Bugfix: macros not being expanded in expansions embedded in

quasilierals: i.e. the forms X and Y in `@{X}`
and `@{X Y}`, where X and Y can be Lisp symbol macros or compound
forms that is a macro call.

* eval.c (expand_quasi): Handle the var forms in a quasi.

* parser.y (n_exprs_opt, q_var): New grammar nonterminals.
q_var is a clone of o_var, but with different construction behavior.
It fixes the bug that o_var applies expand_meta to embedded
Lisp forms, which is not appropriate for TXR Lisp quasiliterals.
(quasi_item): Derive q_var rather than o_var.

1 files changed, 14 insertions, 0 deletions

diff --git a/eval.c b/eval.c
index c5e024ee..ec10d1e1 100644
--- a/eval.c
+++ b/eval.c
@@ -2219,6 +2219,20 @@ static val expand_quasi(val quasi_forms, val menv)
 
         if (expr_ex != rest(form))
           form_ex = rlcp(cons(sym, expr_ex), form);
+      } else if (sym == var_s) {
+        val param = second(form);
+        val next = third(form);
+        val mods = fourth(form);
+        val param_ex = expand(param, menv);
+        val mods_ex = expand_forms(mods, menv);
+
+        /* next should be nil because this structure should have
+           been passed through o_elemes_transform in the parser
+           which unravels the nesting. */
+        assert (next == nil);
+
+        if (param_ex != param || mods_ex != mods)
+          form_ex = rlcp(list(sym, param_ex, nil, mods_ex, nao), form);
       }
     }