About

A parser for custom domain-specific language.

First of all, the parser is made for the cli game engine, I recommend you check it out.

Quick start

Install dependencies:

pip install git+https://github.com/philexlive/WisayoParser.git

Script file:

from wisayoparser import Tokenizer, Parser, TokensStream

with open('player.txt') as f:
    tokenizer = Tokenizer()

    stream = TokensStream()
    tokenizer.tokenize(f, stream)

    ast = Parser(stream).parse()

Object to be parsed:

<GameObject
    name="Player"
    x=87.2
    y=2.0 >

    <GameObject name="RightHand" />

    <Sprite>
        <Texture resource="res/some_texture.texture" />
    </>
</>

Pipeline

There are several basic classes involved in the parsing process, these are Tokenizer, TokensStream, and Parser.

Tokenizer handles tokenization of any row file. It have a method parse which takes a file and tokens stream and handles reading the file and assigning appropriate tokens to your the tokens stream.

Tokenizer have some types of literal tokens represent numbers, strings and booleans. Already on tokenization process literal type definition happens. There could be NumberLiteral that is just integer, FloatLiteral represents float, BoolLiteral is true|false, and StringLiteral just a raw string.

Then Parser on initialization takes a tokens stream. then parse method used to make an AST from given tokens stream. It also processes convertion the type of literal to int, float, bool, and str.

Abstract Syntax Tree (AST)

The AST nodes represent two implementations DefinitionNode and AttributeNode.

Definition node an implementation consisting of such fields:

• name: Dependening on your interpreter, it could represent a type of the object or its unique name
• attributes: represents multiple of fields of an object
• nodes: Represents its child-parent relation, there could be its children definition nodes

Attributes:

• name: Represents field name of the definition it's in.
• value: Contains one primitve to be assigned to that field.

It will look something like this:

DefinitionNode('GameObject')
    AttributeNode('name', 'Player')
    AttributeNode('x', 87.2)
    AttributeNode('y', 2.0)

    DefinitionNode('GameObject')
    DefinitionNode('Sprite')
        ...
    ...