xo-alloc/xo-interpreter/include/xo/interpreter/VirtualSchematikaMachine.hpp

66 lines
1.9 KiB
C++

/** @file VirtualSchematikaMachine.hpp **/
#pragma once
#include "VsmInstr.hpp"
#include "SchematikaError.hpp"
#include "xo/expression/Expression.hpp"
#include "xo/alloc/Object.hpp"
namespace xo {
namespace scm {
/** @class VirtualSchematikaMachine
* @brief Virtual machine implementing a Schematika interpreter
*
**/
class VirtualSchematikaMachine {
public:
VirtualSchematikaMachine();
/** evaluate expression @p expr.
* borrows calling thread until completion
* return [value, error]. error ignored unless value is nullptr.
* conversely when value is nullptr, error gives details of original
* error.
**/
std::pair<gp<Object>, SchematikaError> eval(bp<Expression> expr);
private:
/** borrow calling thread to run schematika machine
* indefinitely, or until null continuation
**/
void run();
/** execute vsm instruction @p pc
* Note: may possibly be able to replace with just opcode
**/
void execute_vsm(const VsmInstr * pc);
/** implementation class; contains instruction implementations **/
friend class VsmOps;
private:
/** program counter.
* (Perhaps replace with VsmInstr::Opcode ?)
**/
const VsmInstr * pc_ = nullptr;
/** expression **/
rp<Expression> expr_;
/** non-error result value from eval() / apply() **/
gp<Object> value_;
/** error result value from eval() / apply() **/
SchematikaError error_;
/** continuation
* (Perhaps replace with VsmInstr::Opcode ?)
**/
const VsmInstr * cont_ = nullptr;
};
} /*namespace scm*/
} /*namespace xo*/
/* end VirtualSchematikaMachine.hpp */