double eval(struct ast *a) {
double v;
if(!a) { // default value
return 0.0;
}
switch(a->nodetype) {
// constant number
case 'K': v = ((struct numval *)a)->number; break;
// name reference
case 'N': v = ((struct symref *)a)->s->value; break;
// assignment
case '=': v = ((struct symasgn *)a)->s->value = eval(((struct symasgn *)a)->v); break;
// expressions
case '+': v = eval(a->l) + eval(a->r); break;
case '-': v = eval(a->l) - eval(a->r); break;
case '*': v = eval(a->l) * eval(a->r); break;
case '/': v = eval(a->l) / eval(a->r); break;
case '|': v = fabs(eval(a->l)); break;
case 'M': v = -eval(a->l); break;
// comparisons
case '1': v = (eval(a->l) > eval(a->r))? 1 : 0; break;
case '2': v = (eval(a->l) < eval(a->r))? 1 : 0; break;
case '3': v = (eval(a->l) != eval(a->r))? 1 : 0; break;
case '4': v = (eval(a->l) == eval(a->r))? 1 : 0; break;
case '5': v = (eval(a->l) >= eval(a->r))? 1 : 0; break;
case '6': v = (eval(a->l) <= eval(a->r))? 1 : 0; break;
// if flow
case 'I':
if( eval( ((struct flow *)a)->cond) != 0) {
if( ((struct flow *)a)->tl) { // else branch if exists
v = eval( ((struct flow *)a)->tl);
} else {
v = 0.0; // default value
}
} else {
if( ((struct flow *)a)->el) { // if branch if exists
v = eval(((struct flow *)a)->el);
} else {
v = 0.0; // default value
}
}
break;
case 'W': // while flow
v = 0.0; /* default value */
if( ((struct flow *)a)->tl) {
while( eval(((struct flow *)a)->cond) != 0) { // loop
v = eval(((struct flow *)a)->tl);
}
}
break; // last value is the value returned
// define user function
case 'L': eval(a->l); v = eval(a->r); break;
// call built-in function
case 'F': v = callbuiltin((struct fncall *)a); break;
// call user-defined function
case 'C': v = calluser((struct ufncall *)a); break;
// error
default: printf("internal error: bad node %c\n", a->nodetype);
}
return v;
}
double
eval(struct pcdata *pp, struct ast *a)
{
double v;
if(!a) {
yyerror(pp, "internal error, null eval");
return 0.0;
}
switch(a->nodetype) {
/* constant */
case 'K': v = ((struct numval *)a)->number; break;
/* name reference */
case 'N': v = ((struct symref *)a)->s->value; break;
/* assignment */
case '=': v = ((struct symasgn *)a)->s->value =
eval(pp, ((struct symasgn *)a)->v); break;
/* expressions */
case '+': v = eval(pp, a->l) + eval(pp, a->r); break;
case '-': v = eval(pp, a->l) - eval(pp, a->r); break;
case '*': v = eval(pp, a->l) * eval(pp, a->r); break;
case '/': v = eval(pp, a->l) / eval(pp, a->r); break;
case '|': v = fabs(eval(pp, a->l)); break;
case 'M': v = -eval(pp, a->l); break;
/* comparisons */
case '1': v = (eval(pp, a->l) > eval(pp, a->r))? 1 : 0; break;
case '2': v = (eval(pp, a->l) < eval(pp, a->r))? 1 : 0; break;
case '3': v = (eval(pp, a->l) != eval(pp, a->r))? 1 : 0; break;
case '4': v = (eval(pp, a->l) == eval(pp, a->r))? 1 : 0; break;
case '5': v = (eval(pp, a->l) >= eval(pp, a->r))? 1 : 0; break;
case '6': v = (eval(pp, a->l) <= eval(pp, a->r))? 1 : 0; break;
/* control flow */
/* null if/else/do expressions allowed in the grammar, so check for them */
case 'I':
if( eval(pp, ((struct flow *)a)->cond) != 0) {
if( ((struct flow *)a)->tl) {
v = eval(pp, ((struct flow *)a)->tl);
} else
v = 0.0; /* a default value */
} else {
if( ((struct flow *)a)->el) {
v = eval(pp, ((struct flow *)a)->el);
} else
v = 0.0; /* a default value */
}
break;
case 'W':
v = 0.0; /* a default value */
if( ((struct flow *)a)->tl) {
while( eval(pp, ((struct flow *)a)->cond) != 0)
v = eval(pp, ((struct flow *)a)->tl);
}
break; /* last value is value */
case 'L': eval(pp, a->l); v = eval(pp, a->r); break;
case 'F': v = callbuiltin(pp, (struct fncall *)a); break;
case 'C': v = calluser(pp, (struct ufncall *)a); break;
default: printf("internal error: bad node %c\n", a->nodetype);
}
return v;
}
double eval(struct ast *a)
{
double v; /* calculated value of this subtree */
if(NULL == a)
{
yyerror("internal error, null eval");
return 0.0;
}
switch(a->nodetype)
{
case 'K':
v = ((struct numval *)a)->number;
break;
case 'N':
v = ((struct symref *)a)->s->value;
break;
case '=':
v = ((struct symasgn *)a)->s->value = eval( ((struct symasgn *)a)->v );
break;
case '+':
v = eval(a->l) + eval(a->r);
break;
case '-':
v = eval(a->l) - eval(a->r);
break;
case '*':
v = eval(a->l) * eval(a->r);
break;
case '/':
v = eval(a->l) / eval(a->r);
break;
case '|':
v = fabs(eval(a->l));
break;
case 'M':
v = -eval(a->l);
break;
case '1':
v = (eval(a->l) > eval(a->r)) ? 1 : 0;
break;
case '2':
v = (eval(a->l) < eval(a->r)) ? 1 : 0;
break;
case '3':
v = (eval(a->l) != eval(a->r)) ? 1 : 0;
break;
case '4':
v = (eval(a->l) == eval(a->r)) ? 1 : 0;
break;
case '5':
v = (eval(a->l) >= eval(a->r)) ? 1 : 0;
break;
case '6':
v = (eval(a->l) <= eval(a->r)) ? 1 : 0;
break;
/* control flow */
case 'I':
if( eval( ((struct flow *)a)->cond) != 0)
{
if( ((struct flow *)a)->tl )
{
v = eval( ((struct flow *)a)->tl );
}
else
v = 0.0;
}
else
{
if( ((struct flow *)a)->el )
{
v = eval( ((struct flow *)a)->el );
}
else
v = 0.0;
}
break;
case 'W':
v = 0.0;
if( ((struct flow *)a)->tl )
{
while( eval(((struct flow *)a)->cond) != 0)
v = eval(((struct flow *)a)->tl);
}
break;
case 'L':
eval(a->l);
v = eval(a->r);
break;
case 'F':
v = callbuiltin( (struct fncall *)a );
break;
case 'C':
v = calluser( (struct ufncall *)a );
break;
default:
printf("internal error: bad node %c\n", a->nodetype);
}
return v;
}
