Please, can you provide a simple example using this pym library?

[microgenios]

Please, can you provide a simple example using this pym library?

[cxw42]

Sure! What's your use case, or what problem are you trying to solve?

[microgenios]

Hi Csw42
I would like that, from a script template, it was possible to generate code in C language, so that in the future it could be compiled into GCC.

I still have difficulties in understanding how it is possible to generate code in C or C++ language, through diagram and flowchart software. I believe that there should be some script in TCL language or shell that receives a script template and replaces it with a code (template) in C.

An example of an application would be the MIT App Inventor, which makes use of some template-based script to generate machine code or in C.

https://community.appinventor.mit.edu/uploads/default/original/2X/b/b374762a9ffd8c570d53ff629331ef233d87b347.jpeg

[microgenios]

Sure! What's your use case, or what problem are you trying to solve?

Hi Csw42
I would like that, from a script template, it was possible to generate code in C language, so that in the future it could be compiled into GCC.

I still have difficulties in understanding how it is possible to generate code in C or C++ language, through diagram and flowchart software. I believe that there should be some script in TCL language or shell that receives a script template and replaces it with a code (template) in C.

An example of an application would be the MIT App Inventor, which makes use of some template-based script to generate machine code or in C.

https://community.appinventor.mit.edu/uploads/default/original/2X/b/b374762a9ffd8c570d53ff629331ef233d87b347.jpeg

[cxw42]

OK - App Inventor (or Scratch, which looks very similar) is a complicated program. It is beyond the scope of pym :) . The general idea is of "fourth-generation languages".

I believe App Inventor is not just a template system. It has a simpler syntax than C. However, you still have to write the loops and other structures just like you would in C.

I have actually written several program generators over the years. They are very rewarding but none of them is short :) . One example is 212 lines of Perl to expand graph constructors. Something like turning

C::compile(...)->C::link(...)->target

into

my $compile = C::compile(...);
my $link = C::link(...);
$compile->connect_to($link);
$link->connect_to(target)

I think you will get to the point where you can write a C-code generator, or adapt Pym (or other template systems) to your needs! I unfortunately can't give you a simple example --- I'm not aware that there is one.

If you want to dive in, one good resource is Crafting Interpreters by Bob Nystrom. He covers programming-language design from the ground up in a very engaging fashion.

[cxw42]

@microgenios I just tripped over another example. This one uses the C preprocessor.

TEST_CASE(test_foo);

expands to

    do { 
        try { 
            LOG_F_DOMAIN(" test", LOG, "=> Starting test %s", #fn); 
            test_foo(); 
            LOG_F_DOMAIN(" test", LOG, "<= Finished test %s", #fn); 
            reached(); 
        } catch(std::exception& e) { 
            LOG_F_DOMAIN(" test", ERROR, "Caught exception: %s", e.what()); 
            unreached(); 
        } catch(...) { 
            LOG_F_DOMAIN(" test", ERROR, "Caught unexpected exception"); 
            unreached(); 
        } 
    } while(0)