Common Text Transformation Library http://cttl.sourceforge.net/

wchar_c_double_quote(RM) wide char C double quote

• Category:

  • Symmetric quoted expression, optimized for double-quoted C wide character string literal,
    such as L"ABC".

• Description:

  • C double-quoted wide character string literals are enclosed in double quotation marks wchar_t(").

  • CTTL quote format for C string literal recognizes C-style escape characters, found inside the string.

• Format:

  • 
        wchar_c_double_quote( RM )
    
        wchar_c_double_quote()
    
    
    

    where optional RM clause describes grammar to match input symbols at the beginning of the string, providing access to the interior of the quoted string constant.

  • The implementation of wchar_c_double_quote(RM) is optimized for matching C strings formed by the double quotation marks.

  • Function wchar_c_double_quote() is an abbreviated version of the wchar_c_double_quote(RM). It is a shorthand notation for wchar_c_double_quote(true).

• Algorithm:

  • Balanced search for a pair of the opening and closing double quotation marks wchar_t(").

• Space sensitivity:

  • The space sensitivity of C double-quoted wide character string is enabled.

• Searchability:

  • Search grammar evaluation algorithms

    • terminal symbol search and

    • non-terminal symbol search

    are enabled for C double quotes, as in the following fragment:

    
    #include "cttl/cttl.h"
    
    using namespace cttl;
    
    int main()
    {
        std::wstring inp = L"Text \"\\\"\" one; \"A\" two ;  ";
        typedef const_edge< policy_space<>, std::wstring > substr_T;
        substr_T substring( inp );
        substr_T exterior = substring;
        substr_T interior = substring;
    
        size_t result = (
            exterior( wchar_c_double_quote( interior( entity() ) ) )
            +
            ( entity( iswalpha ) & symbol( L"two" ) )
            +
            symbol( L';' )
        ).bang_find( substring );
    
        assert( result != std::wstring::npos );
        assert( exterior == L"\"A\"" );
        assert( interior == L"A" );
        return 0;
    }
    
    

• Example:

  • Programming languages, such as C and C++, recognize double-quoted wide character string literals. CTTL parser can handle such literal by using wchar_c_double_quote():

    
    #include "cttl/cttl.h"
    
    using namespace cttl;
    
    int main()
    {
        std::wstring inp = L"\"\\x20\\\"ABC\"";
        typedef const_edge< policy_default, std::wstring > substr_T;
        substr_T substring( inp );
        substr_T exterior = substring;
        substr_T interior = substring;
    
        size_t result = exterior(
            wchar_c_double_quote( interior( entity() ) )
        ).match( substring );
    
        assert( result != std::wstring::npos );
        assert( exterior == L"\"\\x20\\\"ABC\"" );
        assert( interior == L"\\x20\\\"ABC" );
        return 0;
    }
    
    

• Trace output format:

  • CTTL tracing is not supported when the program is compiled in wide character mode.

   

Copyright © 1997-2009 Igor Kholodov mailto:cttl@users.sourceforge.net.

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