Summary  edit

An instance of Category Humor.

Description  edit

Richard Suchenwirth 2006-01-28: Exhibit A was found in the waste-paper bin of a defunct software company:

#
#
#      add.tcl
#
#      Implemented function:
#
#      add
#
#      Usage: add a b
#   
#      Input:
#      a       a number
#      b       another number
#
#      Output:
#
#      The sum of the numbers
#
#      Side effects:
#
#      None
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL ACME SOFTWARE
# DESIGN L.L.C. OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
# INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
# BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
# OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
# ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR
# TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
# USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
# DAMAGE.
#

proc add { a b } \
{
    set sum [ expr "$a" * "$b" ];
    return $sum;
};

#
# Test suite:
#
# add 0 0 == 0
#
# add 2 2 == 4
#
# Passed on Apr 1, 2005 - phb
#

Acknowledgement: part of the documentation (the LEGALESE) was copied from tclCarbonProcesses, which however does not imply that the said page is in any material or immaterial connection with the defunct company :^)

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Lars H: Yuck! A really gross coding style -- no wonder the company went belly-up (well, one can at least meekly hope that "who evil does he evil fares" even in the dotcom era). You're wrong about the test suite though -- e.g. [add 3 1.5] should pass without any problem. However, had the specs said "int" instead of "number" then it would have been another matter ...

RS: True indeed. I moved the note down to here, it said: "Note also that the test suite is absolutely maximal - you can't add any test without getting failures..." The question boils down to solutions for

a + b = a * b

which can be transformed to

b = a / (a-1)

and there's indeed infinitely many solutions - examples:

a   b
0   0
1   undefined, divide by zero
2   2
3   1.5
5   1.25
101 1.01
...

So even bad jokes can lead to good mathematical excursions... :^)

AvL: Does it need to be mentioned that the code itself is an example of bad style, because of the unbraced expression? Probably not :-)

RS: The code intentionally contains all bad features I could think of. Canonically, it would be

proc add {a b} {
    expr {$a + $b}
}

AMG: Per Math Operators as Commands, you could also do interp alias "" add "" ::tcl::mathop::+, except this also supports argument counts other than two. (DKF: It also does the right thing, in case you weren't watching...)

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willdye Those who enjoyed this page might also find http://thedailywtf.com/ amusing.

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[bjornh] Run, fools! It's "Passed on Apr 1, 2005"

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