I found this on the web and I split a seam laughing....
How To Write Unmaintainable Code
<https://www.doc.ic.ac.uk/%7Esusan/475/index.html>Last updated Thursday,
18-Nov-1999 20:27:28 PDT by Roedy Green
<https://www.doc.ic.ac.uk/%7Esusan/475/index.html#CONTACT> ©1997-1999
Canadian Mind Products.
In the interests of creating employment opportunities in the Java
programming field, I am passing on these tips from the masters on how to
write code that is so difficult to maintain, that the people who come
after you will take years to make even the simplest changes. Further, if
you follow all these rules religiously, you will even guarantee
*yourself* a lifetime of employment, since no one but you has a hope in
hell of maintaining the code.
General Principles
To foil the maintenance programmer, you have to understand how he
thinks. He has your giant program. He has no time to read it all, much
less understand it. He wants to rapidly find the place to make his
change, make it and get out and have no unexpected side effects from the
change.
He views your code through a tube taken from the centre of a roll of
toilet paper. He can only see a tiny piece of your program at a time.
You want to make sure he can never get the big picture from doing that.
You want to make it as hard as possible for him to find the code he is
looking for. But even more important, you want to make it as awkward as
possible for him to safely *ignore* anything.
Specific Techniques
1. Lie in the comments. You don't have to actively lie, just fail to
keep comments as up to date with the code.
2. Pepper the code with comments like /* add 1 to i */ however, never
document wooly stuff like the overall purpose of the package or method.
3. Make sure that every method does a little bit more (or less) than
its name suggests. As a simple example, a method named isValid(x)
should as a side effect convert x to binary and store the result in
a database.
4. Use acronyms to keep the code terse. Real men never define acronyms;
they understand them genetically.
5. In the interests of efficiency, avoid encapsulation. Callers of a
method need all the external clues they can get to remind them how
the method works inside.
6. If, for example, you were writing an airline reservation system,
make sure there are at least 25 places in the code that need to be
modified if you were to add another airline. Never document where
they are. People who come after you have no business modifying your
code without thoroughly understanding every line of it.
7. In the name of efficiency, use cut/paste/clone/modify. This works
much faster than using many small reusable modules.
8. *Never never *put a comment on a variable. Facts about how the
variable is used, its bounds, its legal values, its
implied/displayed number of decimal points, its units of measure,
its display format, its data entry rules (e.g. total fill, must
enter), when its value can be trusted etc. should be gleaned from
the procedural code. If your boss forces you to write comments, lard
method bodies with them, but never comment a variable, not even a
temporary!
9. Try to pack as much as possible into a single line. This saves the
overhead of temporary variables, and makes source files shorter by
eliminating new line characters and white space. Tip: remove all
white space around operators. Good programmers can often hit the 255
character line length limit imposed by some editors. The bonus of
long lines is that programmers who cannot read 6 point type must
scroll to view them.
10. Cd wrttn wtht vwls s mch trsr. When using abbreviations inside
variable or method names, break the boredom with several variants
for the same word, and even spell it out longhand once in while.
This helps defeat those lazy bums who use text search to understand
only some aspect of your program. Consider variant spellings as a
variant on the ploy, e.g. mixing International /colour/, with
American /color/ and dude-speak /kulerz/. If you spell out names in
full, there is only one possible way to spell each name. These are
too easy for the maintenance programmer to remember. Because there
are so many different ways to abbreviate a word, with abbreviations,
you can have several different variables that all have the same
apparent purpose. As an added bonus, the maintenance programmer
might not even notice they are separate variables.
11. Never use an automated source code tidier to keep your code aligned.
Lobby to have them banned them from your company on the grounds they
create false deltas in PVCS (version control tracking) or that every
programmer should have his own indenting style held forever
sacrosanct for any module he wrote. Banning them is quite easy, even
though they save the millions of keystrokes doing manual alignment
and days wasted misinterpreting poorly aligned code. Just insist
that everyone use the *same* tidied format, not just for storing in
the common repository, but while they are editing. This starts an
RWAR and the boss, to keep the peace, will ban automated tidying.
Without automated tidying, you are now free to /accidentally/
misalign the code to give the optical illusion that bodies of loops
and ifs are longer or shorter than they really are, or that else
clauses match a different if than they really do. e.g.
if (a)
if (b) x = y;
else x = z;
12. Never put in any { } surrounding your if/else blocks unless they are
syntactically obligatory. If you have a deeply nested mixture of
if/else statements and blocks, especially with misleading
indentation, you can trip up even an expert maintenance programmer.
13. Rigidly follow the guidelines about no goto, no early returns, and
no labelled breaks especially when you can increase the if/else
nesting depth by at least 5 levels.
14. Use very long variable names that differ from each other by only one
character, or only in upper/lower case. An ideal variable name pair
is /swimmer/ and /swimner/. Exploit the failure of most fonts to
clearly discriminate between ilI1| or oO08 with identifier pairs
like parselnt and parseInt or D0Calc and DOCalc. l is an
exceptionally fine choice for a variable name since it will, to the
casual glance, masquerade as the constant 1. Create varible names
that differ from each other only in case e.g. HashTable and Hashtable.
15. Wherever scope rules permit, reuse existing unrelated variable
names. Similarly, use the same temporary variable for two unrelated
purposes (purporting to save stack slots). For a fiendish variant,
morph the variable, for example, assign a value to a variable at the
top of a very long method, and then somewhere in the middle, change
the meaning of the variable in a subtle way, such as converting it
from a 0-based coordinate to a 1-based coordinate. Be certain not to
document this change in meaning.
16. Use lower case l to indicate long constants. e.g. 10l is more likely
to be mistaken for 101 that 10L is.
17. Ignore the conventions in Java for where to use upper case in
variable and class names i.e. Classes start with upper case,
variables with lower case, constants are all upper case, with
internal words capitalised. After all, Sun does (e.g. instanceof vs
isInstanceOf, Hashtable). Not to worry, the compiler won't even
issue a warning to give you away. If your boss forces you to use the
conventions, when there is any doubt about whether an internal word
should be capitalised, avoid capitalising or make a random choice,
e.g. use both inputFileName and outputfilename. You can of course
drive your team members insane by inventing your *own* insanely
complex naming conventions then berate others for not following
them. The ultimate technique is to create as many variable names as
possible that differ subtlely from each other only in case.
18. Never use i for the innermost loop variable. Use anything but. Use i
liberally for any other purpose especially for non-int variables.
Similary use n as a loop index.
19. Never use local variables. Whenever you feel the temptation to use
one, make it into an instance or static variable instead to
unselfishly share it with all the other methods of the class. This
will save you work later when other methods need similar
declarations. C++ programmers can go a step further by making all
variables global.
20. Never document gotchas in the code. If you suspect there may be a
bug in a class, keep it to yourself. If you have ideas about how the
code should be reorganised or rewritten, for heaven's sake, do not
write them down. Remember the words of Thumper /"If you can't say
anything nice, don't say anything at all"/. What if the programmer
who wrote that code saw your comments? What if the owner of the
company saw them? What if a customer did? You could get yourself fired.
21. To break the boredom, use a thesaurus to look up as much alternate
vocabulary as possible to refer to the same action, e.g. /display/,
/show/, /present/. Vaguely hint there is some subtle difference,
where none exists. However, if there are two similar functions that
have a crucial difference, always use the same word in describing
both functions (e.g. /print/ to mean write to a file, and to a print
on a laser, and to display on the screen). Under no circumstances,
succumb to demands to write a glossary with the special purpose
project vocabulary unambiguously defined. Doing so would be
unprofessional breach of the structured design principle of
/information hiding./
22. In naming functions, make heavy use of abstract words like /it/,
/everything/, /data/, /handle/, /stuff/, /do/, /routine/, /perform/
and the digits e.g. routineX48, PerformDataFunction, DoIt,
HandleStuff and do_args_method.
23. In Java, all primitives passed as parameters are effectively
read-only because they are passed by value. The callee can modify
the parameters, but that has no effect on the caller's variables. In
contrast all objects passed are read-write. The reference is passed
by value, which means the object itself is effectively passed by
reference. The callee can do whatever it wants to the fields in your
object. Never document whether a method actually modifies the fields
in each of the passed parameters. Name your methods to suggest they
only look at the fields when they actually change them.
24. Never document the units of measure of any variable, input, output
or parameter. e.g. feet, metres, cartons. This is not so important
in bean counting, but it is very important in engineering work. As a
corollary, never document the units of measure of any conversion
constants, or how the values were derived. It is mild cheating, but
very effective, to salt the code with some incorrect units of
measure in the comments. If you are feeling particularly malicious,
make up your *own* unit of measure; name it after yourself or some
obscure person and never define it. If somebody challenges you, tell
them you did so that you could use integer rather than floating
point arithmetic.
25. In engineering work there are two ways to code. One is to convert
all inputs to S.I. (metric) units of measure, then do your
calculations then convert back to various civil units of measure for
output. The other is to maintain the various mixed measure systems
throughout. Always choose the second. It's the American way!
26. I am going to let you in on a little-known coding secret. Exceptions
are a pain in the behind. Properly-written code never fails, so
exceptions are actually unnecessary. Don't waste time on them.
Subclassing exceptions is for incompetents who know their code will
fail. You can greatly simplify your program by having only a single
try/catch in the entire application (in main) that calls
System.exit(). Just stick a perfectly standard set of throws on
every method header whether they could throw any exceptions or not.
27. C compilers transform myArray[i] into *(myArray + i), which is
equivalent to *(i + myArray) which is equivalent to i[myArray].
Experts know to put this to good use. Unfortunately, this technique
can only be used in native classes.
28. If you have an array with 100 elements in it, hard code the literal
100 in as many places in the program as possible. Never use a static
final named constant for the 100, or refer to it as myArray.length.
To make changing this constant even more difficult, use the literal
50 instead of 100/2, or 99 instead of 100-1. You can futher disguise
the 100 by checking for a == 101 instead of a > 100 or a > 99
instead of a >= 100.
Consider things like page sizes, where the lines consisting of x
header, y body, and z footer lines, you can apply the obfuscations
independently to each of these *and* to their partial or total sums.
These time-honoured techniques are especially effective in a program
with two unrelated arrays that just accidentally happen to both have
100 elements. There are even more fiendish variants. To lull the
maintenance programmer into a false sense of security, dutifully
create the named constant, but very occasionally /"accidentally"/
use the literal 100 value instead of the named constant. Most
fiendish of all, in place of the literal 100 or the correct named
constant, sporadically use some other unrelated named constant that
just accidentally happens to have the value 100, for now. It almost
goes without saying that you should avoid any consistent naming
scheme that would associate an array name with its size constant.
29. Eschew any form of table-driven logic. It starts out innocently
enough, but soon leads to end users proofreading and then /shudder/,
even modifying the tables for themselves.
30. Nest as deeply as you can. Good coders can get up to 10 levels of (
) on a single line and 20 { } in a single method. C++ coders have
the additional powerful option of preprocessor nesting totally
independent of the nest structure of the underlying code. You earn
extra Brownie points whenever the beginning and end of a block
appear on separate pages in a printed listing. Wherever possible,
convert nested ifs into nested [? :] ternaries.
31. Join a computer book of the month club. Select authors who appear to
be too busy writing books to have had any time to actually write any
code themselves. Browse the local bookstore for titles with lots of
cloud diagrams in them and no coding examples. Skim these books to
learn obscure pedantic words you can use to intimidate the
whippersnappers that come after you. Your code should impress. If
people can't understand your vocabulary, they must assume that you
are very intelligent and that your algorithms are very deep. Avoid
any sort of homely analogies in your algorithm explanations.
32. Make "improvements" to your code often, and force users to upgrade
often - after all, no one wants to be running an outdated version.
Just because they think they're happy with the program as it is,
just think how much happier they will be after you've "fixed" it!
Don't tell anyone what the differences between versions are unless
you are forced to - after all, why tell someone about bugs in the
old version they might never have noticed otherwise?
33. The About Box should contain only the name of the program, the names
of the coders and a copyright notice written in legalese. Ideally it
should link to several megs of code that produce an entertaining
animated display. However, it should *never* contain a description
of what the program is for, its minor version number, or the date of
the most recent code revision, or the website where to get the
updates, or the author's email address. This way all the users will
soon all be running on different versions, and will attempt to
install version N+2 before installing version N+1.
34. The more changes you can make between versions the better, you don't
want users to become bored with the same old API or user interface
year after year. Finally, if you can make this change without the
users noticing, this is better still - it will keep them on their
toes, and keep them from becoming complacent.
35. If you have to write classes for some other programmer to use, put
environment-checking code (getenv() in C++ / System.getProperty() in
Java) in your classes' nameless static initializers, and pass all
your arguments to the classes this way, rather than in the
constructor methods. The advantage is that the initializer methods
get called as soon as the class program binaries get /loaded/, even
before any of the classes get instantiated, so they will usually get
executed before the program main(). In other words, there will be no
way for the rest of the program to modify these parameters before
they get read into your classes - the users better have set up all
their environment variables just the way you had them!
36. Choose your variable names to have absolutely no relation to the
labels used when such variables are displayed on the screen. E.g. on
the screen label the field /"Postal Code"/ but in the code call the
associated variable /"zip"/.
37. Java lets you create methods that have the same name as the class,
but that are not constructors. Exploit this to sow confusion.
38. Never use layouts. That way when the maintenance programmer adds one
more field he will have to manually adjust the absolute co-ordinates
of every other thing displayed on the screen. If your boss forces
you to use a layout, use a single giant GridBagLayout, and hard code
in absolute grid co-ordinates.
39. In Java, disdain the interface. If your supervisors complain, tell
them that Java interfaces force you to "cut-and-paste" code between
different classes that implement the same interface the same way,
and they /know/ how hard that would be to maintain. Instead, do as
the Java AWT designers did - put lots of functionality in your
classes that can only be used by classes that inherit from them, and
use lots of "instanceof" checks in your methods. This way, if
someone wants to reuse your code, they have to extend your classes.
If they want to reuse your code from two different classes - tough
luck, they can't extend both of them at once!
40. Make all of your leaf classes final. After all, /you're/ done with
the project - certainly no one else could possibly improve on your
work by extending your classes. And it might even be a security flaw
- after all, isn't java.lang.String final for just this reason? If
other coders in your project complain, tell them about the execution
speed improvement you're getting.
41. Make as many of your variables as possible static. If /you/ don't
need more than one instance of the class in this program, no one
else ever will either. Again, if other coders in the project
complain, tell them about the execution speed improvement you're
getting.
42. Keep all of your unused and outdated methods and variables around in
your code. After all - if you needed to use it once in 1976, who
knows if you will want to use it again sometime? Sure the program's
changed since then, but it might just as easily change back, you
"don't want to have to reinvent the wheel" (supervisors love talk
like that). If you have left the comments on those methods and
variables untouched, and sufficiently cryptic, anyone maintaining
the code will be too scared to touch them.
43. On a method called /makeSnafucated /insert only the comment /* make
snafucated */. Never define what /snafucated /means */anywhere/*.
Only a fool does not already know, with complete certainty, what
/snafucated/ means.
44. Reverse the parameters on a method called drawRectangle(height,
width) to drawRectangle(width, height) without making any change
whatsoever to the name of the method. Then a few releases later,
reverse it back again. The maintenance programmers can't tell by
quickly looking at any call if it has been adjusted yet.
Generalisations are left as an exercise for the reader.
45. Instead of using a parameters to a single method, create as many
separate methods as you can. For example instead of setAlignment(int
alignment) where alignment is an enumerated constant, for left,
right, center, create three methods: setLeftAlignment,
setRightAlignment, and setCenterAlignment. Of course, for the full
effect, you must clone the common logic to make it hard to keep in sync.
46. The /Kama Sutra/ technique has the added advantage of driving any
users or documenters of the package to distraction as well as the
maintenance programmers. Create a dozen overloaded variants of the
same method that differ in only the most minute detail. I think it
was Oscar Wilde who observed that positions 47 and 115 of the Kama
Sutra were the same except in 115 the woman had her fingers crossed.
Users of the package then have to carefully peruse the long list of
methods to figure out just which variant to use. The technique also
balloons the documentation and thus ensures it will more likely be
out of date. If the boss asks why you are doing this, explain it is
solely for the convenience of the users. Again for the full effect,
clone any common logic.
47. Declare every method and variable public. After all, somebody,
sometime might want to use it. Once a method has been declared
public, it can't very well be retracted, now can it? This makes it
very difficult to later change the way anything works under the
covers. It also has the delightful side effect of obscuring what a
class is for. If the boss asks if you are out of your mind, tell him
you are following the classic principles of transparent interfaces.
48. In C++, overload library functions by using #define. That way it
looks like you are using a familiar library function where in
actuality you are using something totally different.
49. In C++, overload +,-,*,/ to do things totally unrelated to addition,
subtraction etc. After all, if the Stroustroup can use the shift
operator to do I/O, why should you not be equally creative? If you
overload +, make sure you do it in a way that i = i + 5; has a
totally different meaning from i += 5;
50. When documenting, and you need an arbitrary name to represent a
filename use /"file"/. Never use an obviously arbitrary name like
/"Charlie.dat"/ or /"Frodo.txt"/. In general, in your examples, use
arbitrary names that sound as much like reserved keywords as
possible. For example, good names for parameters or variables would
be: /"bank"/, /"blank"/, /"class"/, /"const"/, /"constant"/,
/"input"/, /"key"/, /"keyword"/, /"kind"/, /"output"/,
/"parameter""parm"/, /"system"/, /"type"/, /"value"/, /"var"/ and
/"variable"/. If you use actual reserved words for your arbitrary
names, which would be rejected by your command processor or
compiler, so much the better. If you do this well, the users will be
hopelessly confused between reserved keywords and arbitrary names in
your example, but you can look innocent, claiming you did it to help
them associate the appropriate purpose with each variable.
51. Always document your command syntax with your own, unique,
undocumented brand of BNF notation. Never explain the syntax by
providing a suite of annotated sample valid and invalid commands.
That would demonstrate a complete lack of academic rigour. Railway
diagrams are almost as gauche. Make sure there is no obvious way of
telling a terminal symbol (something you would actually type) from
an intermediate one -- something that represents a phrase in the
syntax. Never use typeface, colour, caps, or any other visual clues
to help the reader distinguish the two. Use the exact same
punctuation glyphs in your BNF notation that you use in the command
language itself, so the reader can never tell if a (...), [...],
{...} or "..." is something you actually type as part of the
command, or is intended to give clues about which syntax elements
are obligatory, repeatable or optional in your BNF notation. After
all, if they are too stupid to figure out your variant of BNF, they
have no business using your program.
52. The macro preprocessor offers great opportunities for obfuscation.
The key technique is to nest macro expansions several layers deep so
that you have to discover all the various parts in many different
*.hpp files. Placing executable code into macros then including
those macros in every *.cpp file (even those that never use those
macros) will maximize the amount of recompilation necessary if ever
that code changes.
53. Java is schizophrenic about array declarations. You can do them the
old C, way String x[], (which uses mixed pre-postfix notation) or
the new way String[] x, which uses pure prefix notation. If you want
to really confuse people, mix the notations: e.g.
byte*[]* rowvector*,* colvector*,* matrix*[]*; which is equivalent to:
byte*[]* rowvector;
byte*[]* colvector;
byte*[][]* matrix; Java offers great opportunity for obfuscation
whenever you have to
54. convert. As a simple example, if you have to convert a double to a
String, go circuitously, via Double with new Double(d).toString
rather than the more direct Double.toString(d). You can, of course,
be far more circuitous than that! Avoid any conversion techniques
recommended by the Conversion Amanuensis
<https://www.doc.ic.ac.uk/%7Esusan/475/ConverterNative.html>. You
get bonus points for every extra temporary object you leave
littering the heap after your conversion.
55. Use threads with abandon.
Philosophy
The people who design languages are the people who write the compilers
and system classes. Quite naturally they design to make their work easy
and mathematically elegant. However, there are 10,000 maintenance
programmers to every compiler writer. The grunt maintenance programmers
have absolutely no say in the design of languages. Yet the total amount
of code they write dwarfs the code in the compilers.
An example of the result of this sort of elitist thinking is the JDBC
interface. It makes life easy for the JDBC implementor, but a nightmare
for the maintenance programmer. It is far *clumsier* than the Fortran
interface that came out with SQL three decades ago.
Maintenance programmers, if somebody ever consulted them, would demand
ways to hide the housekeeping details so they could see the forest for
the trees. They would demand all sorts of shortcuts so they would not
have to type so much and so they could see more of the program at once
on the screen. They would complain loudly about the myriad petty
time-wasting tasks the compilers demand of them.
There are some efforts in this direction: NetRexx
<http://www2.hursley.ibm.com/netrexx/>, Bali
<https://www.doc.ic.ac.uk/%7Esusan/475/bali.html>, and visual editors
(e.g. IBM's Visual Age is a start) that can collapse detail irrelevant
to the current purpose.
The Shoemaker Has No Shoes
Imagine having an accountant as a client who insisted on maintaining his
general ledgers using a word processor. You would do you best to
persuade him that his data should be structured. He needs validation
with cross field checks. You would persuade him he could do so much more
with that data when stored in a database, including controlled
simultaneous update.
Imagine taking on a software developer as a client. He insists on
maintaining all his data with a text editor. He is not yet even
exploiting the word processor's colour, type size or fonts.
Think of what might happen if we started storing source code as
structured data. We could view the *same* source code in many alternate
ways, e.g. as Java, as NextRex, as a decision table, as a flow chart, as
a loop structure skeleton (with the detail stripped off), as Java with
various levels of detail or comments removed, as Java with highlights on
the variables and method invocations of current interest, or as Java
with generated comments about argument names and/or types. We could
display complex arithmetic expressions in 2D, the way TeX and
mathematicians do. You could see code with additional or fewer
parentheses, (depending on how comfortable you feel with the precedence
rules ). Parenthesis nests could use varying size and colour to help
matching by eye. With changes as transparent overlay sets that you can
optionally remove or apply, you could watch in real time as other
programmers on your team, working in a different country, modified code
in classes that you were working on too.
You could use the full colour abilities of the modern screen to give
subliminal clues, e.g. by automatically assigning a portion of the
spectrum to each package/class using a pastel shades as the backgrounds
to any references to methods or variables of that class. You could bold
face the definition of any identifier to make it stand out.
You could ask what methods/constructors will produce an object of type
X? What methods will accept an object of type X as a parameter? What
variables are accessible in this point in the code? By clicking on a
method invocation or variable reference, you could see its definition,
helping sort out which version of a given method will actually be
invoked. You could ask to globally visit all references to a given
method or variable, and tick them off once each was dealt with. You
could do quite a bit of code writing by point and click.
Some of these ideas would not pan out. But the best way to find out
which would be valuable in practice is to try them. Once we had the
basic tool, we could experiment with hundreds of similar ideas to make
like easier for the maintenance programmer.
I discuss this further under SCID and in the SCID student project
<https://www.doc.ic.ac.uk/%7Esusan/475/projects.html#SCID>.
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