[solarexplorer]

> rounding modes and overflow behavior are not addressed

He provides a reference implementation. That means this and many other details are defined by code. Quoting dec64.asm: "Rounding is to the nearest value. Ties are rounded away from zero. Integer division is floored."

> Compare the level of thought and detail in this "specification" to ... [Goldberg]

I don't think this comparison is fair. David Goldberg's text is an introduction to the topic. Douglas Crockford describes an idea and gives you a reference implementation.

[phaker]

Said reference implementation is written in x86 assembly. 1261 lines, 650 lines sans comments and blanks.

To be fair it is extensively commented, but the comments describe what it does, not why. And for fuck's sake, hundreds of lines of assembly is not a spec, even if it is most readable code in the world

[chimeracoder]

> He provides a reference implementation. That means this and many other details are defined by code.

I dream of a day when we stop thinking of "reference implementations" as proper specifications. The whole concept of a "reference implementation" leads to an entire class of nightmarish problems.

What happens if there is an unintentional bug in the reference implementation that causes valid (but incorrect) output for certain inputs? What if feeding it certain input reliably produces a segfault? Does that mean that other implementations should mimic that behavior? What if a patch is issued to the reference implementation that changes the behavior of certain inputs? Is this the same as issuing an amendment to the specification? Does this mean that other implementations now need to change their behavior as well?

Or, worse, what if there is certain behavior that should be explicitly left undefined in a proper specification? A reference implementation cannot express this concept - by definition, everything is defined based on the output that the reference implementation provides.

Finally, there's the fact that it takes time and effort to produce a proper specification, and this process usually reveals (to the author) complexities about the problem and edge cases that may not become apparent simply by providing a reference implementation.

[fragsworth]

Bitcoin suffers from this problem. In fact, some people in the community frown upon attempts to make mining software or clients when bitcoin-qt/bitcoind can just be used instead, for the exact reasons you mentioned.

The spec for a valid transaction in Bitcoin can currently only be defined as "a transaction that bitcoin-qt accepts." The problem is magnified by how disorganized the source code is.

[solarexplorer]

I suppose that Crockford is just tossing around this idea to test the waters. If he were serious, he would have to deliver a written spec of course!

[kabdib]

On the other hand, if you don't have a reference specification you shouldn't declare something standard.

(re: all the web standards that had very wide "interpretation" by different browser efforts, leading to chaos and a whole industry based on fear an uncertainty)

[nolok]

But nobody did, you're the first person in the thread to mention the word "standard". You might be confusing specification with standard.

[wbl]

And what if the code has a bug? Code is also difficult to analyze. The people who do numerical computing need to prove theorems about what their algorithms produce.