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22:13:04
Gnuxie[m]
ACTION uploaded an image: image.png (7KB) < https://matrix.org/_matrix/media/v1/download/matrix.org/OcSHkBixcvAhXoHlyTlqwvZi >
6:13:41
no-defun-allowed
I was thinking if that would actually be doable, but images in HTDP/Racket are self-quoting and not symbols. Bummer.
7:53:09
beach
There are a number of instructions that take a dynamic environment (and some other stuff) as input, and produce another dynamic environment as output.
7:53:45
beach
One such instruction would be BIND that takes a symbol and a value as additional inputs. This instruction would eliminate the need for CALL-WITH-VARIABLE-BOUND.
7:54:38
beach
Another such instruction is of course CATCH. I think a single CATCH is generated for a BLOCK and a single CATCH is generated for a TAGBODY.
7:56:12
beach
For a TAGBODY, it has as many successors as there are tags plus 2 I guess, one for the first statement and one for the end.
7:56:28
beach
The UNWIND instruction takes a dynamic environment variable as input, but it also needs a successor.
7:56:57
no-defun-allowed
I was thinking of Gnuxie 💜🐝's thinking infinite lambda and how in HTDP there are drawings as objects.
7:57:19
beach
Oh, and a CATCH instruction generated from a BLOCK has two successors as now, one for the first instruction and one for the end.
7:58:23
beach
For BLOCK, the successor of the UNWIND is the same as the second (end) successor of the catch.
7:59:02
beach
Or, rather for RETURN-FROM, the successor of the UNWIND is the same as the second (end) successor of the catch.
7:59:43
beach
For GO, the successor of the UNWIND instruction is the successor of the CATCH that corresponds to the tag in question.
8:00:21
beach
So UNWIND means "unwind the stack to this dynamic environment location, and then jump to this instruction".
8:02:37
beach
I have yet to come up with an instruction for unwind-protect, but I think it has two successors, one for the protected form and one for the cleanup form.
8:13:40
no-defun-allowed
Over on matrix.org land, she has a small collection of funny pictures relating to Lisp people.
8:16:46
no-defun-allowed
Unfortunately, also, emotes only appear as textual representations on the IRC side so I'd have to PM you the image probably.