Yarn Parser

[SiENcE]

I've created a new Yarn parser library that converts Yarn Spinner dialogues into Lua.

https://github.com/SiENcE/yarnparser/

It fully supports the current Yarn Spinner syntax. Additionally, I reverse-engineered the eBNF since there was no official one available (which is unfortunate).

Features
- Parses Yarn scripts into structured node objects
- Groups related content (like choices and their responses)
- Can locate dialogue lines preceding choice groups
Supports:

• Dialogue lines
• Choices (including nested choices)
• Conditional statements (if/else)
• Variable assignments, declarations, and interpolation
• Commands (jump, set, declare, etc.)
• Comments (both single-line and multi-line)

It's not an interpreter .

Previously, there was only this outdated parser, which is no longer compatible with the current yarn syntax.

Pull requests are welcome.

[Hugues Ross]

Oh nice, I'm going to need a better way of writing dialogue in my game and Yarn looks like it might fit the bill! I'll be keeping this in mind for later

[pgimeno]

@SiENcE maybe you can include a link to your repo?

[SiENcE]

@pgimeno Right, thx ... sure I'll make it more explicit :-)

[SiENcE]

I added a sample implementation of an interpreter along with a Yarn test sample. The interpreter supports callbacks for every step.

https://github.com/SiENcE/yarnparser/bl ... r_test.lua

Code: Select all

local YarnParser = require("yarn_parser")
local YarnInterpreter = require("yarn_interpreter")

-- Parse your Yarn script
local nodes = YarnParser:parse(your_script)

-- Create a new interpreter instance
local interpreter = YarnInterpreter.new(nodes)

-- Define callbacks
local callbacks = {
    on_dialogue = function(text)
        print("Dialogue:", text)
    end,
    on_choice = function(choices, path)
        print("Choice path:", path or "root")
        for i, choice in ipairs(choices) do
            print(i .. ": " .. choice)
        end
        io.write("Select (1-" .. #choices .. "): ")
        return tonumber(io.read())
    end,
    on_variable = function(name, value)
        print("Variable changed:", name, "=", value)
    end,
    on_node_enter = function(title)
        print("Entering node:", title)
    end,
    on_node_exit = function(title)
        print("Exiting node:", title)
    end
}

-- Set the callbacks
interpreter:set_callbacks(callbacks)

-- Start the interpretation
interpreter:run()