A very, very simple example of a typed packet.


input: 4 bytes


output: int64

Initial Verification:

if there are 4 bytes remaining in the stream
  grab the next 4 bytes
  declare error
end if
wrap header and trailer onto the 4 bytes


tag = flexible number of bytes, last byte has low bit set

for example

int8 = 00000001
int16 = 00000011
int32 = 00000101
int64 = 00000111

See early dynamically typed languages for ideas on how best to arrange tags.

See, also, Huffman encoding.

See, also, network packet layout.

Physical Layer

The physical layer carries bytes from one Component to another.

Each packet has a header and a trailer, in the form of flexi-tags.

  • header (array of bytes terminated by low bit set)
  • payload - array of bytes
  • trailer - must match the head (exactly)


ECC means Error Correcting Code.

We can check the packets using a variety of techniques, at a layer above the physical layer.

Producing Output

In this example, we produce 6 bytes (header, 4 bytes, trailer)

0x07, ??, ??, ??, ??, 0x07

output of this stage = 6 bytes

Network Packets

Note the similarities between this scheme and network packets.

OSI Model

A useful starting point might be the OSI Model for data packets.

Validotor Components

Some Components “do something” and others simply perform type-checking.

Today, we chop type-checking up into two pieces:

  1. input validtation
  2. type checking.


This scheme appears to be inefficient, except when compared to passing JSON character data around in a network.


Is it possible to optimize this model?

We simply perform type-checks in the PE1 (at “compile time”) as we hook Components up.

This kind of optimization is nothing new.

We simply move “compile time” into the PE.

See Also

Table of Contents

  1. Programming Environment.