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LUAK - Kotlin port of LuaJ (fork of https://github.com/korlibs/korge-luak)
/*******************************************************************************
* Copyright (c) 2010-2011 Luaj.org. All rights reserved.
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
package org.luaj.vm2
import org.luaj.vm2.internal.runBlockingNoSuspensions
/**
* Subclass of [Varargs] that represents a lua tail call
* in a Java library function execution environment.
*
*
* Since Java doesn't have direct support for tail calls,
* any lua function whose [Prototype] contains the
* [Lua.OP_TAILCALL] bytecode needs a mechanism
* for tail calls when converting lua-bytecode to java-bytecode.
*
*
* The tail call holds the next function and arguments,
* and the client a call to [.eval] executes the function
* repeatedly until the tail calls are completed.
*
*
* Normally, users of luaj need not concern themselves with the
* details of this mechanism, as it is built into the core
* execution framework.
* @see Prototype
*
* @see org.luaj.vm2.luajc.LuaJC
*/
class TailcallVarargs : Varargs {
private var func: LuaValue? = null
private var args: Varargs? = null
private var result: Varargs? = null
constructor(f: LuaValue, args: Varargs) {
this.func = f
this.args = args
}
constructor(`object`: LuaValue, methodname: LuaValue, args: Varargs) {
this.func = `object`.get(methodname)
this.args = LuaValue.varargsOf(`object`, args)
}
override fun isTailcall(): Boolean {
return true
}
override suspend fun evalSuspend(): Varargs {
while (result == null) {
val r = func!!.onInvokeSuspend(args!!)
if (r.isTailcall()) {
val t = r as TailcallVarargs
func = t.func
args = t.args
} else {
result = r
func = null
args = null
}
}
return result!!
}
override fun eval(): Varargs {
return runBlockingNoSuspensions { evalSuspend() }
/*
while (result == null) {
val r = func!!.onInvoke(args!!)
if (r.isTailcall()) {
val t = r as TailcallVarargs
func = t.func
args = t.args
} else {
result = r
func = null
args = null
}
}
return result!!
*/
}
override fun arg(i: Int): LuaValue {
if (result == null) eval()
return result!!.arg(i)
}
override fun arg1(): LuaValue {
if (result == null) eval()
return result!!.arg1()
}
override fun narg(): Int {
if (result == null) eval()
return result!!.narg()
}
override fun subargs(start: Int): Varargs {
if (result == null) eval()
return result!!.subargs(start)
}
}