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Source code changes of the file "doc/ragel-guide.txt" between
ragel-7.0.0.9.tar.gz and ragel-7.0.0.10.tar.gz

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ragel-guide.txt  (ragel-7.0.0.9):ragel-guide.txt  (ragel-7.0.0.10)
= Ragel State Machine Compiler User Guide = Ragel State Machine Compiler User Guide
Adrian Thurston <thurston@colm.net> Adrian Thurston <thurston@colm.net>
Ragel Version 7.0 Ragel Version 7.0
:toc: :toc:
:toclevels: 3 :toclevels: 3
:numbered: :numbered:
.License .License
This document is part of Ragel, and as such, this document is released Permission is hereby granted, free of charge, to any person obtaining a c
under the terms of the GNU General Public License as published by the opy
Free Software Foundation; either version 2 of the License, or (at your of this software and associated documentation files (the "Software"), to
option) any later version. deal in the Software without restriction, including without limitation th
e
Ragel is distributed in the hope that it will be useful, but WITHOUT rights to use, copy, modify, merge, publish, distribute, sublicense, and/
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or or
FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License sell copies of the Software, and to permit persons to whom the Software i
for more details. s
furnished to do so, subject to the following conditions:
You should have received a copy of the GNU General Public License along
with Ragel; if not, write to the Free Software Foundation, Inc., 59 The above copyright notice and this permission notice shall be included i
Temple Place, Suite 330, Boston, MA 02111-1307 USA. n all
copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS O
R
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL T
HE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING F
ROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE
SOFTWARE.
== Introduction == Introduction
=== Abstract === Abstract
In today's computing landscape, regular expressions are used heavily for the In today's computing landscape, regular expressions are used heavily for the
purpose of specifying parsers. They are normally treated as black boxes, linked purpose of specifying parsers. They are normally treated as black boxes, linked
together with program logic. User code is executed in between invocations of together with program logic. User code is executed in between invocations of
the regular expression engine. To add code before a pattern terminates, the the regular expression engine. To add code before a pattern terminates, the
programmer is required to break patterns and paste them back together with programmer is required to break patterns and paste them back together with
skipping to change at line 3420 skipping to change at line 3424
needs to be able to allocate characters from the alphabet space. Ragel uses needs to be able to allocate characters from the alphabet space. Ragel uses
these allocated characters to express "character C with condition P true" or "C these allocated characters to express "character C with condition P true" or "C
with P false." Since internally Ragel uses longs to store characters there is with P false." Since internally Ragel uses longs to store characters there is
no room left in the alphabet space unless an alphabet type smaller than long is no room left in the alphabet space unless an alphabet type smaller than long is
used. used.
==== Condition Based Repetition ==== Condition Based Repetition
New in ragel 7 is a construct designed to simplify the use of conditions to New in ragel 7 is a construct designed to simplify the use of conditions to
control repetition. While possible to count properly using condition embedding control repetition. While possible to count properly using condition embedding
operators, there is a corner case that prove difficult. If the zero-width case operators, there is a corner case that proves difficult. If the zero-width case
is to be accepted properly, some knowledge of what is before and after is is to be accepted properly, some knowledge of what is before and after is
necessary and tests need to be embedded there. The `:cond()` operator is necessary and tests need to be embedded there. The `:cond()` operator is
designed to solve this problem, automatically embedding actions such that a designed to solve this problem, automatically embedding actions such that a
zero count is possible. zero count is possible.
-------------- --------------
:cond( <expression>, :cond( <expression>,
<init>, <inc>, <min> [ , <max> ] ): <init>, <inc>, <min> [ , <max> ] ):
-------------- --------------
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