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> One of the problems with most PL type systems is that they predate ubiquitous networking; so they're not designed to address the problem of describing externa

> One of the problems with most PL type systems is that they predate ubiquitous networking; so they're not designed to address the problem of describing external data, eg with MIME types, XML DTDs, protobuf schemas or whatever. The problem existed before "ubiquitous networking" if you realise that networking is just a specific kind of I/O. But I/O from a PL perspective is nothing more than sending or receiving bytes. PLs usually do not impose a format and a meaning on I/O because it would restrict the capabilities of the applications and libraries. One could argue that PLs should impose such restrictions just like some PLs impose restrictions on memory access ("managed languages"). However, a huge difference between memory and I/O - and especially networking - is that they are unreliable by default: transmission errors, disconnections, lags, etc. But even if you solve that, your PL can only speak to itself, which quite significantly restricts its practical usefulness. As far as I know, only languages specialized in distributed computing do that. But for a general purpose language, high level networking is usually not something you want to be carved in stone (in the language's specs). You'd rather want to leave that in libraries, that can be replaced and enhanced.

yarvin9 11y ago
Not to be all Winnebago Man here, but all the code in Urbit (protocols and language alike) can be replaced and enhanced, except Nock. In fact, the normal way to drive this process is just by merging the new version of the code. It's certainly true, however, that you don't want locked-down components. Urbit is very happy to be an HTTP client and server. (Alas, HTTP has become the "everything protocol.") It also has its own network protocol, which it prefers for conversations between urbits. The unreliability of network packet delivery (or more exactly, the unreasonable effectiveness of unreliable networking) is basically the greatest technical idea of the 20th century as far as I'm concerned. There is actually a significant difference between processing unordered, unreliable packet streams, and ordered, reliable, message streams, with the "universal design." Neat thing about packets: you can drop them. If a packet sends the server into an infinite loop? Or at least, a timer detects an infinite loop? Drop the packet. From the network's perspective, the CPU is simply detecting congestion. You can refuse to process a message, but that's not a stateless and passive operation; you have to return a failure report. But dropping a bad packet is the most wonderful thing in the world. By definition it doesn't change your server's state. It also doesn't leak information to the sender...

yarvin9 11y ago

Not to be all Winnebago Man here, but all the code in Urbit (protocols and language alike) can be replaced and enhanced, except Nock. In fact, the normal way to drive this process is just by merging the new version of the code. It's certainly true, however, that you don't want locked-down components. Urbit is very happy to be an HTTP client and server. (Alas, HTTP has become the "everything protocol.") It also has its own network protocol, which it prefers for conversations between urbits. The unreliability of network packet delivery (or more exactly, the unreasonable effectiveness of unreliable networking) is basically the greatest technical idea of the 20th century as far as I'm concerned. There is actually a significant difference between processing unordered, unreliable packet streams, and ordered, reliable, message streams, with the "universal design." Neat thing about packets: you can drop them. If a packet sends the server into an infinite loop? Or at least, a timer detects an infinite loop? Drop the packet. From the network's perspective, the CPU is simply detecting congestion. You can refuse to process a message, but that's not a stateless and passive operation; you have to return a failure report. But dropping a bad packet is the most wonderful thing in the world. By definition it doesn't change your server's state. It also doesn't leak information to the sender...