Allow setting of the output Writer for PRINT and DUMP

[andydotxyz]

Requires a concrete Environment type for builtin. Env was not used for anything so this seemed safe...

[andydotxyz]

I could not see any code using "env interface{}" so I replaced it. If that functionality needs to be maintained then I could add Environment.Data as interface{}?

[skx]

I'm not averse to this, I guess it would be useful to make the library more useful for embedded users?

I guess there are two obvious comments:

• This should also be done for INPUT.
• There should be tests.
  • i.e. setup an interpreter, with a fake output, then run PRINT 3 * 3 and assert the output is 9.

[andydotxyz]

Great! I agree on both points. This is already tested - I added the assertion to the PRINT and DUMP tests that existed already - do you want more?

I will look at the INPUT next - I think it should be moved to builtin now that it is possible.

[skx]

I could not see any code using "env interface{}" so I replaced it.

Take a look at goserver/main.go. That uses env to invoke allowing state to be maintained between save and other code. It is a contrived example, but without that you can't have any builtins that set/update global state, so it is worth keeping for embedded users.

If that functionality needs to be maintained then I could add Environment.Data as interface{}?

That works, I think.

[skx]

Great! I agree on both points. This is already tested - I added the assertion to the PRINT and DUMP tests that existed already - do you want more?

No, that's fine. I read quickly and missed them. Perfect :)

I will look at the INPUT next - I think it should be moved to builtin now that it is possible.

Sadly you can't make it a built-in, with the way they work at the moment. (Ditto READ for the same reason)

If you move the code to a builtin and call:

10 INPUT "Steve", A

The builtin-handler will be called with two arguments:

• The string "Steve"
• The contents of the variable A, if it exists.

What the INPUT handler needs is to be able to be passed a reference to the variable, so it can update the value. (+/- A vs. A$).

I think I might have documented that at some point, but it's a blocker to move it to builtin, and out of the core.

Anyway I'll check back tomorrow. Thanks for your contribution (and your fast replies! Bedtime here now though.)

[andydotxyz]

I think that addresses your comments, thanks for the input. Goserver seems to be working to the best of my knowledge.

[skx]

Merged, thanks again for your contribution :)