filesystem/reading_what_is_there_no_parens.rb

tests/_examples/filesystem/reading_what_is_there_no_parens.rb in the metorex repository.

# readpartial and read_nonblock hand back what is already there, including
# what ungetc put back, without waiting for more.
reader, writer = IO.pipe
writer.write "foobar"
character = reader.getc
reader.ungetc character
p reader.readpartial(3)
p reader.readpartial(3)
reader.ungetc "w"
p reader.read_nonblock(5)
p reader.read_nonblock(5, exception: false)

Output:

"foo"
"bar"
"w"
:wait_readable