include/nana/Q.h Source File

00001 /*
00002  * Q.h -  support for ForAll, ThereExists, Count and Sum (i.e. quantifiers).
00003  *
00004  * Portability: this file uses the GNU C Statement Expression extension and
00005  *    so requires GCC/C++ with extensions enabled (this is checked by the
00006  *    header file).
00007  * 
00008  * Copyright (c) 1997 Phil Maker
00009  * All rights reserved.
00010  *
00011  * Redistribution and use in source and binary forms, with or without
00012  * modification, are permitted provided that the following conditions
00013  * are met:
00014  * 1. Redistributions of source code must retain the above copyright
00015  *    notice, this list of conditions and the following disclaimer.
00016  * 2. Redistributions in binary form must reproduce the above copyright
00017  *    notice, this list of conditions and the following disclaimer in the
00018  *    documentation and/or other materials provided with the distribution.
00019  *
00020  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
00021  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
00022  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
00023  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
00024  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
00025  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
00026  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
00027  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
00028  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
00029  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
00030  * SUCH DAMAGE.
00031  *
00032  * Id: Q.h,v 1.1.1.1 1997/11/23 11:45:50 pjm Exp 
00033  */
00034 
00035 
00036 #ifndef _Q_h_
00037 #define _Q_h_ 1
00038 
00039 #ifdef __cplusplus
00040 extern "C" {
00041 #endif
00042 
00043 #ifndef WITHOUT_NANA 
00044 
00045 #ifndef __GNUC__ /* not compiling with GCC/G++ extensions */
00046 error 
00047 This file requires the GNU C/C++ "statement expression" extension;
00048 so use GCC/G++ with extensions enabled. If you have not got GCC then 
00049 misery follows though we may be able to do something about it
00050 in the future.
00051 #endif
00052 
00053 /*
00054  * A(i,c,n,a) - true iff a is true for all values generated by for(i;c;n) 
00055  * 
00056  * Note: local variables can be introduced in this statement even in C.
00057  */
00058 
00059 #define A(i,c,n,a) /* ForAll */ \
00060         ({ \
00061                 int _A_result = 1; \
00062                 i; \
00063                 while(c) { \
00064                         if(!(a)) { \
00065                                 _A_result = 0; \
00066                                 break; \
00067                         } \
00068                         n; \
00069                 } \
00070                 _A_result; \
00071         })
00072 
00073 /* 
00074  * E(i,c,n,a) - true iff exists any true a for values generated by for(i;c;n)
00075  */
00076 
00077 #define E(i,c,n,a) /* Exists */ \
00078         ({ \
00079                 int _E_result = 0; \
00080                 i; \
00081                 while(c) { \
00082                         if(a) { \
00083                                 _E_result = 1; \
00084                                 break; \
00085                         } \
00086                         n; \
00087                 } \
00088                 _E_result; \
00089         })
00090 
00091 /* 
00092  * C(i,c,n,a) - count the number of times a is true over the values
00093  * generated by for(i;c;n)
00094  */
00095 
00096 #define C(i,c,n,a) /* Count */ \
00097         ({ \
00098                 long _C_result = 0; \
00099                 i; \
00100                 while(c) { \
00101                         if(a) { \
00102                                 _C_result++; \
00103                         } \
00104                         n; \
00105                 } \
00106                 _C_result; \
00107         })
00108 
00109 /*
00110  * E1(i,c,n,a) - exists a single value generated by for(i;c;n)
00111  * suchthat i is true.
00112  */
00113 
00114 #define E1(i,c,n,a) (C(i,c,n,a) == 1) /* There Exists 1 */
00115 
00116 /*
00117  * S(i,c,n,v) - sum of v over the values generated by for(i;c;n)
00118  */
00119 
00120 #define S(i,c,n,v) \
00121         ({ \
00122                 i; \
00123                 typeof(v) _S_result = 0; \
00124                 while(c) { \
00125                         _S_result += (v); \
00126                         n; \
00127                 } \
00128                 _S_result; \
00129         })
00130 
00131 /*
00132  * P(i,c,n,v) - product of v over the values generated by for(i;c;n)
00133  */
00134 
00135 #define P(i,c,n,v) \
00136         ({ \
00137                 i; \
00138                 typeof(v) _P_result = 1; \
00139                 while(c) { \
00140                         _P_result *= (v); \
00141                         n; \
00142                 } \
00143                 _P_result; \
00144         })
00145 
00146 #else /* defined(WITHOUT_NANA) */
00147 
00148 /*
00149  * we don't produce any empty stubs for Q.h when compiling without nana
00150  * since calls to A(...), etc should only occur in stubbed out code such
00151  * as I(...).
00152  */
00153 
00154 #endif /* !defined(WITHOUT_NANA) */
00155 #ifdef __cplusplus
00156 }
00157 #endif
00158 
00159 #endif /* _Q_h_ */
00160