A Stream Class for Calling Perl from C++

Listing 1: Example code using PerlStream and PerlValue

PerlStream ps;

// Have Perl do simple addition in a scalar context
ps << "10+5" << perl_execute;
int fifteen = ps[0];
   
// Return a list of values, including a hash reference
ps.array() << "(2,5,{'a'=>'foo', 'b'=>'bar'})" << perl_execute;
int two = ps[0]; // line 9
double five = ps[-2]; // line 10
string foo = ps[2]["a"]; // line 11

ps.voidc() << "require Cwd;" << perl_execute;  // void context

// Bad string of references are tolerated
int undefined = ps[0]["a"][-3]["bar"];         // line 16; undefined = 0

// iterate over an array and hash
ps.array() << "( [4, 9, 16], {'a'=>25, 'b'=>36, 'c'=>49} )" <<
    perl_execute;
PerlValue::array_iter ai; // line 21
for (ai = ps[0].array_begin(); ai != ps[0].array_end(); ++ai) {
  if (ai->isInt())
    cout << "Value = " << static_cast<int>(*ai) << endl;
}
PerlValue::hash_iter hi; // line 26
for (hi = ps[1].hash_begin(); hi != ps[1].hash_end(); ++hi) {
  cout << "Key=" << hi->first << " Val=" << hi->second << endl;
}

// Cause an evaluation exception
ps.setExceptionFlags(PerlStream::eEvalFail);
try { // line 33
  ps << "[ 10, 15" << perl_execute;       // Missing ']'
}
catch (exception &e) {
  cerr << "Error: " << e.what() << endl;  // e is PerlEvalError
}
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