Re: [Haskell-beginners] Beginners Digest, Vol 154, Issue 7

Ah, thank you. I just went with the more up-to-date version of the code, and didn't look at the original. Regards, Michael Turner Executive Director Project Persephone 1-25-33 Takadanobaba Shinjuku-ku Tokyo 169-0075 Mobile: +81 (90) 5203-8682 turner@projectpersephone.org Understand - http://www.projectpersephone.org/ Join - http://www.facebook.com/groups/ProjectPersephone/ Donate - http://www.patreon.com/ProjectPersephone Volunteer - https://github.com/ProjectPersephone "Love does not consist in gazing at each other, but in looking outward together in the same direction." -- Antoine de Saint-Exupéry On Tue, May 18, 2021 at 9:06 PM wrote:

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Today's Topics:

1. Type inference or just ... a typo in a paper? (Michael Turner) 2. Re: Type inference or just ... a typo in a paper? (Francesco Ariis)

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Message: 1 Date: Tue, 18 May 2021 17:24:37 +0900 From: Michael Turner To: beginners@haskell.org Subject: [Haskell-beginners] Type inference or just ... a typo in a paper? Message-ID: Content-Type: text/plain; charset="UTF-8"

I've inherited some Haskell code, which you can find here:

http://web.cecs.pdx.edu/~mpj/pubs/aug.html

The text of the accompanying paper says, "we extend the Text class..." -- but the identifier "Text" appears nowhere in the code. Is this just an error in the paper, or is the Text class getting involved in some indirect way, e.g. through String or perhaps because of the line "instance Show Tree where . . ."?

Regards, Michael Turner Executive Director Project Persephone 1-25-33 Takadanobaba Shinjuku-ku Tokyo 169-0075 Mobile: +81 (90) 5203-8682 turner@projectpersephone.org

Understand - http://www.projectpersephone.org/ Join - http://www.facebook.com/groups/ProjectPersephone/ Donate - http://www.patreon.com/ProjectPersephone Volunteer - https://github.com/ProjectPersephone

"Love does not consist in gazing at each other, but in looking outward together in the same direction." -- Antoine de Saint-Exupéry

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Message: 2 Date: Tue, 18 May 2021 13:30:58 +0200 From: Francesco Ariis To: beginners@haskell.org Subject: Re: [Haskell-beginners] Type inference or just ... a typo in a paper? Message-ID: <20210518113058.GB879@extensa> Content-Type: text/plain; charset=utf-8

Hello Michael,

Il 18 maggio 2021 alle 17:24 Michael Turner ha scritto:

...

I've inherited some Haskell code, which you can find here:

http://web.cecs.pdx.edu/~mpj/pubs/aug.html

The text of the accompanying paper says, "we extend the Text class..." -- but the identifier "Text" appears nowhere in the code. Is this just an error in the paper, or is the Text class getting involved in some indirect way, e.g. through String or perhaps because of the line "instance Show Tree where . . ."?

In the updated source (`augupdated.hs`) that is missing, but in the /original/ one (`aug.hs`) I read at line 255

instance Text Tree where

Which was then replaced with:

instance Show Tree where

in the updated version.

Weird to know something like `Show` was not named like that in the early nineties! —F

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