[pnako]

The story of Scheme is that it was so easy to implement (relatively) that they ended up with dozens of implementations, so they decided to write a standard... and then started doing the same thing with the standard(s).

It's a language family, or even philosophy, rather than a single language.

[pjmlp]

The standard was quite ok, until the version 7 disagreement of what should be actually in.

[dTal]

There's always been disagreement. R7RS (small|large) is an effort to resolve that disagreement.

[pjmlp]

I thought that R7RS was the one that sparked it.

[jgon]

R6RS was the one that really sparked the divide, and for a long time only had a limited number of implementations due to this controversy. The big thing that R6RS brought, in my opinion, was a syntax for creating modules and sharing them. R7RS was an attempt to create an R5RS-like minimal standard that still had a library/module syntax so that you could get a bunch of implementations and share code between them. R7RS-small did this, and then R7RS-large attempts to use the module syntax to create a big body of "industrial strength" code that you can use to get "real things" done with scheme. The R7RS-large process seems to be using the SRFIs as a staging ground for the new modules, standardizing on chunks of them as they go in different "editions".

So the theory now is that you can write a smaller R7RS-small compliant scheme, and do all your language experimentation in that, and someone else could come along and bootstrap that into a fairly useful large implementation without a ton of effort, and modules you write on that scheme could then be reused on other implementations.

[pjmlp]

Likewise, thanks for clarifying it as well.

[samth]

There are three ways to think about this.

1. R7RS explicitly decided to repudiate R6RS, leading to the disagreement.

2. R6RS made changes that did not have consensus and the resulting vote didn't have a big enough super majority requirement, leading to a controversial standard.

3. There was always major disagreement about all the relevant points, and R5RS itself was only created by not introducing anything new post 1992, and by not taking a position on the controversial topics. So any standard effort was bound to be controversial.

[pjmlp]

Thanks for clarifying it.