Consistency with calling and auto-calling (#59)

This is NOT a code-consistency or refactor PR. This is just to get the
following working:

- [x] Make lists be lists (no auto-calling for them anymore)
- [x] Add a method to `Engine` specifically for calling an Expr, like a
list or function
- [x] Make s-expressions be auto-called just like functions

stack-core/src/engine.rs

@@ -99,7 +99,18 @@ impl Engine {
     Ok(context)
   }
 
-  #[allow(clippy::only_used_in_recursion)]
+  pub fn call_expr(
+    &self,
+    mut context: Context,
+    expr: Expr,
+  ) -> Result<Context, RunError> {
+    let expr = context.scan_expr(expr)?;
+    match expr.kind {
+      ExprKind::List(exprs) => self.run(context, exprs),
+      _ => self.run_expr(context, expr),
+    }
+  }
+
   pub fn run_expr(
     &self,
     mut context: Context,
@@ -122,6 +133,7 @@ impl Engine {
       | ExprKind::Integer(_)
       | ExprKind::Float(_)
       | ExprKind::String(_)
+      | ExprKind::List(_)
       | ExprKind::Record(_) => {
         context.stack_push(expr)?;
         Ok(context)
@@ -179,6 +191,9 @@ impl Engine {
                 CallResult::None => unreachable!(),
               }
             }
+          }
+          if let ExprKind::SExpr { .. } = item.kind {
+            self.call_expr(context, item)
           } else {
             if let Some(journal) = context.journal_mut() {
               journal.push_op(JournalOp::Call(expr.clone()));
@@ -202,7 +217,6 @@ impl Engine {
         context.stack_push(*x)?;
         Ok(context)
       }
-      ExprKind::List(ref x) => self.run(context, x.to_vec()),
       ExprKind::Function {
         ref scope,
         ref body,
@@ -451,7 +465,7 @@ mod tests {
   // TODO: Move test for lets into a better place?
   #[test]
   fn can_use_lets() {
-    let source = Source::new("", "10 2 '[a b -] '[a b] let");
+    let source = Source::new("", "10 2 [a b -] [a b] let");
     let mut lexer = Lexer::new(source);
     let exprs = crate::parser::parse(&mut lexer).unwrap();
 
@@ -471,7 +485,7 @@ mod tests {
 
   #[test]
   fn lets_take_precedence_over_scope() {
-    let source = Source::new("", "0 'a def 1 '[a] '[a] let");
+    let source = Source::new("", "0 'a def 1 [a] [a] let");
     let mut lexer = Lexer::new(source);
     let exprs = crate::parser::parse(&mut lexer).unwrap();
 
@@ -491,7 +505,7 @@ mod tests {
 
   #[test]
   fn lets_do_not_act_as_overlays() {
-    let source = Source::new("", "0 'a def 1 '[a 2 'a def a] '[a] let a");
+    let source = Source::new("", "0 'a def 1 [a 2 'a def a] [a] let a");
     let mut lexer = Lexer::new(source);
     let exprs = crate::parser::parse(&mut lexer).unwrap();
 
@@ -515,7 +529,7 @@ mod tests {
 
   #[test]
   fn functions_work_in_lets() {
-    let source = Source::new("", "0 'a def 1 '[(fn a 2 'a def a)] '[a] let a");
+    let source = Source::new("", "0 'a def 1 [(fn a 2 'a def a)] [a] let a");
     let mut lexer = Lexer::new(source);
     let exprs = crate::parser::parse(&mut lexer).unwrap();
 
@@ -542,9 +556,9 @@ mod tests {
     let source = Source::new(
       "",
       "0 'a def
-      1 '[a] '[a] let
-      1 '[(fn! a)] '[a] let
-      1 '[(fn a)] '[a] let
+      1 [a] [a] let
+      1 [(fn! a)] [a] let
+      1 [(fn a)] [a] let
       a",
     );
     let mut lexer = Lexer::new(source);
@@ -571,7 +585,7 @@ mod tests {
 
   #[test]
   fn lets_can_set() {
-    let source = Source::new("", "1 '[a 2 'a set a] '[a] let");
+    let source = Source::new("", "1 [a 2 'a set a] [a] let");
     let mut lexer = Lexer::new(source);
     let exprs = crate::parser::parse(&mut lexer).unwrap();
 

stack-core/src/intrinsic.rs

@@ -797,7 +797,7 @@ impl Intrinsic {
         let cond = context.stack_pop(&expr)?;
 
         if cond.kind.is_truthy() {
-          context = engine.run_expr(context, body)?;
+          context = engine.call_expr(context, body)?;
         }
 
         Ok(context)
@@ -812,7 +812,7 @@ impl Intrinsic {
       // MARK: Call
       Self::Call => {
         let item = context.stack_pop(&expr)?;
-        engine.run_expr(context, item)
+        engine.call_expr(context, item)
       }
 
       // MARK: Let
@@ -851,7 +851,7 @@ impl Intrinsic {
             }
 
             context.push_scope(scope);
-            context = engine.run_expr(context, body)?;
+            context = engine.call_expr(context, body)?;
             context.pop_scope();
 
             if let Some(journal) = context.journal_mut() {

stack-core/tests/intrinsics/pop.stack

@@ -1,2 +1,2 @@
-(pop '[1 2 3])
+(pop [1 2 3])
 (pop "he")

stack-core/tests/intrinsics/push.stack

@@ -1,4 +1,4 @@
-'[]
+[]
 
 (push _ 1)
 (push _ 2)

stack-core/tests/intrinsics/record.stack

@@ -6,7 +6,7 @@
 drop
 
 ;; Test casting
-(cast '[["name" "john"] ["type" "person"]] "record")
+(cast [["name" "john"] ["type" "person"]] "record")
 
 (= "john" (prop _ "name")) swap
 (= "person" (prop _ "type")) swap