Re: Intro for newbie

[Paolo Redælli]

Il 17/04/20 11:57, Oleg Terentiev ha scritto:

Hello.

 

I'd want to meet eiffel. One person takes me one project on Eiffel and I trying build this one. I am absolutely newbie in Eiffel but have some skills in general (C, python, VHDL ).

Lot of programmers liten about eiffel, but nobody who tryied to use it. First my question - how to use external C prorams?

There are two separate mechanics to interface with another language such as C.

The first one belongs to another era, predating the creation of Java, when Windows was at release 3.11 or something like this. It is the external "C" or external "C++". It is detailed in the standard but it is quite limited, to the point that Andreas Leitner many years ago built an entire pre-processor program to deal with it.

You can read about them at https://wiki.liberty-eiffel.org/index.php/Externals where you see that we propose a "plug-in" approach, detailed in https://wiki.liberty-eiffel.org/index.php/Plugins

For example - I have some interface like void generate(char* ); and what should I do next?

    You write something like 
feature {} -- Implementation
 generate (a_char: POINTER) 
  external "C the_header_where_generate_is_declared.h"
  end
feature -- public interface
  my_generate (a_string: ABSTRACT_STRING) 
  do 
     generate(a_string.to_external)
  end

or you use my wrappers_generator tool. :)

I see how I left fading my tools reading its README which refers to Ubuntu **ten**

wrappers_generator read the output of castxml which produces an xml description of C/C++ code. This way we can automatically generate low-level wrappers which we use to write high-level interface to external libraries.

How to say where placed C-sources, headers and other classes on my filesystem?

    You place a libs file in the directory of the plugin.

I have read about c_include_c and c_include_h but it isn't clean for me. Can you explain me litle bit more?

I would suggest to avoid it. Try reading https://github.com/LibertyEiffel/Liberty/tree/master/src/wrappers/readline it's short enough to be understandable but it is fully usable. It uses wrappers_generator