[parenscript-devel] Macro symbols affect GENSYMing in LET

[sblist at me.com]

Here is an even more confusing case where BAR
is rewritten inside the + form, but not the -.

 > (ps (let ((foo (lambda (bar)
                           (quote bar)))
                    (bar 5))
                (+ bar (- 10 bar))))
"var foo = function (bar) {
    'bar';
};
var bar28523 = 5;
bar28523 + (10 - bar);"
 > (ps (let ((foo (lambda (bar)
                           (quote bar)))
                    (bar 5))
                (+ bar (+ 10 bar))))
"var foo = function (bar) {
    'bar';
};
var bar28524 = 5;
bar28524 + (10 + bar28524);"

- Scott

On 4-Jun-09, at 11:10 AM, sblist at me.com wrote:

> I haven't done a very good job of distilling down this bug,
> but we're experiencing an issue with the GENSYMing
> done by LET in the presence of macros with the same
> names as variables bound in LET.
>
> This is the simplest example I could come up with:
>
>> (ps
>             (macrolet ((a (n) `(+ ,n 5)))
>               (let ((a (a 1)))
>                 (let ((b (a (- a 4))))
>                   (+ a b)))))
> "var a1661 = 1 + 5;
> var b = (a - 4) + 5;
> a1661 + b;"
>
> You can see here that the symbol A is GENSYM'd since
> it occurs elsewhere in the LET binding forms, but it seems
> to be missed in the inner LET form. If the symbol A is not
> inside the subtraction form, it is caught:
>
>> (ps
>             (macrolet ((a (n) `(+ ,n 5)))
>               (let ((a (a 1)))
>                 (let ((b (a a)))
>                   (+ a b)))))
> "var a1662 = 1 + 5;
> var b = a1662 + 5;
> a1662 + b;"
>
> - Scott
>
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