wip: refactor dsl

dsl/src/ast.rs

@@ -0,0 +1,31 @@
+use crate::*;
+
+#[derive(Debug, Clone, Default, PartialEq)]
+pub struct Ast(pub AstValue);
+
+/// The abstract syntax tree (AST) can be produced from the CST
+/// by cloning source slices into owned [Arc] values.
+pub type AstValue = DslValue<Arc<str>, VecDeque<Ast>>;
+
+//#[derive(Debug, Clone, Default, PartialEq)]
+//pub struct AstIter();
+
+impl<'src> From<Cst<'src>> for Ast {
+    fn from (token: Cst<'src>) -> Self {
+        token.value().into()
+    }
+}
+
+impl<'src> From<CstValue<'src>> for Ast {
+    fn from (value: CstValue<'src>) -> Self {
+        Self(match value {
+            DslValue::Nil       => DslValue::Nil,
+            DslValue::Err(e)    => DslValue::Err(e),
+            DslValue::Num(u)    => DslValue::Num(u),
+            DslValue::Sym(s)    => DslValue::Sym(s.into()),
+            DslValue::Key(s)    => DslValue::Key(s.into()),
+            DslValue::Str(s)    => DslValue::Str(s.into()),
+            DslValue::Exp(d, x) => DslValue::Exp(d, x.map(|x|x.into()).collect()),
+        })
+    }
+}