[added] assert methods return first argument so they can be used inline

assert.lua

@@ -3,6 +3,7 @@
 		- avoid garbage generation upon success,
 		- build nice formatted error messages
 		- post one level above the call site by default
+		- return their first argument so they can be used inline
 
 	default call is builtin global assert
 
@@ -16,23 +17,25 @@ local _assert = assert
 local assert = setmetatable({}, {
 	__call = function(self, ...)
 		return _assert(...)
-	end,	
+	end,
 })
 
 local function _extra(msg)
 	if not msg then
 		return ""
 	end
-	return "(note: " .. msg .. ")"
+	return "\n\n\t(note: " .. msg .. ")"
 end
 
 --assert a value is not nil
+--return the value, so this can be chained
 function assert:some(v, msg, stack_level)
 	if v == nil then
 		error(("assertion failed: value is nil %s"):format(
 			_extra(msg)
 		), 2 + (stack_level or 0))
 	end
+	return v
 end
 
 --assert two values are equal
@@ -44,6 +47,7 @@ function assert:equal(a, b, msg, stack_level)
 			_extra(msg)
 		), 2 + (stack_level or 0))
 	end
+	return a
 end
 
 --assert two values are not equal
@@ -53,6 +57,7 @@ function assert:not_equal(a, b, msg, stack_level)
 			_extra(msg)
 		), 2 + (stack_level or 0))
 	end
+	return a
 end
 
 --assert a value is of a certain type
@@ -65,15 +70,19 @@ function assert:type(a, t, msg, stack_level)
 			_extra(msg)
 		), 2 + (stack_level or 0))
 	end
+	return a
 end
 
---replace everything in assert with nop functions, for near-zero overhead on release
+--replace everything in assert with nop functions that just return their second argument, for near-zero overhead on release
 function assert:nop()
+	local nop = function(self, a)
+		return a
+	end
 	setmetatable(self, {
-		__call = function() end,
+		__call = nop,
 	})
 	for k, v in pairs(self) do
-		self[k] = function() end
+		self[k] = nop
 	end
 end