Python docs [was: function with a state]
xah at xahlee.org
Fri Mar 25 00:02:21 CET 2005
The Python doc is relatively lousy, from content organization to the
tech writing quality.
I think i'll just post snippets of my comments as i find them. (and
feel like exposing)
Comparison operations are supported by all objects. They all have the
same priority (which is higher than that of the Boolean operations).
Comparisons can be chained arbitrarily; for example, x < y <= z is
equivalent to x < y and y <= z, except that y is evaluated only once
(but in both cases z is not evaluated at all when x < y is found to be
Problem: “Comparison operations are supported by all objects.”
This is very vague and ambiguous.
The word “object” has generic English meaning as well might have
very technical meaning in a language. In Python, it does not have very
pronounced technical meaning. For example, there's a chapter in Python
Library Ref titled “2. Built-In Objects”, and under it a section
“2.1 Built-in Functions”. Apparently, functions can't possibly be
meant as a “object” for comparisons.
Now suppose we take the object in the sentence to be sensible items as
numbers, lists etc. The clause “supported by all objects” is
ambiguous. What is meant by “supported”?
Problem: They all have the same priority (which is higher than that of
the Boolean operations).
This sentence is very stupid, in multitude of aspects.
The “priority” referred to here means operator precedence.
It tries to say that the comparison operator has higher syntactical
connectivity than boolean operators. E.g. “False and False==False”
means “False and (False==False)” and not “(False and
However, the “they” pronoun from the context of previous sentence,
refers to “the comparison operation”, not “operator”. So, it
conjures the reader to think about some “operation precedence”,
which in itself cannot be ruled out as nonsense depending on the
context. Very fucking stupid confusional writing.
And, from pure writing aspect, the sentence “...(which is ...)” is
some kind of a juvenile latch on. If the author intent to make that
point, say it in its own sentence. e.g. The comparison operators have
higher precedence than boolean operators. It would be better to not
mention this at all. For practical considerations, very rare is the
case of mixing boolean and comparison operators, and if so, parenthesis
are likely used and is indeed a good practice. The proper place for
operator precedence is a table list all such, giving a clear view, and
in some appendix of language spec.
Problem: Comparisons can be chained arbitrarily; for example, x < y <=
z is equivalent to x < y and y <= z, except that y is evaluated only
once (but in both cases z is not evaluated at all when x < y is found
to be false).
Drop the word “arbitrarily”. It has no meaning here.
the whole sentence is one fucked up verbiage of pell-mell thinking and
writing. Here's one example of better:
Comparisons can be chained, and is evaluated from left to right. For
example, x < y <= z is equivalent to (x < y) <= z.
With respect to documentation style, it is questionable that this
aspect needs to be mentioned at all. In practice, if programers need to
chain comparisons, they will readily do so. This is not out of ordinary
in imperative languages, and evaluation from left to right is also not
extraordinary to cost a mention.
Problem: <> and != are alternate spellings for the same operator. != is
the preferred spelling; <> is obsolescent
Very bad choice of term “spellings” -- not a standard usage for
computer language operators.
Better: “!=” can also be written as “<>”.
If “<>” is not likely to go out in future versions, don't even
mention about “preference”, because it has no effective meaning.
(if one wants to wax philosophical about “programing esthetics”, go
nag it outside of language documentation.)
In general, when something is obsolete or might go defunct in the
future, consider not even mentioning that construct. If necessary, add
it in a obscure place, and not adjacent to critical info. In many
places of Python documentation, this is breached.
This is just a quick partial analysis of one episode of incompetence i
see in Python docs in the past months i've had the pleasure to scan
here and there. A extreme pain in the ass.
I'm in fact somewhat surprised by this poor quality in writing. The
more egregious error is the hardware-oriented organization aka
technical drivel. But that i accept as common in imperative language
communities and in general the computing industry. But the poor quality
in the effectiveness and clarity of the writing itself surprised me. As
exhibited above, the writing is typical of programers, filled with
latch on sentences and unclear thinking. (they in general don't have a
clear picture of what they are talking about, and in cases they do,
they don't have the writing skills to express it effectively. (just as
a footnote: this writing problem isn't entirely the fault of programers
or Python doc writers. In part the English language (or in general
natural languages) are to blame, because they are exceptionally
illogical and really take years to master as a art by itself.))
The Python doc, though relatively incompetent, but the author have
tried the best. This is in contrast to documentations in unix related
things (unix tools, perl, apache, and so on etc), where the writers
have absolutely no sense of clear writing, and in most cases don't give
a damn and delight in drivel thinking of it as literary. A criminal of
this sort that does society huge damage is Larry Wall and the likes of
his cohorts in the unix community. (disclaimer: this is a piece of
addendum: quality writing takes time. Though, the critical part lies
not in the mastery of writing itself, but in clarity of thinking of
what exactly one wants to say. So, next time you are writing a tech
doc, first try to have a precise understanding of the object, and then
know exactly what is that you want to say about it, then the writing
will come out vastly better. If the precise understanding of the object
is not readily at hand (which is common and does not indicate
incompetence), being aware of it helps greatly in its exposition.
This and past critics on Python documentation and IT doc in general is
xah at xahlee.org
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