conlang: Add Quote expression as a hack for testing

Possibly removed later, or replaced with something that turns Conlang AST nodes into Conlang data structures.

compiler/cl-interpret/src/convalue.rs

@@ -1,7 +1,7 @@
 //! Values in the dynamically typed AST interpreter.
 //!
 //! The most permanent fix is a temporary one.
-use cl_ast::{format::FmtAdapter, Sym};
+use cl_ast::{format::FmtAdapter, ExprKind, Sym};
 
 use super::{
     error::{Error, IResult},
@@ -42,6 +42,8 @@ pub enum ConValue {
     Struct(Box<(Sym, HashMap<Sym, ConValue>)>),
     /// An entire namespace
     Module(Box<HashMap<Sym, Option<ConValue>>>),
+    /// A quoted expression
+    Quote(Box<ExprKind>),
     /// A callable thing
     Function(Rc<Function>),
     /// A built-in function
@@ -165,6 +167,7 @@ from! {
     &str => ConValue::String,
     String => ConValue::String,
     Rc<str> => ConValue::String,
+    ExprKind => ConValue::Quote,
     Function => ConValue::Function,
     Vec<ConValue> => ConValue::Tuple,
     &'static dyn BuiltIn => ConValue::BuiltIn,
@@ -319,6 +322,9 @@ impl std::fmt::Display for ConValue {
                 }
                 Ok(())
             }
+            ConValue::Quote(q) => {
+                write!(f, "`{q}`")
+            }
             ConValue::Function(func) => {
                 write!(f, "{}", func.decl())
             }

compiler/cl-interpret/src/interpret.rs

@@ -147,6 +147,7 @@ impl Interpret for ExprKind {
     fn interpret(&self, env: &mut Environment) -> IResult<ConValue> {
         match self {
             ExprKind::Empty => Ok(ConValue::Empty),
+            ExprKind::Quote(q) => q.interpret(env),
             ExprKind::Let(v) => v.interpret(env),
             ExprKind::Assign(v) => v.interpret(env),
             ExprKind::Modify(v) => v.interpret(env),
@@ -174,6 +175,13 @@ impl Interpret for ExprKind {
     }
 }
 
+impl Interpret for Quote {
+    fn interpret(&self, _env: &mut Environment) -> IResult<ConValue> {
+        // TODO: squoosh down into a ConValue?
+        Ok(ConValue::Quote(self.quote.clone()))
+    }
+}
+
 mod assignment {
     /// Pattern matching engine for assignment
     use super::*;