3 ms·

Thats pretty awesome. Regex's the tool (vs. the concept of "regular expressions" that comes up in interpreters/compilers) is a supremely useful utility when use

by scrame 15y ago

Thats pretty awesome. Regex's the tool (vs. the concept of "regular expressions" that comes up in interpreters/compilers) is a supremely useful utility when used sparingly, and surprisingly portable between languages. Regex's are in a (not-)sweet spot of practical languages that aren't taught in school. For all the hype of ruby, et al. being able to make "DSL's", its surprising how mystical an _actual_ DSL, that is portable between languages (through PCRE) is held. Unfortunately, like many other tools, can be used sparingly after a lot of practice writing crappy regex's, and having to eat your own dogfood (so you learn its not an "ultra-fast parser", or that you shouldn't chain substitutions on user-generated input). A rote tutorial -- in the style of LPTHW -- is excellent.

itmag 15y ago
What are some other examples of DSL's that are useful in the same way as regexes? I am thinking LINQ might qualify. Also, JQuery is strictly not a DSL, but it kinda feels DSLy.
- lmkg 15y ago
  Personally, I classify any sort of sequence comprehension as a DSL, including LINQ and python's list and generator comprehensions. JQuery is basically as close to a LINQ-like DSL as you can get in a language like JavaScript that doesn't have metaprogramming support. Related to sequence comprehensions, there is Common Lisp's controversial LOOP macro, which is basically an iteration comprehension DSL. I'm somewhat on the fence about whether format control strings qualify as DSL's. They don't as much, but they tend to have very complicated and specialized syntax. I feel that Monads are a DSL in Haskell, but whenever I see "Monads in Blub!" I don't feel the same way about them. Part of it is probably that Haskell provides not only infix operators, but do-notation for supporting monads. Part of it is also that monads don't do as much in other languages, because their type systems aren't rich enough to fully express them, nor restrictive enough that their capabilities are useful.
  - itmag 15y ago
    A DSL doesn't have to be Turing-complete IIRC so format strings could probably qualify.

by scrame 15y ago

itmag 15y ago

What are some other examples of DSL's that are useful in the same way as regexes? I am thinking LINQ might qualify. Also, JQuery is strictly not a DSL, but it kinda feels DSLy.

lmkg 15y ago
Personally, I classify any sort of sequence comprehension as a DSL, including LINQ and python's list and generator comprehensions. JQuery is basically as close to a LINQ-like DSL as you can get in a language like JavaScript that doesn't have metaprogramming support. Related to sequence comprehensions, there is Common Lisp's controversial LOOP macro, which is basically an iteration comprehension DSL. I'm somewhat on the fence about whether format control strings qualify as DSL's. They don't as much, but they tend to have very complicated and specialized syntax. I feel that Monads are a DSL in Haskell, but whenever I see "Monads in Blub!" I don't feel the same way about them. Part of it is probably that Haskell provides not only infix operators, but do-notation for supporting monads. Part of it is also that monads don't do as much in other languages, because their type systems aren't rich enough to fully express them, nor restrictive enough that their capabilities are useful.
- itmag 15y ago
  A DSL doesn't have to be Turing-complete IIRC so format strings could probably qualify.