Weird behavior with syntax error: all-underscore identifier used as rvalue

Question

Weird behavior with syntax error: all-underscore identifier used as rvalue

spirosbax opened this issue 5 years ago · 7 comments

First of all let me say that this package has implemented almost the perfect version of the pipeline operator. Thank you. However I started using it today and noticed this very weird behavior. Observe:

Let br be a list of elements. Countmap creates frequency => value pairs and is defined in the Statsbase package.
@hose br |> countmap |> collect .|> (x->tuple(x...)) |> sort(by=last,rev=true)
The above works as expected. Producing a sorted list of tuples in reverse order. However if I add a filter in front:
@hose br |> filter(x->x!=0,_) |> countmap |> collect .|> (x->tuple(x...)) |> sort(by=last,rev=true)
It fails with error:

syntax: all-underscore identifier used as rvalue around In[107]:1 Stacktrace: [1] top-level scope at /home/spiros/.julia/packages/IJulia/F1GUo/src/kernel.jl:52

If then, I remove the .|> operator as such:
@hose br |> filter(x->x!=0,_) |> countmap |> collect |> sort(by=last,rev=true)
It works and produces an array of pairs. It seems to me than the .|> operator and the filter function cannot coexist when using the @hose macro.
Can you shed some light into this issue ?

Answer 1 · 2020-02-17T19:14:00.000Z

Hello. Thanks for your kind words. Have you tried expanding the macros and see where exactly the problem happens in the actual code that gets generated? Unfortunately, I don't have the time to go in the weeds with you. I really haven't considered the .|> operator at all when developing the package - it's not used at all in any of the tests. If you find what causes the problem, let me know Good luck (and have fun).

…

On Fri, 14 Feb 2020 at 18:29, Spiros Baxevanakis ***@***.***> wrote: First of all let me say that this package has implemented almost the perfect version of the pipeline operator. Thank you. However I started using it today and noticed this very weird behavior. Observe: Let br be a list of elements. Countmap creates frequency => value pairs and is defined in the Statsbase package. @hose br |> countmap |> collect .|> (x->tuple(x...)) |> sort(by=last,rev=true) The above works as expected. Producing a sorted list of tuples in reverse order. However if I add a filter in front: @hose br |> filter(x->x!=0,_) |> countmap |> collect .|> (x->tuple(x...)) |> sort(by=last,rev=true) It fails with error: syntax: all-underscore identifier used as rvalue around In[107]:1 Stacktrace: [1] top-level scope at /home/spiros/.julia/packages/IJulia/F1GUo/src/kernel.jl:52 If then, I remove the .|> operator as such: @hose br |> filter(x->x!=0,_) |> countmap |> collect |> sort(by=last,rev=true) It works and produces an array of pairs. It seems to me than the .|> operator and the filter function cannot coexist when using the @hose macro. Can you shed some light into this issue ? — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#3?email_source=notifications&email_token=AAUZ6A3S23VGO2KJJC742C3RC3II3A5CNFSM4KVMQQK2YY3PNVWWK3TUL52HS4DFUVEXG43VMWVGG33NNVSW45C7NFSM4INUIEVA>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAUZ6A4GCHXAERJ4R36FVRTRC3II3ANCNFSM4KVMQQKQ> .

Answer 2 · 2020-02-18T11:47:16.000Z

Hi,
I have implemented locally a change in the code that allows for the correct use of the .|> operator. Basically I just modified the functions to recognize when the operator is a .|> rather than |> in which case it just produces broadcast(ff,target). I will add some tests and maybe open a pull request.
Will you have the time to review it ?

(PS. What do you think about a name change of this package? I believe that "Hose" does not indicate the functionality of the package and thus it hurts its discoverability. Maybe "Thread" would be better, inspired by Clojure's threading macro.)

Answer 3 · 2020-02-18T14:07:58.000Z

Hi. As long as it doesn't break the current functionality as defined in the tests, I'll be happy to review and accept your pull request. Please, also add some new tests for the dotted operator. Dne út 18. 2. 2020 12:47 uživatel Spiros Baxevanakis < notifications@github.com> napsal:

…

Hi, I have implemented locally a change in the code that allows for the correct use of the .|> . Basically I just modified the functions to recognize when the operator is a .|> rather than |> in which case it just produces broadcast(ff,target) . I will add some tests and maybe open a pull request. Will you have the time to review it ? — You are receiving this because you commented. Reply to this email directly, view it on GitHub <#3?email_source=notifications&email_token=AAUZ6A3J44S4Z5H3FXTQLCTRDPDEJA5CNFSM4KVMQQK2YY3PNVWWK3TUL52HS4DFVREXG43VMVBW63LNMVXHJKTDN5WW2ZLOORPWSZGOEMBVVMA#issuecomment-587422384>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAUZ6AZIQMFNO3ZTIYK3753RDPDEJANCNFSM4KVMQQKQ> .

Answer 4 · 2020-02-23T19:53:45.000Z

Hi, what do you think about my renaming suggestion ?

Answer 5 · 2020-02-23T20:12:29.000Z

Hi. What suggestion? I can't see any pull request. Dne ne 23. 2. 2020 20:53 uživatel Spiros Baxevanakis < notifications@github.com> napsal:

…

Hi, what do you think about my renaming suggestion ? — You are receiving this because you commented. Reply to this email directly, view it on GitHub <#3?email_source=notifications&email_token=AAUZ6A7MJNLUCFSUOQ5ETQDRELH4TA5CNFSM4KVMQQK2YY3PNVWWK3TUL52HS4DFVREXG43VMVBW63LNMVXHJKTDN5WW2ZLOORPWSZGOEMWFRPI#issuecomment-590108861>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAUZ6A6QSUZVHQVJ5OCZRP3RELH4TANCNFSM4KVMQQKQ> .

Answer 6 · 2020-02-23T20:14:32.000Z

Hi,
I have implemented locally a change in the code that allows for the correct use of the .|> operator. Basically I just modified the functions to recognize when the operator is a .|> rather than |> in which case it just produces broadcast(ff,target). I will add some tests and maybe open a pull request.
Will you have the time to review it ?

(PS. What do you think about a name change of this package? I believe that "Hose" does not indicate the functionality of the package and thus it hurts its discoverability. Maybe "Thread" would be better, inspired by Clojure's threading macro.)

I added the suggestion on the bottom of my reply from a couple of days ago.

Answer 7 · 2020-02-23T20:22:56.000Z

Wouldn't that be confusing? The term ‚thread‘ usually refers to threads within a process (as in ‚multi-threading‘). Dne ne 23. 2. 2020 21:14 uživatel Spiros Baxevanakis < notifications@github.com> napsal:

…

Hi, I have implemented locally a change in the code that allows for the correct use of the .|> operator. Basically I just modified the functions to recognize when the operator is a .|> rather than |> in which case it just produces broadcast(ff,target). I will add some tests and maybe open a pull request. Will you have the time to review it ? (PS. What do you think about a name change of this package? I believe that "Hose" does not indicate the functionality of the package and thus it hurts its discoverability. Maybe "Thread" would be better, inspired by Clojure's threading macro.) I added the suggestion on the bottom of my reply from a couple of days ago. — You are receiving this because you commented. Reply to this email directly, view it on GitHub <#3?email_source=notifications&email_token=AAUZ6A7GBS47N7CDRZJY4VTRELKKTA5CNFSM4KVMQQK2YY3PNVWWK3TUL52HS4DFVREXG43VMVBW63LNMVXHJKTDN5WW2ZLOORPWSZGOEMWGBSA#issuecomment-590110920>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAUZ6A45GZIHZLG423Z5DP3RELKKTANCNFSM4KVMQQKQ> .