adding slurs to notes passed form a user defined function

[Paul Malcolm]

This is my problem. 

Ive written a crude little function 

ScaleDegree = #(define-music-function (parser location Degree) (ly:music?)   

#{

$Degree 

#})

All this thing does is write one note according to the argument passed to it.  

Say for example I define "the" note as

zero = \relative c' { g4 }

Then in the code I write 

\ScaleDegree \zero  \ScaleDegree \zero

then I get two notes, both the g4. 

However what I would to be able to do, is "sometimes" add a slur. 

So ultimately I want g4(  g4) etc. 

How can I do this please ? 

I cannot write 

\ScaleDegree \zero( \ScaleDegree \zero)

Suppose further I wanted to tie these two notes, that is a similar problem 

isn't it ? 

Perhaps there is a far simpler way to do this 

Paul