
index bff4fdab..00000000
--- a/src/func.rs
+++ /dev/null
@@ -1,43 +0,0 @@
-//! Tools for building custom functions.
-
-/// Useful things for creating functions.
-pub mod prelude {
-    pub use async_trait::async_trait;
-    pub use crate::layout::prelude::*;
-    pub use crate::layout::Commands;
-    pub use crate::layout::Command::{self, *};
-    pub use crate::style::*;
-    pub use crate::syntax::expr::*;
-    pub use crate::syntax::parsing::{parse, FuncCall, ParseState};
-    pub use crate::syntax::span::{Pos, Span, SpanVec, Spanned};
-    pub use crate::syntax::tree::{DynamicNode, SyntaxNode, SyntaxTree};
-    pub use crate::{Pass, Feedback};
-    pub use super::*;
-}
-
-use prelude::*;
-
-/// Extra methods on `Option`s used for function argument parsing.
-pub trait OptionExt<T>: Sized {
-    /// Call `f` with `val` if this is `Some(val)`.
-    fn with(self, f: impl FnOnce(T));
-
-    /// Report an error about a missing argument with the given name and span if
-    /// the option is `None`.
-    fn or_missing(self, span: Span, arg: &str, f: &mut Feedback) -> Self;
-}
-
-impl<T> OptionExt<T> for Option<T> {
-    fn with(self, f: impl FnOnce(T)) {
-        if let Some(val) = self {
-            f(val);
-        }
-    }
-
-    fn or_missing(self, span: Span, arg: &str, f: &mut Feedback) -> Self {
-        if self.is_none() {
-            error!(@f, span, "missing argument: {}", arg);
-        }
-        self
-    }
-}