I want a C routine, which is supplied with an Eiffel 'agent' to call the routine 'apply' in the class PROCEDURE.

int c_nng_aio_set_procedure_target(void *item, EIF_OBJECT target) {
    void **pptr = (void **) (item);
    EIF_TYPE_ID type_id;    /* Eiffel type identifier for class `class_name' */
    EIF_PROCEDURE e_proc;   /* Eiffel procedure `proc_name' */
    EIF_PROCEDURE *p_proc;
    EIF_OBJECT *p_object;

    type_id = eif_type (target);
    if (type_id == EIF_NO_TYPE) {
        printf ("PROCEDURE type_id not found\n");
        return (0);
    }
    e_proc = eif_procedure ("apply", type_id);
    if (e_proc == (EIF_PROCEDURE) 0) {
        printf ("'apply' procedure not found\n");
        return (0);
    }
    
    /* Success in finding procedure address, */
    /* now store that and the target into the storage block */
    pptr[4] = e_proc;
    pptr[5] = target;
    return (1);
}

My code currently prints [as above] that the 'apply' procedure is not found.

I have ensured that 'apply' is used from within the Eiffel code [apply_check is called]:

report_completion
    do
        print ("report_completion ... OK%N")
    end

apply_check
    local
        p: PROCEDURE
    do
        p := agent report_completion
        p.apply
    end

Any ideas ?

I am hoping to create some software with Eiffel & Eiffel Studio

I have a Mac mini with the Apple M1 Arm Processor.

Is there a port of EiffelStudio to native Mac M1?

Does Eiffel Studio support native MacOS Windowing or is it still requiring Windows?

How to produce the Finalized executable with contract checking enabled? It is possible to keep the check statements intact, but can we keep all the pre/postconditions and class invariants?

I need this for testing a computationally expensive application and frozen with contracts executable is a bit too slow in my case.

When implementing a recursive data structure like TREE, I need a common attribute per TREE, and I wonder how to implement it:

• Adding the attribute to a TREE node, replicates the attribute for every node, not once per TREE
• Using a once attribute, I get only one shared attribute for all TREEs, not one per TREE.

Is there any elegant Eiffel-style solution for that?

I was trying to have a structure which talks himself about variants and invariants into Eiffel loops, but don't understand the variant part!

from
    l_array := <<1,2,30,60>>
    l_index := l_array.lower
invariant
    valid_local_index: l_array.valid_index (l_index) or l_index = l_array.upper + 1
until
    l_index > l_array.upper
loop
    l_item := l_array.item (l_index)
    l_index := l_index + 1
variant
    --l_index <= l_array.upper -- will never be false
    --l_index -- doesnt work
end

Discovering late (used to define classes instead) TUPLES and looking through the documentation I was wondering if there is a mechanism to get the right type of a given TUPLE. The goal is both anchoring its types and avoid having to test its type before getting an item. Is there a language mechanism?

I also found few documentation about them, maybe I'm not looking at the right place.

For the following code I'd like to tell like tuple_items.types[1] and tuple_items.typed_item (1)

use_it
    do
        if attached {STRING} tuple_items.item (1) as l_tuple_item_1 then
            io.put_string (l_tuple_item_1)
        end
        if attached {DATE} tuple_items.item (1) as l_tuple_item_2 then
            io.put_string (l_tuple_item_2.out)
        end
        - ...
    end

tuple_items: TUPLE[STRING, DATE, INTEGER]
    local
        l_first: STRING -- like tuple_items.first?
    do
        Result := [l_first, create {DATE}.make_now, 1]
    end

how would you calculate the number of seconds since epoch in eiffel for a DATE_TIME object?

What is the proper way to do it with the current libraries?

I have the following Eiffel code. I am doing test-driven-design with contracts.

check
    sorter.sorted (<<1>>).is_equal (<<1>>)
end

The code correctly detects that my sort returns the wrong value. However it would be nice to see what sorted returned. I can see that it is too late as is_equals consumes both values, and returns false, before the check throws the exception.

I have seen in other testing frameworks they have a special is_equal for the test framework. That allows better feedback. e.g.

check_equal(expected, value_under_test)

Is there anything like this in eiffel?

Let's say that I have a function f which should return an attached T by calling g. However, g returns a detachable T. If g results in a Void, I want to raise an exception like this:

f: T
  do
    if attached g as res then
      Result := res
    else
      raise
    end
  end
  
raise
  do
    (create {DEVELOPER_EXCEPTION}).raise
  end

In this setup EiffelStudio gives me an error VEVI: Variable is not properly set. Variable: Result at the end of f.

Indeed, Result can be Void at the end of f but the execution should not reach the end of f in this case, an exception should have been raised.

How can I restructure the code to achieve a similar result?

Is there a way in Eiffel to exit a program, possible with a defined exit code like exit in C?

In my case I would like to just end the program like exit(0) would do.

I'm looking how to get a custom header value from a received WSF_REQUEST. I read the docs quickly and didn't find the answer.

'Authorization': 'Bearer my_long_token'

How do I raise an exception further in eiffel? I have 3 cases

1. I want to retry

   a_feature
       local
           l_retries_count: INTEGER
       do
           some_potential_failing_feature
       rescue
           if l_retries_count <= 3 then
               l_retries_count := l_retries_count + 1
               retry
           end
       end
   

2. I want to do close db connection and ignore exception

   a_feature
       do
           some_potential_failing_feature
       rescue
           db_connection.close
       end
   

3. I want to do close db connection and send an email to an admin and ignore

   a_feature
       do
           some_potential_failing_feature
       rescue
           db_connection.close
           send_email_to_admin
       end
   

4. I want to close db_connection and raise the exception further, I'll put all the cases I can think about into the above code

   a_feature
       local
           l_retries_count: INTEGER
       do
           some_potential_failing_feature
       rescue
           if l_retries_count <= 3 then
               l_retries_count := l_retries_count + 1
               log_error ("Error, retrying for " + l_retries_count.out + "th time")
               retry
           else
               db_connection.close
               send_email_to_admin
               -- raise the_created_exception_from_some_potential_failing_feature -- how do I do that?
           end
       end
   

I want to make a derived class of HASH_TABLE which implements a few additional features. I tried implementing it like this:

class HASH_TABLE2[G->HASHABLE]
inherit
    HASH_TABLE[G,G]
        rename
            make as make_2
        end
create
    make
feature
    make (capacity_ : INTEGER)
        do
            make_2(capacity_)
        end
end

I get this error:

Error: Creation instruction uses call to improper feature.

Feature name: make_2 (n: INTEGER_32)
Line: 1156
      do
->      create Result.make (n)
        if object_comparison then

I don't understand why. If I do the same with inherit ARRAY[G], then it works fine.

After installing EiffelStudio I can't compile and run any project because I always get VD43 warning and C Compiler Error.

2   VD43    Precompiled file is missing or unreadable. File 'c:\users\username\documents\eiffel user files\19.05\precomp\spec\win64\EIFGENs\base-scoop-safe\W_code\msc_vc140\driver.exe'.   

        
1   C Compiler Error    Please review the External Compilation output of the Outputs Tool.              
    Error code: C Compiler Error

Error: External C/C++ compilation failed.
What to do: Check the external C/C++ compilation for details.

Please review the External Compilation output of the Outputs Tool.  

        

I found this page: https://www.eiffel.org/doc/version/trunk/faq/FAQ. The key ISE_C_COMPILER must be additionally defined in order for EiffelStudio to work at all. But how does one "Tell EiffelStudio to use Visual Studio 2017-compatible libraries"? I tried setting it as an environment variable, and changing the compile_library.bat and esvars.bat, so that in every place it's set ISE_C_COMPILER=msc_vc140. I also added variable ISE_C_COMPILER - msc_vc140 on the EiffelStudio GUI, under Project->Project Settings->Target:project->Advanced->Variables

I deleted all the projects and the precomp folder. I ran espawn -l just to verify that I have the good c++ compiler:

Available C/C++ compilers:

   VC160:  Microsoft Visual Studio 2019 VC++ (19.0)
   VC150:  Microsoft Visual Studio 2017 VC++ (15.0)

To me it seems that I installed everything and I set every variable but it still gives me the same warning and error.

Into my EWF_APP[EWF_APP_EXECUTION] the EWF_APP_EXECUTION inherits from WSF_FILTERED_ROUTED_EXECUTION defining setup_router.

To be able to access informations globally by thread (as far as I understand the implementation also SCOOP region in this case), I have defined a {MY_APPLICATION_ENVIRONMENT}.app_instance which is once (by default, thread). This app_instance as a handlers: LINKED_LIST[MY_HANDLER] which is also a once and by that mecanism I'm able to access a handler instance to get some polymorphic item_prototype I reuse into my business.

I also do the same mecanism with db_services: LINKED_LIST[DB_SERVICE[DB_ENTITY]] to be able to get a DB_SERVICE from its DB_ENTITY name.

With the above mecanism so far, only into the {EWF_APP_EXECUTION}.setup_router I create the db services, handlers, and extend the thread app_instance.

I figured out that the setup_router being called on each request, my handlers and db_services collections into {MY_APPLICATION_ENVIRONMENT}.app_instance grows up infinitly causing memory leaks.

What would be the best strategy on this case? is it doable on this context as the router seems to be recreated on every request to setup the router with the existing handlers?

Hoping I made me clear enough...

I tried to enable the debug syntax into estudio without afording it. In this case it is from a library and it doesnt enter into the

debug
     io.put_string ("any debug statement here")
end

What's wrong with my configuration?

Running a debug session with estudio with all assertions set to true (I checked into cluster, common target, specific target, etc.) pass over a check assertion?

I also tried to remove EIFGENs and recompile the whole project.

Inheriting from WSF_FILTERED_ROUTER_EXECUTION I redefine the clean to be able to close DB Connections. But when there is an assertion failure, I don't know where to call the clean on a rescue clause. In which feature do I have to call my clean on a rescue clause??

When to use which type of STRING in eiffel? I saw using READABLE_STRING_GENERAL and having to l_readable_string.out' to convert it to STRING`

how would you calculate the number of seconds since epoch in eiffel for a DATE_TIME object?

What is in eiffel the best way to have a constant which can be redefined?

• class A => color: STRING = "green"
• color B inherit A => cannot redefine

while having a function which only returns "green" or "blue" needs the string to be created again, performance problem or doesnt matter?

As far as I understood, the onces cannot be redeclared...

How to deal with cluster has two classes with the same name with eiffel studio?

when I want to choose between 2 versions? Where can I find documentation about that?

Think that there is a trick with sources->renaming

Sometimes the checks and contract constructions need an elaboration which wants to be avoided when assertions removed to improve performances and avoid doing useless things with the "only" work of the compiler. I refer for ex. to job in loops checks or other things. Sometimes having to build a function or having to think how to build it without being executed when assertions are on goes away of the intuitive way of the contract and its sense. I refer particularly to the check structure

Is there a way to do something such as

if checks_are_enabled then
    do check stuff here
end
do_some_normal_job
if checks_are_enabled then
    do other check stuff here
end

I am trying to iterate an array in Eiffel. And select some elements, using do_if.

What I have tried.

my_method (list:ARRAY[INTEGER])
    local
        low : ARRAYED_LIST[INTEGER]
        piv : INTEGER
    do
    create low.make(0)

    --works for all, but not what I need
    list.do_all ( agent low.extend )
    --I can't get these to work
    list.do_if ( agent low.extend, agent piv > ? )
    list.do_if ( agent low.extend, agent piv.is_greater_equal (?) )
    list.do_if ( agent low.extend, agent piv.is_greater_equal )
    list.do_if ( agent low.extend, agent (v:INTEGER):BOOLEAN do Result := v<piv end )

I know why the last one does not work (piv is in outer scope), but not how to fix. I don't know why the others don't work.

Version = EiffelStudio 19.5 (19.05.10.3187 GPL Edition - linux-x86-64)

I didn't find the documentation about the difference between is and as

I'd like to implement an iterator something similar to this MAP, I'd like to know what TYPE is returned with the is keyword and with the as one.

• I think the is will be the item of the ITERATION_CURSOR [G] class
• Does the as return an ITERATION_CURSOR [G] which would be like {ITERABLE}.new_cursor of ITERABLE[G]?