xo-alloc/xo-reader/examples/exprrepl/exprrepl.cpp

61 lines
1.2 KiB
C++

/** @file exprrepl.cpp **/
#include "xo/reader/reader.hpp"
#include <iostream>
#include <unistd.h> // for isatty
bool repl_getline(bool interactive, std::istream& in, std::ostream& out, std::string& input)
{
if (interactive) {
out << "> ";
std::flush(out);
}
bool retval = static_cast<bool>(std::getline(in, input));
if (retval) {
// want reader to see newline, it's syntax
input.push_back('\n');
}
return retval;
}
int
main() {
using namespace xo::scm;
using namespace std;
using span_type = xo::scm::span<const char>;
bool interactive = isatty(STDIN_FILENO);
reader rdr;
rdr.begin_interactive_session();
string input_str;
bool eof = false;
span_type input;
while (repl_getline(interactive, cin, cout, input_str)) {
input = span_type::from_string(input_str);
while (!input.empty()) {
auto [expr, consumed] = rdr.read_expr(input, eof);
if (expr) {
cout << expr << endl;
}
input = input.after_prefix(consumed);
}
}
auto [expr, _] = rdr.read_expr(input, true /*eof*/);
if (expr) {
cout << expr << endl;
}
}