Path: utzoo!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!mailrus!ncar!boulder!ccncsu!sor.CS.ColoState.Edu!wongkc
From: wongkc@sor.CS.ColoState.Edu (kam chooi wong)
Newsgroups: comp.lang.eiffel
Subject: class environment, suffix .env
Message-ID: <5193@ccncsu.ColoState.EDU>
Date: 8 Mar 90 20:03:43 GMT
Sender: news@ccncsu.ColoState.EDU
Reply-To: wongkc@sor.CS.ColoState.Edu (kam chooi wong)
Organization: Colorado State University, Ft. Collins CO 80523
Lines: 37


I was using the ENVIRONMENT class in Eiffel and discovered some
misleading/incorrect descriptions in the Eiffel Language Manual.
On page 188, the example code shows in order to store
persistent objects and associate  them with an environment, 

   ....(env and ext_file declared here)

    env.Create;                   -- create an environment
    ext_file.Create("session1.S"); -- create a  file to be
                             -- associated with the environment
    ext_file.open_write;
    env.set_file(file1);     -- associate file with environment
    env.store_on_end;

   ....(some other manipulations)

(1) The suffix ".S" as in the "session1.S" file  should really 
    be ".ENV". The file1 variable listed above in the example 
    should really  be ext_file.

(2) There is no information in the Language manual or in the
    Library manual that hints at the required ".ENV" suffix.
    I had to look at the online ENVIRONMENT.E code file 
    under the installed Eiffel's library/support subdirectory 
    to find out why I got the run-time error in my own 
    program. One of the preconditions (in the require clause)
    of the set_file feature in class ENVIRONMENT is good_suffix 
    which is an instance of the boolean routine is_env_of(f: file). 
    A short on the class ENVIRONMENT does not reveal the 
    precondition  "good_suffix" nor the "is_env_of(f)" routine 
    as this is a non-exported feature.

If I am missing something altogether, I appreciate people letting
me know. Otherwise, I would like to suggest that there should be 
some documentation on such "secret"  required features and their 
semantics in the relevant chapters in future updates of the manuals.