Add metatag test.

test/lua/metatags.lua

@@ -0,0 +1,39 @@
+print( '---- initial metatables' )
+local values = { 1, false, coroutine.create( function() end ) }
+for i=1,#values do
+	print( debug.getmetatable( values[i] ) )
+end
+
+local mt = {
+	__call=function(a,b,c) 
+		print( 'mt.__call()', type(a), type(b), type(c), b, c )
+		return '__call-result'
+	end,
+}
+
+-- pcall a function and check for a pattern in the error string
+ecall = function(pattern, ...)
+	local s,e = pcall(...)
+	if not s then e = string.match(e,pattern) or e end
+	return s,e
+end 
+
+print( '---- __call' )
+for i=1,#values do
+	print( type(values[i]), 'before', ecall( 'attempt to call', function() return values[i]('a','b') end ) )
+	print( debug.setmetatable( values[i], mt ) )
+	print( type(values[i]), 'after', pcall( function() return values[i]() end ) )
+	print( type(values[i]), 'after', pcall( function() return values[i]('a') end ) )
+	print( type(values[i]), 'after', pcall( function() return values[i]('a','b') end ) )
+	print( type(values[i]), 'after', pcall( function() return values[i]('a','b','c') end ) )
+	print( type(values[i]), 'after', pcall( function() return values[i]('a','b','c','d') end ) )
+	print( debug.setmetatable( values[i], nil ) )
+end
+
+
+
+print( '---- final metatables' )
+for i=1,#values do 
+	print( debug.getmetatable( values[i] ) )
+end
+