R help - Nov 2013 - Using Unicode inside R's expression() command

I'm using 'expression()' in R plots in order to get italicized text.
But it appears as if I cannot use Unicode symbols inside 'expression'
outside of ASCII characters. Is there some way I can work around this?
My goal is to get the '?' ligature in various labels in my R barplots
(together with italicized text). I think I could work around this if
there was another way of italicizing selected characters in a string
than using 'expression()'.

I'm using R for Windows version 3.0.2.

    CairoPDF(file = "Ligature1.pdf")
    plot.new()
    text(x =.5, y = .5, labels = "?", family = "Times New
Roman")
    dev.off()

    CairoPDF(file = "Ligature2.pdf")
    plot.new()
    text(x =.5, y = .5, labels = expression(paste(italic(m), "u",
"?",
italic(m), sep = "")), family = "Times New Roman")
    dev.off()
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On Nov 9, 2013, at 11:01 AM, Sverre Stausland wrote:
> I'm using 'expression()' in R plots in order to get italicized
text.
> But it appears as if I cannot use Unicode symbols inside
'expression'
> outside of ASCII characters. Is there some way I can work around this?
> My goal is to get the '?' ligature in various labels in my R
barplots
> (together with italicized text). I think I could work around this if
> there was another way of italicizing selected characters in a string
> than using 'expression()'.
> 
> I'm using R for Windows version 3.0.2.
> 
>    CairoPDF(file = "Ligature1.pdf")
>    plot.new()
>    text(x =.5, y = .5, labels = "?", family = "Times New
Roman")
>    dev.off()
> 
>    CairoPDF(file = "Ligature2.pdf")
>    plot.new()
>    text(x =.5, y = .5, labels = expression(paste(italic(m), "u",
"?",
> italic(m), sep = "")), family = "Times New Roman")
>    dev.off()
> <lig1.png><lig2.png>
To the list readers: I posted a comment to the identical SO question that
changing the font with CairoFonts before the CairoPDF call might be more
effective. (I used a font name of "TimesNewRoman" rather than
"Times New Roman" but testing with

 CairoFontMatch(fontpattern="Times New Roman",sort=FALSE,verbose=TRUE)

... proved that the spaces were not causing problems. I happen to have a copy of
Times New Roman since I have purchased MS Office, but I do not know if everyone
would have that font installed. )

This succeeded
CairoFonts(
	regular="Roman-12:normal", italic="Roman-12:italic" 
)
# The default family is Helvetica on my machine running OSX 10.7.5
-- 

David Winsemius
Alameda, CA, USA