Aegisub/OverLua/expression_engine.h

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/*
* OverLua expression engine
*
Copyright 2007 Niels Martin Hansen
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License along
with this program; if not, write to the Free Software Foundation, Inc.,
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
Contact:
E-mail: <jiifurusu@gmail.com>
IRC: jfs in #aegisub on irc.rizon.net
*/
#ifndef EXPRESSION_ENGINE_H
#define EXPRESSION_ENGINE_H
#include <vector>
#include <string>
namespace ExpressionEngine {
// The stack passed around
typedef std::vector<double> Stack;
// Type of callable functions
typedef bool (*FunctionPtr)(Stack &stack, void *data);
// A callable function
struct Function {
// The name of the function
const char *name;
// Function pointer; null for builtins
FunctionPtr function;
// Function data
void *data;
};
// A machine specification that can compile programs
struct Specification {
// The input and output register names
// The index of a register name in this vector translates to the register's number in the machine
std::vector<std::string> registers;
// The callable functions
std::vector<Function> functions;
// Just adds standard functions to functions vector
Specification();
};
// Operation type
enum Opcode {
INST_PUSH_CONST = 0,
INST_PUSH_REG,
INST_ADD,
INST_SUB,
INST_MUL,
INST_DIV,
INST_POW,
INST_UNM, // unary minus
INST_CALL,
INST_STORE
};
// A single program instruction
struct Instruction {
Opcode op;
union {
double vd; // double value, for const push
size_t vu; // uint value, for register indices
struct {
FunctionPtr vf; // function to call
void *vfd; // data for function
};
};
};
// A program is a sequence of instructions
typedef std::vector<Instruction> Program;
// A machine running a program
struct Machine {
// Values in the registers
std::vector<double> registers;
// The program
Program program;
// Run the machine.
// Return true is no errors, false if error
bool Run();
// Create a machine from a specification and a program source
Machine(const Specification &spec, const char *source);
};
};
#endif