From: eric_at_[hidden]
Date: 2007-10-11 13:02:13
Author: eric_niebler
Date: 2007-10-11 13:02:13 EDT (Thu, 11 Oct 2007)
New Revision: 39933
URL: http://svn.boost.org/trac/boost/changeset/39933
Log:
new number parser example from dave jenkins
Text files modified:
trunk/libs/xpressive/example/numbers.cpp | 32 +++++++++++++++++---------------
1 files changed, 17 insertions(+), 15 deletions(-)
Modified: trunk/libs/xpressive/example/numbers.cpp
==============================================================================
--- trunk/libs/xpressive/example/numbers.cpp (original)
+++ trunk/libs/xpressive/example/numbers.cpp 2007-10-11 13:02:13 EDT (Thu, 11 Oct 2007)
@@ -51,39 +51,39 @@
map_list_of("zero",0)("dozen",12)("score",20);
// n is the integer result
- long n = 0;
+ local<long> n(0);
// temp stores intermediate values
- long temp = 0;
+ local<long> temp(0);
- // initialize the delimiters between words
+ // delimiters between words must be spaces, end-of-sequence, or punctuation
sregex delim =
- +_s | eos | '-' | ',';
+ +_s | eos | +punct;
// initialize the regular expressions for named numbers
sregex ones_rx =
- ( a1 = ones_map ) [ ref(n) += a1 ] >> delim;
+ ( a1 = ones_map ) [ n += a1 ] >> delim;
sregex tens_rx =
ones_rx
|
(
- ( a1 = tens_map ) [ ref(n) += a1 ] >> delim
+ ( a1 = tens_map ) [ n += a1 ] >> delim
>> !ones_rx
)
|
- ( ( a1 = teens_map ) [ ref(n) += a1 ] >> delim
+ ( ( a1 = teens_map ) [ n += a1 ] >> delim
);
sregex hundreds_rx =
( ( tens_rx >> "hundred" >> delim )
- [ ref(n) *= 100 ]
+ [ n *= 100 ]
>> !tens_rx
)
| tens_rx;
sregex thousands_rx =
( ( hundreds_rx >> "thousand" >> delim )
- [ ref(temp) += ref(n) * 1000, ref(n) = 0 ]
+ [ temp += n * 1000, n = 0 ]
>> !hundreds_rx
)
| hundreds_rx
@@ -91,16 +91,18 @@
sregex millions_rx =
( ( hundreds_rx >> "million" >> delim )
- [ ref(temp) += ref(n) * 1000000, ref(n) = 0 ]
+ [ temp += n * 1000000, n = 0 ]
>> !thousands_rx
)
| thousands_rx;
+ // Note: this uses two attribues, a1 and a2, and it uses
+ // a default attribute value of 1 for a1.
sregex specials_rx =
( !((a1 = ones_map) >> delim) >> (a2 = specials_map) )
- [ ref(n) = (a1 | 1) * a2 ]
+ [ n = (a1 | 1) * a2 ]
>> delim
- >> !("and" >> delim >> ones_rx);
+ >> !("and" >> +_s >> ones_rx);
sregex number_rx =
bow
@@ -108,7 +110,7 @@
( specials_rx
|
millions_rx
- [ref(n) += ref(temp), ref(temp) = 0 ]
+ [n += temp, temp = 0 ]
);
// this is the input string
@@ -142,8 +144,8 @@
for( ; cur != end; ++cur )
{
- std::cout << *cur << " = " << n << '\n';
- n = 0;
+ std::cout << *cur << " = " << n.get() << '\n';
+ n.get() = 0;
}
std::cout << '\n';
}