changed cli to use stdin and str instead of filenames

[surprisetalk]

The CLI currently accepts commands like this:

scrap eval file.scrap
scrap apply "1+1"
scrap yard push /tmp/yard file.scrap

I changed it to work like this:

SCRAPYARD=/tmp/scrapyard
scrap eval "1+1"
scrap apply "x->x" "1+1"
scrap yard push "x->x"

and it also works with stdin:

SCRAPYARD=/tmp/scrapyard
echo "1+1" | scrap eval
echo "1+1" | scrap apply "x->x"
echo "x->x" | scrap yard push

the previous filename behavior can be emulated like this:

SCRAPYARD=/tmp/scrapyard
scrap eval `cat file.scrap`
scrap apply `cat f.scrap` `cat x.scrap`
scrap yard push `cat file.scrap`

[gregorybchris]

This would be really nice to have in the main branch.. I tried to fiddle around with eval/apply stuff a lot when we first started, have always known the file pointer vs string input was wonky and wrong. Do you want to just push this to trunk?

[tekknolagi]

I agree--would be good to have in trunk right now. Also,

1. you need quoting for the ...
2. can you change README?

[surprisetalk]

Okay, I'll open a cleaner PR on the main branch with more documentation and "..." fixed 👍🏼