gaiman

Gaiman Engine

Storytelling Text Based Game Engine

Main part of Gaiman is a minimalistic language that generate Text Advanture Games.

Examples

This is basic Gaiman DLS example:

def ask_email(message)
   set reply = ask message
   if reply ~= /y|yes/i then
      echo "OK"
   else if reply ~= /n|no/i then
      echo "FAIL"
   else
      global(message)
   end
end

def global(command)
   if command ~= /help/ then
      echo "available commands help"
   else if command ~= /ls/
      echo get "/exec?command=ls"
   else
      echo "wrong command"
   end
end

if cookie.visited then
  if cookie.USER_NAME then
    echo "hello $user"
  else if cookie.EMAIL then
    echo "Will contact with with any updates"
  else
    echo "Do you want me to contact you with updates?"
    set confirm = ask "yes/no: "
    if confirm ~= /y|yes/i then
      echo "what is your name?"
      set command = ask "name: "
      if command then
        set user = command
        set cookie.user = command
        set response = post "/register" { name: user, email: email }
        if response then
          echo "Welcome $user. You're successfully registered"
        end
      end
    end
  end
end

TODO

• Parser
  • variables
    • strings
    • regexes
    • arrays
    • booleans
    • integers
    • floats
  • property access
    • nested property access
  • Here docs - for figlet ASCII art
  • array indexing
  • dicts/structs for data
  • if/else statements
  • globals
    • argv (process.argv) or null
    • location or null
  • loop
    • for..in
    • while
  • do..end blocks
  • comments with #
  • Functions
    • Functions return keyword
    • Functions return functions
    • Lambda
    • Implementation of map/reduce/filter using gaiman
    • standard library
      • Array methods join/push/pop (maybe allow all JS methods)
      • String methods split/replace
      • ord/chr
  • Commands (restricted names)

    • ask - set prompt

    • echo - print message

    • get - send HTTP GET request

    • post - send HTTP POST request

    • set - save expression or command into variable

    • exists ... in - check if item is in array

    • parse - parse string to number, boolean or regex

    • split - to create array with string or regex separator

    • join - return string from array

    • push - item into array

    • pop - remote item from

  • Not operator inside if statements
  • Expressions
    • regex match ~=
    • $1 variables
    • comparators ==/<=/>=/</>
    • parentheses for grouping
    • -=, +=, /=, *= operators ????
    • -, +, /, * and % operators
• compiler functions to JavaScript code escodegen.
• Compile everything to JavaScript
• Interpreter
• Unit tests
• jQuery Terminal integration
• Async Adapters for Web and next for Terminal
• XML like syntax for colors <bold><red>hello</red></bold>
• Hooks to embed JS code ???

TODO: syntax example

echo <<GREET
   ____       _
  / ___| __ _(_)_ __ ___   __ _ _ __
 | |  _ / _` | | '_ ` _ \ / _` | '_ \
 | |_| | (_| | | | | | | | (_| | | | |
  \____|\__,_|_|_| |_| |_|\__,_|_| |_|

Gaiman Engine
Copyright (C) 2021 Jakub Jankiewicz <https://jcubic.pl/me>
Released under GPLv3 license
GREET

if location then
    echo "Wellcome on this website"
else
    echo "Wellcome to this CLI app"
end

var env = []

var items = ["bottle", "flower"]

set command = ask "? "
if command ~= /pick (.+)/ then
   if $1 then
      if exists $1 in items then
          env.push($1)
          pop items
       else
          echo "invalid item"
       end
    else
       echo "What do you want topick"
    end
end


var stop = false
var count = 0
while not stop do
    var command = ask "? "
    if command ~= /exit/
        stop = true
        echo "goodby"
    else if command ~= /add ([0-9]+)/ then
        count += parse $1
        echo "corrent count $count"
    else
        echo "your command $command"
    end
end

def once(fn)
    var result = null
    return lambda(...args)
        if result == null then
           result = fn(...args)
        end
        return result
    end
end

def map(fn, array)
    var result = []
    for item in array do
        result.push(fn(item))
    end
    return result
end

To consider

• do we need set maybe foo = ?? is enough
• scope for variales (php with global is not good idea)
• methods
• standard library (e.g.: push/pop/split/join)
• functions should be compiled to JavaScript, use

command = ask "? "

should be compile to:

var command = await term.read('? ')

Compile:

do
    var x = 10
    echo x + x
end
x # throw exception x is not defined

to

{
    let $_x = 10
    term.echo($_x + $_x);
}
x

All names prefixed with $_ to solve conflicts

Adapter API

class Adapter {
    constructor() { }
    async ask(message) { }
    echo(string) { }
    async get(url) { }
    async post(url, data) { }
    start() { }
}

functon is_node() {
    return typeof process !== 'undefined' &&
        process.release.name === 'node';
}

var term, $_location, $_argv
if (is_node()) {
  term = new NodeAdapter();
  $_argv = process.argv;
} else {
  term = new WebAdapter();
  $_location = location;
}

term.start();

Name

Name came from Neil Gaiman, Author of novels, comic books, graphic novels and films. Great storyteller.

Acknowledge

Logo use:

• Font Calling Heart by Lettersiro Studio
• Clipart Book with bookmarks by Kevin David Pointon

License

Released under GPLv3 license
Copyright (c) 2021 Jakub T. Jankiewicz