From: Hans Hagen <j.hagen@xs4all.nl>
To: mailing list for ConTeXt users <ntg-context@ntg.nl>,
Geert Verhaag <verhaaggchm@ziggo.nl>
Subject: Re: Struggling with startuseMPgraphic and string argument!
Date: Fri, 18 Sep 2020 09:03:04 +0200 [thread overview]
Message-ID: <106359b9-955b-429f-0170-2f1489577449@xs4all.nl> (raw)
In-Reply-To: <5b228cc2-c230-3446-b3e6-0957426374ac@ziggo.nl>
On 9/17/2020 9:41 PM, Geert Verhaag wrote:
> Hi ConTeXt users,
>
> That's indeed magic and it works! Hans, thanks for your prompt answer!
>
> But I would like to take this a step further, by introducing a macro
> within the start/stopuseMPgraphic structure like so:
>
> \startuseMPgraphic{name}{s::lbl}
> def mymacro (text lb) =
> pair a ; a := (3cm,3cm) ;label.top("String: " & str lb,a) ;
> enddef ;
> mymacro(\MPvariable{lbl}) ;
> \stopuseMPgraphic
>
> and this works too, but what if I introduce another text argument like:
>
> \startuseMPgraphic{name}{s::lbl,s::label}
> def mymacro (text lb,lbx) =
> pair a ; a := (3cm,3cm) ;label.top("String: " & str lb & ", " & str
> lbx,a) ;
> enddef ;
> mymacro(\MPvariable{lbl},\MPvariable{label}) ;
> \stopuseMPgraphic
>
> However this doesn't work! It gives the following error:
>
> ! Missing argument to mymacro.
>
> Isn't that weird? But perhaps it has to do with me not understanding
> argument passing properly within METAPOST macros!
>
> Can someone please explain why this 2 argument example doesn't work?
>
> (But maybe this isn't the proper list to ask questions like these. If
> so, I'm sorry for bothering you!)
>
> Regards,
> Gerard
>
>
> On 16-09-2020 16:32, Geert Verhaag wrote:
>>
>> Hi,
>>
>> I'm trying to pass a string argument value to an MPgraphic but it
>> doesn't seem to work:
>>
>> Tried the following:
>>
>> \startuseMPgraphic{name}{lbl}
>> pair a ; a := (3cm,3cm) ;label.top("\MPvariable{lbl}",a) ;
>> \stopuseMPgraphic
>>
>> \starttext
>> \useMPgraphic{name}{lbl=1}
>> \stoptext
>>
>> The above works as expected!
>>
>> But the following doesn't:
>>
>> \startuseMPgraphic{name}{lbl}
>> pair a ; a := (3cm,3cm) ;label.top("\MPvariable{lbl}",a) ;
>> \stopuseMPgraphic
>>
>> \starttext
>> \useMPgraphic{name}{lbl=abc}
>> \stoptext
>>
>> It yields:
>>
>> 1 \startuseMPgraphic{name}{lbl}
>> 2 pair a ; a := (3cm,3cm) ;label.top("\MPvariable{lbl}",a) ;
>> 3 \stopuseMPgraphic
>> 4
>> 5 %\startuseMPgraphic{name}fill fullcircle scaled 200pt withcolor
>> .625yellow ;\stopuseMPgraphic
>> 6
>> 7 \starttext
>> 8 Example:
>> 9 >> \useMPgraphic{name}{lbl=abc}
>> 10 \stoptext
>> 11
>>
>> <to be read again>
>> a
>> \m_meta_current_variable a-a
>> bc
>> <argument> ... \hbox {\scratchdimen \m_meta_current_variable
>> sp}\ifzeropt \wd
>> \b_meta_v...
>> \secondoftwoarguments #1#2b-#2
>>
>> \9>>1 #1,2-\meta_prepare_instance_variable {#1}
>> \syst_helpers_do_process_comm...
>> \syst_helpers_do_process_comma_list ...rgument #1,
>> ]\relax \global
>> \advance \...
>> ...
>> l.9 \useMPgraphic{name}{lbl=abc}
>>
>> So it seems that only numbers can be passed not character strings! Why
>> is that? Is there a possibility to achieve this functionality?
\startuseMPgraphic{name}{s::lbl,s::label}
def mymacro(expr a, b) =
label.top("str:(" & a & "," & b & ")",(3cm,3cm)) ;
enddef ;
mymacro("\MPvariable{lbl}","\MPvariable{label}")
\stopuseMPgraphic
\starttext
\useMPgraphic{name}{lbl=abc,label=pqr}
\useMPgraphic{name}{lbl=def,label=xyz}
\stoptext
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next prev parent reply other threads:[~2020-09-18 7:03 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-16 14:32 Geert Verhaag
2020-09-17 8:01 ` Hans Hagen
2020-09-17 19:41 ` Geert Verhaag
2020-09-18 7:03 ` Hans Hagen [this message]
2020-09-18 11:48 ` Geert Verhaag
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