4 ms·

Are we having a code example party? I like Clojure: (map :total orders)

tome 14y ago
Yeah you're welcome to bring Clojure to my party. I've never met him/her before but he/she looks like other languages I get on well with.
bcoates 14y ago
I'm partial to select total from orders myself. I really wish was as much progress on syntaxes for expressing relational algebra as there is for the functional stuff. Dealing with map and apply seems a bit fiddly and low-level for what should be a straightforward thing to express declaratively.
- adambard 14y ago
  (defmacro select [total _ coll] (let [total (keyword total)] `(map ~total ~coll))) (select total from orders) Problem solved!
  - draegtun 14y ago
    Nice. Here are some interesting non-macro variants, first in Rebol: select: func [block] [ totals: [] parse block [ set this word! 'from set coll word! (totals: map-each n (get coll) [get in n this]) ] totals ] ; then later... select [total from orders] ;; nb. `select` is a core function provided by Rebol ;; so remember this example overwrites that ;; (in this scope/context) :) ;; ;; Alternative `dialect` to strive for would be.. ;; ;; doMap [select total from orders] And also in Io: select := method( msg := call argAt(0) this := msg name coll := msg next next name newMsg := message(COLL map) // COLL just a placeholder message newMsg setName(coll) // Now been changed to correct var provided newMsg next appendArg(this asMessage) call sender doMessage(newMsg) ) # then later... select(total from orders) Both examples work at runtime. However in Io you can also amend the AST directly.
- tome 14y ago
  I agree, but I think that `map` is already a declarative interface (albeit to an implementation that is presumably functional).
- njs12345 14y ago
  There's a GHC (Haskell) extension which lets you use list comprehensions which read like SQL: http://www.haskell.org/ghc/docs/7.2.1/html/users_guide/syntax-extns.html#7.3.9.%20Generalised%20(SQL-Like)%20List%20Comprehensions http://www.haskell.org/ghc/docs/7.2.1/html/users_guide/synta...
jimbokun 14y ago
Frankly, I would like to have more code example parties. Too often, differences between programming languages are treated as strictly philosophical arguments. Comparing and contrasting actual code is far more interesting, in my opinion.
damncabbage 14y ago
Party time with Ruby: orders.map(&:total) ... Where :total is a symbol, and & is asking :total for the Proc version of itself (a Proc being an anonymous function of sorts), and map is then calling that Proc with a single argument (an order from the list of orders). More detail: http://stackoverflow.com/a/1217114/3528 http://stackoverflow.com/a/1217114/3528
draegtun 14y ago
These are also nice and would like to join in the party :) map *.total, @orders; # perl6 @orders.map: *.total; # perl6 OO map {$_->total} @orders; # perl5 orders map(total) # Io map-each n orders [n/total] ; Rebol

tome 14y ago

Yeah you're welcome to bring Clojure to my party. I've never met him/her before but he/she looks like other languages I get on well with.

bcoates 14y ago

I'm partial to select total from orders myself. I really wish was as much progress on syntaxes for expressing relational algebra as there is for the functional stuff. Dealing with map and apply seems a bit fiddly and low-level for what should be a straightforward thing to express declaratively.

adambard 14y ago
(defmacro select [total _ coll] (let [total (keyword total)] `(map ~total ~coll))) (select total from orders) Problem solved!
- draegtun 14y ago
  Nice. Here are some interesting non-macro variants, first in Rebol: select: func [block] [ totals: [] parse block [ set this word! 'from set coll word! (totals: map-each n (get coll) [get in n this]) ] totals ] ; then later... select [total from orders] ;; nb. `select` is a core function provided by Rebol ;; so remember this example overwrites that ;; (in this scope/context) :) ;; ;; Alternative `dialect` to strive for would be.. ;; ;; doMap [select total from orders] And also in Io: select := method( msg := call argAt(0) this := msg name coll := msg next next name newMsg := message(COLL map) // COLL just a placeholder message newMsg setName(coll) // Now been changed to correct var provided newMsg next appendArg(this asMessage) call sender doMessage(newMsg) ) # then later... select(total from orders) Both examples work at runtime. However in Io you can also amend the AST directly.
tome 14y ago
I agree, but I think that `map` is already a declarative interface (albeit to an implementation that is presumably functional).
njs12345 14y ago
There's a GHC (Haskell) extension which lets you use list comprehensions which read like SQL: http://www.haskell.org/ghc/docs/7.2.1/html/users_guide/syntax-extns.html#7.3.9.%20Generalised%20(SQL-Like)%20List%20Comprehensions http://www.haskell.org/ghc/docs/7.2.1/html/users_guide/synta...

jimbokun 14y ago

Frankly, I would like to have more code example parties. Too often, differences between programming languages are treated as strictly philosophical arguments. Comparing and contrasting actual code is far more interesting, in my opinion.

damncabbage 14y ago

Party time with Ruby: orders.map(&:total) ... Where :total is a symbol, and & is asking :total for the Proc version of itself (a Proc being an anonymous function of sorts), and map is then calling that Proc with a single argument (an order from the list of orders). More detail: http://stackoverflow.com/a/1217114/3528 http://stackoverflow.com/a/1217114/3528

draegtun 14y ago

These are also nice and would like to join in the party :) map *.total, @orders; # perl6 @orders.map: *.total; # perl6 OO map {$_->total} @orders; # perl5 orders map(total) # Io map-each n orders [n/total] ; Rebol