2025-05-12 00:00:02 +0200 | acidjnk | (~acidjnk@p200300d6e71c4f78180f209d949bdd6b.dip0.t-ipconnect.de) acidjnk |
2025-05-12 00:02:20 +0200 | tromp | (~textual@2001:1c00:3487:1b00:880c:a961:240d:9720) (Quit: My iMac has gone to sleep. ZZZzzz…) |
2025-05-12 00:03:00 +0200 | turlando | (~turlando@user/turlando) (Ping timeout: 265 seconds) |
2025-05-12 00:03:45 +0200 | turlando | (~turlando@user/turlando) turlando |
2025-05-12 00:06:25 +0200 | jmcantrell | (~weechat@user/jmcantrell) (Ping timeout: 252 seconds) |
2025-05-12 00:07:27 +0200 | balthxzar | (~balthxzar@user/Balthxzar) (Remote host closed the connection) |
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2025-05-12 00:07:56 +0200 | tomboy64 | (~tomboy64@user/tomboy64) tomboy64 |
2025-05-12 00:13:39 +0200 | xff0x | (~xff0x@2405:6580:b080:900:5c9:3756:500a:fde9) (Ping timeout: 260 seconds) |
2025-05-12 00:14:32 +0200 | xff0x | (~xff0x@2405:6580:b080:900:9d68:c704:b1b0:2e99) |
2025-05-12 00:17:00 +0200 | weary-traveler | (~user@user/user363627) user363627 |
2025-05-12 00:41:16 +0200 | <EvanR> | must be for inevitable alpha conversion |
2025-05-12 00:42:05 +0200 | Lord_of_Life_ | (~Lord@user/lord-of-life/x-2819915) Lord_of_Life |
2025-05-12 00:42:14 +0200 | Lord_of_Life | (~Lord@user/lord-of-life/x-2819915) (Ping timeout: 252 seconds) |
2025-05-12 00:43:28 +0200 | Lord_of_Life_ | Lord_of_Life |
2025-05-12 00:56:49 +0200 | acidjnk | (~acidjnk@p200300d6e71c4f78180f209d949bdd6b.dip0.t-ipconnect.de) (Ping timeout: 248 seconds) |
2025-05-12 00:59:33 +0200 | merijn | (~merijn@host-vr.cgnat-g.v4.dfn.nl) (Ping timeout: 265 seconds) |
2025-05-12 01:11:03 +0200 | merijn | (~merijn@host-vr.cgnat-g.v4.dfn.nl) merijn |
2025-05-12 01:18:09 +0200 | bitdex | (~bitdex@gateway/tor-sasl/bitdex) (Remote host closed the connection) |
2025-05-12 01:18:40 +0200 | bitdex | (~bitdex@gateway/tor-sasl/bitdex) bitdex |
2025-05-12 01:31:56 +0200 | sprotte24 | (~sprotte24@p200300d16f052e00b01ecb3cf5e5d8f9.dip0.t-ipconnect.de) (Quit: Leaving) |
2025-05-12 01:32:16 +0200 | zdercti^ | (~zdercti@50.168.231.214) |
2025-05-12 01:39:12 +0200 | ttybitnik | (~ttybitnik@user/wolper) (Quit: Fading out...) |
2025-05-12 01:47:48 +0200 | siliconcritters | (~siliconcr@syn-068-188-168-151.res.spectrum.com) |
2025-05-12 01:50:39 +0200 | <monochrom> | Too lazy to read that paper, but here is a common mistake ("variable capture") when using names: ((\x y -> x + y) y) z = (\y -> y + y) z = z + z instead of y + z. De Bruijn numbering (or other numbering schemes) are not vulnerable to this mistake, the two "y"s have different IDs. |
2025-05-12 01:53:25 +0200 | <monochrom> | Lisp macros, at least for old Lisp, are also vulnerable. When the Scheme people say "hygienic macros" they mean that macro expansion takes care not to make that mistake again. |
2025-05-12 01:53:44 +0200 | machinedgod | (~machinedg@d108-173-18-100.abhsia.telus.net) (Ping timeout: 252 seconds) |
2025-05-12 01:55:41 +0200 | <monochrom> | Template Haskell gives you two functions for creating names, so that you can choose whether you want variable capture or not per variable. (There are legit use cases when you want it.) |
2025-05-12 02:01:52 +0200 | sajenim | (~sajenim@user/sajenim) sajenim |
2025-05-12 02:02:20 +0200 | <EvanR> | I'm probably wrong about my observation, but using your example I'll show what I mean, (\x y -> x + y) y z, evaluate x+y in environment [x=>y, y=>z], y + z. I'll see if I can fix the example |
2025-05-12 02:03:04 +0200 | weary-traveler | (~user@user/user363627) (Remote host closed the connection) |
2025-05-12 02:04:55 +0200 | <EvanR> | (\x y -> \z -> x) z |
2025-05-12 02:06:09 +0200 | <EvanR> | yields an identity function instead of a constant function |
2025-05-12 02:07:27 +0200 | <EvanR> | so when you convert from debruijn back to named variables you better use unique names |
2025-05-12 02:08:32 +0200 | <EvanR> | (in the first example one of the y and in this example the z are free so wouldn't get IDs afaiui) |
2025-05-12 02:08:41 +0200 | j1n37- | (~j1n37@user/j1n37) j1n37 |
2025-05-12 02:09:28 +0200 | j1n37 | (~j1n37@user/j1n37) (Ping timeout: 272 seconds) |
2025-05-12 02:18:05 +0200 | xff0x | (~xff0x@2405:6580:b080:900:9d68:c704:b1b0:2e99) (Ping timeout: 260 seconds) |
2025-05-12 02:18:44 +0200 | xff0x | (~xff0x@2405:6580:b080:900:d755:12f8:638d:5cf9) |
2025-05-12 02:21:30 +0200 | xff0x | (~xff0x@2405:6580:b080:900:d755:12f8:638d:5cf9) (Client Quit) |
2025-05-12 02:21:36 +0200 | Tuplanolla | (~Tuplanoll@91-159-69-59.elisa-laajakaista.fi) (Quit: Leaving.) |
2025-05-12 02:27:33 +0200 | <monochrom> | Environment is also a way to be invulnerable. |
2025-05-12 02:28:55 +0200 | <monochrom> | The mistake happens if you really do what you tell beginners: substitute. :) |
2025-05-12 02:31:57 +0200 | <monochrom> | The pros do one of. They do one of: numbering, environment, alpha-convert lambdas to fresh vars before substitute (e.g., rewrite (\x y -> x + y) to (\uuid1934 uuid3141 -> uuid1934 + uuid3141)) |
2025-05-12 02:32:23 +0200 | califax | (~califax@user/califx) (Remote host closed the connection) |
2025-05-12 02:32:29 +0200 | <monochrom> | I think Scheme hygienic macros use the alpha-convert way. |
2025-05-12 02:34:34 +0200 | califax | (~califax@user/califx) califx |
2025-05-12 02:35:14 +0200 | xff0x | (~xff0x@2405:6580:b080:900:42e0:bce1:22f1:2695) |
2025-05-12 02:38:31 +0200 | <EvanR> | it seems to me that environment is real solution only if stuff in the environment doesn't have free variables, like in eager evaluation |
2025-05-12 02:39:31 +0200 | <EvanR> | so ghc must do none of the above |
2025-05-12 02:42:05 +0200 | meinside | (uid24933@id-24933.helmsley.irccloud.com) meinside |
2025-05-12 02:45:55 +0200 | jmcantrell | (~weechat@user/jmcantrell) jmcantrell |
2025-05-12 03:01:11 +0200 | siliconcritters | (~siliconcr@syn-068-188-168-151.res.spectrum.com) (Quit: siliconcritters) |
2025-05-12 03:05:13 +0200 | ljdarj | (~Thunderbi@user/ljdarj) (Ping timeout: 265 seconds) |
2025-05-12 03:06:59 +0200 | ljdarj | (~Thunderbi@user/ljdarj) ljdarj |
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2025-05-12 03:48:44 +0200 | hughjfch1 | (~hughjfche@vmi2417424.contaboserver.net) (Quit: WeeChat 4.4.3) |
2025-05-12 03:49:14 +0200 | hughjfchen | (~hughjfche@vmi2417424.contaboserver.net) hughjfchen |
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2025-05-12 03:50:26 +0200 | j1n37 | (~j1n37@user/j1n37) j1n37 |
2025-05-12 03:53:23 +0200 | <EvanR> | I'm wrong, since the environment would have first class functions with their own environment in a closure |
2025-05-12 03:54:49 +0200 | j1n37- | (~j1n37@user/j1n37) j1n37 |
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2025-05-12 04:07:53 +0200 | xff0x | (~xff0x@fsb6a9491c.tkyc517.ap.nuro.jp) |
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2025-05-12 04:40:15 +0200 | aditya_an1l | (~aditya_an@user/aditya-an1l:63825) aditya_an1l |
2025-05-12 04:56:24 +0200 | Frostillicus | (~Frostilli@pool-71-174-119-56.bstnma.fios.verizon.net) |
2025-05-12 05:00:00 +0200 | Taneb0 | (~Taneb@2001:41c8:51:10d:aaaa:0:aaaa:0) (Quit: I seem to have stopped.) |