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Here's something I don't understand: How are "little languages" different from a bunch of functionality wrapped into a library/module? Is it just that (with som

Here's something I don't understand: How are "little languages" different from a bunch of functionality wrapped into a library/module? Is it just that (with some convenient syntax sprinkled on top), or is there more to it? I would imagine that most of the value comes from being able to "refactor" thought patterns to match the best way to cleave the domain into composable concepts -- and it seems like we do this all the time (and in all programming languages?).

honungsburk 4y ago
I agree, they are the same! regex is an example of an eDSL that most general-purpose languages support. The king of eDSL:s is of course Haskell. I recommend looking up parser combinators for anyone who has ever struggled with an understanding way to complex regex expressions.
bazoom42 4y ago
An “internal DSL” is a library with a a design which makes it “feel” like a language. JQuery is the classic example. An “external DSL” has its own syntax, like regexes.
francasso 4y ago
With a DSL you need to learn syntax, semantics and either the API for interacting with your GP language or the tooling for external DSLs. With a library you just need to learn the new semantics. I much prefer this to a DSL. Plus a library has all the debug tools the language has. DSLs usually don't have any debug tools except for printing when you are lucky
hackandthink 4y ago
"How are "little languages" different from a bunch of functionality wrapped into a library/module?" This is called a shallow embedding in the Haskell world. Deep Embedding is more like writing a full blown interpreter. Then there is tagless final (Oleg Kiselyov) - it feels shallow but is more flexible as simple library functions and it is optimisable like deep embedded DSLs. http://www.cse.chalmers.se/~josefs/publications/TFP12.pdf http://www.cse.chalmers.se/~josefs/publications/TFP12.pdf https://wiki.haskell.org/Embedded_domain_specific_language https://wiki.haskell.org/Embedded_domain_specific_language

honungsburk 4y ago

I agree, they are the same! regex is an example of an eDSL that most general-purpose languages support. The king of eDSL:s is of course Haskell. I recommend looking up parser combinators for anyone who has ever struggled with an understanding way to complex regex expressions.

bazoom42 4y ago

An “internal DSL” is a library with a a design which makes it “feel” like a language. JQuery is the classic example. An “external DSL” has its own syntax, like regexes.

francasso 4y ago

With a DSL you need to learn syntax, semantics and either the API for interacting with your GP language or the tooling for external DSLs. With a library you just need to learn the new semantics. I much prefer this to a DSL. Plus a library has all the debug tools the language has. DSLs usually don't have any debug tools except for printing when you are lucky

hackandthink 4y ago

"How are "little languages" different from a bunch of functionality wrapped into a library/module?" This is called a shallow embedding in the Haskell world. Deep Embedding is more like writing a full blown interpreter. Then there is tagless final (Oleg Kiselyov) - it feels shallow but is more flexible as simple library functions and it is optimisable like deep embedded DSLs. http://www.cse.chalmers.se/~josefs/publications/TFP12.pdf http://www.cse.chalmers.se/~josefs/publications/TFP12.pdf https://wiki.haskell.org/Embedded_domain_specific_language https://wiki.haskell.org/Embedded_domain_specific_language