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https://github.com/textX/textX

Domain-Specific Languages and parsers in Python made easy http://textx.github.io/textX/
https://github.com/textX/textX

domain-specific-language parser python

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Domain-Specific Languages and parsers in Python made easy http://textx.github.io/textX/

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README 

        
![](https://raw.githubusercontent.com/textX/textX/master/art/textX-logo.png)



[![PyPI Version](https://img.shields.io/pypi/v/textX.svg)](https://pypi.python.org/pypi/textX)

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textX is a meta-language for building Domain-Specific Languages (DSLs) in

Python. It is inspired by [Xtext].



In a nutshell, textX will help you build your textual language in an easy way.

You can invent your own language or build a support for already existing textual

language or file format.



From a single language description (grammar), textX will build a parser and a

meta-model (a.k.a. abstract syntax) for the language. See the docs for the

details.



textX follows the syntax and semantics of Xtext but [differs in some

places](http://textx.github.io/textX/about/comparison.html) and is

implemented 100% in Python using [Arpeggio] PEG parser - no grammar ambiguities,

unlimited lookahead, interpreter style of work.



## Quick intro



Here is a complete example that shows the definition of a simple DSL for

drawing. We also show how to define a custom class, interpret models and search

for instances of a particular type.



```python

from textx import metamodel_from_str, get_children_of_type



grammar = """

Model: commands*=DrawCommand;

DrawCommand: MoveCommand | ShapeCommand;

ShapeCommand: LineTo | Circle;

MoveCommand: MoveTo | MoveBy;

MoveTo: 'move' 'to' position=Point;

MoveBy: 'move' 'by' vector=Point;

Circle: 'circle' radius=INT;

LineTo: 'line' 'to' point=Point;

Point: x=INT ',' y=INT;

"""



# We will provide our class for Point.

# Classes for other rules will be dynamically generated.

class Point:

    def __init__(self, parent, x, y):

        self.parent = parent

        self.x = x

        self.y = y



    def __str__(self):

        return "{},{}".format(self.x, self.y)



    def __add__(self, other):

        return Point(self.parent, self.x + other.x, self.y + other.y)



# Create meta-model from the grammar. Provide `Point` class to be used for

# the rule `Point` from the grammar.

mm = metamodel_from_str(grammar, classes=[Point])



model_str = """

    move to 5, 10

    line to 10, 10

    line to 20, 20

    move by 5, -7

    circle 10

    line to 10, 10

"""



# Meta-model knows how to parse and instantiate models.

model = mm.model_from_str(model_str)



# At this point model is a plain Python object graph with instances of

# dynamically created classes and attributes following the grammar.



def cname(o):

    return o.__class__.__name__



# Let's interpret the model

position = Point(None, 0, 0)

for command in model.commands:

    if cname(command) == 'MoveTo':

        print('Moving to position', command.position)

        position = command.position

    elif cname(command) == 'MoveBy':

        position = position + command.vector

        print('Moving by', command.vector, 'to a new position', position)

    elif cname(command) == 'Circle':

        print('Drawing circle at', position, 'with radius', command.radius)

    else:

        print('Drawing line from', position, 'to', command.point)

        position = command.point

print('End position is', position)



# Output:

# Moving to position 5,10

# Drawing line from 5,10 to 10,10

# Drawing line from 10,10 to 20,20

# Moving by 5,-7 to a new position 25,13

# Drawing circle at 25,13 with radius 10

# Drawing line from 25,13 to 10,10



# Collect all points starting from the root of the model

points = get_children_of_type("Point", model)

for point in points:

    print('Point: {}'.format(point))



# Output:

# Point: 5,10

# Point: 10,10

# Point: 20,20

# Point: 5,-7

# Point: 10,10

```



## Video tutorials



### Introduction to textX



[![Introduction to

textX](https://img.youtube.com/vi/CN2IVtInapo/0.jpg)](https://www.youtube.com/watch?v=CN2IVtInapo)



### Implementing Martin Fowler's State Machine DSL in textX



[![Implementing State Machine

DSL](https://img.youtube.com/vi/HI14jk0JIR0/0.jpg)](https://www.youtube.com/watch?v=HI14jk0JIR0)



## Docs and tutorials



The full documentation with tutorials is available at

http://textx.github.io/textX/stable/



You can also try textX in [our

playground](https://textx.github.io/textx-playground/). There is a dropdown with

several examples to get you started.



# Support in IDE/editors



Projects that are currently in progress are:



- [textX-LS](https://github.com/textX/textX-LS) - support for Language Server

  Protocol and VS Code for any textX based language. This project is about to

  supersede the following projects:

  - [textX-languageserver](https://github.com/textX/textX-languageserver) -

    Language Server Protocol support for textX languages

  - [textX-extensions](https://github.com/textX/textX-extensions) - syntax

    highlighting, code outline

- [viewX](https://github.com/danielkupco/viewX-vscode) - creating visualizers

  for textX languages

  

If you are a vim editor user check

out [support for vim](https://github.com/textX/textx.vim/).



For emacs there is [textx-mode](https://github.com/textX/textx-mode) which is

also available in [MELPA](https://melpa.org/#/textx-mode).



You can also check

out [textX-ninja project](https://github.com/textX/textX-ninja). It is

currently unmaintained.



## Discussion and help



For general questions, suggestions, and feature requests please use [GitHub

Discussions](https://github.com/textX/textX/discussions).



For issues please use [GitHub issue

tracker](https://github.com/textX/textX/issues).



## Citing textX



If you are using textX in your research project we would be very grateful if you

cite our paper:



Dejanović I., Vaderna R., Milosavljević G., Vuković Ž. (2017). [TextX: A Python

tool for Domain-Specific Languages

implementation](https://www.doi.org/10.1016/j.knosys.2016.10.023).

Knowledge-Based Systems, 115, 1-4.



## License



MIT



## Python versions



Tested for 3.8+



[Arpeggio]: https://github.com/textX/Arpeggio

[Xtext]: http://www.eclipse.org/Xtext/