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Re: Why should build phases not return unspecified values?
From: |
Clément Lassieur |
Subject: |
Re: Why should build phases not return unspecified values? |
Date: |
Sun, 17 Dec 2017 11:35:12 +0100 |
User-agent: |
mu4e 0.9.18; emacs 25.3.1 |
Arun Isaac <address@hidden> writes:
> Alex Vong <address@hidden> writes:
>
>> I think the problem is that when the scheme standard says "the returned
>> value is unspecified", it means anything can be returned. In this case,
>> guile choose to return an unspecified value to avoid returning an
>> arbitary value.
>>
>> I think the answer written by soegaard in [0] explains it pretty well.
>>
>> [0]:
>> https://stackoverflow.com/questions/28910911/detecting-unspecified-in-scheme-list
>
> This is new to me. But, since we only use the Guile implementation, I
> think we should be ok with phases returning #<unspecified>.
But is there any guarantee that a Guile function returning
#<unspecified> won't return, say, #f in later versions? If it does,
there would be a bug in phases that don't add #t at the end.