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Re: Syntax locations are ambiguous: can we track source 'offset' and 'le
From: |
Linus Björnstam |
Subject: |
Re: Syntax locations are ambiguous: can we track source 'offset' and 'length'? |
Date: |
Tue, 03 Aug 2021 21:29:52 +0200 |
User-agent: |
Cyrus-JMAP/3.5.0-alpha0-548-g3a0b1fef7b-fm-20210802.001-g3a0b1fef |
On Tue, 3 Aug 2021, at 00:50, Vivien Kraus via General Guile related
discussions wrote:
> Dear guilers,
>
> I’m playing with syntaxes as first-class objects, and I notice that the
> syntax source location is ambiguous:
>
> (syntax-case
> (call-with-input-string "(a\r b)" read-syntax) ()
> ((a b)
> (values (syntax-source #'a) (syntax-source #'b))))
>
> =>
>
> $1 = ((line . 0) (column . 1))
> $2 = ((line . 0) (column . 1))
>
> This is obviously because of #\return.
Well, if anything this has confused the guile reader. It is probably a bug: I
suspect it resets the column because it anticipates a windows-style newline.
But are you often dealing with lonely "\r" in sources? Using either \n
(unix-style) or \r\n (window-style) will give you the correct results.