[Boost-commit] svn:boost r39774 - trunk/libs/xpressive/example

From: eric_at_[hidden]
Date: 2007-10-07 20:44:52

Author: eric_niebler
Date: 2007-10-07 20:44:52 EDT (Sun, 07 Oct 2007)
New Revision: 39774
URL: http://svn.boost.org/trac/boost/changeset/39774

Log:
add awesome number parser from Dave Jenkins
Added:
   trunk/libs/xpressive/example/numbers.cpp   (contents, props changed)
Text files modified: 
   trunk/libs/xpressive/example/Jamfile.v2 |     7 +++++++                                 
   1 files changed, 7 insertions(+), 0 deletions(-)

Modified: trunk/libs/xpressive/example/Jamfile.v2
==============================================================================
--- trunk/libs/xpressive/example/Jamfile.v2	(original)
+++ trunk/libs/xpressive/example/Jamfile.v2	2007-10-07 20:44:52 EDT (Sun, 07 Oct 2007)
@@ -14,3 +14,10 @@
     :
         <include>$(BOOST_ROOT)
     ;
+
+exe numbers
+    :
+        numbers.cpp
+    :
+        <include>$(BOOST_ROOT)
+    ;

Added: trunk/libs/xpressive/example/numbers.cpp
==============================================================================
--- (empty file)
+++ trunk/libs/xpressive/example/numbers.cpp	2007-10-07 20:44:52 EDT (Sun, 07 Oct 2007)
@@ -0,0 +1,161 @@
+///////////////////////////////////////////////////////////////////////////////
+// main.hpp
+//
+//  Copyright 2007 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
+    long n = 0;
+    // temp stores intermediate values
+    long temp = 0;
+
+    // initialize the delimiters between words
+    sregex delim =
+        +_s | eos | '-' | ',';
+
+    // initialize the regular expressions for named numbers
+    sregex ones_rx =
+        ( a1 = ones_map ) [ ref(n) += a1 ] >> delim;
+
+    sregex tens_rx =
+            ones_rx
+        |
+        (
+            ( a1 = tens_map ) [ ref(n) += a1 ] >> delim
+            >> !ones_rx
+        )
+        | 
+        (   ( a1 = teens_map ) [ ref(n) += a1 ] >> delim
+        );
+
+    sregex hundreds_rx =
+        (   ( tens_rx >> "hundred"  >> delim )
+            [ ref(n) *= 100 ]
+            >> !tens_rx
+        ) 
+        | tens_rx;
+
+    sregex thousands_rx = 
+        (   ( hundreds_rx >> "thousand" >> delim )
+            [ ref(temp) += ref(n) * 1000, ref(n) = 0 ]
+            >> !hundreds_rx
+        )
+        | hundreds_rx
+        ;
+
+    sregex millions_rx = 
+        (   ( hundreds_rx >> "million" >> delim )
+            [ ref(temp) += ref(n) * 1000000, ref(n) = 0 ]
+            >> !thousands_rx
+        )
+        | thousands_rx;
+
+    sregex specials_rx =
+        ( !((a1 = ones_map) >> delim) >> (a2 = specials_map) ) 
+            [ ref(n) = (a1 | 1) * a2 ] 
+        >> delim
+        >> !("and" >> delim >> ones_rx);
+
+    sregex number_rx = 
+        bow 
+        >> 
+        (   specials_rx
+        | 
+            millions_rx
+            [ref(n) += ref(temp), ref(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 -- skip me "
+        "two dozen "
+        "four score and seven ");
+
+    // the 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 )
+    {
+        std::cout << *cur << " = " << n << '\n';
+        n = 0;
+    }
+    std::cout << '\n';
+}
+
+///////////////////////////////////////////////////////////////////////////////
+// main
+int main()
+{
+    std::cout << "\n\nExample 1:\n\n";
+    example1();
+
+    std::cout << "\n\n" << std::flush;
+
+    return 0;
+}