From: Gerben Wierda <gerben.wierda@rna.nl>
To: mailing list for ConTeXt users <ntg-context@ntg.nl>
Subject: Re: METAPOST vardef returning multiple and non-numeric types as a single answer?
Date: Mon, 16 Mar 2020 09:53:22 +0100 [thread overview]
Message-ID: <2FD519BE-556C-4F09-B5DA-FED097A08400@rna.nl> (raw)
In-Reply-To: <9CC17BDA-18C9-431B-ABAE-0B018CDF054F@elvenkind.com>
Hola! So, the arguments passed to macros are by reference and not by value? I could have known of course, they are simple expansions, but I’d like to be sure. IfI assign to a variable inside a vardef macro and that variable is not ’save’d I’m changing the original?
G
> On 16 Mar 2020, at 09:31, Taco Hoekwater <taco@elvenkind.com> wrote:
>
>
>
>> On 15 Mar 2020, at 11:22, Gerben Wierda <gerben.wierda@rna.nl> wrote:
>>
>> I would like a vardef macro to return the pair of a picture and a bounding box. I don't want to use the setbound operator, because as soon as I do that, I cannot access the components of the picture anymore with pathpart.
>>
>> I found metapost vardef returning multiple values on StackExchange but that is about returning multiple values of the same numeric type. Is it possible to have vardef return a set of (picture, path) or (picture, picture) in some way? If not, I need to make two vardef macros for each result type.
>
> Sure, using that same endgroup,begingroup trick. But since there is no multi-assignment in metapost that doesn’t you help much.
> Either two separate vardefs or passing the to-be-assigned variable(s) as an extra argument(s) are generally more practical.
>
> Best wishes,
> Taco
>
>
>
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next prev parent reply other threads:[~2020-03-16 8:53 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-15 10:22 Gerben Wierda
2020-03-16 8:31 ` Taco Hoekwater
2020-03-16 8:53 ` Gerben Wierda [this message]
2020-03-16 9:10 ` Taco Hoekwater
2020-03-16 9:23 ` Taco Hoekwater
2020-03-16 9:38 ` Hans Hagen
2020-03-16 9:52 ` Gerben Wierda
2020-03-16 9:48 ` Gerben Wierda
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