4 ms·

Micro languages in Clojure via macros and let

20 points by macmac 16y ago

petervandijck 16y ago
Cool, but what about code maintainability? Why add microlanguages? I'm sure your microlanguage is superintuitive to you, because you wrote it, but I, as a new coder on your code, don't want to learn it.
- macmac 16y ago
  That is a valid concern, although a well designed micro language will likely also reduce the code base significantly and thereby leave less to learn. If it is well constructed it will also serve as an easy way of learning about the domain which you will have to anyway.
  - petervandijck 16y ago
    Fair enough. Or, a well designed micro language may just be that, well designed but entirely unnecessary :)
    - wilig 16y ago
      Touché!
    - gruseom 16y ago
      As anamax points out, you could say the same thing about a well designed anything, so this isn't an argument against languages, so it isn't an argument at all. It reminds me of how most of the objections people make to macros apply just as well to functions.
- chc 16y ago
  Every codebase and accompanying API is something you have to learn. If you don't want to learn, best not ever do maintenance. A "microlanguage" is just better suited to the problem domain than a normal API.
- anamax 16y ago
  > I'm sure your microlanguage is superintuitive to you, because you wrote it, but I, as a new coder on your code, don't want to learn it. I'm sure your API is superintuitive to you, because you wrote it, but I, as a new coder on your code, don't want to learn it. I'm sure your library is superintuitive to you, because you wrote it, but I, as a new coder on your code, don't want to learn it.
  - petervandijck 16y ago
    Mmm. No. It takes longer to learn a language than an API, in general. I don't think I'm wrong about that?
- s-phi-nl 16y ago
  See http://paulgraham.com/progbot.html http://paulgraham.com/progbot.html
- jimbokun 16y ago
  In this case, he's trying to make it more idiomatic within the surrounding Clojure code, and thus, more intuitive for the intended user.
wilig 16y ago
In most general of terms a programming language would be ideal for a problem domain if the domains problems could be expressed directly in the language. You would sit down with the domain experts and have a conversation, that conversation could be converted directly to code. In fact if the language was expressive enough the experts could express the problems directly to the computer. No current language, that I'm aware of, achieves this goal. However Clojure by nature of it being a Lisp, allows you to easily add to the language to bring it closer to the domain it will be used in. It's certainly no silver bullet, and does add to the learning curve of new programmers, but if used properly can be a great tool for writing concise and correct code.
- bad_user 16y ago
  My problem is that the code linked in the article looks ugly as hell. Even the micro-language created. Compare this ... (filter (and (< :table1/a 5) (= :table1/b "x")) (collect :table1)) To this ... from row in table1 where row.a < 5 and row.b == "x" Also, compare this ... (collect :projects :invoices [:projects/id :projects/name (as :inv_id :invoices/id) :invoices/date]) To this ... from proj in projects from inv in invoices select { proj.id, proj.name, inv_id => inv.id, inv.date } For me the ideal programming language would be one readable by humans.
  - scott_s 16y ago
    But are you complaining about Lisp syntax in general, or this DSL implemented using Lisp macros in particular?
    - bad_user 16y ago
      Both I think. I'd like a language that lets me define syntax that's readable by kids with basic english/math skills. From the languages I've tried, Boo came closest to that, but the error messages it throws are awful, and development seems to have stagnated. Maybe Perl6 will be that language, who knows? Haskell also seems to have a macro-system, but I wouldn't call Haskell a language readable by kids.

20 points by macmac 16y ago

Cool, but what about code maintainability? Why add microlanguages? I'm sure your microlanguage is superintuitive to you, because you wrote it, but I, as a new coder on your code, don't want to learn it.

macmac 16y ago
That is a valid concern, although a well designed micro language will likely also reduce the code base significantly and thereby leave less to learn. If it is well constructed it will also serve as an easy way of learning about the domain which you will have to anyway.
- petervandijck 16y ago
  Fair enough. Or, a well designed micro language may just be that, well designed but entirely unnecessary :)
  - wilig 16y ago
    Touché!
  - gruseom 16y ago
    As anamax points out, you could say the same thing about a well designed anything, so this isn't an argument against languages, so it isn't an argument at all. It reminds me of how most of the objections people make to macros apply just as well to functions.
chc 16y ago
Every codebase and accompanying API is something you have to learn. If you don't want to learn, best not ever do maintenance. A "microlanguage" is just better suited to the problem domain than a normal API.
anamax 16y ago
> I'm sure your microlanguage is superintuitive to you, because you wrote it, but I, as a new coder on your code, don't want to learn it. I'm sure your API is superintuitive to you, because you wrote it, but I, as a new coder on your code, don't want to learn it. I'm sure your library is superintuitive to you, because you wrote it, but I, as a new coder on your code, don't want to learn it.
- petervandijck 16y ago
  Mmm. No. It takes longer to learn a language than an API, in general. I don't think I'm wrong about that?
s-phi-nl 16y ago
See http://paulgraham.com/progbot.html http://paulgraham.com/progbot.html
jimbokun 16y ago
In this case, he's trying to make it more idiomatic within the surrounding Clojure code, and thus, more intuitive for the intended user.

wilig 16y ago

In most general of terms a programming language would be ideal for a problem domain if the domains problems could be expressed directly in the language. You would sit down with the domain experts and have a conversation, that conversation could be converted directly to code. In fact if the language was expressive enough the experts could express the problems directly to the computer. No current language, that I'm aware of, achieves this goal. However Clojure by nature of it being a Lisp, allows you to easily add to the language to bring it closer to the domain it will be used in. It's certainly no silver bullet, and does add to the learning curve of new programmers, but if used properly can be a great tool for writing concise and correct code.

bad_user 16y ago
My problem is that the code linked in the article looks ugly as hell. Even the micro-language created. Compare this ... (filter (and (< :table1/a 5) (= :table1/b "x")) (collect :table1)) To this ... from row in table1 where row.a < 5 and row.b == "x" Also, compare this ... (collect :projects :invoices [:projects/id :projects/name (as :inv_id :invoices/id) :invoices/date]) To this ... from proj in projects from inv in invoices select { proj.id, proj.name, inv_id => inv.id, inv.date } For me the ideal programming language would be one readable by humans.
- scott_s 16y ago
  But are you complaining about Lisp syntax in general, or this DSL implemented using Lisp macros in particular?
  - bad_user 16y ago
    Both I think. I'd like a language that lets me define syntax that's readable by kids with basic english/math skills. From the languages I've tried, Boo came closest to that, but the error messages it throws are awful, and development seems to have stagnated. Maybe Perl6 will be that language, who knows? Haskell also seems to have a macro-system, but I wouldn't call Haskell a language readable by kids.