From e35522189f5217987bc455d70c3b9056541ef8c6 Mon Sep 17 00:00:00 2001
From: Joel Kronqvist <joel.kronqvist@iki.fi>
Date: Sat, 16 Aug 2025 02:04:09 +0300
Subject: feat: type conversion from (Vec/Quote X) -> X and add vec/quote to
 rest pattern substitutions

---
 src/sexp/case.rs | 18 +++++++++---------
 src/sexp/step.rs | 16 ++++++++++++----
 2 files changed, 21 insertions(+), 13 deletions(-)

(limited to 'src/sexp')

diff --git a/src/sexp/case.rs b/src/sexp/case.rs
index 40310e4..0c3d82d 100644
--- a/src/sexp/case.rs
+++ b/src/sexp/case.rs
@@ -1,5 +1,5 @@
 
-use crate::sexp::{SExp, SExp::*, SLeaf::*};
+use crate::sexp::{SExp, SLeaf, SExp::*, SLeaf::*, util::*};
 
 impl SExp {
     /**
@@ -20,7 +20,7 @@ impl SExp {
      *     scons(1, scons(scons(2, scons(3, Nil)), Nil))
      *         .matches_pat(&var("x")),
      *     Some(vec![(
-     *         "x".to_string(),
+     *         Var("x".to_string()),
      *         scons(1, scons(scons(2, scons(3, Nil)), Nil))
      *     )])
      * );
@@ -34,8 +34,8 @@ impl SExp {
      *     scons(1, scons(scons(2, scons(3, Nil)), Nil))
      *         .matches_pat(&scons(var("x"), scons(var("y"), Nil))),
      *     Some(vec![
-     *         ("x".to_string(), Atom(Int(1))),
-     *         ("y".to_string(), scons(2, scons(3, Nil)))
+     *         (Var("x".to_string()), Atom(Int(1))),
+     *         (Var("y".to_string()), scons(2, scons(3, Nil)))
      *     ])
      * );
      * ```
@@ -47,24 +47,24 @@ impl SExp {
      *     scons(1, scons(2, scons(3, Nil)))
      *         .matches_pat(&scons(var("x"), scons(RestPat("y".to_string()), Nil))),
      *     Some(vec![
-     *         ("x".to_string(), Atom(Int(1))),
-     *         ("y".to_string(), scons(2, scons(3, Nil)))
+     *         (Var("x".to_string()), Atom(Int(1))),
+     *         (RestPat("y".to_string()), scons(2, scons(3, Nil)))
      *     ])
      * );
      * ```
      */
-    pub fn matches_pat(&self, pat: &SExp) -> Option<Vec<(String, SExp)>> {
+    pub fn matches_pat(&self, pat: &SExp) -> Option<Vec<(SLeaf, SExp)>> {
 	match (self, pat) {
 	    
 	    (a, b) if a == b => Some(vec![]),
 
-	    (a, Atom(Var(name))) => Some(vec![(name.clone(), a.clone())]),
+	    (a, Atom(Var(name))) => Some(vec![(Var(name.to_string()), a.clone())]),
 
 	    (SCons(a1, a2), SCons(b1, b2)) => {
 		let lefthand = a1.matches_pat(b1);
 		let checkres = (*b2).check_res_pat();
 		let righthand = match checkres {
-		    Some(name) => Some(vec![(name, *a2.clone())]),
+		    Some(name) => Some(vec![(RestPat(name.clone()), *a2.clone())]),
 		    None => a2.matches_pat(b2),
 		};
 		lefthand.zip(righthand)
diff --git a/src/sexp/step.rs b/src/sexp/step.rs
index 99925ac..9077401 100644
--- a/src/sexp/step.rs
+++ b/src/sexp/step.rs
@@ -352,9 +352,10 @@ impl SExp {
 		    return Ok(SExp::back_to_case(scrutinee.step()?, patarms));
 		}
 
-		let scrutinee = match scrutinee {
-		    SCons(q, v) if *q == Atom(Quote) || *q == Atom(Vector) => *v,
-		    t => t,
+		let (scrutinee, rest_pat_struct) = match scrutinee {
+		    SCons(q, v) if *q == Atom(Quote)  => (*v, Some(Quote)),
+		    SCons(q, v) if *q == Atom(Vector) => (*v, Some(Vector)),
+		    t => (t, None),
 		};
 
 		for patarm in patarms {
@@ -369,7 +370,14 @@ impl SExp {
 
 		    if let Some(ctx) = scrutinee.matches_pat(&pat) {
 			for (name, value) in ctx {
-			    arm = arm.subst(&name, &value);
+			    arm = match name {
+				Var(name) => arm.subst(&name, &value),
+				RestPat(name) => match rest_pat_struct.clone() {
+				    Some(kw) => arm.subst(&name, &scons(kw, value)),
+				    None => arm.subst(&name, &value)
+				},
+				_ => panic!("unreachable")
+			    };
 			}
 			return Ok(arm);
 		    }
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