The expression evaluator using complex numbers

This expression evaluator is very similar to the usual one. It can be defined as the default one with the command ch_expr (cf. 7.7.3, 11).

The mathematical functions that the complex expression evaluator knows are in the array Funcs_C[] (it is an array of structures FUNCTIONC). This array must be defined by the user. The total number of functions is _NBFONC_C, which must be set by the user. An array of functions is predefined in the library, it is called Func_interp_C, and the number of functions defined in Func_interp is contained in the integer _NBFONC0_C.

FUNCTIONC Funcs_interp_C[] =
{
   /* name, funtion to call */
   { "Csin",    1,    _I_dCsin_c },        /* 0    */
   { "Ccos",    1,    _I_dCcos_c },        /* 1    */
   { "Ctan",    1,    _I_dCtan_c },        /* 2    */
   { "Csinh",   1,    _I_dCsinh_c },       /* 3    */
   { "Ccosh",   1,    _I_dCcosh_c },       /* 4    */
   { "Ctanh",   1,    _I_dCtanh_c },       /* 5    */
   { "Cexp",    1,    _I_dCexp_c },        /* 6    */
   { "Clog",    1,    _I_dClog_c },        /* 7    */
   { "Csqrt",   1,    _I_xdCsqrt },        /* 8    */
   { "Cabs",    1,    _I_CdCabs },         /* 9    */
   { 0 }                                   /* 10   */
};

int    _NBFONC0_C=10;

For instance if the program uses only the predefined array of functions, the main source file would look as follows :

 ......
FUNCTIONC *Funcs_C;

int main(int argc, char *argv[])
{ 
 ......
     Funcs_C = Funcs_interp_C;
     _NBFONC_C = _NBFONC0_C;
 ......
 }

The structure FUNCTIONC is defined as follows :

typedef struct
{
   char*      name;                   /* Function name                 */
   int        args;                   /* Number of arguments to expect */
   dcomplex   (*func)(dcomplex *);    /* Pointer to function           */
} FUNCTIONC;

Its first member is the character string that will be used to call the function. The second member is the number of parameters of the function. It must be between 1 and the constant MAX_F_ARGS defined in interp.h (it is 10). The third member is the name of the function. It must be a function returning a double precision complex value, having only one argument : an array of double precision complex numbers. In the first term of the array Func_interp_C the function _I_dCsin_c looks like this

dcomplex
_I_dCsin_c(dcomplex *x)
{
    return dCsin_c(*x);
}

(the function dCsin_c is defined in complex.c).