It seems weird to require an entirely new programming language for this tbh. They make the claim that it is special because it's not Turing-complete, but that's nonsense. Turing completeness is almost never a property that is important. I think in this case they're equating Turing incompleteness with "doesn't take a long time to execute" but that isn't really the case at all.

The property you really want is "can be cancelled after a certain amount of compute time - ideally a deterministic amount", and you can obviously do that with Turing complete languages.

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nxobject an hour ago | parent | next [-]

It's not fully applicable here, but industry standard DSLs also stick around because non-programmers find learning it a good investment.

I have a business analytics friend that knows SQL because it's part of his workflows.

But Excel, Notion, Power BI, and other low/no-code tools all have their own data filtering and transformation languages (or dialects). He'd rather spend his time learning more about his line of business, than an aspect of yet another cloud tool that gets forced on him.

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aleksiy123 2 hours ago | parent | prev | next [-]

Ease/ability to embed in other language safely. Predictability of memory, execution. Known constraints like guaranteed to terminate is useful.

no Doom running on cel.

I recently wanted to expose some basic user auto tagging/labeling based on the json data.

I chose cel, over python, SQL because I could just import the runtime in C++, or any language that implements it (python, js etc..)

Safely running a sandboxed python execution engine is significantly more effort and lower performance.

At this cel excels.

Where it didn't was user familiarity and when the json data itself was complex.

	▲	IshKebab an hour ago \| parent [-]
		> Known constraints like guaranteed to terminate is useful. "Guaranteed to terminate" actually means "guaranteed to terminate in finite but possibly arbitrarily large time" which is really not a useful property. There's no practical difference between a filter that might take 1 billion years to run and one that might take more than a billion years.

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talideon 2 hours ago | parent | prev | next [-]

No, they're equating _Turing completeness_ with _might not terminate_. CEL, Expr, Rego, and other languages like them are intended to guarantee to complete. You can't do that cleanly with a Turing complete language.

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IshKebab an hour ago | parent [-]

Right but "guaranteed to terminate" is not a useful property. You could write a program that terminates... after a billion years.

	▲	dilyevsky an hour ago \| parent [-]
		You can estimate cost of CEL program using static analysis before running it. "estimate" only because size of runtime data is generally unknown (but obv you could limit that).

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joshuamorton 3 hours ago | parent | prev [-]

What you really want is "can be completed after a certain amount of time", not "can be cancelled". You don't want iam policy rules to be skipped because they took too long.

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IshKebab an hour ago | parent [-]

Well CEL doesn't offer that guarantee. For any given "certain amount of time" you can write a CEL filter that takes longer.

	▲	dilyevsky an hour ago \| parent [-]
		See my other comment - you can refuse to accept CEL filters that take too long to begin with.