Make a roadmap from now to 1.0 and begin to make Black Hole releases with version numbers

[per-gron]

This is important to do to make Black Hole easier to use for people other than me.

A draft of a proposal for a version roadmap:

0.1: Syntactic tower 0.1.1: Bug fixes: Issue 23, issue 7, issue 15, issue 16 0.2: Implicit phasing on imports and making it a syntax error to have unbound variables in modules 0.3: A command line interface 0.4: syntax-case macros

[per-gron]

I tagged the master branch (pre-syntactictower) v0.1. Progress! =)

[wsxiaoys]

Is there any plan to add r7rs style module?

[per-gron]

Currently, there is no plan to add R7RS style modules. Not because I'm opposed to the idea, but because I currently have no time to do it.

There are a couple of lower-level things that probably need to be done before adding R7RS module support becomes relevant:

• Implement syntax-case macros. It should be possible to implement that on top of the current hygiene system, but it is non-trivial because syntax-case macros require macros to be a closure that takes one argument, but in Black Hole's implementation macros are closures that take three arguments. It should be possible to use some of the syntax-rules code though.
• Properly implement implicit phasing on imports (see issue 22). This is partially implemented, but the current implementation does, because of a small detail, not in practise support macros that depend on other modules.
• We also might want to go away from the current implementation of having each module be invoked once per phase: The paper linked to on issue 22 argues rather convincingly that it's best to have one module instance even across phases.