[ESS] ESS[S] freezes until job completion?

[Richard M. Heiberger]

C-c C-l  loads the file, it does source() without echoing

If you want to see everything, then use the C-c C-r
command to send the highlighted region over, or use C-c C-b
to send the entire buffer over.  These two commands show
all inputs and all outputs.

You could also manually use the
   source("filename", echo=TRUE)

This is a style question.  Usually C-c C-l is used to get a group of
known functions into the working environment and then you use them.

When designing the functions, C-c C-r, or even better C-c C-c which
sends over the function in which the point resides, would be preferable.