[calc.git] / parser.c

#include <malloc.h>
#include <math.h>
#include <stdlib.h>

#include "debug.h"
#include "fdprintf.h"

#include "parser.h"

/* compare codes */

int codecmp (char *ref, char *str)
{
    int sig;

    while (*ref != '\0') {
        if (*ref == '\t') {
             sig = (*str == '.') ? -1 : ((*str >= '0') && (*str <= '9'));
        } else {
            sig = *str - *ref;
        }
        if (sig != 0) {
            return (sig > 0) ? 1 : -1;
        }
        str++;
        ref++;
    }

    return 0;
}

/* allocate new element */

element_t *newelement (func_t function, int nbops, int prio)
{
    element_t *new = (element_t *) calloc (1, sizeof (element_t));
    if (new == NULL) {
        VERBOSE (ERROR, fdprintf (stdfderr, "can't allocate memory\n"));
        return NULL;
    }
    new->func = function;
    new->nbops = nbops;
    new->prio = prio;

    return new;
}

/* desallocate element */

void delelement (element_t *root)
{
    int i;
    if ((root != NULL) && (root != ERROR_OP)) {
        for (i = 0; i < root->nbops; i++) {
            if ((root->ops[i] != NULL) && (root->ops[i] != ERROR_OP)) {
                delelement (root->ops[i]);
            }
        }
        free (root);
    }
}

/* functions */

#define NB_OPERATORS 6

keyword_t operators[NB_OPERATORS] = {
    { "+\t", Add, 2, 1, 1},
    { "-\t", Sub, 2, 1, 1},
    { "*",   Mul, 2, 1, 2},
    { "/",   Div, 2, 1, 2},
    { "%",   Mod, 2, 1, 3},
    { "^",   Pow, 2, 1, 4}
};

#define NB_FUNCTIONS 9
keyword_t functions[NB_FUNCTIONS] = {
    { "sqrt", Sqr, 1, 4, 5},
    { "pow",  Pow, 2, 3, 5},
    { "cos",  Cos, 1, 3, 5},
    { "sin",  Sin, 1, 3, 5},
    { "atan", Atn, 1, 4, 5},
    { "exp",  Exp, 1, 3, 5},
    { "log",  Log, 1, 3, 5},
    { "quit", Qui, 0, 4, 5},
    { "help", Hel, 0, 4, 5}
};

/* subparser function */

element_t *subparser (element_t **proot, char **pstr, func_t func, int nbops, int prio)
{
    element_t *new = newelement (func, nbops, prio);
    if (new == NULL) {
        return ERROR_OP;
    }
    new->ops[0] = *proot;
    new->ops[1] = parser (*pstr, pstr, new->prio);
    if (new->ops[1] == ERROR_OP) {
        delelement (new);
        *proot = NULL;
        return ERROR_OP;
    }
    *proot = newelement (Val, 1, 5);
    if (*proot == NULL) {
        delelement (new);
        return ERROR_OP;
    }
    (*proot)->ops[0] = new;

    return *proot;
}

/* parser function */

element_t *parser (char *str, char **next, int prio)
{
    element_t *root = NULL;
    int i;

    VERBOSE (DEBUG, PRINTOUT ("Starting parsing\n"));

    /* main loop */
    while (*str != '\0') {
        int found = 0;
        element_t *new = NULL;
        VERBOSE (INFO, PRINTOUT ("Processing: %s\n", str));

        /* skip spaces and tabs */

        if ((*str == ' ') || (*str == '\t')) {
            str++;
            continue;
        }

        /* check for open bracket */

        if (*str == '(') {
            VERBOSE (DEBUG, PRINTOUT ("start processing bracket\n"));
            if (root) {
                do {
                    found = 0;
                    new = parser (str + 1, &str, 0);
                    if (new == ERROR_OP) {
                        delelement (root);
                        return ERROR_OP;
                    }
                    for (i = 0; i < root->nbops; i++) {
                        if (root->ops[i] == NULL) {
                            root->ops[i] = new;
                            found = 1;
                            break;
                        }
                    }
                    if (!found) {
                        delelement (new);
                        delelement (root);
                        return ERROR_OP;
                    }
                } while (*str == ',');
            } else {
                root = newelement (Val, 1, 5);
                if (root == NULL) {
                    return ERROR_OP;
                }
                new = parser (str + 1, &str, 0);
                if ((new == ERROR_OP) || (*str == ',')) {
                    delelement (new);
                    delelement (root);
                    return ERROR_OP;
                }
                root->ops[0] = new;
            }
            str++;
            VERBOSE (DEBUG, PRINTOUT ("stop processing bracket\n"));
            continue;
        }

        /* check for closing bracket or koma */

        if ((*str == ')') || (*str == ',')) {
            if (next != NULL) {
                *next = str;
            }
            return root;
        }

        /* look for operators */

        for (i = 0; i < NB_OPERATORS; i++) {
            keyword_t *operator = operators + i;
            if (codecmp (operator->keyword, str) == 0) {
                VERBOSE (DEBUG, PRINTOUT ("start processing operator\n"));
                if (root) {
                    if ((prio) && (prio > operator->prio)) {
                        VERBOSE (DEBUG, PRINTOUT ("stop because operator priority\n"));
                        *next = str;
                        return root;
                    }
                    str += operator->offset;
                    VERBOSE (INFO, PRINTOUT ("Oper: %d\n", operator->func));
                    if (subparser (&root, &str, operator->func, operator->nbops, operator->prio) == ERROR_OP) {
                        delelement (root);
                        return ERROR_OP;
                    }
                } else if (*str == '-') {
                    new = newelement (Sig, 1, 9);
                    if (new == NULL) {
                        return ERROR_OP;
                    }
                    root = new;
                } else {
                    return ERROR_OP;
                }
                found = 1;
                VERBOSE (DEBUG, PRINTOUT ("stop processing operator\n"));
                break;
            }
        }
        if (found) {
            continue;
        }

        /* look for functions */

        for (i = 0; i < NB_FUNCTIONS; i++) {
            keyword_t *function = functions + i;
            if (codecmp (function->keyword, str) == 0) {
                VERBOSE (DEBUG, PRINTOUT ("start processing function\n"));
                if (root == NULL) {
                    VERBOSE (INFO, PRINTOUT ("Func: %d\n", function->func));
                    new = newelement (function->func, function->nbops, function->prio);
                    if (new == NULL) {
                        return ERROR_OP;
                    }
                    root = new;
                } else {
                    delelement (root);
                    return ERROR_OP;
                }
                str += function->offset;
                found = 1;
                VERBOSE (DEBUG, PRINTOUT ("stop processing function\n"));
                break;
            }
        }
        if (found) {
            continue;
        }

        /* look for number */

        if (((*str >= '0') && (*str <= '9')) ||
            (*str == '.') || (*str == '+') || (*str == '-')) {
            VERBOSE (DEBUG, PRINTOUT ("start processing value\n"));
            char *pt;
            double value = strtod (str, &pt);
            VERBOSE (INFO, PRINTOUT ("Value: %f\n", value));
            if (str != pt) {
                if (root == NULL) {
                    new = newelement (Val, 1, 5);
                    if (new == NULL) {
                        return ERROR_OP;
                    }
                    new->value = value;
                    root = new;
                    str = pt;
                } else if (root->func == Val) {
                    if ((*str == '+') || (*str == '-')) {
                        if ((prio) && (prio > 1)) {
                            VERBOSE (DEBUG, PRINTOUT ("stop because operator priority\n"));
                            *next = str;
                            return root;
                        }
                        if (subparser (&root, &str, Add, 2, 1) == ERROR_OP) {
                            delelement (root);
                            return ERROR_OP;
                        }
                    } else {
                        delelement (root);
                        return ERROR_OP;
                    }
                } else {
                    delelement (root);
                    return ERROR_OP;
                }
                found = 1;
            }
            VERBOSE (DEBUG, PRINTOUT ("stop processing value\n"));
        }

        /* error */

        if (!found) {
            delelement (root);
            return ERROR_OP;
        }

    }

    if (next != NULL) {
        *next = str;
    }

    return root;
}

/* print element tree */

void print_element (element_t *root, int level)
{
    char *func = NULL;
    int i;

    if ((root == NULL) || (root == ERROR_OP)) {
        return;
    }

    for (i = 0; i < level; i++) {
        PRINTOUT (" ");
    }

    switch (root->func) {
    case Val: func = "Value"; break;
    case Sig: func = "Sign"; break;
    case Add: func = "Addition"; break;
    case Sub: func = "Subtraction"; break;
    case Mul: func = "Multiplication"; break;
    case Div: func = "Division"; break;
    case Mod: func = "Modulo"; break;
    case Pow: func = "Power"; break;
    case Sqr: func = "Square Root"; break;
    case Cos: func = "Cosine"; break;
    case Sin: func = "Sine"; break;
    case Atn: func = "Arc Tangent"; break;
    case Log: func = "Logarithm"; break;
    case Exp: func = "Exponantial"; break;
    case Qui: func = "Quit"; break;
    case Hel: func = "Help"; break;
    }

    PRINTOUT ("Function: %s\n", func);

    if ((root->func == Val) && (root->ops[0] == NULL)) {
        for (i = 0; i < level; i++) {
            PRINTOUT (" ");
        }
        PRINTOUT ("value: %f\n", root->value);
    } else {
        for (i = 0; i < root->nbops; i++) {
            print_element (root->ops[i], level + 1);
        }
    }
}

/* quit function */

void quit (void)
{
    PRINTOUT ("bye\n");
    exit (0);
}

/* help message */

void help (void)
{
    PRINTOUT ("calc is a simple calculator\n\n");
    PRINTOUT ("supported operators:\n");
    PRINTOUT (" + - * / %% ^\n\n");
    PRINTOUT ("supported functions:\n");
    PRINTOUT (" pow sqrt cos sin atan log exp\n\n");
    PRINTOUT ("miscellaneous functions:\n");
    PRINTOUT (" quit help\n");
}

/* evaluate element tree */

#define MASK_SUB 0x1
#define MASK_DIV 0x2

double evaluate_element (element_t *root, char mask)
{
    double op0 = 0, op1 = 0;
    char nextmask = mask;

    if ((root == NULL) || (root == ERROR_OP)) {
        VERBOSE (WARNING, PRINTOUT ("error while evaluating\n"));
        return 0;
    }

    /* mask to manage sub operator sub and div */
    switch (root->func) {
    case Add:
        nextmask &= ~MASK_SUB;
        nextmask &= ~MASK_DIV;
        break;
    case Sub:
        nextmask |= MASK_SUB;
        nextmask &= ~MASK_DIV;
        break;
    case Mul:
        nextmask &= ~MASK_DIV;
        break;
    case Div:
        nextmask |= MASK_DIV;
        break;
    default:
        nextmask = mask;
    }

    switch (root->func) {
    case Val:
    case Sig:
        op0 = (root->ops[0]) ? evaluate_element (root->ops[0], nextmask) : root->value;
        break;
    case Add:
    case Sub:
    case Mul:
    case Div:
    case Mod:
    case Pow:
        if (root->ops[1]) {
            op1 = evaluate_element (root->ops[1], nextmask);
        } else {
            VERBOSE (WARNING, PRINTOUT ("error while evaluating (op[1])\n"));
            return 0;
        }
        /* fallthrough */
    case Sqr:
    case Cos:
    case Sin:
    case Atn:
    case Log:
    case Exp:
        if (root->ops[0]) {
            op0 = evaluate_element (root->ops[0], 0);
        } else {
            VERBOSE (WARNING, PRINTOUT ("error while evaluating (op[0])\n"));
            return 0;
        }
        break;
    case Qui:
    case Hel:
        break;
    }

    switch (root->func) {
    case Val: return op0;
    case Sig: return -op0;
    case Add: return ((mask & MASK_SUB) == 0) ? op0 + op1 : op0 - op1;
    case Sub: return ((mask & MASK_SUB) == 0) ? op0 - op1 : op0 + op1;
    case Mul: return ((mask & MASK_DIV) == 0) ? op0 * op1 : op0 / op1;
    case Div: return ((mask & MASK_DIV) == 0) ? op0 / op1 : op0 * op1;
    case Mod: return fmod (op0, op1);
    case Pow: return pow (op0, op1);
    case Sqr: return sqrt (op0);
    case Cos: return cos (op0);
    case Sin: return sin (op0);
    case Atn: return atan (op0);
    case Log: return log (op0);
    case Exp: return exp (op0);
    case Qui: quit (); break;
    case Hel: help (); break;
    }

    return 0;
}

/* vim: set ts=4 sw=4 et: */
Commit	Line	Data
bc97a989	1	#include <malloc.h>
f2927108	2	#include <math.h>
bc97a989 LM	3	#include <stdlib.h>
	4
	5	#include "debug.h"
	6	#include "fdprintf.h"
	7
	8	#include "parser.h"
	9
	10	/* compare codes */
	11
	12	int codecmp (char ref, char str)
	13	{
	14	int sig;
	15
	16	while (*ref != '\0') {
0b9cc9b0 LM	17	if (*ref == '\t') {
	18	sig = (str == '.') ? -1 : ((str >= '0') && (*str <= '9'));
	19	} else {
	20	sig = str - ref;
	21	}
bc97a989 LM	22	if (sig != 0) {
	23	return (sig > 0) ? 1 : -1;
	24	}
0b9cc9b0 LM	25	str++;
0b9cc9b0 LM	26	ref++;
bc97a989 LM	27	}
	28
	29	return 0;
	30	}
	31
	32	/* allocate new element */
	33
11cda8d7	34	element_t *newelement (func_t function, int nbops, int prio)
bc97a989 LM	35	{
	36	element_t new = (element_t ) calloc (1, sizeof (element_t));
	37	if (new == NULL) {
	38	VERBOSE (ERROR, fdprintf (stdfderr, "can't allocate memory\n"));
	39	return NULL;
	40	}
	41	new->func = function;
	42	new->nbops = nbops;
11cda8d7	43	new->prio = prio;
bc97a989 LM	44
	45	return new;
	46	}
	47
031d7bba LM	48	/* desallocate element */
	49
	50	void delelement (element_t *root)
	51	{
	52	int i;
	53	if ((root != NULL) && (root != ERROR_OP)) {
	54	for (i = 0; i < root->nbops; i++) {
	55	if ((root->ops[i] != NULL) && (root->ops[i] != ERROR_OP)) {
	56	delelement (root->ops[i]);
	57	}
	58	}
	59	free (root);
	60	}
	61	}
	62
bc97a989 LM	63	/* functions */
bc97a989 LM	64
c47a9298	65	#define NB_OPERATORS 6
bc97a989 LM	66
bc97a989 LM	67	keyword_t operators[NB_OPERATORS] = {
11cda8d7 LM	68	{ "+\t", Add, 2, 1, 1},
	69	{ "-\t", Sub, 2, 1, 1},
	70	{ "*", Mul, 2, 1, 2},
	71	{ "/", Div, 2, 1, 2},
c47a9298 LM	72	{ "%", Mod, 2, 1, 3},
c47a9298 LM	73	{ "^", Pow, 2, 1, 4}
bc97a989 LM	74	};
bc97a989 LM	75
89cf0955	76	#define NB_FUNCTIONS 9
bc97a989	77	keyword_t functions[NB_FUNCTIONS] = {
c47a9298 LM	78	{ "sqrt", Sqr, 1, 4, 5},
	79	{ "pow", Pow, 2, 3, 5},
	80	{ "cos", Cos, 1, 3, 5},
	81	{ "sin", Sin, 1, 3, 5},
	82	{ "atan", Atn, 1, 4, 5},
	83	{ "exp", Exp, 1, 3, 5},
89cf0955 LM	84	{ "log", Log, 1, 3, 5},
	85	{ "quit", Qui, 0, 4, 5},
	86	{ "help", Hel, 0, 4, 5}
bc97a989 LM	87	};
bc97a989 LM	88
d2ff8478 LM	89	/* subparser function */
	90
	91	element_t subparser (element_t proot, char *pstr, func_t func, int nbops, int prio)
	92	{
	93	element_t *new = newelement (func, nbops, prio);
	94	if (new == NULL) {
	95	return ERROR_OP;
	96	}
	97	new->ops[0] = *proot;
	98	new->ops[1] = parser (*pstr, pstr, new->prio);
	99	if (new->ops[1] == ERROR_OP) {
031d7bba LM	100	delelement (new);
031d7bba LM	101	*proot = NULL;
d2ff8478 LM	102	return ERROR_OP;
d2ff8478 LM	103	}
3b4b0bbe	104	*proot = newelement (Val, 1, 5);
031d7bba LM	105	if (*proot == NULL) {
031d7bba LM	106	delelement (new);
d2ff8478 LM	107	return ERROR_OP;
	108	}
	109	(*proot)->ops[0] = new;
	110
	111	return *proot;
	112	}
	113
bc97a989 LM	114	/* parser function */
bc97a989 LM	115
ef37d966	116	element_t parser (char str, char **next, int prio)
0b489a77	117	{
bc97a989	118	element_t *root = NULL;
85b4a72c	119	int i;
bc97a989	120
49223129 LM	121	VERBOSE (DEBUG, PRINTOUT ("Starting parsing\n"));
49223129 LM	122
bc97a989 LM	123	/* main loop */
	124	while (*str != '\0') {
	125	int found = 0;
	126	element_t *new = NULL;
49223129	127	VERBOSE (INFO, PRINTOUT ("Processing: %s\n", str));
bc97a989 LM	128
	129	/* skip spaces and tabs */
	130
	131	if ((str == ' ') \|\| (str == '\t')) {
	132	str++;
	133	continue;
	134	}
	135
85b4a72c	136	/* check for open bracket */
0b489a77	137
0b489a77	138	if (*str == '(') {
49223129	139	VERBOSE (DEBUG, PRINTOUT ("start processing bracket\n"));
0b489a77	140	if (root) {
85b4a72c LM	141	do {
85b4a72c LM	142	found = 0;
ef37d966	143	new = parser (str + 1, &str, 0);
85b4a72c	144	if (new == ERROR_OP) {
031d7bba	145	delelement (root);
85b4a72c LM	146	return ERROR_OP;
	147	}
	148	for (i = 0; i < root->nbops; i++) {
	149	if (root->ops[i] == NULL) {
0b489a77 LM	150	root->ops[i] = new;
	151	found = 1;
	152	break;
	153	}
	154	}
85b4a72c	155	if (!found) {
031d7bba LM	156	delelement (new);
031d7bba LM	157	delelement (root);
85b4a72c LM	158	return ERROR_OP;
	159	}
	160	} while (*str == ',');
	161	} else {
3b4b0bbe	162	root = newelement (Val, 1, 5);
85b4a72c	163	if (root == NULL) {
0b489a77 LM	164	return ERROR_OP;
0b489a77 LM	165	}
ef37d966	166	new = parser (str + 1, &str, 0);
85b4a72c	167	if ((new == ERROR_OP) \|\| (*str == ',')) {
031d7bba LM	168	delelement (new);
031d7bba LM	169	delelement (root);
efdfb543 LM	170	return ERROR_OP;
efdfb543 LM	171	}
85b4a72c	172	root->ops[0] = new;
0b489a77	173	}
85b4a72c	174	str++;
49223129	175	VERBOSE (DEBUG, PRINTOUT ("stop processing bracket\n"));
efdfb543	176	continue;
49223129	177	}
85b4a72c LM	178
	179	/* check for closing bracket or koma */
	180
	181	if ((str == ')') \|\| (str == ',')) {
49223129	182	if (next != NULL) {
85b4a72c	183	*next = str;
49223129 LM	184	}
49223129 LM	185	return root;
0b489a77 LM	186	}
0b489a77 LM	187
bc97a989 LM	188	/* look for operators */
	189
	190	for (i = 0; i < NB_OPERATORS; i++) {
	191	keyword_t *operator = operators + i;
	192	if (codecmp (operator->keyword, str) == 0) {
49223129	193	VERBOSE (DEBUG, PRINTOUT ("start processing operator\n"));
11cda8d7	194	if (root) {
ef37d966	195	if ((prio) && (prio > operator->prio)) {
c47a9298	196	VERBOSE (DEBUG, PRINTOUT ("stop because operator priority\n"));
ef37d966 LM	197	*next = str;
	198	return root;
	199	}
	200	str += operator->offset;
49223129	201	VERBOSE (INFO, PRINTOUT ("Oper: %d\n", operator->func));
d2ff8478	202	if (subparser (&root, &str, operator->func, operator->nbops, operator->prio) == ERROR_OP) {
031d7bba	203	delelement (root);
ef37d966	204	return ERROR_OP;
11cda8d7	205	}
3b4b0bbe LM	206	} else if (*str == '-') {
	207	new = newelement (Sig, 1, 9);
	208	if (new == NULL) {
	209	return ERROR_OP;
	210	}
	211	root = new;
49223129	212	} else {
0b489a77	213	return ERROR_OP;
bc97a989	214	}
bc97a989	215	found = 1;
49223129	216	VERBOSE (DEBUG, PRINTOUT ("stop processing operator\n"));
bc97a989 LM	217	break;
	218	}
	219	}
	220	if (found) {
bc97a989 LM	221	continue;
bc97a989 LM	222	}
49223129	223
bc97a989 LM	224	/* look for functions */
	225
	226	for (i = 0; i < NB_FUNCTIONS; i++) {
	227	keyword_t *function = functions + i;
	228	if (codecmp (function->keyword, str) == 0) {
49223129	229	VERBOSE (DEBUG, PRINTOUT ("start processing function\n"));
bc97a989	230	if (root == NULL) {
49223129	231	VERBOSE (INFO, PRINTOUT ("Func: %d\n", function->func));
11cda8d7	232	new = newelement (function->func, function->nbops, function->prio);
bc97a989	233	if (new == NULL) {
0b489a77	234	return ERROR_OP;
bc97a989 LM	235	}
bc97a989 LM	236	root = new;
031d7bba LM	237	} else {
031d7bba LM	238	delelement (root);
0b489a77	239	return ERROR_OP;
bc97a989 LM	240	}
	241	str += function->offset;
	242	found = 1;
49223129	243	VERBOSE (DEBUG, PRINTOUT ("stop processing function\n"));
bc97a989 LM	244	break;
	245	}
	246	}
	247	if (found) {
bc97a989 LM	248	continue;
	249	}
	250
bc97a989 LM	251	/* look for number */
bc97a989 LM	252
0b9cc9b0 LM	253	if (((str >= '0') && (str <= '9')) \|\|
0b9cc9b0 LM	254	(str == '.') \|\| (str == '+') \|\| (*str == '-')) {
49223129	255	VERBOSE (DEBUG, PRINTOUT ("start processing value\n"));
bc97a989	256	char *pt;
fd88e359	257	double value = strtod (str, &pt);
49223129	258	VERBOSE (INFO, PRINTOUT ("Value: %f\n", value));
bc97a989	259	if (str != pt) {
bc97a989	260	if (root == NULL) {
3b4b0bbe	261	new = newelement (Val, 1, 5);
c47a9298 LM	262	if (new == NULL) {
	263	return ERROR_OP;
	264	}
	265	new->value = value;
bc97a989	266	root = new;
c47a9298	267	str = pt;
0b9cc9b0 LM	268	} else if (root->func == Val) {
0b9cc9b0 LM	269	if ((str == '+') \|\| (str == '-')) {
c47a9298 LM	270	if ((prio) && (prio > 1)) {
	271	VERBOSE (DEBUG, PRINTOUT ("stop because operator priority\n"));
	272	*next = str;
	273	return root;
	274	}
d2ff8478	275	if (subparser (&root, &str, Add, 2, 1) == ERROR_OP) {
031d7bba	276	delelement (root);
0b489a77 LM	277	return ERROR_OP;
0b489a77 LM	278	}
0b9cc9b0	279	} else {
031d7bba	280	delelement (root);
0b489a77	281	return ERROR_OP;
bc97a989	282	}
0b9cc9b0	283	} else {
031d7bba	284	delelement (root);
0b9cc9b0	285	return ERROR_OP;
bc97a989	286	}
bc97a989 LM	287	found = 1;
bc97a989 LM	288	}
49223129	289	VERBOSE (DEBUG, PRINTOUT ("stop processing value\n"));
bc97a989 LM	290	}
	291
	292	/* error */
	293
	294	if (!found) {
031d7bba	295	delelement (root);
0b489a77	296	return ERROR_OP;
bc97a989 LM	297	}
	298
	299	}
	300
49223129 LM	301	if (next != NULL) {
	302	*next = str;
	303	}
031d7bba	304
bc97a989 LM	305	return root;
	306	}
	307
	308	/* print element tree */
	309
	310	void print_element (element_t *root, int level)
	311	{
	312	char *func = NULL;
	313	int i;
	314
49223129	315	if ((root == NULL) \|\| (root == ERROR_OP)) {
bc97a989	316	return;
49223129 LM	317	}
49223129 LM	318
bc97a989 LM	319	for (i = 0; i < level; i++) {
	320	PRINTOUT (" ");
	321	}
	322
	323	switch (root->func) {
	324	case Val: func = "Value"; break;
89cf0955	325	case Sig: func = "Sign"; break;
bc97a989 LM	326	case Add: func = "Addition"; break;
	327	case Sub: func = "Subtraction"; break;
	328	case Mul: func = "Multiplication"; break;
	329	case Div: func = "Division"; break;
c47a9298	330	case Mod: func = "Modulo"; break;
bc97a989 LM	331	case Pow: func = "Power"; break;
	332	case Sqr: func = "Square Root"; break;
	333	case Cos: func = "Cosine"; break;
	334	case Sin: func = "Sine"; break;
	335	case Atn: func = "Arc Tangent"; break;
	336	case Log: func = "Logarithm"; break;
	337	case Exp: func = "Exponantial"; break;
89cf0955 LM	338	case Qui: func = "Quit"; break;
89cf0955 LM	339	case Hel: func = "Help"; break;
bc97a989 LM	340	}
	341
	342	PRINTOUT ("Function: %s\n", func);
	343
85b4a72c	344	if ((root->func == Val) && (root->ops[0] == NULL)) {
bc97a989 LM	345	for (i = 0; i < level; i++) {
	346	PRINTOUT (" ");
	347	}
	348	PRINTOUT ("value: %f\n", root->value);
	349	} else {
	350	for (i = 0; i < root->nbops; i++) {
	351	print_element (root->ops[i], level + 1);
	352	}
	353	}
	354	}
	355
89cf0955 LM	356	/* quit function */
	357
	358	void quit (void)
	359	{
	360	PRINTOUT ("bye\n");
	361	exit (0);
	362	}
	363
	364	/* help message */
	365
	366	void help (void)
	367	{
	368	PRINTOUT ("calc is a simple calculator\n\n");
	369	PRINTOUT ("supported operators:\n");
5fe6254a	370	PRINTOUT (" + - * / %% ^\n\n");
89cf0955 LM	371	PRINTOUT ("supported functions:\n");
	372	PRINTOUT (" pow sqrt cos sin atan log exp\n\n");
	373	PRINTOUT ("miscellaneous functions:\n");
	374	PRINTOUT (" quit help\n");
	375	}
3b4b0bbe	376
f2927108 LM	377	/* evaluate element tree */
f2927108 LM	378
89cf0955 LM	379	#define MASK_SUB 0x1
	380	#define MASK_DIV 0x2
	381
3b4b0bbe	382	double evaluate_element (element_t *root, char mask)
f2927108 LM	383	{
f2927108 LM	384	double op0 = 0, op1 = 0;
3b4b0bbe	385	char nextmask = mask;
f2927108 LM	386
	387	if ((root == NULL) \|\| (root == ERROR_OP)) {
	388	VERBOSE (WARNING, PRINTOUT ("error while evaluating\n"));
	389	return 0;
	390	}
	391
3b4b0bbe LM	392	/* mask to manage sub operator sub and div */
	393	switch (root->func) {
	394	case Add:
	395	nextmask &= ~MASK_SUB;
	396	nextmask &= ~MASK_DIV;
	397	break;
	398	case Sub:
	399	nextmask \|= MASK_SUB;
	400	nextmask &= ~MASK_DIV;
	401	break;
	402	case Mul:
	403	nextmask &= ~MASK_DIV;
	404	break;
	405	case Div:
	406	nextmask \|= MASK_DIV;
	407	break;
	408	default:
	409	nextmask = mask;
	410	}
	411
f2927108 LM	412	switch (root->func) {
f2927108 LM	413	case Val:
3b4b0bbe LM	414	case Sig:
3b4b0bbe LM	415	op0 = (root->ops[0]) ? evaluate_element (root->ops[0], nextmask) : root->value;
f2927108 LM	416	break;
	417	case Add:
	418	case Sub:
	419	case Mul:
	420	case Div:
c47a9298	421	case Mod:
f2927108 LM	422	case Pow:
f2927108 LM	423	if (root->ops[1]) {
3b4b0bbe	424	op1 = evaluate_element (root->ops[1], nextmask);
f2927108 LM	425	} else {
	426	VERBOSE (WARNING, PRINTOUT ("error while evaluating (op[1])\n"));
	427	return 0;
	428	}
	429	/* fallthrough */
	430	case Sqr:
	431	case Cos:
	432	case Sin:
	433	case Atn:
	434	case Log:
	435	case Exp:
	436	if (root->ops[0]) {
3b4b0bbe	437	op0 = evaluate_element (root->ops[0], 0);
f2927108 LM	438	} else {
	439	VERBOSE (WARNING, PRINTOUT ("error while evaluating (op[0])\n"));
	440	return 0;
	441	}
89cf0955 LM	442	break;
	443	case Qui:
	444	case Hel:
	445	break;
f2927108 LM	446	}
	447
	448	switch (root->func) {
3b4b0bbe LM	449	case Val: return op0;
	450	case Sig: return -op0;
	451	case Add: return ((mask & MASK_SUB) == 0) ? op0 + op1 : op0 - op1;
	452	case Sub: return ((mask & MASK_SUB) == 0) ? op0 - op1 : op0 + op1;
	453	case Mul: return ((mask & MASK_DIV) == 0) ? op0 * op1 : op0 / op1;
	454	case Div: return ((mask & MASK_DIV) == 0) ? op0 / op1 : op0 * op1;
c47a9298	455	case Mod: return fmod (op0, op1);
f2927108 LM	456	case Pow: return pow (op0, op1);
	457	case Sqr: return sqrt (op0);
	458	case Cos: return cos (op0);
	459	case Sin: return sin (op0);
	460	case Atn: return atan (op0);
	461	case Log: return log (op0);
	462	case Exp: return exp (op0);
89cf0955 LM	463	case Qui: quit (); break;
89cf0955 LM	464	case Hel: help (); break;
f2927108 LM	465	}
	466
	467	return 0;
	468	}
	469
bc97a989	470	/* vim: set ts=4 sw=4 et: */