Initial sources for planned 2.0 luaj vm release. Most interpreter features and library functions working.

test/lua/tailcalls.lua

@@ -0,0 +1,100 @@
+
+-- tostring replacement that assigns ids
+local ts,id,nid,types = tostring,{},0,{table='tbl',thread='thr',userdata='uda',['function']='func'}
+tostring = function(x)
+	if not x or not types[type(x)] then return ts(x) end
+	if not id[x] then nid=nid+1; id[x]=types[type(x)]..'.'..nid end
+	return id[x]
+end
+
+	
+function a() 
+	return pcall( function() end )
+end
+
+function b() 
+	return pcall( function() print 'b' end )
+end
+
+function c() 
+	return pcall( function() return 'c' end )
+end
+
+print( pcall( a )  )
+print( pcall( b )  )
+print( pcall( c )  )
+
+local function sum(...)
+	local s = 0
+	for i,v in ipairs({...}) do
+		s = s + v
+	end
+	return s
+end
+
+local function f1(n,a,b,c)
+	local a = a or 0
+	local b = b or 0
+	local c = c or 0
+	if n <= 0 then 
+		return a,a+b,a+b+c
+	end
+	return f1(n-1,a,a+b,a+b+c)
+end
+
+local function f2(n,...)
+	if n <= 0 then 
+			print( " --f2, n<=0, returning sum(...)", ... )
+		return sum(...)
+	end
+	print( " --f2, n>0, returning f2(n-1,n,...)", n-1,n,... )
+	return f2(n-1,n,...)
+end
+
+local function f3(n,...)
+	if n <= 0 then 
+		return sum(...)
+	end
+	print( "    f3,n-1,n,...", f3,n-1,n,... )
+	return pcall(f3,n-1,n,...)
+end
+
+local function all(f)
+	for n=0,3 do
+		t = {}
+		for m=1,5 do 
+			print( "--f, n, unpack(t)", f, n, unpack(t) )
+			print( pcall( f, n, unpack(t)) )
+			t[m] = m
+		end
+	end
+end
+
+all(f1)
+all(f2)
+all(f3)
+
+
+local function f(x)
+	-- tailcall to a builtin
+	return math.abs(x)
+end
+
+local function factorial(i)
+	local function helper(product, n)
+		if n <= 0 then
+			return product
+		else
+			-- tail call to a nested Lua function
+			return helper(n * product, n - 1)
+		end
+	end
+	return helper(1, i)
+end
+
+local result1 = factorial(5)
+print(result1)
+print(factorial(5))
+
+local result2 = f(-1234)
+print( result2 )