xo-pyexpression/include/xo/interpreter2/VsmFrame.hpp

86 lines
2.7 KiB
C++

/** @file VsmFrame.hpp
*
* @author Roland Conybeare, Feb 2026
**/
#pragma once
#include "VsmInstr.hpp"
#include <xo/procedure2/Procedure.hpp>
#include <xo/object2/DArray.hpp>
namespace xo {
namespace scm {
class VsmFrame {
public:
VsmFrame(VsmFrame * parent, VsmInstr cont) : parent_{parent}, cont_{cont} {}
VsmFrame * parent() const noexcept { return parent_; }
VsmInstr cont() const noexcept { return cont_; }
protected:
/** saved VSM stack; restore when this frame consumed **/
VsmFrame * parent_ = nullptr;
/** saved continuation; restore when this frame consumed **/
VsmInstr cont_;
};
class VsmApplyFrame : public VsmFrame {
public:
using AProcedure = xo::scm::AProcedure;
using AAllocator = xo::mm::AAllocator;
public:
VsmApplyFrame(VsmFrame * old_parent,
VsmInstr old_cont,
DArray * args);
static VsmApplyFrame * make(obj<AAllocator> mm,
VsmFrame * old_parent,
VsmInstr old_cont,
DArray * args);
obj<AProcedure> fn() const noexcept { return fn_; }
DArray * args() const noexcept { return args_; }
private:
/** evaluated target procedure.
*
* note: when initially created, this will be unpopulated;
* don't know correct value until we evaluate
* expression in head position
**/
obj<AProcedure> fn_;
/** evaluated arguments (to target procedure) **/
DArray * args_;
};
/** frame for executing an apply expression **/
class VsmEvalArgsFrame : public VsmFrame {
public:
using AAllocator = xo::mm::AAllocator;
public:
/** see picture in VirtualSchematikaMachine._do_eval_apply_op()
*
* old_parent = [apply frame]
* old_cont = [xfer to called function]
*
**/
VsmEvalArgsFrame(VsmApplyFrame * old_parent,
VsmInstr old_cont);
static VsmEvalArgsFrame * make(obj<AAllocator> mm,
VsmApplyFrame * apply_frame,
VsmInstr old_cont);
private:
/** next argument to be evaluated. -1 means function head **/
int32_t i_arg_ = -1;
};
} /*namespace scm*/
} /*namespace xo*/
/* end VsmFrame.hpp */