From 52e1a059ea7feae38efb71330c83a671560e29fa Mon Sep 17 00:00:00 2001
From: Kaz Kylheku <kaz@kylheku.com>
Date: Fri, 7 Jul 2017 07:00:14 -0700
Subject: Lisp: lambda expressions are function names now.

* eval.c (lookup_fun): With this two-liner change, the
forms ((lambda (x) x) 42) and (fun (lambda ()))
just work. This is not just compatibility with other
dialects; it is necessary for consistency with func-get-name,
which already returns lambda expressions, effectively
asserting that they are function names.

* txr.1: Fix documentation for fun operator. The
Dialect Note saying that a lambda expression is not a
function name in TXR Lisp is removed. Document that
function names may be any of those produced by
func-get-name. This has already been true for macros
and methods, just not for lambda expressions.
Under fun-get-name, document that lambda expressions
are produced for interpreted functions not found in
any binding by the previous searches.
---
 eval.c |  2 ++
 txr.1  | 31 +++++++++++++++++++++++--------
 2 files changed, 25 insertions(+), 8 deletions(-)

diff --git a/eval.c b/eval.c
index f8186977..e2759186 100644
--- a/eval.c
+++ b/eval.c
@@ -490,6 +490,8 @@ val lookup_fun(val env, val sym)
                    cons(sym, static_slot(type, slot)));
       } else if (car(sym) == macro_s) {
         return lookup_mac(nil, cadr(sym));
+      } else if (car(sym) == lambda_s) {
+        return cons(sym, func_interp(env, sym));
       }
     }
     return or2(gethash(top_fb, sym),
diff --git a/txr.1 b/txr.1
index 11b1ece9..d2f88b71 100644
--- a/txr.1
+++ b/txr.1
@@ -13544,22 +13544,26 @@ function in the current lexical environment.
 
 The
 .meta function-name
-is a symbol denoting a named function: a built in
+may be a symbol denoting a named function: a built in
 function, or one defined by
 .codn defun .
 
+The
+.meta function-name
+may also take any of the forms specified in the description of the
+.code func-get-name
+function. If such a
+.meta function-name
+refers to a function which exists, then the
+.code fun
+operator yields that function.
+
 Note: the
 .code fun
 operator does not see macro bindings. It is possible to
 retrieve a global macro expander using the function
 .codn symbol-macro .
 
-.TP* "Dialect Note:"
-A lambda expression is not a function name in \*(TL. The
-syntax
-.code "(fun (lambda ...))"
-is invalid.
-
 .coNP Operator @ dwim
 .synb
 .mets (dwim << argument *)
@@ -16278,7 +16282,18 @@ is a symbol denoting the struct type and
 is the static slot of the struct type which holds
 .metn func .
 
-If all the searches fail, then
+If
+.meta func
+is an interpreted function not found under any name,
+then a lambda expression denoting that function
+is returned in the syntax
+.cblk
+.meti (lambda < args << form *)
+.cble
+
+If
+.meta func
+cannot be identified as a function, then
 .code nil
 is returned.
 
-- 
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