IParse
Lark
IParse | Lark | |
---|---|---|
5 | 35 | |
11 | 4,519 | |
- | 2.1% | |
3.3 | 7.5 | |
6 months ago | about 1 month ago | |
C++ | Python | |
GNU General Public License v3.0 only | MIT License |
Stars - the number of stars that a project has on GitHub. Growth - month over month growth in stars.
Activity is a relative number indicating how actively a project is being developed. Recent commits have higher weight than older ones.
For example, an activity of 9.0 indicates that a project is amongst the top 10% of the most actively developed projects that we are tracking.
IParse
-
I Wrote a String Type
Nice library with many features. But I do not always understand the focus on memory usage. I guess that the reason behind this is that less memory allocations, have a positive effect on execution times. In a parser, where you often have to compare identifiers, it is a good idea to put all strings for identifiers into a unique pointer with the help of a hash table.
In my interpreting parser [1] I use a hexa hash tree [2] for storing identifiers. It is not very memory efficient, but very fast. It turns every string (from the input buffer) into a unique pointer for that string pointing to a copy of the string. In this way comparing string (identifiers) is equivalent to comparing pointers.
The idea of the hexa hash tree is that is a tree where each node has sixteen child nodes. Which node is selected is based on a step wise evaluated hash function that first takes the lower four bytes of the string, and after reaching the end of the string, the higher four bytes of the string. The nodes often taken up more memory space than the strings themselves.
[1] https://github.com/FransFaase/IParse/
[2] https://github.com/FransFaase/IParse/blob/master/software/Id...
- Noulith: A new programming language currently used by the Advent of Code leader
-
The Tools I Use to Write Books (2018)
I wrote a tool that can process a number of MarkDown files with fragments of C code and put all those fragments in the right order to produce a file that can be compiled. It is grammar based and works with manipulating Abstract Syntax Trees, so I guess, it could be adapted for different programming languages. See: https://github.com/FransFaase/IParse#markdownc
-
C++ Compile Time Parser Generator
Interesting. I have not looked into the code, but I wonder whether it is a compiler, or just an interpreter, e.g. it converts the grammar into some internal representation that is executed by an interpreter or virtual machine. I started worked on an interpreting parser in C many years ago. And later also made Java, C++ and JavaScript version of it. For the JavaScript implementation, see: https://fransfaase.github.io/ParserWorkshop/Online_inter_par... For the C++ version, see: https://github.com/FransFaase/IParse
-
Parser generators vs. handwritten parsers: surveying major languages in 2021
I implemented an unparse function in IParse, which is not a parser generator, but a parser that interprets a grammar. See for example https://github.com/FransFaase/IParse/blob/master/software/c_... where symbols starting with a back slash are a kind of white space terminals during the unparse. For example, \inc stands for incrementing the indentation where \dec decrements it. The \s is used to indicate that at given location a space should be included.
Lark
-
Show HN: I wrote a RDBMS (SQLite clone) from scratch in pure Python
Lark supports, and recommends, writing and storing the grammar in a .lark file. We have syntax highlighting support in all major IDEs, and even in github itself. For example, here is Lark's built-in grammar for Python: https://github.com/lark-parser/lark/blob/master/lark/grammar...
You can also test grammars "live" in our online IDE: https://www.lark-parser.org/ide/
The rationale is that it's more terse and has less visual clutter than a DSL over Python, which makes it easier to read and write.
-
Oops, I wrote yet another SQLAlchemy alternative (looking for contributors!)
First, let me introduce myself. My name is Erez. You may know some of the Python libraries I wrote in the past: Lark, Preql and Data-diff.
-
Hey guys, have any of you tried creating your own language using Python? I'm interested in giving it a shot and was wondering if anyone has any tips or resources to recommend. Thanks in advance!
It's not super maintained but you might enjoy building something with ppci, Pure Python Compiler Infrastructure. It has some front-ends and some back-ends. There's also PeachPy for an assembler. People like using Lark for parsing, I hear.
-
Is it possible to propagate higher level constructs (+, *) to the generated parse tree in an LR-style parser?
lark, a parsing library where I am somewhat involved has a really nice solution to this: Rules starting with _ are inlined in a post processing step.
-
can you create your own program language in python, if yes how?
Lark is a good library to assist with this.
- Lark a Python lexer/parser library
-
Create your own scripting language in Python with Sly
If I may ask, did you consider Lark, and if so, why wasn't it fit for your purposes?
- Creating a language with Python.
-
Not Your Grandfather’s Perl
A grammar provides the high level constructs you need to define the "shape" of your data, and it largely takes care of the rest. Grammar libraries exist in other language (eg. lark or Parsimonius in Python) and they weren't created just to make XML parsing easier.
-
Earley Parsing Explained
I made a solid attempt at an Earley parser framework of my own, but apparently to get the most reliable performance from Earley parsing you need to implement Joop Leo's improvement for right-recursive grammars, which nobody has been able to adequately explain to me. I've read Kegler's open letter to Vaillant, I've tried to read other implementations, I've even tried to beat my head against the original academic paper, but I don't have the background knowledge to make sense of it all.
What are some alternatives?
aoc - My Advent of Code solutions.
pyparsing - Python library for creating PEG parsers [Moved to: https://github.com/pyparsing/pyparsing]
Crate - CrateDB is a distributed and scalable SQL database for storing and analyzing massive amounts of data in near real-time, even with complex queries. It is PostgreSQL-compatible, and based on Lucene.
PLY - Python Lex-Yacc
ruby - The Ruby Programming Language
pydantic - Data validation using Python type hints
ctpg - Compile Time Parser Generator is a C++ single header library which takes a language description as a C++ code and turns it into a LR1 table parser with a deterministic finite automaton lexical analyzer, all in compile time.
sqlparse - A non-validating SQL parser module for Python
wefx - Basic WASM graphics package to draw to an HTML Canvas using C. In the style of the gfx library
Atoma - Atom, RSS and JSON feed parser for Python 3
pp - PP - Generic preprocessor (with pandoc in mind) - macros, literate programming, diagrams, scripts...
Construct - Construct: Declarative data structures for python that allow symmetric parsing and building