Re: -> operator and monads
Yes, I said that it's *like *function composition in reverse order. And only if you apply the function returned by comp, as I did in my example. It's not to be taken too literally, but it is perhaps helpful for people coming from language that have function composition but no analogue to ->. On Sunday, 14 April 2013 21:03:20 UTC+1, Marko Topolnik wrote: > > On Sunday, April 14, 2013 7:51:10 PM UTC+2, Matthew Hill wrote: > >> Function composition is done via comp. Using -> and ->> is like function >> composition in reverse order (though there's a difference between how the >> two thread return values), and often it reads more naturally. > > > -> applies the functions immediately whereas comp returns a new function > that is the composition of its arguments. > > -> works with functions of any arity; comp only with unary functions. > > As pointed out above, -> merely combines the unevaluated forms it is > given, and only if they happen to be function application forms will the > result be similar to function composition. > > -marko > -- -- You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups "Clojure" group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
Re: -> operator and monads
On Sun, Apr 14, 2013 at 1:03 PM, Marko Topolnik wrote: > On Sunday, April 14, 2013 7:51:10 PM UTC+2, Matthew Hill wrote: > >> Function composition is done via comp. Using -> and ->> is like function >> composition in reverse order (though there's a difference between how the >> two thread return values), and often it reads more naturally. > > > -> applies the functions immediately whereas comp returns a new function > that is the composition of its arguments. > > -> works with functions of any arity; comp only with unary functions. > > As pointed out above, -> merely combines the unevaluated forms it is > given, and only if they happen to be function application forms will the > result be similar to function composition. > Even that's somewhat misleading. user=> (defn make-adder [n] (fn [x] (+ n x))) #'user/make-adder user=> ((comp println (make-adder 4)) 3) 7 nil user=> (-> 3 (make-adder 4) println) ArityException Wrong number of args (2) passed to: user$make-adder clojure.lang.AFn.throwArity (AFn.java:437) user=> (-> 3 ((make-adder 4)) println) 7 nil (make-adder 4) is a "function application form" but the result isn't similar to function composition because the threading operators rewrite their arguments, so we end up with (make-adder 3 4). If it were expected that all arguments but the first would be functions, rather than lists corresponding to function-invocations-with-one-argument-deleted, then -> *could* be equivalent to function composition (and could be written as a regular function): user=> (defn ->* [a & cs] ((apply comp (reverse cs)) a)) #'user/->* user=> (->* 3 (make-adder 4) println) 7 nil user=> (->* [1 2 3] (partial map inc) set #(contains? % 4)) true -- Ben Wolfson "Human kind has used its intelligence to vary the flavour of drinks, which may be sweet, aromatic, fermented or spirit-based. ... Family and social life also offer numerous other occasions to consume drinks for pleasure." [Larousse, "Drink" entry] -- -- You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups "Clojure" group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
Re: -> operator and monads
On Sunday, April 14, 2013 7:51:10 PM UTC+2, Matthew Hill wrote: > Function composition is done via comp. Using -> and ->> is like function > composition in reverse order (though there's a difference between how the > two thread return values), and often it reads more naturally. -> applies the functions immediately whereas comp returns a new function that is the composition of its arguments. -> works with functions of any arity; comp only with unary functions. As pointed out above, -> merely combines the unevaluated forms it is given, and only if they happen to be function application forms will the result be similar to function composition. -marko -- -- You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups "Clojure" group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
Re: -> operator and monads
Function composition is done via comp. Using -> and ->> is like function composition in reverse order (though there's a difference between how the two thread return values), and often it reads more naturally. user> (-> [1 2 5] rest first) 2 user> ((comp first rest) [1 2 5]) 2 On Wednesday, 3 April 2013 19:21:43 UTC+1, Plinio Balduino wrote: > > Hi there > > Is it correct to say that -> operator is a kind of monad in Clojure? > > Thank you in advance. > > Plínio Balduino > -- -- You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups "Clojure" group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
Re: -> operator and monads
Isn't the dot just like Clojure's *comp*? As Allan correctly points out, the thrushes are macros that combine the given forms in a specified way, which only under certain constraints has the effect of composing function applications, whereas *comp* is truly a function composition operator. On Thursday, April 4, 2013 4:25:18 PM UTC+2, Maik Schünemann wrote: > > if you come from the haskell world, it is like . piplining - but in > reverse order > I needed some time to get used to it but I really like -> ->> as-> ... to > structure my code. > It helps to see the sequence of functions that operate on your data > > > On Wed, Apr 3, 2013 at 11:05 PM, Alan Malloy > > wrote: > >> Not even that: -> is not a function composition operator at all, but a >> form-rewriting macro. You can perfectly well write (-> [x xs] (for (inc >> x))) to get (for [x xs] (inc x)), and that is not composing any functions. >> The two things are entirely separate. >> >> >> On Wednesday, April 3, 2013 12:45:55 PM UTC-7, Marko Topolnik wrote: >>> >>> I guess you mean the monadic bind operation, but -> is not it. The only >>> conceptual connection between *bind* and -> is that they are both some >>> kind of function composition operators. >>> >>> -marko >>> >>> On Wednesday, April 3, 2013 8:21:43 PM UTC+2, Plinio Balduino wrote: Hi there Is it correct to say that -> operator is a kind of monad in Clojure? Thank you in advance. Plínio Balduino >>> -- >> -- >> You received this message because you are subscribed to the Google >> Groups "Clojure" group. >> To post to this group, send email to clo...@googlegroups.com >> Note that posts from new members are moderated - please be patient with >> your first post. >> To unsubscribe from this group, send email to >> clojure+u...@googlegroups.com >> For more options, visit this group at >> http://groups.google.com/group/clojure?hl=en >> --- >> You received this message because you are subscribed to the Google Groups >> "Clojure" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to clojure+u...@googlegroups.com . >> For more options, visit https://groups.google.com/groups/opt_out. >> >> >> > > -- -- You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups "Clojure" group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
Re: -> operator and monads
if you come from the haskell world, it is like . piplining - but in reverse order I needed some time to get used to it but I really like -> ->> as-> ... to structure my code. It helps to see the sequence of functions that operate on your data On Wed, Apr 3, 2013 at 11:05 PM, Alan Malloy wrote: > Not even that: -> is not a function composition operator at all, but a > form-rewriting macro. You can perfectly well write (-> [x xs] (for (inc > x))) to get (for [x xs] (inc x)), and that is not composing any functions. > The two things are entirely separate. > > > On Wednesday, April 3, 2013 12:45:55 PM UTC-7, Marko Topolnik wrote: >> >> I guess you mean the monadic bind operation, but -> is not it. The only >> conceptual connection between *bind* and -> is that they are both some >> kind of function composition operators. >> >> -marko >> >> On Wednesday, April 3, 2013 8:21:43 PM UTC+2, Plinio Balduino wrote: >>> >>> Hi there >>> >>> Is it correct to say that -> operator is a kind of monad in Clojure? >>> >>> Thank you in advance. >>> >>> Plínio Balduino >>> >> -- > -- > You received this message because you are subscribed to the Google > Groups "Clojure" group. > To post to this group, send email to clojure@googlegroups.com > Note that posts from new members are moderated - please be patient with > your first post. > To unsubscribe from this group, send email to > clojure+unsubscr...@googlegroups.com > For more options, visit this group at > http://groups.google.com/group/clojure?hl=en > --- > You received this message because you are subscribed to the Google Groups > "Clojure" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to clojure+unsubscr...@googlegroups.com. > For more options, visit https://groups.google.com/groups/opt_out. > > > -- -- You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups "Clojure" group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
Re: -> operator and monads
Not even that: -> is not a function composition operator at all, but a form-rewriting macro. You can perfectly well write (-> [x xs] (for (inc x))) to get (for [x xs] (inc x)), and that is not composing any functions. The two things are entirely separate. On Wednesday, April 3, 2013 12:45:55 PM UTC-7, Marko Topolnik wrote: > > I guess you mean the monadic bind operation, but -> is not it. The only > conceptual connection between *bind* and -> is that they are both some > kind of function composition operators. > > -marko > > On Wednesday, April 3, 2013 8:21:43 PM UTC+2, Plinio Balduino wrote: >> >> Hi there >> >> Is it correct to say that -> operator is a kind of monad in Clojure? >> >> Thank you in advance. >> >> Plínio Balduino >> > -- -- You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups "Clojure" group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
Re: -> operator and monads
Now it's clear. Thank you Plínio On Wed, Apr 3, 2013 at 4:45 PM, Marko Topolnik wrote: > I guess you mean the monadic bind operation, but -> is not it. The only > conceptual connection between *bind* and -> is that they are both some > kind of function composition operators. > > -marko > > > On Wednesday, April 3, 2013 8:21:43 PM UTC+2, Plinio Balduino wrote: >> >> Hi there >> >> Is it correct to say that -> operator is a kind of monad in Clojure? >> >> Thank you in advance. >> >> Plínio Balduino >> > -- > -- > You received this message because you are subscribed to the Google > Groups "Clojure" group. > To post to this group, send email to clojure@googlegroups.com > Note that posts from new members are moderated - please be patient with > your first post. > To unsubscribe from this group, send email to > clojure+unsubscr...@googlegroups.com > For more options, visit this group at > http://groups.google.com/group/clojure?hl=en > --- > You received this message because you are subscribed to the Google Groups > "Clojure" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to clojure+unsubscr...@googlegroups.com. > For more options, visit https://groups.google.com/groups/opt_out. > > > -- -- You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups "Clojure" group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
Re: -> operator and monads
I guess you mean the monadic bind operation, but -> is not it. The only conceptual connection between *bind* and -> is that they are both some kind of function composition operators. -marko On Wednesday, April 3, 2013 8:21:43 PM UTC+2, Plinio Balduino wrote: > > Hi there > > Is it correct to say that -> operator is a kind of monad in Clojure? > > Thank you in advance. > > Plínio Balduino > -- -- You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups "Clojure" group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
-> operator and monads
Hi there Is it correct to say that -> operator is a kind of monad in Clojure? Thank you in advance. Plínio Balduino -- -- You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups "Clojure" group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
