wildling

Lua library and CLI for pattern-based string generation. Zero third-party dependencies (pure Lua 5.4 stdlib — hand-rolled JSON). Requires Lua 5.4+.

Docs: Website · Sandbox · Syntax · Source

Registry: LuaRocks

Example

http://${'dev,stage,prod'}\-${'api,web'}#{0-2}.example.${'com,net,org'}/@.html

(The \- is a literal hyphen; bare - would mean “one letter or digit”. @ is one lowercase letter.)

That builds URL-shaped candidates: scheme http://, then environment × service × optional digits × TLD, then a one-letter path page. Three environments, two services, zero–two digits ('', 0–9, 00–99), three TLDs, and a–z → 51948 strings — the kind of list you generate for fuzzing links or probing staging hosts, not type out.

A few of them:

http://dev-api.example.com/a.html / http://stage-web.example.com/z.html
http://dev-api0.example.net/a.html / http://prod-web9.example.org/m.html
http://dev-api00.example.com/a.html / http://prod-web99.example.org/z.html

Named dictionaries (%{'hosts'}) work the same way when the word lists live in files.

Try it in the sandbox, or see pattern syntax for length ranges, dictionaries, and escapes.

Install

From this repository:

cd lua
./build.sh
./bin/wildling "Year 19##"

Git (from a monorepo clone; module paths in the rockspec are relative to the repo root):

git clone --branch v2.0.7 --depth 1 https://github.com/dotmonk/wildling.git
cd wildling
luarocks make lua/wildling-2.0.7-1.rockspec

Registry: luarocks install wildling

Releases through 2.0.6 on LuaRocks used source.dir = "lua" while packing the full monorepo, so a plain luarocks install wildling fails with “Could not determine source directory”. Workarounds for those rocks: clone and luarocks make as above, or luarocks download wildling --source, unpack, then luarocks make from the nested lua/ tree. Newer publishes use repo-root module paths and install normally.

package.path = "./lib/?.lua;" .. "./lib/?/init.lua;" .. package.path
local wildling = require("wildling")

local w = wildling.create({ "Year 19##" })
local value = w:next()
while value ~= false do
    print(value)
    value = w:next()
end

CLI

./bin/wildling "Year 19##"
./bin/wildling --dictionary planets:../dictionaries/planets.txt "%{'planets'}"
./bin/wildling --template ./config.json

Help text and --check output follow docs/cli.md / docs/help.txt.

Build

./build.sh   # Docker (python:3.13-alpine + lua5.4): copy help.txt + luac -p syntax check

Project tests live in ../tests/ and are run with ../test.sh.