[R] YAPMQ - Yet Another PlotMath Question

[Peter Dalgaard]

Thompson, David (MNR) wrote:
>> -----Original Message-----
>> From: Peter Dalgaard [mailto:p.dalgaard at biostat.ku.dk] 
>> Sent: June 19, 2008 04:23 PM
>> To: Thompson, David (MNR)
>> Cc: r-help at r-project.org
>> Subject: Re: [R] YAPMQ - Yet Another PlotMath Question
>>
>> Thompson, David (MNR) wrote:
>>     
>>> Hello,
>>>
>>> I'm having trouble finding (remembering) how to pass values into text
>>> functions in plots, as demonstrated by:
>>>
>>> slope <- 45 ; plot(1:10) ; text(2, 7, labels = 
>>>       
>> expression(45~degree)) ;
>>     
>>> text(2, 5, labels = paste(bquote(.(slope)), expression(degree)))
>>>   
>>>       
>> text(2, 5, labels = bquote(paste(.(slope), degree)))
>>
>> Notice that paste()ing two expressions does not yield an expression 
>> result. Instead, it deparses both arguments and gives a 
>> character string.
>>     
>
> Thank you Peter.
> Are all the syntactic elements noted in plotmath{grDevices} available to
> bquote()?
>   
I think so. All it does is to create an unevaluated expression (object 
of mode "call") with the .() constructs replaced by their evaluated 
content. What plotmath can do with the result is its unaffected.

-- 
   O__  ---- Peter Dalgaard             Øster Farimagsgade 5, Entr.B
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