Lua错误尝试对局部变量执行算术运算 [英] Lua Error Attempt to perform arithmetic on local variable

问题描述

这是功能 calc.lua:

Here is the function calc.lua:

function foo(n) 
return n*2 
end

这是我的LuaJavaCall

Here is my LuaJavaCall

L.getGlobal("foo");
L.pushJavaObject(8);
int retCode=L.pcall(1,1,0); // nResults)//L.pcall(1, 1,-2);
String errstr =  L.toString(-1);   // Attempt to perform arithmetic on local variable 'n'

更新:如下所示，我需要使用L.pushNumber(8.0)而不是L.pushJavaObject()

Update: as indicated below I needed to use L.pushNumber(8.0) instead of L.pushJavaObject()

推荐答案

尝试像这样使用L.pushNumber代替L.pushJavaObject:

L.getGlobal("foo");
L.pushNumber(8.0);
int retCode = L.pcall(1,1,0);
String errstr = L.toString(-1);

Lua可能会将JavaObject视为一种用户数据"，在这种情况下，没有针对它的预定义操作； Lua不知道如何处理JavaObject * 2，因为您没有定义如何处理它.

Lua probably sees JavaObject as a type of 'userdata' in which case there are no predefined operations for it; Lua won't know what to do with a JavaObject * 2 since you didn't define how to handle it.

OTOH，Lua确实知道如何处理数字，因为那是内置的原始类型.对于您介绍的代码段，压入数字是使它起作用的最痛苦的方法，而不是编写额外的代码来告诉Lua如何使用包装在JavaObject中的数字.

OTOH, Lua does know how to handle a number since that's a builtin primitive type. For the code snippet you presented, pushing a number would be the least painful way to get it working instead of writing extra code that tells Lua how to work with numbers wrapped inside a JavaObject.

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