examples/pony.peg is missing definitions

[SeanTAllen]

The pony.peg grammar file is missing definitions and fails to work. For example, doing:

Note to see this error, you have to be on main. There's a different bug hiding this in 0.1.5

Here's a snippet of the long long error output.

peg/examples on  main ➜ ../build/release/compiler pony.peg ../peg/ast.pony
-- Missing Definition --

/home/sean/code/ponylang/peg/examples/pony.peg:3:51:5

3: use <- -"use" (ID -"=")? (STRING / useffi) (-"if" infix)?
                                                     ^^^^^
                                                     rule has not been defined

One of the parse rules references another rule that has not been defined.

-- Missing Definition --

/home/sean/code/ponylang/peg/examples/pony.peg:5:29:8

5: useffi <- "@" (ID / STRING) typeargs -"(" params? -")" "?"?
                               ^^^^^^^^
                               rule has not been defined

[SeanTAllen]

Given the large number of missing definitions, I think we should remove pony.peg and any associated mention that might be in README's etc.

[SeanTAllen]

We decided during sync to delete the pony.peg.