src: Source a File from the Current Working Directory
Description
src concatenates ".s" to its argument, quotes the result,
and sources in the file. It sets options(last.source) to
this file name so that src() can be issued to re-source
the file when it is edited.
Usage
src(x)
Arguments
x
an unquoted file name aside from ".s". This base file
name must be a legal S name.