Re: docstrings of if-let and when-let incorrect
Wow, the discussion continued! I agree on what most people have said: AND-combined and none of the bindings available in the else. On Friday, May 18, 2012 7:20:06 AM UTC+2, FrankS wrote: Christophe Grand was experimenting with some extensions to if-let and when-let that had implicit ANDs for the let-forms: https://github.com/cgrand/parsley/blob/master/src/net/cgrand/parsley/util.clj It feels intuitive to me to allow multiple if-let-forms like cgrand implements, and I can certainly remember situations where I could have used such a feature. -FrankS. On May 16, 2012, at 11:26 AM, dgrnbrg wrote: I too assumed that if/when-let would support multiple bindings, short- circuiting if one failed, when I started learning Clojure. It seems that short-circuiting multiple bindings isn't surprising. On May 16, 10:56 am, Jay Fields j...@jayfields.com wrote: I've also attempted to use if/when-let with multiple bindings in the past. I assumed that it would behave as 'AND' and that no bindings would be available in 'else' Cheers, Jay On Wed, May 16, 2012 at 10:29 AM, Dan Cross cro...@gmail.com wrote: On Wed, May 16, 2012 at 9:16 AM, Aaron Cohen aa...@assonance.org wrote: On Wed, May 16, 2012 at 9:10 AM, Walter Tetzner robot.ninja.saus...@gmail.com wrote: To make the bindings work like let, where later bindings can see previous bindings, I think the most natural way to do it is to have the bindings behave like the maybe monad. [...] Saying something is obvious and then using the word monad a paragraph later is contradictory. ;) Hypothetically, this is obvious, unlike most monads. Zing! What should happen on the else branch of the if-let; which bindings are in scope and what would be their values? None of the bindings should be in scope. - Dan C. -- 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 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 On Friday, May 18, 2012 7:20:06 AM UTC+2, FrankS wrote: Christophe Grand was experimenting with some extensions to if-let and when-let that had implicit ANDs for the let-forms: https://github.com/cgrand/parsley/blob/master/src/net/cgrand/parsley/util.clj It feels intuitive to me to allow multiple if-let-forms like cgrand implements, and I can certainly remember situations where I could have used such a feature. -FrankS. On May 16, 2012, at 11:26 AM, dgrnbrg wrote: I too assumed that if/when-let would support multiple bindings, short- circuiting if one failed, when I started learning Clojure. It seems that short-circuiting multiple bindings isn't surprising. On May 16, 10:56 am, Jay Fields j...@jayfields.com wrote: I've also attempted to use if/when-let with multiple bindings in the past. I assumed that it would behave as 'AND' and that no bindings would be available in 'else' Cheers, Jay On Wed, May 16, 2012 at 10:29 AM, Dan Cross cro...@gmail.com wrote: On Wed, May 16, 2012 at 9:16 AM, Aaron Cohen aa...@assonance.org wrote: On Wed, May 16, 2012 at 9:10 AM, Walter Tetzner robot.ninja.saus...@gmail.com wrote: To make the bindings work like let, where later bindings can see previous bindings, I think the most natural way to do it is to have the bindings behave like the maybe monad. [...] Saying something is obvious and then using the word monad a paragraph later is contradictory. ;) Hypothetically, this is obvious, unlike most monads. Zing! What should happen on the else branch of the if-let; which bindings are in scope and what would be their values? None of the bindings should be in scope. - Dan C. -- 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
Re: docstrings of if-let and when-let incorrect
On Wed, May 16, 2012 at 9:53 AM, Walter Tetzner robot.ninja.saus...@gmail.com wrote: On Wednesday, May 16, 2012 9:16:29 AM UTC-4, Aaron Cohen wrote: Saying something is obvious and then using the word monad a paragraph later is contradictory. ;) What should happen on the else branch of the if-let; which bindings are in scope and what would be their values? None of the bindings should be available in the else branch, since there would be no way to know which will succeed before run-time. I actually think that having all the bindings available and just nil for everything past the first failure would be more useful, and also matches the intuition that it expands out to nested if-lets (if-let [a 1 b 2 c nil] [a b c]) (if-let [a 1] (if-let [b 2] (if-let [c nil] [a b c] [a b c]) [a b c]) [a b c]) = [1 2 nil] -- 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
Re: docstrings of if-let and when-let incorrect
I guess it wouldn't hurt having them available in the else, even if people won't use them often. On Monday, May 21, 2012 7:11:05 PM UTC+2, Aaron Cohen wrote: On Wed, May 16, 2012 at 9:53 AM, Walter Tetzner robot.ninja.saus...@gmail.com wrote: On Wednesday, May 16, 2012 9:16:29 AM UTC-4, Aaron Cohen wrote: Saying something is obvious and then using the word monad a paragraph later is contradictory. ;) What should happen on the else branch of the if-let; which bindings are in scope and what would be their values? None of the bindings should be available in the else branch, since there would be no way to know which will succeed before run-time. I actually think that having all the bindings available and just nil for everything past the first failure would be more useful, and also matches the intuition that it expands out to nested if-lets (if-let [a 1 b 2 c nil] [a b c]) (if-let [a 1] (if-let [b 2] (if-let [c nil] [a b c] [a b c]) [a b c]) [a b c]) = [1 2 nil] -- 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
Re: docstrings of if-let and when-let incorrect
There's a few issues there, first of which is that the code doesn't evaluate to what's shown: REPL started; server listening on localhost port 21867 user= (if-let [a 1] (if-let [b 2] (if-let [c nil] [a b c] [a b c]) [a b c]) [a b c]) java.lang.Exception: Unable to resolve symbol: c in this context (NO_SOURCE_FILE:3) The c isn't nil in the else form, it's unbound. The same would be true if it failed at any of the other levels, if the original if fails, a, b, c are all unbound. So, setting them to nil isn't consistent. It might be a good option, but it's not consistent with the code above. I can't imagine that you'd want the else statement to have a bunch of possibly nil vars for any reason other than printing - otherwise you'd end up putting a bunch of conditional logic in the else to know which vars are nil, in which case you're better off using nested if-lets anyway. But, maybe the printing (i.e. logging) scenario is reason enough to bind these variables. I'd probably lean towards keeping them all unbound, as it's clear that each var would be bound (if form) or unbound (else form), versus each var being possibly truthy or nil in the else form. But, I don't feel strongly either way. On Mon, May 21, 2012 at 1:32 PM, Borkdude michielbork...@gmail.com wrote: I guess it wouldn't hurt having them available in the else, even if people won't use them often. On Monday, May 21, 2012 7:11:05 PM UTC+2, Aaron Cohen wrote: On Wed, May 16, 2012 at 9:53 AM, Walter Tetzner robot.ninja.saus...@gmail.com** wrote: On Wednesday, May 16, 2012 9:16:29 AM UTC-4, Aaron Cohen wrote: Saying something is obvious and then using the word monad a paragraph later is contradictory. ;) What should happen on the else branch of the if-let; which bindings are in scope and what would be their values? None of the bindings should be available in the else branch, since there would be no way to know which will succeed before run-time. I actually think that having all the bindings available and just nil for everything past the first failure would be more useful, and also matches the intuition that it expands out to nested if-lets (if-let [a 1 b 2 c nil] [a b c]) (if-let [a 1] (if-let [b 2] (if-let [c nil] [a b c] [a b c]) [a b c]) [a b c]) = [1 2 nil] -- 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 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
Re: docstrings of if-let and when-let incorrect
On Mon, May 21, 2012 at 1:43 PM, Jay Fields j...@jayfields.com wrote: There's a few issues there, first of which is that the code doesn't evaluate to what's shown: REPL started; server listening on localhost port 21867 user= (if-let [a 1] (if-let [b 2] (if-let [c nil] [a b c] [a b c]) [a b c]) [a b c]) java.lang.Exception: Unable to resolve symbol: c in this context (NO_SOURCE_FILE:3) The c isn't nil in the else form, it's unbound. The same would be true if it failed at any of the other levels, if the original if fails, a, b, c are all unbound. So, setting them to nil isn't consistent. It might be a good option, but it's not consistent with the code above. I can't imagine that you'd want the else statement to have a bunch of possibly nil vars for any reason other than printing - otherwise you'd end up putting a bunch of conditional logic in the else to know which vars are nil, in which case you're better off using nested if-lets anyway. But, maybe the printing (i.e. logging) scenario is reason enough to bind these variables. I'd probably lean towards keeping them all unbound, as it's clear that each var would be bound (if form) or unbound (else form), versus each var being possibly truthy or nil in the else form. Yeah, I was typing theory code. However, none defined in the else doesn't fully match the nested if-lets behavior either. In the second if-let stanza, a would be bound in the else case. In any event, this is all just bike-shedding and illustrating that what appears obvious isn't necessarily. -- 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
Re: docstrings of if-let and when-let incorrect
Christophe Grand was experimenting with some extensions to if-let and when-let that had implicit ANDs for the let-forms: https://github.com/cgrand/parsley/blob/master/src/net/cgrand/parsley/util.clj It feels intuitive to me to allow multiple if-let-forms like cgrand implements, and I can certainly remember situations where I could have used such a feature. -FrankS. On May 16, 2012, at 11:26 AM, dgrnbrg wrote: I too assumed that if/when-let would support multiple bindings, short- circuiting if one failed, when I started learning Clojure. It seems that short-circuiting multiple bindings isn't surprising. On May 16, 10:56 am, Jay Fields j...@jayfields.com wrote: I've also attempted to use if/when-let with multiple bindings in the past. I assumed that it would behave as 'AND' and that no bindings would be available in 'else' Cheers, Jay On Wed, May 16, 2012 at 10:29 AM, Dan Cross cro...@gmail.com wrote: On Wed, May 16, 2012 at 9:16 AM, Aaron Cohen aa...@assonance.org wrote: On Wed, May 16, 2012 at 9:10 AM, Walter Tetzner robot.ninja.saus...@gmail.com wrote: To make the bindings work like let, where later bindings can see previous bindings, I think the most natural way to do it is to have the bindings behave like the maybe monad. [...] Saying something is obvious and then using the word monad a paragraph later is contradictory. ;) Hypothetically, this is obvious, unlike most monads. Zing! What should happen on the else branch of the if-let; which bindings are in scope and what would be their values? None of the bindings should be in scope. - Dan C. -- 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 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 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
Re: docstrings of if-let and when-let incorrect
As the logical AND of all of the multiple forms? The OR? Only use the first expression? Only the last? It should be AND. -- 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
Re: docstrings of if-let and when-let incorrect
How would multiple bindings for if-let or when-let work? Should every binding be testedd? Should they be and-ed together? Should it short-circuit if the first is false? I don't think there are obvious answers to those questions. -S -- 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
Re: docstrings of if-let and when-let incorrect
On Wednesday, May 16, 2012 9:01:49 AM UTC-4, Stuart Sierra wrote:How would multiple bindings for if-let or when-let work? Should every binding be testedd? Should they be and-ed together? Should it short-circuit if the first is false? I don't think there are obvious answers to those questions. Well, considering everyone on here that's answered that question said 'AND', it seems to be obvious. To make the bindings work like let, where later bindings can see previous bindings, I think the most natural way to do it is to have the bindings behave like the maybe monad. The first time you encounter a false value, it fails. This way, you are using 'AND', but you don't run the risk of a NullPointerException in later bindings if a previous one fails. -Walter -- 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
Re: docstrings of if-let and when-let incorrect
On Wed, May 16, 2012 at 9:10 AM, Walter Tetzner robot.ninja.saus...@gmail.com wrote: On Wednesday, May 16, 2012 9:01:49 AM UTC-4, Stuart Sierra wrote:How would multiple bindings for if-let or when-let work? Should every binding be testedd? Should they be and-ed together? Should it short-circuit if the first is false? I don't think there are obvious answers to those questions. Well, considering everyone on here that's answered that question said 'AND', it seems to be obvious. To make the bindings work like let, where later bindings can see previous bindings, I think the most natural way to do it is to have the bindings behave like the maybe monad. The first time you encounter a false value, it fails. This way, you are using 'AND', but you don't run the risk of a NullPointerException in later bindings if a previous one fails. Saying something is obvious and then using the word monad a paragraph later is contradictory. ;) What should happen on the else branch of the if-let; which bindings are in scope and what would be their values? --Aaron -- 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
Re: docstrings of if-let and when-let incorrect
On Wed, May 16, 2012 at 3:16 PM, Aaron Cohen aa...@assonance.org wrote: What should happen on the else branch of the if-let; which bindings are in scope and what would be their values? This is kind of tricky. My opinion tends to all bindings, but then it's difficult to handle lazy evaluation like in (or (cheap-computation) (long-computation)). One solution for this would be evaluating all arguments 'til the first fails, then nil-ing the rest. The problem with this is, that it throws away values which could be useful. -- Moritz Ulrich -- 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
Re: docstrings of if-let and when-let incorrect
On May 16, 2012, at 8:16 AM, Aaron Cohen wrote: Saying something is obvious and then using the word monad a paragraph later is contradictory. ;) If the word monad is scary, just pretend he said it should short-circuit instead. ;) What should happen on the else branch of the if-let; which bindings are in scope and what would be their values? That's an interesting question. For consistency with the current behavior of single-binding if-let, the binding whose value was false should be left unbound (as well as successive bindings, given short-circuiting); but I could see going either way for the bindings that succeeded. I don't think it matters as much that this behavior would be non-obvious, though, because I'd predict the common case in the else-branch of a multi-binding if-let would be to not care about any of the bindings. That's just my guess, though. -- 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
Re: docstrings of if-let and when-let incorrect
Personally, I would intuitively assume that none of the bindings from if-let would be available in the else branch. On 16 May 2012 14:36, Moritz Ulrich ulrich.mor...@googlemail.com wrote: On Wed, May 16, 2012 at 3:16 PM, Aaron Cohen aa...@assonance.org wrote: What should happen on the else branch of the if-let; which bindings are in scope and what would be their values? This is kind of tricky. My opinion tends to all bindings, but then it's difficult to handle lazy evaluation like in (or (cheap-computation) (long-computation)). One solution for this would be evaluating all arguments 'til the first fails, then nil-ing the rest. The problem with this is, that it throws away values which could be useful. -- Moritz Ulrich -- 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 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
Re: docstrings of if-let and when-let incorrect
On Wednesday, May 16, 2012 9:16:29 AM UTC-4, Aaron Cohen wrote: Saying something is obvious and then using the word monad a paragraph later is contradictory. ;) What should happen on the else branch of the if-let; which bindings are in scope and what would be their values? None of the bindings should be available in the else branch, since there would be no way to know which will succeed before run-time. -Walter -- 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
Re: docstrings of if-let and when-let incorrect
On Wed, May 16, 2012 at 9:16 AM, Aaron Cohen aa...@assonance.org wrote: On Wed, May 16, 2012 at 9:10 AM, Walter Tetzner robot.ninja.saus...@gmail.com wrote: To make the bindings work like let, where later bindings can see previous bindings, I think the most natural way to do it is to have the bindings behave like the maybe monad. [...] Saying something is obvious and then using the word monad a paragraph later is contradictory. ;) Hypothetically, this is obvious, unlike most monads. Zing! What should happen on the else branch of the if-let; which bindings are in scope and what would be their values? None of the bindings should be in scope. - Dan C. -- 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
Re: docstrings of if-let and when-let incorrect
I've also attempted to use if/when-let with multiple bindings in the past. I assumed that it would behave as 'AND' and that no bindings would be available in 'else' Cheers, Jay On Wed, May 16, 2012 at 10:29 AM, Dan Cross cro...@gmail.com wrote: On Wed, May 16, 2012 at 9:16 AM, Aaron Cohen aa...@assonance.org wrote: On Wed, May 16, 2012 at 9:10 AM, Walter Tetzner robot.ninja.saus...@gmail.com wrote: To make the bindings work like let, where later bindings can see previous bindings, I think the most natural way to do it is to have the bindings behave like the maybe monad. [...] Saying something is obvious and then using the word monad a paragraph later is contradictory. ;) Hypothetically, this is obvious, unlike most monads. Zing! What should happen on the else branch of the if-let; which bindings are in scope and what would be their values? None of the bindings should be in scope. - Dan C. -- 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 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
Re: docstrings of if-let and when-let incorrect
I too assumed that if/when-let would support multiple bindings, short- circuiting if one failed, when I started learning Clojure. It seems that short-circuiting multiple bindings isn't surprising. On May 16, 10:56 am, Jay Fields j...@jayfields.com wrote: I've also attempted to use if/when-let with multiple bindings in the past. I assumed that it would behave as 'AND' and that no bindings would be available in 'else' Cheers, Jay On Wed, May 16, 2012 at 10:29 AM, Dan Cross cro...@gmail.com wrote: On Wed, May 16, 2012 at 9:16 AM, Aaron Cohen aa...@assonance.org wrote: On Wed, May 16, 2012 at 9:10 AM, Walter Tetzner robot.ninja.saus...@gmail.com wrote: To make the bindings work like let, where later bindings can see previous bindings, I think the most natural way to do it is to have the bindings behave like the maybe monad. [...] Saying something is obvious and then using the word monad a paragraph later is contradictory. ;) Hypothetically, this is obvious, unlike most monads. Zing! What should happen on the else branch of the if-let; which bindings are in scope and what would be their values? None of the bindings should be in scope. - Dan C. -- 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 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
Re: docstrings of if-let and when-let incorrect
Reasonable enough. Patch welcome. -S -- 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
Re: docstrings of if-let and when-let incorrect
Or maybe if-let and when-let should support multiple bindings, like the doc states. воскресенье, 13 мая 2012 г., 4:55:40 UTC+6 пользователь Borkdude написал: The docstring of if-let is as follows: bindings = binding-form test If test is true, evaluates then with binding-form bound to the value of test, if not, yields else I think it should be mentioned in the docs that if-let and when-let support only *one binding*, not multiple bindings (like for example https://www.refheap.com/paste/2700). Kind regards, Michiel -- 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
Re: docstrings of if-let and when-let incorrect
I tried using if-let with multiple binding in past as well. Following least surprise principle, I would like to see support for multiple bindings. Cheers, Hubert. Vinzent mailto:ru.vinz...@gmail.com May 15, 2012 5:47 PM Or maybe if-let and when-let should support multiple bindings, like the doc states. воскресенье, 13 мая 2012 г., 4:55:40 UTC+6 пользователь Borkdude написал: -- 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 Borkdude mailto:michielbork...@gmail.com May 13, 2012 12:55 AM The docstring of if-let is as follows: bindings = binding-form test If test is true, evaluates then with binding-form bound to the value of test, if not, yields else I think it should be mentioned in the docs that if-let and when-let support only /one binding/, not multiple bindings (like for example https://www.refheap.com/paste/2700). Kind regards, Michiel -- 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 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=eninline: compose-unknown-contact.jpginline: postbox-contact.jpg
Re: docstrings of if-let and when-let incorrect
If if-let and when-let don't get support for multiple bindings, you could try https://github.com/egamble/let-else . On Tuesday, May 15, 2012 12:09:08 PM UTC-7, Hubert Iwaniuk wrote: I tried using if-let with multiple binding in past as well. Following least surprise principle, I would like to see support for multiple bindings. Cheers, Hubert -- 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
Re: docstrings of if-let and when-let incorrect
Does the principle of least surprise suggest that multiple bindings be combined with AND or OR? --Aaron On Tue, May 15, 2012 at 3:09 PM, Hubert Iwaniuk neo...@kungfoo.pl wrote: I tried using if-let with multiple binding in past as well. Following least surprise principle, I would like to see support for multiple bindings. Cheers, Hubert. Vinzent ru.vinz...@gmail.com May 15, 2012 5:47 PM Or maybe if-let and when-let should support multiple bindings, like the doc states. воскресенье, 13 мая 2012 г., 4:55:40 UTC+6 пользователь Borkdude написал: -- 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 Borkdude michielbork...@gmail.com May 13, 2012 12:55 AM The docstring of if-let is as follows: bindings = binding-form test If test is true, evaluates then with binding-form bound to the value of test, if not, yields else I think it should be mentioned in the docs that if-let and when-let support only *one binding*, not multiple bindings (like for example https://www.refheap.com/paste/2700). Kind regards, Michiel -- 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 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 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=encompose-unknown-contact.jpgpostbox-contact.jpg
Re: docstrings of if-let and when-let incorrect
On Tuesday, May 15, 2012 3:26:52 PM UTC-4, Aaron Cohen wrote: Does the principle of least surprise suggest that multiple bindings be combined with AND or OR? For `when-let', I would expect it to work like nested when-lets: (when-let [x (exp-1) y (exp-2 x) z (exp-3 y)] [x y z]) would be the same as (when-let [x (exp-1)] (when-let [y (exp-2 x)] (when-let [z (exp-3 y)] [x y z]))) For the behavior of `if-let' to not be suprising given this definition of `when-let', I think it would have to behave similarily: (if-let [x (exp-1) y (exp-2 x) z (exp-3 y)] [x y z] 'failed) would be the same as (if-let [x (exp-1)] (if-let [y (exp-2 x)] (if-let [z (exp-3 y)] [x y z] 'failed) 'failed) 'failed) So, AND I guess. But later expressions can refer to earlier ones, just like in `let'. -- 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
Re: docstrings of if-let and when-let incorrect
On Tue, May 15, 2012 at 3:26 PM, Aaron Cohen aa...@assonance.org wrote: Does the principle of least surprise suggest that multiple bindings be combined with AND or OR? My own personal opinion is that it makes sense in combination with 'and', but others may feel differently. E.g., (when-let [a (allocate-thing) b (read-into-thing a) c (extract-something-from-thing b)] (do-something-with c)) makes intuitive sense to me. If, at any stage of the execution, any of a, b or c was nil, the evaluation would stop and the (when-let) form would return nil. - Dan C. -- 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
Re: docstrings of if-let and when-let incorrect
On Tuesday, May 15, 2012 3:41:58 PM UTC-4, Dan Cross wrote: My own personal opinion is that it makes sense in combination with 'and', but others may feel differently. E.g., (when-let [a (allocate-thing) b (read-into-thing a) c (extract-something-from-thing b)] (do-something-with c)) makes intuitive sense to me. If, at any stage of the execution, any of a, b or c was nil, the evaluation would stop and the (when-let) form would return nil. So judging by both your response and my response, it should behave like the maybe monad. -Walter -- 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
Re: docstrings of if-let and when-let incorrect
If if-let/when-let had multiple bindings, how would you propose to define the condition of whether to do the then branch? As the logical AND of all of the multiple forms? The OR? Only use the first expression? Only the last? I don't see that any of those is any more clear or least surprising than any of the others. Permitting only one makes that part of the behavior clear, at least. Andy On May 15, 2012, at 12:09 PM, Hubert Iwaniuk wrote: I tried using if-let with multiple binding in past as well. Following least surprise principle, I would like to see support for multiple bindings. Cheers, Hubert. Vinzent May 15, 2012 5:47 PM Or maybe if-let and when-let should support multiple bindings, like the doc states. -- 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=eninline: compose-unknown-contact.jpg
Re: docstrings of if-let and when-let incorrect
On May 15, 2012, at 3:15 PM, Andy Fingerhut wrote: If if-let/when-let had multiple bindings, how would you propose to define the condition of whether to do the then branch? As the logical AND of all of the multiple forms? The OR? Only use the first expression? Only the last? I don't see that any of those is any more clear or least surprising than any of the others. Permitting only one makes that part of the behavior clear, at least. AND is the obvious choice, IMO. People will probably still have to look up what happens with multiple bindings from time to time, but that doesn't seem worse than having to look up whether if-let and when-let even support multiple bindings. -- 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
Re: docstrings of if-let and when-let incorrect
On Tue, May 15, 2012 at 3:47 PM, Walter Tetzner robot.ninja.saus...@gmail.com wrote: On Tuesday, May 15, 2012 3:41:58 PM UTC-4, Dan Cross wrote: My own personal opinion is that it makes sense in combination with 'and', but others may feel differently. E.g., (when-let [a (allocate-thing) b (read-into-thing a) c (extract-something-from-thing b)] (do-something-with c)) makes intuitive sense to me. If, at any stage of the execution, any of a, b or c was nil, the evaluation would stop and the (when-let) form would return nil. So judging by both your response and my response, it should behave like the maybe monad. Yes, that's a very good characterization. - Dan C. -- 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
docstrings of if-let and when-let incorrect
The docstring of if-let is as follows: bindings = binding-form test If test is true, evaluates then with binding-form bound to the value of test, if not, yields else I think it should be mentioned in the docs that if-let and when-let support only *one binding*, not multiple bindings (like for example https://www.refheap.com/paste/2700). Kind regards, Michiel -- 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
