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///////////////////////////////////////////////////////////////////////////////
// numbers.cpp
//
// Copyright 2008 David Jenkins. Distributed under the Boost
// Software License, Version 1.0. (See accompanying file
// LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
#if defined(_MSC_VER)
//disbale warning C4996: 'std::xxx' was declared deprecated
# pragma warning(disable:4996)
#endif
#include <iostream>
#include <string>
#include <map>
#include <boost/assign/list_of.hpp> // for 'map_list_of()'
#include <boost/xpressive/xpressive.hpp>
#include <boost/xpressive/regex_actions.hpp>
///////////////////////////////////////////////////////////////////////////////
// Match all named numbers in a string and return their integer values
//
// For example, given the input string:
// "one two sixty three thousand ninety five eleven"
// the program will output:
// "one = 1"
// "two = 2"
// "sixty three thousand ninety five = 63095"
// "eleven = 11"
void example1()
{
using namespace boost::xpressive;
using namespace boost::assign;
// initialize the maps for named numbers
std::map< std::string, int > ones_map =
map_list_of("one",1)("two",2)("three",3)("four",4)("five",5)
("six",6)("seven",7)("eight",8)("nine",9);
std::map< std::string, int > teens_map =
map_list_of("ten",10)("eleven",11)("twelve",12)("thirteen",13)
("fourteen",14)("fifteen",15)("sixteen",16)("seventeen",17)
("eighteen",18)("nineteen",19);
std::map< std::string, int > tens_map =
map_list_of("twenty",20)("thirty",30)("fourty",40)
("fifty",50)("sixty",60)("seventy",70)("eighty",80)("ninety",90);
std::map< std::string, int > specials_map =
map_list_of("zero",0)("dozen",12)("score",20);
// n is the integer result
local<long> n(0);
// temp stores intermediate values
local<long> temp(0);
// initialize the regular expressions for named numbers
sregex tens_rx =
// use skip directive to skip whitespace between words
skip(_s)
(
( a3 = teens_map )
|
( a2 = tens_map ) >> !( a1 = ones_map )
|
( a1 = ones_map )
)
[ n += (a3|0) + (a2|0) + (a1|0) ];
sregex hundreds_rx =
skip(_s)
(
tens_rx >>
!(
as_xpr("hundred") [ n *= 100 ]
>> !tens_rx
)
)
;
sregex specials_rx = // regex for special number names like dozen
skip(_s)
(
// Note: this uses two attribues, a1 and a2, and it uses
// a default attribute value of 1 for a1.
( !( a1 = ones_map ) >> ( a2 = specials_map ) )
[ n = (a1|1) * a2 ]
>> !( "and" >> tens_rx )
)
;
sregex number_rx =
bow
>>
skip(_s|punct)
(
specials_rx // special numbers
|
( // normal numbers
!( hundreds_rx >> "million" ) [ temp += n * 1000000, n = 0 ]
>>
!( hundreds_rx >> "thousand" ) [ temp += n * 1000, n = 0 ]
>>
!hundreds_rx
)
[n += temp, temp = 0 ]
);
// this is the input string
std::string str( "one two three eighteen twenty two "
"nine hundred ninety nine twelve "
"eight hundred sixty three thousand ninety five "
"sixty five hundred ten "
"two million eight hundred sixty three thousand ninety five "
"zero sixty five hundred thousand "
"extra stuff "
"two dozen "
"four score and seven");
// the MATCHING results of iterating through the string are:
// one = 1
// two = 2
// three = 3
// eighteen = 18
// twenty two = 22
// nine hundred ninety nine = 999
// twelve = 12
// eight hundred sixty three thousand ninety five = 863095
// sixty five hundred ten = 6510
// two million eight hundred sixty three thousand ninety five = 2863095
// zero = 0
// sixty five hundred thousand = 6500000
// two dozen = 24
// four score and seven = 87
sregex_token_iterator cur( str.begin(), str.end(), number_rx );
sregex_token_iterator end;
for( ; cur != end; ++cur )
{
if ((*cur).length() > 0)
std::cout << *cur << " = " << n.get() << '\n';
n.get() = 0;
}
std::cout << '\n';
// the NON-MATCHING results of iterating through the string are:
// extra = unmatched
// stuff = unmatched
sregex_token_iterator cur2( str.begin(), str.end(), number_rx, -1 );
for( ; cur2 != end; ++cur2 )
{
if ((*cur2).length() > 0)
std::cout << *cur2 << " = unmatched" << '\n';
}
}
///////////////////////////////////////////////////////////////////////////////
// main
int main()
{
std::cout << "\n\nExample 1:\n\n";
example1();
std::cout << "\n\n" << std::flush;
return 0;
}
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