Wire Protocol

This document describes the design of the PumpkinDB wire protocol. It is intrinsically linked to PumpkinScript as all communication with PumpkinDB is done via PumpkinScript scripts execution.

Since core PumpkinScript, having only binary type, is an essentially untyped language (with typing capabilities planned to be built on top of it), the wire protocol is extremely simple as it needs to be able to convey only two types of information: binaries and instructions (instructions).

Data

• <len @ 0..120u8> [_;len] — byte arrays of up to 120 bytes can have their size indicated in the first byte, followed by that size's number of bytes;
• <121u8> <len u8> [_; len] — byte array from 121 to 255 bytes can have their size indicated in the second byte, followed by that size's number of bytes, with 121u8 as the first byte;
• <122u8> <len u16> [_; len] — byte array from 256 to 65535 bytes can have their size indicated in the second and third bytes (u16), followed by that size's number of bytes, with 122u8 as the first byte;
• <123u8> <len u32> [_; len] — byte array from 65536 to 4294967296 bytes can have their size indicated in the second, third, fourth and fifth bytes (u32), followed by that size's number of bytes, with 123u8 as the first byte.

Instructions

• <len @ 129u8..255u8> [_; len ^ 128u8] — if len is greater than 128u8, the following byte array of len & 128u8 length (len without the highest bit set) is considered a instruction. Length must be greater than zero;
• 128u8 is reserved as a prefix to be followed by an internal Scheduler's instruction (not to be accessible to the end users).

The rest of tags (124u8 to 127u8) are reserved for future use.