static string pop_check(std.stack <string> stk, string expr)
{
if (stk.empty())
{
throw new pexception(new plib.pfmt("pfunction: stack underflow during infix parsing of: <{0}>").op(expr));
}
string res = stk.top();
stk.pop();
return(res);
}
public void compile_infix(string expr, std.vector <string> inputs) //void compile_infix(const pstring &expr, const inputs_container &inputs = inputs_container()) noexcept(false);
{
// Shunting-yard infix parsing
std.vector <string> sep = new std.vector <string> {
"(", ")", ",", "*", "/", "+", "-", "^", "<=", ">=", "==", "!=", "<", ">"
};
std.vector <string> sexpr2 = plib.pg.psplit(plib.pg.replace_all(expr, " ", ""), sep);
std.stack <string> opstk = new std.stack <string>();
std.vector <string> postfix = new std.vector <string>();
std.vector <string> sexpr1 = new std.vector <string>();
std.vector <string> sexpr = new std.vector <string>();
// FIXME: We really need to switch to ptokenizer and fix negative number
// handling in ptokenizer.
// copy/paste to the int version below
// Fix numbers exponential numbers
for (size_t i = 0; i < sexpr2.size();)
{
if (i + 2 < sexpr2.size() && sexpr2[i].length() > 1)
{
var r = plib.pg.right(sexpr2[i], 1);
var ne = sexpr2[i + 1];
if (is_number(sexpr2[i]) &&
(r == "e" || r == "E") &&
(ne == "-" || ne == "+"))
{
sexpr1.push_back(sexpr2[i] + ne + sexpr2[i + 2]);
i += 3;
}
else
{
sexpr1.push_back(sexpr2[i++]);
}
}
else
{
sexpr1.push_back(sexpr2[i++]);
}
}
// Fix numbers with unary minus/plus
for (size_t i = 0; i < sexpr1.size();)
{
if (sexpr1[i] == "-" && (i + 1 < sexpr1.size()) && is_number(sexpr1[i + 1]))
{
if (i == 0 || !(is_number(sexpr1[i - 1]) || sexpr1[i - 1] == ")" || is_id(sexpr1[i - 1])))
{
sexpr.push_back("-" + sexpr1[i + 1]);
i += 2;
}
else
{
sexpr.push_back(sexpr1[i++]);
}
}
else if (sexpr1[i] == "-" && (i + 1 < sexpr1.size()) && (is_id(sexpr1[i + 1]) || sexpr1[i + 1] == "("))
{
if (i == 0 || !(is_number(sexpr1[i - 1]) || sexpr1[i - 1] == ")" || is_id(sexpr1[i - 1])))
{
sexpr.emplace_back("neg");
sexpr.push_back(sexpr1[i + 1]);
i += 2;
}
else
{
sexpr.push_back(sexpr1[i++]);
}
}
else
{
sexpr.push_back(sexpr1[i++]);
}
}
for (size_t i = 0; i < sexpr.size(); i++)
{
string s = sexpr[i];
if (s == "(")
{
opstk.push(s);
}
else if (s == ")")
{
string x = pop_check(opstk, expr);
while (x != "(")
{
postfix.push_back(x);
x = pop_check(opstk, expr);
}
if (!opstk.empty() && get_prio(opstk.top()) == 0)
{
postfix.push_back(pop_check(opstk, expr));
}
}
else if (s == ",")
{
string x = pop_check(opstk, expr);
while (x != "(")
{
postfix.push_back(x);
x = pop_check(opstk, expr);
}
opstk.push(x);
}
else
{
int prio = get_prio(s);
if (prio > 0)
{
if (opstk.empty())
{
opstk.push(s);
}
else
{
if (get_prio(opstk.top()) >= prio)
{
postfix.push_back(pop_check(opstk, expr));
}
opstk.push(s);
}
}
else if (prio == 0) // Function or variable
{
if ((i + 1 < sexpr.size()) && sexpr[i + 1] == "(")
{
opstk.push(s);
}
else
{
postfix.push_back(s);
}
}
else
{
postfix.push_back(s);
}
}
}
while (!opstk.empty())
{
postfix.push_back(opstk.top());
opstk.pop();
}
//for (auto &e : postfix)
// printf("\t%s\n", e.c_str());
compile_postfix(inputs, postfix, expr);
}