Re: ob-java compile only

[ian martins]

Thanks for explaining. That makes sense.

I'm hesitant to add the compile-only header for a couple reasons. Generally C-c C-c on a source block means "run this" but with compile-only it'll mean "run this but don't run it." It's semantically inconsistent. Also I want to bring more feature parity to ob-java, so that there's more consistency across babel. I'm reluctant to add headers not found elsewhere.

Consider some alternatives:

1. one option is to add a dummy main to every class. it could do nothing or run unit tests. it's not a bad place to kick off unit tests, but I don't think you should have to.

2. you could use org-babel-tangle to write out the source files, and compile from an emacs compile buffer. this might be more convenient than compiling from babel since recompiles are a single keystroke.

3. a future version of ob-java will know if a class has a "public static void main." at that point it'll be easy to automatically skip execution of the class if it doesn't define a main, without the need for a new header.

On Mon, Sep 28, 2020 at 4:11 AM John Herrlin <jherrlin@gmail.com> wrote:

Hey Ian,

Thank you for the quick feedback!

That workflow seems to work perfectly if it's Java all the way. Then it
compiles all the related files. I am mostly working with the classes
from Clojure.

Here is an example:

   #+HEADER: :classname se/my_test_package/Hey
   #+HEADER: :compile-only t
   #+HEADER: :results none
   #+HEADER: :dir src
   #+BEGIN_SRC java
     package se.my_test_package;

     public class Hey {
         public static String hey(String name) {
             return "Hey " + name;
         }
     }
   #+END_SRC

   #+BEGIN_SRC clojure :results output code
     (import [se.my_test_package Hey])

     (Hey/hey "John")
   #+END_SRC


Best regards



ian martins <ianxm@jhu.edu> writes:

> Hi John,
>
> Thanks for the suggestion and patch. Is the reason for this so that you can
> have classes without needing dummy "main" methods?
>
> Did you consider using org-babel-tangle to generate the source files? This
> works for me:
>
> Steps:
> 1. put javatangle.org (below) on your local.
> 2. create "pkg" directory where javatangle.org is
> 3. run org-babel-tangle on javatangle.org (this writes two source files to
> the pkg dir)
> 4. run C-c C-c on the top source block (this compiles both source files and
> runs main)
>
> ----- javatangle.org -----
>
> #+begin_src java :results output :classname pkg/Main :tangle pkg/Main.java
>   package pkg;
>
>   public class Main {
>       public static void main(String[] args) {
>           System.out.println(Hey.hey());
>       }
>   }
> #+end_src
>
> #+begin_src java :results output :classname pkg/Hey :tangle pkg/Hey.java
>   package pkg;
>
>   public class Hey {
>       public static String hey() {
>           return "hey";
>       }
>   }
> #+end_src
>
>
>
> On Sun, Sep 27, 2020 at 5:19 PM John Herrlin <jherrlin@gmail.com> wrote:
>
>>
>> Hey Ian!
>>
>> Happy to see you as the maintainer of the ob-java!
>>
>> I would like to propose a feature to ob-java. The feature allows a
>> source code block to write and compile only, without executing.
>>
>> Here is a common use case for me.
>>
>> Class without a entry point have an :compile-only header.
>>
>>    #+HEADER: :classname se/my_test_package/Hey
>>    #+HEADER: :dir src
>>    #+HEADER: :compile-only t
>>    #+HEADER: :results none
>>    #+BEGIN_SRC java
>>      package se.my_test_package;
>>
>>      public class Hey {
>>          public static String hey(String name) {
>>              return "Hey " + name;
>>          }
>>      }
>>    #+END_SRC
>>
>> The provided diff works for my small use case. What do you think?
>>
>> --
>> Best regards
>> John
>>
>>


--
Mvh John