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DSLs are a waste of time

leebriggs.co.uk

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Re: DSLs are a waste of time

#41

Post by nly »

joshmarinacci wrote: post #27

This really rings true for me. I’ve used many DSLs over the last 20+ years. Build systems. UI definition files. Orchestration languages. They always start simple and easy, but they always eventually grow so complex that using a real language would be preferable. I’ve never seen a system remain at the same level of complexity (or much less shrink) over a multi year timeline.

This is simply because over times systems destructure.

Some developer eventually can't be arsed to stop and _think_ for half an hour about how to solve a problem, so proposes replacing the carefully thought out DSL with a Python script.

The typical programmer does have any respect for code they didn't write themselves or what it was trying to accomplish.

Re: DSLs are a waste of time

#42

Post by throwawaymaths »

bob1029 wrote: post #28
eduction wrote: post #20

We stop calling the useful ones “DSLs” so this is a truism. Is SQL a “waste of time?” Regular expressions, HTML, Makefiles, CSS (and CSS selectors aka jquery selectors)? It’s the bad ones that are a waste of time. The ones still called “dsl” instead of just “language, “format,” or “syntax.”

SQL would be my #1 example too. It is probably the ultimate DSL if you are willing to get deviant with your tech stack.

it's kind of a catch-22, right? SQL is declarative. And while people seem to love declarative DSLs, they are generally really only awesome on the happy path. For SQL, sometimes, it can be incredibly obtuse when something goes horribly wrong (in terms of query speed) -- even with great tools like EXPLAIN. And a query that is fast on one SQL might not be so fast on another SQL.

For other declarative DSLs, I've definitely bashed my head against the wall and gotten a few gray hairs over "why the f* doesn't this goddamn thing that should work work". Sometimes it's because I'm not grokking how the platform works. Sometimes it's a bug, or unimplemented feature.

I suspect the reason why people don't absolutely abhor SQL is that the biggest players (MySQL, Postgres, Sqlite) have actually done a reasonably good job of making the 98% paths very good and 90% of the rest "good enough".

Re: DSLs are a waste of time

#43

Post by OhMeadhbh »

jen20 wrote: post #6
OJFord wrote: post #4

I think calling terraform a DSL in comparison to general purpose programming languages misses the point. If it used a declarative GPPL instead of HCL I wouldn't care, but imperative alternatives general purpose or not are 'a waste of time' & not fit for the domain, IMO.

CDK for Prolog would be quite the trip. As it turns out, what matters is whether the model is declarative. As some uses of YAML go to show, declarative vs not is an orthogonal axis to how general purpose or otherwise a language is, and orthogonal again to whether it looks like a configuration file or code.

CDK for Prolog sounds sick and disgusting. I LIKE IT!

I'm a little more familiar with DSLs w/ Lisp, but I built a simple make replacement with Prolog a few decades ago and it turned out to be useful. Replacing CloudFormation or TerraForm with a Prolog based DSL seems like it could be a win. I like Prolog much more than Pulimi in this role as you can succinctly and unambiguously declare dependency relations.

Re: DSLs are a waste of time

#44

Post by dale_glass »

sgt wrote: post #9
turtleyacht wrote: post #2

Why don't we have a tool that lets us associate monetary budgets to concrete hardware specs, and then generates a cross-cloud (or cloud-agnostic) configuration? budget: $23000 pricing: cheapest cpu: preferred: xeon cores: 8 mem: 64gb disk: preferred: ssd And some --import-usage flag to specify a folder of historical CPU and memory usage from Grafana.

Found a great option for you at $23000. Amazingly we managed to accommodate your budget. /s

Obviously you don't want to tell AWS what your budget is. You want your local tool that does work for your benefit to have a way to sanity check the configuration, and warn you if the only suitable VM at the provider turns out to cost a lot more than you expected.

Re: DSLs are a waste of time

#45

Post by schmichael »

eduction wrote: post #20

We stop calling the useful ones “DSLs” so this is a truism. Is SQL a “waste of time?” Regular expressions, HTML, Makefiles, CSS (and CSS selectors aka jquery selectors)? It’s the bad ones that are a waste of time. The ones still called “dsl” instead of just “language, “format,” or “syntax.”

JavaScript was a cute little DSL once too!

I feel like the author missed a more obvious comparison between Puppetlang and HCL: vendor specific languages.

When you consider them from that perspective it’s clear that the decision is based more on which company you trust to serve your long term needs over any point in time implementation details. Is that company Puppet? HashiCorp? Pulumi? The implementation details obviously matter but if you’re investing 7+ years into an ecosystem like the author did, then there are a lot more factors than just syntax.

Re: DSLs are a waste of time

#46

Post by throwawaymaths »

nly wrote: post #41
joshmarinacci wrote: post #27

This really rings true for me. I’ve used many DSLs over the last 20+ years. Build systems. UI definition files. Orchestration languages. They always start simple and easy, but they always eventually grow so complex that using a real language would be preferable. I’ve never seen a system remain at the same level of complexity (or much less shrink) over a multi year timeline.

This is simply because over times systems destructure. Some developer eventually can't be arsed to stop and _think_ for half an hour about how to solve a problem, so proposes replacing the carefully thought out DSL with a Python script. The typical programmer does have any respect for code they didn't write themselves or what it was trying to accomplish.

I don't think this is the root cause. Declarative languages really paper over details in many cases, and the mapping from the declaration to the imperative execution might not be obvious. When you're on the happy path, it's amazing (if it's a good DSL: because you can be confident you haven't forgotten details, that it's systematically correct, etc). When you encounter a regression, bug, or misunderstanding, in anger, it can be very very difficult to figure out what's going on.

Re: DSLs are a waste of time

#47

Post by turtleyacht »

dale_glass wrote: post #44
sgt wrote: post #9

Earlier quoted context omitted.

Found a great option for you at $23000. Amazingly we managed to accommodate your budget. /s

Obviously you don't want to tell AWS what your budget is. You want your local tool that does work for your benefit to have a way to sanity check the configuration, and warn you if the only suitable VM at the provider turns out to cost a lot more than you expected.

Thank-you.

> local tool... to sanity check

Yes, exactly. Some open-source project as a layer between the cloud providers, and budget and other elements are just knobs to twiddle.

If this "open pricing" project could swarm various known constraints between money and virtual hardware, would it be a kind of constraint satisfaction problem?

Re: DSLs are a waste of time

#48

Post by jen20 »

OhMeadhbh wrote: post #43
jen20 wrote: post #6

Earlier quoted context omitted.

CDK for Prolog would be quite the trip. As it turns out, what matters is whether the model is declarative. As some uses of YAML go to show, declarative vs not is an orthogonal axis to how general purpose or otherwise a language is, and orthogonal again to whether it looks like a configuration file or code.

CDK for Prolog sounds sick and disgusting. I LIKE IT! I'm a little more familiar with DSLs w/ Lisp, but I built a simple make replacement with Prolog a few decades ago and it turned out to be useful. Replacing CloudFormation or TerraForm with a Prolog based DSL seems like it could be a win. I like Prolog much more than Pulimi in this role as you can succinctly and unambiguously declare dependency relations.

> I like Prolog much more than Pulimi in this role as you can succinctly and unambiguously declare dependency relations.

Prolog for Pulumi is an absolutely doable thing - and indeed sounds sufficiently diabolical that someone should do it ;-)

Re: DSLs are a waste of time

#49

Post by eduction »

schmichael wrote: post #45
eduction wrote: post #20

We stop calling the useful ones “DSLs” so this is a truism. Is SQL a “waste of time?” Regular expressions, HTML, Makefiles, CSS (and CSS selectors aka jquery selectors)? It’s the bad ones that are a waste of time. The ones still called “dsl” instead of just “language, “format,” or “syntax.”

JavaScript was a cute little DSL once too! I feel like the author missed a more obvious comparison between Puppetlang and HCL: vendor specific languages. When you consider them from that perspective it’s clear that the decision is based more on which company you trust to serve your long term needs over any point in time implementation details. Is that company Puppet? HashiCorp? Pulumi? The implementation details obvi…

This is a good point but also a little circular since the good vendor specific languages tend to break free — like Netscape’s (and nominally Sun’s) JavaScript :-)

(and I think SQL started at IBM but I’m not sure if they tried to keep it proprietary or make it a standard)

Re: DSLs are a waste of time

#50

Post by spion »

The frontend ecosystem realized (at the time of React) that the (template) DSL isn't really the point. Its the declarative description of what the end result should look like (as well as applying the diff) which is the important bit, not how you generate that declarative description. The devops space is slowly moving in this direction too.

TypeScript is a great fit to model the unwieldy yaml / json schemas with precision, getting less in the way compared to most languages with sum types. Deno could be a great player in this space that avoids the complexity of npm, especially with its sandbox to restrict side-effects, networking and external commands.

CDKs come with their own multi-language compiler (jsii-rosetta) which results with a ~300MB npm install. Even when all you wanted was to use simple typescript functions to output some JSON and/or yaml.

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