How to chain two nongeneric functions in opencpu

How to chain two nongeneric functions in opencpu

OpenCPU is said to support chaining of function calls to calculate e.g.
f(g(x), h(y))
The docs about argument formats:
https://public.opencpu.org/api.html#api-arguments includes an example that
illustrates this by calculating
summary(read.csv("mydata.csv"))
In this example f is the generic function summary that takes as an
argument an object.
I need to calculate something like:
mycalc(read.csv("mydata.csv")) or
myplot(read.csv("my data.csv"))
where f take as an argument a dataframe
This doesn't seem to work when giving as object argument the sessionid or
hash key returned by the read.csv function.
How can this chaining of two nongeneric functions be solved ?