Value* Value_eval(const Value* val, const Context* ctx) {
if(val == NULL) return ValErr(nullError());
Value* ret;
Variable* var;
switch(val->type) {
/* These can be evaluated to a simpler form */
case VAL_EXPR:
ret = BinOp_eval(val->expr, ctx);
break;
case VAL_UNARY:
ret = UnOp_eval(val->term, ctx);
break;
case VAL_CALL:
ret = FuncCall_eval(val->call, ctx);
break;
case VAL_FRAC:
ret = Value_copy(val);
Fraction_reduce(ret);
break;
case VAL_VAR:
var = Variable_get(ctx, val->name);
if(var) {
ret = Variable_eval(var, ctx);
}
else {
ret = ValErr(varNotFound(val->name));
}
break;
case VAL_VEC:
ret = Vector_eval(val->vec, ctx);
break;
/* These can't be simplified, so just copy them */
case VAL_INT:
case VAL_REAL:
case VAL_NEG:
case VAL_ERR:
ret = Value_copy(val);
break;
default:
/* Shouldn't be reached */
badValType(val->type);
}
return ret;
}
Value* Expression_eval(Expression* expr, Context* ctx) {
Value* ret;
Variable* var = expr->var;
if(var->type == VAR_VALUE) {
/* Evaluate right side */
ret = Value_eval(var->val, ctx);
/* If an error occurred, bail */
if(ret->type == VAL_ERR)
return ret;
/* Variable assignment? */
if(ret->type == VAL_VAR) {
/* This means ret must be a function */
Variable* func = Variable_get(ctx, ret->name);
if(func == NULL) {
Value* err = ValErr(varNotFound(ret->name));
Value_free(ret);
return err;
}
if(func->type == VAR_BUILTIN) {
Value_free(ret);
return ValErr(typeError("Cannot assign a variable to a builtin value."));
}
if(var->name != NULL) {
Context_setGlobal(ctx, var->name, Variable_copy(func));
}
}
else {
/* This means ret must be a Value */
Value_free(var->val);
var->val = Value_copy(ret);
/* Update ans */
Context_setGlobal(ctx, "ans", Variable_copy(var));
/* Save the newly evaluated variable */
if(var->name != NULL)
Context_setGlobal(ctx, var->name, Variable_copy(var));
}
}
else if(var->type == VAR_FUNC) {
ret = ValVar(var->name);
Context_setGlobal(ctx, var->name, Variable_copy(var));
}
else {
badVarType(var->type);
}
return ret;
}
Value* Value_coerce(const Value* val, const Context* ctx) {
Value* ret = Value_eval(val, ctx);
if(ret->type == VAL_VAR) {
Variable* var = Variable_get(ctx, ret->name);
if(var == NULL) {
Value* tmp = ValErr(varNotFound(ret->name));
Value_free(ret);
ret = tmp;
}
else {
ret = Variable_coerce(var, ctx);
}
}
return ret;
}
