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Haiku Numbersystem Variable Rules

The Haiku Numbersystem is a variable naming convention for cmd.exe batch scripts designed to avoid conflicts with reserved words, environment variables, and the delayed expansion parser. The name derives from the constraint-based structure: variable names follow a fixed syllabic pattern similar to haiku poetry (5-7-5), enforcing short, non-conflicting identifiers that are easy to track across nested FOR loops and macro calls.

Overview

What this page covers

This page documents the Haiku Numbersystem variable naming convention:

  • Naming Convention — Project-specific prefix pattern with semantic descriptors
  • Forbidden Names — Reserved words, dynamic variables, environment variables
  • Delayed Expansion Safety — Characters to avoid in variable names
  • Scope Management — SETLOCAL/ENDLOCAL boundaries
  • Indexed Variables — Array simulation via naming convention

For cmd.exe parser behavior and delayed expansion, see cmd.exe Literacy. For clipboard automation patterns, see Clipboard Automation.

Naming Convention

Prefix Pattern

All user-defined variables use a project-specific prefix followed by a semantic descriptor. This prevents collision with:

  • Windows environment variables (PATH, TEMP, USERPROFILE, etc.)
  • cmd.exe dynamic variables (CD, DATE, TIME, ERRORLEVEL, RANDOM, CMDEXTVERSION, CMDCMDLINE)
  • Common utility variables (_var, __tmp, etc. that other scripts may export)
Batchfile
REM sHEL project prefix: sh_
set "sh_count=0"
set "sh_name=default"
set "sh_buffer="

REM Nested loop counters use ordinal suffixes
set "sh_i_1=0"
set "sh_i_2=0"
set "sh_i_3=0"

Loop Variable Mapping

FOR loop variables (%%A through %%Z) are mapped to descriptive names immediately upon capture:

Batchfile
FOR /F "delims=" %%A IN ('command') DO (
    set "sh_line=%%A"
    REM All further processing uses !sh_line! (delayed expansion)
)

Forbidden Names

The following categories of names must never be used for user variables:

cmd.exe Reserved Words

CALL, ECHO, ENDLOCAL, FOR, GOTO, IF, NOT, SET, SETLOCAL, SHIFT

Dynamic Variables (Read-Only)

Variable Content Example
%CD% Current directory C:\Users\Name
%DATE% Current date Mon 01/15/2024
%TIME% Current time 14:30:45.12
%RANDOM% Random 0-32767 18473
%ERRORLEVEL% Exit code of last command 0, 1, 9009
%CMDEXTVERSION% Command extensions version 2
%CMDCMDLINE% Original command line cmd /c script.bat
%HIGHESTNUMANODENUMBER% NUMA node count 0

Environment Variables (Common)

ALLUSERSPROFILE, APPDATA, COMPUTERNAME, HOMEDRIVE, HOMEPATH, LOCALAPPDATA, LOGONSERVER, NUMBER_OF_PROCESSORS, OS, PATHEXT, PROCESSOR_ARCHITECTURE, PROGRAMDATA, PROGRAMFILES, PROGRAMFILES(X86), PUBLIC, SYSTEMDRIVE, SYSTEMROOT, TEMP, TMP, USERDOMAIN, USERNAME, USERPROFILE, WINDIR

Delayed Expansion Safe Names

When delayed expansion is enabled, variable names must not contain exclamation marks (the expansion delimiter). Additionally, names should avoid characters that complicate the parser:

flowchart TD
    subgraph Safe["Safe Names"]
        direction TB
        S1["sh_var"]
        S2["sh_count_1"]
        S3["sh_buffer_tmp"]
    end

    subgraph Unsafe["Unsafe Names"]
        direction TB
        U1["var!name<br/>(! triggers expansion)"]
        U2["var(name)<br/>(parentheses break)"]
        U3["var&name<br/>(& is command sep)"]
        U4["var,name<br/>(, is parameter sep)"]
    end

    style Safe fill:#7ed321
    style Unsafe fill:#d0021b
Safe Unsafe Reason
sh_var var!name ! triggers delayed expansion
sh_var var(name) Parentheses break substitution
sh_var var&name & is command separator
sh_var var,name , is parameter separator

Scope Management

Variables should be localized with SETLOCAL to prevent leaking into the parent environment:

Batchfile
@echo off
set "sh_global=visible everywhere"

REM Subroutine with local scope
CALL :Subroutine
REM sh_local no longer exists here
echo %sh_global%        REM Works
echo %sh_local%         REM Empty (undefined)

:Subroutine
SETLOCAL
set "sh_local=only here"
echo %sh_global%        REM Works (parent visible to child)
ENDLOCAL
exit /b

The Numbersystem

For numbered variable series (arrays simulated via naming):

Batchfile
REM Indexed naming: prefix_category_index
set "sh_file_1=readme.txt"
set "sh_file_2=config.ini"
set "sh_file_3=data.csv"

REM Access via delayed expansion and CALL double expansion
setlocal enabledelayedexpansion
set "sh_idx=2"
CALL echo File %%sh_file_%sh_idx%%%    REM Outputs: config.ini

The CALL statement forces a second expansion pass, resolving %%sh_file_2%% to the variable's value. This is the only reliable method for indirect variable access in cmd.exe.