Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!wuarchive!udel!princeton!phoenix!pucc!EGNILGES
From: EGNILGES@pucc.Princeton.EDU (Ed Nilges)
Newsgroups: comp.software-eng
Subject: Re: Experiences with Hungarian Nami
Message-ID: <9513@pucc.Princeton.EDU>
Date: 2 Sep 89 23:23:06 GMT
References: <974@swdev.waterloo.ncr.com> <138300002@cdp>
Reply-To: EGNILGES@pucc.Princeton.EDU
Organization: Princeton University, NJ
Lines: 43
Disclaimer: Author bears full responsibility for contents of this article

I have been following the discussion of Hungarian notation with some
interest.  Actually, the idea is not new: I read an IBM standards
textbook which enjoined something of the same practice, reflecting
data types in data names, on Assembler programmers.

I much prefer a notation which prefixes each variable by a Dewey
Decimal code reflecting the position of the variable's owner in
the program...if routine "aa" declares and uses a variable length,
then the name of the variable becomes aa_length.  Where the overall
architecture of the program is a hierarchy (frequently the case in
business programming, less often the case in scientific or systems
programming), then the Dewey Decimal code accurately reflects the
variable's owner, and the owner's position in the hierarchy:

     a_mainline owns a_i, a_j, and calls
          aa_read_parms, which owns aa_parmcount
          ab_read_next, which calls
               aba_check_next
     .
     .
     .

Where routines crop up that violate the hierarchy, they get prefixes
from the end of the alphabet.  Again, such routines arise more
frequently in scientific, systems software, and event-driven
routines...note that the above is probably a simple batch application.
However, in nontraditional code, there are frequently mini-hierarchies,
miniature city-states of code that are called in a complicated
network, but have themselves a hierarchical structure.

Hungarian notation is a threat to effective maintenance because
incompetent (or simply under-informed) maintainers may make changes
that invalidate the information contained in Hungarian notation.
Of course, the same charge applies to Dewey Decimal notation or
indeed any friendly attempt to document one's code.  My (quite
unscientific) personal observation has been that the sort of
design changes that invalidate the architectural information
provided by Dewey Decimal notation are much less frequent than
the sort of implementation changes that invalidate Hungarian notation.
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"Oh, I could prophesy: but thou art dust, Harry, and food for..."

- Henry IV, Part II