support for - as parameter

[ibeex]

as stated here https://docs.python.org/3/library/fileinput.html sometimes

echo 'one line' | python3 test.py - 
Fire trace:
1. Initial component
2. ('The function received no value for the required argument:', 'file_name')

should use std in instead file for input or output

[dbieber]

Supporting piping is high on the requested features list. We don't have a final design in place yet for what the syntax will be, so I'm open to suggestions if you have ideas.

Some of the questions we have to answer:

• How do you control which arguments use the piped input?
• How is the piped input parsed?
• Do the output serialization methods that Fire uses need to be updated to make piping work better?
  E.g. if a Fire CLI returns a dict and you pipe it to another Fire CLI that expects keyword args matching the dict's keys, maybe it would be good to pass the values from the dict by keyword.
  What if there isn't a clear mapping from the piped input to the receiving Fire command?

[dbieber]

Oh! I misunderstood your request. You can use - as a parameter as long as you change the separator to something else.

e.g. "echo 'one line' | python3 test.py - -- --separator=X" should do the trick.
We don't have a supported way of changing the default separator at the moment.

[ibeex]

I was thinking maybe something like in http:https://click.pocoo.org/5/arguments/#file-arguments regarding pipe input.