General Actor Notation (GAN) Specification
- Version: 1.0.0
- Author: Sashité
- Published: June 23, 2025
- License: MIT License
Overview
General Actor Notation (GAN) provides a rule-agnostic format for identifying game actors in abstract strategy board games by combining Style Name Notation (SNN) and Piece Identifier Notation (PIN) with a colon separator and consistent case encoding.
GAN represents all four fundamental piece attributes from the Game Protocol:
- Type → PIN component (ASCII letter choice)
- Side → Consistent case encoding across both SNN and PIN components
- State → PIN component (optional prefix modifier)
- Style → SNN component (explicit style identifier)
Unlike Piece Name Notation (PNN) which uses derivation markers, GAN explicitly names the style for unambiguous identification.
Format Specification
Structure
<snn>:<pin>
Grammar (BNF)
<gan> ::= <uppercase-gan> | <lowercase-gan>
<uppercase-gan> ::= <uppercase-style> <colon> <uppercase-pin>
<lowercase-gan> ::= <lowercase-style> <colon> <lowercase-pin>
<colon> ::= ":"
<uppercase-style> ::= <letter-uppercase> <identifier-tail-uppercase>*
<lowercase-style> ::= <letter-lowercase> <identifier-tail-lowercase>*
<identifier-tail-uppercase> ::= <letter-uppercase> | <digit>
<identifier-tail-lowercase> ::= <letter-lowercase> | <digit>
<uppercase-pin> ::= <letter-uppercase> | <state-modifier> <letter-uppercase>
<lowercase-pin> ::= <letter-lowercase> | <state-modifier> <letter-lowercase>
<state-modifier> ::= "+" | "-"
<letter-uppercase> ::= "A" | "B" | "C" | ... | "Z"
<letter-lowercase> ::= "a" | "b" | "c" | ... | "z"
<digit> ::= "0" | "1" | "2" | "3" | "4" | "5" | "6" | "7" | "8" | "9"
Regular Expression
\A([A-Z][A-Z0-9]*:[-+]?[A-Z]|[a-z][a-z0-9]*:[-+]?[a-z])\z
Protocol Mapping
GAN encodes piece attributes by combining SNN and PIN information:
| Protocol Attribute | GAN Encoding | Examples |
|---|---|---|
| Type | PIN letter choice | CHESS:K = King, CHESS:P = Pawn |
| Side | Unified case across both components | CHESS:K = First player, chess:k = Second player |
| State | PIN prefix modifier | SHOGI:+P = Enhanced, CHESS:-P = Diminished |
| Style | SNN identifier | CHESS:K = Chess style, SHOGI:K = Shōgi style |
Design Properties
- Rule-agnostic: Independent of specific game mechanics
- Complete identification: Explicit representation of all four piece attributes
- Cross-style support: Enables multi-tradition gaming environments
- Component clarity: Clear separation between style context and piece identity
- Unified case encoding: Consistent case across both components for side identification
- Protocol compliance: Direct implementation of Sashité piece attributes
Implementation
Ruby Reference
- Gan.rb – Reference implementation of the General Actor Notation specification.
Practical Examples
Comprehensive implementation examples for single-style and cross-style scenarios are available in the GAN Examples.