53 lines
1.7 KiB
Plaintext
53 lines
1.7 KiB
Plaintext
From: cwebster at math.tamu.edu (Corran Webster)
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Date: 19 May 1999 13:47:23 GMT
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Subject: Concrete Proposal: while ... and while ...
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References: <7hsv80$g9j$1@news.tamu.edu> <y0j675pmg6c.fsf@vier.idi.ntnu.no>
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Message-ID: <7hufdb$rrh$1@news.tamu.edu>
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Content-Length: 1420
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X-UID: 1964
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In article <y0j675pmg6c.fsf at vier.idi.ntnu.no>,
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Magnus L. Hetland <mlh at idt.ntnu.no> wrote:
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>cwebster at math.tamu.edu (Corran Webster) writes:
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>
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>I thought the Guido-approved version had a condition on the first as
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>well (i.e. an expansion of the standard while loop)?
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>
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>Thus:
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>
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>while 1:
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> ...
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>and while something:
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> ...
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It might be the Guido-approved version - I can't recall the exact form
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of the approved form. If this is in fact it, then I think my proposal
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has a slight advantage over this in simplicity. This form allows two
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tests (presuming something other than '1' is permitted after the first
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while), where my proposal has precisely one test for the loop, which
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seems more natural to me.
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>Of course, that doesn't remove the ugliness of the "while 1" but it
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>does alleviate the use of "break". I guess your suggestion actually
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>adds the syntax of "while:" for "while 1:" as well -- or is it only in
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>the use with "and while" that it is permitted?
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No, "while:" is not permitted without the "and while" later. The precise
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grammar is
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while [':' suite 'and' 'while'] test ':' suite ['else' ':' suite]
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and it's implemented by simply inserting the optional suite before
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the test - this means the changes to the source are fairly simple.
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It seems to me that with this change, 'while 1:' will be used much
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less often, and it's not worth the additional complexity to make
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the '1' optional.
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Corran
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