RE: [eiffel-users] Error: variable is not properly set. Attribute(s):name

[r...@amalasoft.com]

The 'name' feature (a STRING attribute) has not been instantiated, and as such violates Void-safety rules.  It must be instantiated (either created or have a non-Void reference attached to it) by the end of the creation sequence of PERSON to be Void-safe.

If you are OK with it being Void some of the time, then mark it as detachable

 

...

name: detachable STRING

...

 

OR, add a form of attachment or instantiation to the creation sequence

 

class PERSON

 

create

    make_with_name

 

feature

    make_with_name (v: like name)

        do

            name := v

        end

...

 

OR perhaps

 

class PERSON

 

inherit

    ANY

        redefine

            default_create

        end 

 

feature

 

    default_create

        do

            create name.make (0)

            Precursor

        end 

...

 

R   

 

-------- Original Message --------
Subject: [eiffel-users] Error: variable is not properly set.
Attribute(s):name
From: Сергей Владимирович <sch...@gmail.com>
Date: Wed, March 21, 2018 9:40 am
To: Eiffel Users <eiffel...@googlegroups.com>

class PERSON

feature

name: STRING

age: INTEGER

end


what am I doing wrong?

Installation information:
Version = EiffelStudio 18.1 (18.01.10.1424 GPL Edition - win64)
$ISE_EIFFEL = D:\eiffel
$ISE_LIBRARY = D:\eiffel
$ISE_PLATFORM = win64
$ISE_C_COMPILER = mingw

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[Alexander Kogtenkov]

The error says that the attribute `name` should be set after the object creation, because its type is attached. There are several ways to solve the issue:

1. Mark all reference attributes as detachable:

   class PERSON
        name: detachable STRING
        age: INTEGER
   end

2. Mark the class as deferred, so that no instances of it could be created:

   deferred class PERSON

        name: STRING
        age: INTEGER
   end

3. Add a default creation procedure that initializes the attribute:

   class PERSON inherit ANY redefine default_create end feature

      default_create do name := "" end

      name: STRING
      age: INTEGER
   end

4. Add a creation procedure that will be used to initialize the object:

   class PERSON create make feature
      make (n: like name; y: like age)
         do
            name := n
            age := y
         end

      name: STRING
      age: INTEGER
   end

Hope this helps,
Alexander Kogtenkov

Сергей Владимирович <sch...@gmail.com>: