fix: quote/vector disappearing in substitution on cases

1 files changed, 12 insertions, 2 deletions

diff --git a/src/sexp/subst.rs b/src/sexp/subst.rs
index d09732f..44c31ab 100644
--- a/src/sexp/subst.rs
+++ b/src/sexp/subst.rs
@@ -16,7 +16,7 @@ impl SExp {
     /// );
     /// ```
     pub fn subst(self, name: &str, value: &SExp) -> SExp {
-        match self {
+        let ret = match self {
             SCons(a, b) => {
                 if let Some((varname, _)) = a.clone().check_let() {
                     if &varname == name {
@@ -37,6 +37,11 @@ impl SExp {
 		    .get_case_scrut_pats_and_arms()
 		{
 		    let scrut = scrut.subst(name, value);
+		    let (structkind, scrut) = match scrut {
+			SCons(q, v) if *q == Atom(Quote) || *q == Atom(Vector) =>
+			    (Some(*q), *v),
+			t => (None, t)
+		    };
 		    let mut res = vec![];
 		    for (pat, arm) in pavec {
 			if pat
@@ -50,12 +55,17 @@ impl SExp {
 			    res.push(scons(pat, arm.subst(name, value)));
 			}
 		    }
+		    let scrut = match structkind {
+			Some(kind) => scons(kind, scrut),
+			None => scrut,
+		    };
 		    return SExp::back_to_case(scrut, res);
 		}
                 scons((*a).subst(name, value), (*b).subst(name, value))
             },
             Atom(Var(x)) if x == name => value.clone(),
             t => t,
-        }
+        };
+	ret
     }
 }