New: %fun% mechanism for current function name.

* eval.c (pct_fun_s): New symbol variable, holding
the usr:%fun% symbol.
(fun_macro_env): New static function.
(do_expand): For defun and defmacro, use fun_macro_env
to establish an environment binding the %fun% symbol
macro, and expand everything in that environment.
(eval_init): Intern the %fun% symbol, initializing
pct_fun_s, and also register a global symbol macro in
that name so that we can freely use %fun% everywhere
without worrying that the code will blow up.
E.g. a logging macro can use it to get the function name,
but still be useful in a top-level form outside of
a named function.

* stdlib/struct.tl (sys:meth-lambda): New macro.
(defstruct, defmeth): Use sys:meth-lambda as a replacement
for lambda to set up the %fun% symbol macro. In the :init
case which doesn't use a lambda, an open-coded symacrolet
does the job.

* tests/019/pct-fun.tl: New file.

* tests/019/pct-fun.expected: Likewise.

* txr.1: Documented.

* stdlib/doc-syms.tl: Updated.

1 files changed, 1 insertions, 0 deletions

diff --git a/stdlib/doc-syms.tl b/stdlib/doc-syms.tl
index 30c81243..59535d41 100644
--- a/stdlib/doc-syms.tl
+++ b/stdlib/doc-syms.tl
@@ -2,6 +2,7 @@
   (hash-from-pairs
     '(("!>" "N-02B10DF9")
       ("%e%" "N-03F0FA9E")
+      ("%fun%" "N-00719365")
       ("%pi%" "N-03F0FA9E")
       ("*" "N-022396F7")
       ("*args*" "N-03DEE18A")