Allow t symbol in macro parameter lists.

* eval.c (expand_params_rec, bind_macro_params): Handle t
specially everywhere a parameter can occur. Expansion
allows the syntax through without extending the
environment with a t variable; binding walks over
the structure without binding a variable.

* stdlib/compiler.tl (expand-bind-mac-params): Likewise,
handle occurrences of t, suppressing the generation of
and assignment to variables, while ensuring that
initializing expressions are evaluated.

* tests/011/tree-bind.tl: New file.

* txr.1: Documented.

1 files changed, 20 insertions, 0 deletions

diff --git a/tests/011/tree-bind.tl b/tests/011/tree-bind.tl
new file mode 100644
index 00000000..83fcaa33
--- /dev/null
+++ b/tests/011/tree-bind.tl
@@ -0,0 +1,20 @@
+(load "../common")
+
+(mtest
+  (tree-bind b '(1 2) b) (1 2)
+  (tree-bind (t b) '(1 2) b) 2
+  (tree-bind (t . b) '(1 2) b) (2)
+  (tree-bind (b t) '(1 2) b) 1
+  (tree-bind (b . t) '(1 2) b) 1
+  (tree-bind t '(1 2) 3) 3
+  (tree-bind (t : b) '(1 2) b) 2
+  (tree-bind (b : t) '(1) b) 1
+  (tree-bind (b : (t 2)) '(1) b) 1
+  (tree-bind (b : (a 2 t)) '(1) a) 2
+  (let ((i 0)) (tree-bind (b : (t (inc i) t)) '(1) (cons i b))) (1 . 1)
+  (let ((i 0)) (tree-bind (b : (t (inc i) t)) '(1 2) (cons i b))) (0 . 1))
+
+(compile-only
+  (eval-only
+    (compile-file (base-name *load-path*) "temp.tlo")
+    (remove-path "temp.tlo")))