I pushed a refactoring patch (4a55356 - reproduced below) that

needs some review.

The idea is that the equality operators don't need to be printed

differently from the other operators. They were, in order to allow for

a function #'parenthsize-equality to ensure that expressions like 

(= (= a b) c) and (= a (= b c)) are printed with parenthesized operands.

However, as I read the code, there is no possibility that the default

operator printer would ever not parenthesize those operands. In

other words, the mechanism is superfluous. A further explanation

is given in the commit message below.

All the tests pass and I observe no change in the compiled output of

our application, but this is still the kind of change that someone

should look over.

Daniel

commit 4a55356d6d09715fbd10a01c1b9019e013e42663

Author: Daniel Gackle <danielgackle@gmail.com>

Date:   Sun Feb 24 17:09:41 2013 -0700

    Refactoring: got rid of PARENTHESIZE-EQUALITY.

    

    There is no need for PARENTHESIZE-EQUALITY as distinct from

    PRINT-OP-ARGUMENT, because the latter always parenthesizes equality

    expressions when they are an operand in some other equality

    expression. (In such a case, OP and ARG-OP have the same precedence,

    and neither is associative.)

diff --git a/src/printer.lisp b/src/printer.lisp

index 348f55a..f07a5b2 100644

--- a/src/printer.lisp

+++ b/src/printer.lisp

@@ -145,10 +145,8 @@ vice-versa.")

 (defmethod ps-print ((number number))

   (format *psw-stream* (if (integerp number) "~D" "~F") number))

 

-(defvar %equality-ops '(ps-js:== ps-js:!= ps-js:=== ps-js:!==))

-

 (let ((precedence-table (make-hash-table :test 'eq)))

-  (loop for level in `((ps-js:getprop ps-js:aref ps-js:funcall)

+  (loop for level in '((ps-js:getprop ps-js:aref ps-js:funcall)

                        (ps-js:new)

                        (ps-js:lambda) ;; you won't find this in JS books

                        (ps-js:++ ps-js:-- ps-js:post++ ps-js:post--)

@@ -157,7 +155,7 @@ vice-versa.")

                        (ps-js:- ps-js:+)

                        (ps-js:<< ps-js:>> ps-js:>>>)

                        (ps-js:< ps-js:> ps-js:<= ps-js:>= ps-js:instanceof ps-js:in)

-                       ,%equality-ops

+                       (ps-js:== ps-js:!= ps-js:=== ps-js:!==)

                        (ps-js:&)

                        (ps-js:^)

                        (ps-js:\|)

@@ -218,21 +216,12 @@ vice-versa.")

 (defprinter ps-js:post-- (x)

   (ps-print x)"--")

 

-(defprinter (ps-js:+ ps-js:- ps-js:* ps-js:/ ps-js:% ps-js:&& ps-js:\|\| ps-js:& ps-js:\| ps-js:-= ps-js:+= ps-js:*= ps-js:/= ps-js:%= ps-js:^ ps-js:<< ps-js:>> ps-js:&= ps-js:^= ps-js:\|= ps-js:= ps-js:in ps-js:> ps-js:>= ps-js:< ps-js:<=)

+(defprinter (ps-js:+ ps-js:- ps-js:* ps-js:/ ps-js:% ps-js:&& ps-js:\|\| ps-js:& ps-js:\| ps-js:-= ps-js:+= ps-js:*= ps-js:/= ps-js:%= ps-js:^ ps-js:<< ps-js:>> ps-js:&= ps-js:^= ps-js:\|= ps-js:= ps-js:in ps-js:> ps-js:>= ps-js:< ps-js:<= ps-js:== ps-js:!= ps-js:=== ps-js:!==)

     (&rest args)

   (loop for (arg . remaining) on args do

        (print-op-argument op arg)

        (when remaining (format *psw-stream* " ~(~A~) " op))))

 

-(defprinter (ps-js:== ps-js:!= ps-js:=== ps-js:!==) (x y)

-  (flet ((parenthesize-equality (form)

-           (if (and (consp form) (member (car form) %equality-ops))

-               (parenthesize-print form)

-               (print-op-argument op form))))

-    (parenthesize-equality x)

-    (format *psw-stream* " ~A " op)

-    (parenthesize-equality y)))

-

 (defprinter ps-js:aref (array &rest indices)

   (print-op-argument 'ps-js:aref array)

   (dolist (idx indices)