From 183a3b78908a864d6828a57d059dc4f176ef8a04 Mon Sep 17 00:00:00 2001
From: Kaz Kylheku <kaz@kylheku.com>
Date: Tue, 29 Apr 2025 19:39:54 -0700
Subject: infix: bug: (a = b) not parsing.

* stdlib.tl (detect-infix): Do not detect a prefix
operator followed by argument, followed by anything whatsoever
as being infix. The pair must be followed by nothing, or
by a non-argument.

* txr.1: Documented.
---
 stdlib/infix.tl |  3 ++-
 txr.1           | 24 ++++++++++++++++--------
 2 files changed, 18 insertions(+), 9 deletions(-)

diff --git a/stdlib/infix.tl b/stdlib/infix.tl
index 5d92f9ce..cd6b265f 100644
--- a/stdlib/infix.tl
+++ b/stdlib/infix.tl
@@ -243,13 +243,14 @@
           (xa (and (not xu) (not (funp env x)))))
      (or
        (and xa (or yo yb))
-       (and xu ya (neq xu.sym xu.lispsym))
+       (and xu ya (neq xu.sym xu.lispsym) (null rest))
        (and xu (eq y '**) (eq xu.sym xu.lispsym))
        (if-match (@z . @nil) rest
          (let* ((zu [ifx-uops z])
                 (zo [ifx-ops z])
                 (za (and (not zu) (not zo) (not (funp env z)))))
            (or
+             (and xu ya (neq xu.sym xu.lispsym) (not za))
              (and xu yu (or zu za (eq z '**)))
              (and xu ya zo))))))))
 
diff --git a/txr.1 b/txr.1
index 1060f558..5f024a89 100644
--- a/txr.1
+++ b/txr.1
@@ -54217,13 +54217,19 @@ denotes a prefix (unary) operator; the letter
 denotes an infix operator and the letter
 .code A
 denotes an argument which is not the name of a global function, lexical
-function in the current macro environment, or operator.
-Additionally, the symbols
+function in the current macro environment, or an operator;
+and the letter
 .code f
-and
-.codn !f ,
-indicate a prefix operator which, respectively, is and is not,
-the name of a global or lexical function.
+indicates a prefix operator which is also the name of a
+a global or lexical function.
+In addition, the two-character sequence
+.code !A
+denotes any element which is not an argument as defined for
+.codn A ;
+and the sequence
+.code !f
+denotes a prefix operator which is not also the name of a global
+or lexical function.
 The patterns which indicate a form for processing via
 .code parse-infix
 are:
@@ -54245,8 +54251,10 @@ then the parent expression is indicates as infix, otherwise not.
 Three consecutive leading prefix operators.
 .coIP "(u u A ...)"
 Two consecutive leading prefix operators followed by an argument.
-.coIP "(u A o ...)"
-A prefix operator followed by an argument, followed by an infix
+.coIP "(u A)"
+A prefix operator followed by an argument, and nothing else.
+.coIP "(u A !A ...)"
+A prefix operator followed by an argument, followed by a non-argument.
 operator.
 .coIP "(!f A ...)"
 A prefix operator which is not also the name of a global or lexical function,
-- 
cgit v1.2.3