Thomas Mlynarczyk <[EMAIL PROTECTED]> writes:
> John Machin schrieb:
>
>> *IF* you need to access the regex associated with a token in O(1)
>> time, a dict is indicated.
>
> O(1) - Does that mean `mydict[mykey]` takes the same amount of time,
> no matter if mydict has 10 or 10 entries? How
Thomas Mlynarczyk wrote:
> John Machin schrieb:
>
>> *IF* you need to access the regex associated with a token in O(1)
>> time, a dict is indicated.
>
> O(1) - Does that mean `mydict[mykey]` takes the same amount of time, no
> matter if mydict has 10 or 10 entries? How does this magic wor
John Machin schrieb:
*IF* you need to access the regex associated with a token in O(1)
time, a dict is indicated.
O(1) - Does that mean `mydict[mykey]` takes the same amount of time, no
matter if mydict has 10 or 10 entries? How does this magic work?
O(log n) I would understand, but
On Nov 12, 2:54 am, Thomas Mlynarczyk <[EMAIL PROTECTED]>
wrote:
> John Machin schrieb:
>
> > You are getting closer. A better analogy is that using a dict is like
> > transporting passengers along an autobahn in an aeroplane or
> > helicopter that never leaves the ground.
>
> It is not a bad idea
Steve Holden schrieb:
Suppose I use the dict and I want to access the regex associatetd with
the token named "tokenname" (that is, no iteration, but a single
access). I could simple write tokendict["tokenname"]. But with the list
of tuples, I can't think of an equally easy way to do that. But th
Thomas Mlynarczyk wrote:
> John Machin schrieb:
>
>> You are getting closer. A better analogy is that using a dict is like
>> transporting passengers along an autobahn in an aeroplane or
>> helicopter that never leaves the ground.
>
> It is not a bad idea to transport passengers in an airplane, b
John Machin schrieb:
You are getting closer. A better analogy is that using a dict is like
transporting passengers along an autobahn in an aeroplane or
helicopter that never leaves the ground.
It is not a bad idea to transport passengers in an airplane, but then
the airplane should not follow
On Nov 11, 8:35 am, Thomas Mlynarczyk <[EMAIL PROTECTED]>
wrote:
> [Using dict]
>
> > No, not at all. The point is that you were not *using* any of the
> > mapping functionality of the dict object, only ancillary methods like
> > iteritems -- hence, you should not have been using a dict at all.
>
John Machin schrieb:
Single-character tokens like "<" may be more efficiently handled by
doing a dict lookup after failing to find a match in the list of
(name, regex) tuples.
Yes, I will keep that in mind. For the time being, I will use only
regexes to keep the code simpler. Later, or when t
On Nov 11, 12:26 am, Thomas Mlynarczyk <[EMAIL PROTECTED]
webdesign.de> wrote:
> John Machin schrieb:
>
> >> On the other hand: If all my tokens are "mutually exclusive" then,
> > But they won't *always* be mutually exclusive (another example is
> > relational operators (< vs <=, > vs >=)) and AFAI
Paul McGuire schrieb:
Just be sure to account for tabs when computing the column, which this
simple-minded algorithm does not do.
Another thing I had not thought of -- thanks for the hint.
Greetings,
Thomas
--
Ce n'est pas parce qu'ils sont nombreux à avoir tort qu'ils ont raison!
(Coluche)
Some pratt wrote:
> BLAST YOUR AD [...]
and curse yours
--
http://mail.python.org/mailman/listinfo/python-list
On Nov 10, 7:29 am, Thomas Mlynarczyk <[EMAIL PROTECTED]>
wrote:
> Paul McGuire schrieb:
>
> > loc = data.index("list")
> > print data[:loc].count("\n")-1
> > print loc-data[:loc].rindex("\n")-1
>
> > prints 5,14
>
> > I'm sure it's non-optimal, but it *is* an algorithm that does not
> > require ke
Paul McGuire schrieb:
loc = data.index("list")
print data[:loc].count("\n")-1
print loc-data[:loc].rindex("\n")-1
prints 5,14
I'm sure it's non-optimal, but it *is* an algorithm that does not
require keeping track of the start of every line...
Yes, I was thinking of something like this. As l
John Machin schrieb:
On the other hand: If all my tokens are "mutually exclusive" then,
But they won't *always* be mutually exclusive (another example is
relational operators (< vs <=, > vs >=)) and AFAICT there is nothing
useful that the lexer can do with an assumption/guess/input that they
Robert Lehmann schrieb:
You don't have to introduce a `next` method to your Lexer class. You
could just transform your `tokenize` method into a generator by replacing
``self.result.append`` with `yield`. It gives you the just in time part
for free while not picking your algorithm into tiny unr
On Sun, 09 Nov 2008 15:53:01 +0100, Thomas Mlynarczyk wrote:
> Arnaud Delobelle schrieb:
>
>> Adding to John's comments, I wouldn't have source as a member of the
>> Lexer object but as an argument of the tokenise() method (which I would
>> make public). The tokenise method would return what you
On Nov 9, 8:34 pm, Dennis Lee Bieber <[EMAIL PROTECTED]> wrote:
> On Sun, 09 Nov 2008 23:33:30 +0100, Thomas Mlynarczyk
> <[EMAIL PROTECTED]> declaimed the following in
> comp.lang.python:
>
>
>
> > Of course. For the actual message I would use at least the line number.
> > Still, the offset could
On Nov 10, 9:33 am, Thomas Mlynarczyk <[EMAIL PROTECTED]>
wrote:
> John Machin schrieb:
>
> >>> dict.iter() will return its results in essentially random
> >>> order.
> > A list of somethings does seem indicated.
>
> On the other hand: If all my tokens are "mutually exclusive" then,
But they won't
John Machin schrieb:
[...] You have TWO problems: (1) Reporting the error location as
(offset from the start of the file) instead of (line number, column
position) would get you an express induction into the User Interface
Hall of Shame.
Of course. For the actual message I would use at least
On Nov 10, 1:39 am, Thomas Mlynarczyk <[EMAIL PROTECTED]>
wrote:
> John Machin schrieb:
>
> > Be consistent with your punctuation style. I'd suggest *not* having a
> > space after ( and before ), as in the previous line. Read
> >http://www.python.org/dev/peps/pep-0008/
>
> What were the reasons for
Arnaud Delobelle schrieb:
Adding to John's comments, I wouldn't have source as a member of the
Lexer object but as an argument of the tokenise() method (which I would
make public). The tokenise method would return what you currently call
self.result. So it would be used like this.
mylexer =
John Machin schrieb:
Be consistent with your punctuation style. I'd suggest *not* having a
space after ( and before ), as in the previous line. Read
http://www.python.org/dev/peps/pep-0008/
What were the reasons for preferring (foo) over ( foo )? This PEP gives
recommendations for coding styl
Thomas Mlynarczyk <[EMAIL PROTECTED]> writes:
> Hello,
>
> I started to write a lexer in Python -- my first attempt to do
> something useful with Python (rather than trying out snippets from
> tutorials). It is not complete yet, but I would like some feedback --
> I'm a Python newbie and it seems
On Nov 9, 7:55 am, Thomas Mlynarczyk <[EMAIL PROTECTED]>
wrote:
> Hello,
>
> I started to write a lexer in Python -- my first attempt to do something
> useful with Python (rather than trying out snippets from tutorials). It
> is not complete yet, but I would like some feedback -- I'm a Python
> new
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