[Python-checkins] CVS: python/dist/src/Doc/lib libre.tex,1.65,1.66

[Fred L. Drake]

Update of /cvsroot/python/python/dist/src/Doc/lib
In directory usw-pr-cvs1:/tmp/cvs-serv6672/lib

Modified Files:
	libre.tex 
Log Message:

Add a caveat about boundary conditions and RE concatenation, so that the
documents do not make an overly-strong assertion about the properties of
RE concatenation.

Add an example of RE{m,} syntax and what it will and will not match.


Index: libre.tex
===================================================================
RCS file: /cvsroot/python/python/dist/src/Doc/lib/libre.tex,v
retrieving revision 1.65
retrieving revision 1.66
diff -C2 -d -r1.65 -r1.66
*** libre.tex	2001/08/01 16:56:51	1.65
--- libre.tex	2001/08/02 20:52:00	1.66
***************
*** 62,72 ****
  Regular expressions can be concatenated to form new regular
  expressions; if \emph{A} and \emph{B} are both regular expressions,
! then \emph{AB} is also an regular expression.  If a string \emph{p}
  matches A and another string \emph{q} matches B, the string \emph{pq}
! will match AB.  Thus, complex expressions can easily be constructed
! from simpler primitive expressions like the ones described here.  For
! details of the theory and implementation of regular expressions,
! consult the Friedl book referenced below, or almost any textbook about
! compiler construction.
  
  A brief explanation of the format of regular expressions follows.  For
--- 62,73 ----
  Regular expressions can be concatenated to form new regular
  expressions; if \emph{A} and \emph{B} are both regular expressions,
! then \emph{AB} is also a regular expression.  If a string \emph{p}
  matches A and another string \emph{q} matches B, the string \emph{pq}
! will match AB if \emph{A} and \emph{B} do no specify boundary
! conditions that are no longer satisfied by \emph{pq}.  Thus, complex
! expressions can easily be constructed from simpler primitive
! expressions like the ones described here.  For details of the theory
! and implementation of regular expressions, consult the Friedl book
! referenced below, or almost any textbook about compiler construction.
  
  A brief explanation of the format of regular expressions follows.  For
***************
*** 139,145 ****
  match as many repetitions as possible.  For example, \regexp{a\{3,5\}}
  will match from 3 to 5 \character{a} characters.  Omitting \var{n}
! specifies an infinite upper bound; you can't omit \var{m}.  The comma
! may not be omitted or the modifier would be confused with the
! previously described form.
  
  \item[\code{\{\var{m},\var{n}\}?}] Causes the resulting RE to
--- 140,148 ----
  match as many repetitions as possible.  For example, \regexp{a\{3,5\}}
  will match from 3 to 5 \character{a} characters.  Omitting \var{n}
! specifies an infinite upper bound; you can't omit \var{m}.  As an
! example, \regexp{a\{4,\}b} will match \code{aaaab}, a thousand
! \character{a} characters followed by a \code{b}, but not \code{aaab}.
! The comma may not be omitted or the modifier would be confused with
! the previously described form.
  
  \item[\code{\{\var{m},\var{n}\}?}] Causes the resulting RE to