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lark-parser

7 indexed repositories · View on GitHub

lark
Lark is a parsing toolkit for Python, built with a focus on ergonomics, performance and modularity.

Python · 5986 stars
Lark.js
Live port of Lark's standalone parser to Javascript

JavaScript · 88 stars
lark_cython
Cython plugin for Lark, reimplementing the LALR parser & lexer for better performance

Cython · 51 stars
vscode-lark

36 stars
intellij-syntax-highlighting
intellij plugin for the lark grammar

Java · 27 stars
lark-language-server
Provides a language server for grammars based on Lark

Python · 23 stars
lark_syntax
Lark-flavoured EBNF grammar syntax definition for Sublime Text or TextMate

16 stars

Beginner friendly Everything

Open All

Generated parser is not reproducible: token and state numbering varies per run (PYTHONHASHSEED does not help) Open

Difficulty 4/5 3-5 days Newbie friendliness 72/100

lark-parser/Lark.js#49 · Opened Sep 6, 2026
Feature Request: Support / Extension for Zed Editor Open

Difficulty 5/5 Over a week Newbie friendliness 30/100

lark-parser/vscode-lark#8 · Opened Aug 27, 2026
Zero-width regex terminal rejected even when the surrounding rule can never match zero characters Open

Difficulty 4/5 3-5 days Newbie friendliness 68/100

lark-parser/lark#1640 · 1 comment · Opened Aug 16, 2026
Invalid Tree structure and anti-patterns in lark/tests/test_pattern_matching.py Open

Difficulty 2/5 1-3 hours Newbie friendliness 82/100

lark-parser/lark#1608 · Opened Jun 13, 2026
TextSlice implementation breaks codebases based on 1.2.2 Open

Difficulty 2/5 1-3 hours Newbie friendliness 64/100

lark-parser/lark#1599 · 5 comments · Opened Jun 1, 2026
This project seems unmaintained Open

Difficulty 5/5 Over a week Newbie friendliness 15/100

lark-parser/vscode-lark#7 · 7 comments · Opened Apr 30, 2026
Optional closing tag causes runtime error: Earley generates multiple start symbol items Open

Difficulty 4/5 3-5 days Newbie friendliness 48/100

lark-parser/lark#1587 · 1 comment · Opened Apr 9, 2026
Infinite loop in lalr and cyk Open

bug

Difficulty 4/5 3-5 days Newbie friendliness 48/100

lark-parser/lark#1585 · 3 comments · Opened Mar 24, 2026
Export and document lark.tools.standalone.gen_standalone Open

enhancement

Difficulty 3/5 1-2 days Newbie friendliness 55/100

lark-parser/lark#1583 · 2 comments · Opened Mar 23, 2026
__default_token__ and __default__ not called for Lark(transformer=transformer). Open

Difficulty 3/5 1-2 days Newbie friendliness 45/100

lark-parser/lark#1582 · 7 comments · Opened Mar 23, 2026
contextual lexer accept set seems wrong Open

question

Difficulty 4/5 3-5 days Newbie friendliness 45/100

lark-parser/lark#1581 · Opened Mar 23, 2026
version-compatibility issue between `lark` and `lark-js` Open

Difficulty 4/5 3-5 days Newbie friendliness 35/100

lark-parser/Lark.js#48 · Opened Mar 16, 2026
The version on https://pypi.org/project/lark-parser/ is 0.12.0 Open

question

Difficulty 3/5 1-2 days Newbie friendliness 35/100

lark-parser/lark#1574 · 2 comments · Opened Feb 13, 2026
python.lark failed to pare special forms of with_stmt Open

Difficulty 3/5 1-2 days Newbie friendliness 48/100

lark-parser/lark#1570 · 2 comments · Opened Dec 7, 2025
Allow rules in templates Open

enhancement

Difficulty 4/5 3-5 days Newbie friendliness 42/100

lark-parser/lark#1566 · 2 comments · Opened Oct 31, 2025
A Error Open

Difficulty 4/5 3-5 days Newbie friendliness 25/100

lark-parser/intellij-syntax-highlighting#10 · Opened Sep 13, 2025
Improve memory usage in the contextual lexer ? Open

discussion enhancement

Difficulty 4/5 3-5 days Newbie friendliness 35/100

lark-parser/lark#1539 · Opened Jul 5, 2025
support go to symbol Open

Difficulty 5/5 Over a week Newbie friendliness 35/100

lark-parser/vscode-lark#5 · Opened Apr 26, 2025
Misaligned error location when input text contain full-width characters Open

Difficulty 3/5 1-2 days Newbie friendliness 67/100

lark-parser/lark#1530 · 2 comments · 1 reaction · Opened Apr 24, 2025
Add support for the `a` and `L` regex flags Open

enhancement good first issue

Difficulty 2/5 1-3 hours Newbie friendliness 48/100

lark-parser/lark#1527 · 5 comments · Opened Apr 21, 2025
Parsing bytestrings and token values Open

bug

Difficulty 2/5 1-3 hours Newbie friendliness 68/100

lark-parser/lark#1526 · 3 comments · Opened Apr 18, 2025
com.intellij.diagnostic.PluginException: At least one pattern should be specified [Plugin: com.lark.syntax] Open

Difficulty 4/5 3-5 days Newbie friendliness 30/100

lark-parser/intellij-syntax-highlighting#9 · 1 comment · Opened Feb 26, 2025
Lark needs a favicon Open

enhancement IDE

Difficulty 2/5 1-3 hours Newbie friendliness 45/100

lark-parser/lark#1510 · 4 comments · 1 reaction · Opened Jan 24, 2025
Matching line continuation in shell style comment Open

question

Difficulty 3/5 1-2 days Newbie friendliness 25/100

lark-parser/lark#1509 · 3 comments · Opened Jan 23, 2025
Move documentation to bootstrap 5 Open

docs good first issue help wanted

Difficulty 2/5 1-3 hours Newbie friendliness 78/100

lark-parser/lark#1494 · 2 comments · Opened Nov 30, 2024
Difference in LALR Grammar Parsing Open

question

Difficulty 4/5 3-5 days Newbie friendliness 35/100

lark-parser/lark#1489 · Opened Nov 16, 2024
Older Cython versions break when testing with Python 3.13 Open

Difficulty 2/5 1-3 hours Newbie friendliness 55/100

lark-parser/lark_cython#46 · Opened Oct 27, 2024
Ignored terminal used in the grammar is expected with Earley but not with LALR Open

add to docs bug

Difficulty 3/5 1-2 days Newbie friendliness 38/100

lark-parser/lark#1473 · 3 comments · Opened Sep 26, 2024
Syntactic sugar: Tree.has_data() Open

enhancement

Difficulty 2/5 1-3 hours Newbie friendliness 45/100

lark-parser/lark#1465 · 5 comments · Opened Sep 11, 2024
Lark resulting LALR -nor- Earley parser will pick out the longest match of say "a + b + c + ... + d" example input. Bug (?) Open

Difficulty 4/5 3-5 days Newbie friendliness 35/100

lark-parser/lark#1463 · 1 comment · Opened Sep 4, 2024
Generate counter-examples for conflicts in LALR parsing Open

enhancement

Difficulty 5/5 Over a week Newbie friendliness 35/100

lark-parser/lark#1449 · 3 comments · Opened Aug 16, 2024
Terminal collision when importing the same terminal from different grammars Open

discussion enhancement

Difficulty 5/5 Over a week Newbie friendliness 25/100

lark-parser/lark#1448 · Opened Aug 15, 2024
tests/test_cache.py and Python >= 3.12: SyntaxWarning: invalid escape sequence '\w' Open

Difficulty 1/5 Under an hour Newbie friendliness 72/100

lark-parser/lark#1445 · 1 reaction · Opened Aug 13, 2024
Ambiguities and Priorities in 1.2.1 earley Open

question

Difficulty 4/5 3-5 days Newbie friendliness 35/100

lark-parser/lark#1443 · 6 comments · Opened Aug 13, 2024
Priorities not working within recursive rules Open

Difficulty 4/5 3-5 days Newbie friendliness 35/100

lark-parser/lark#1441 · Opened Aug 6, 2024
Porting from pyparsing match_previous_literal Open

question

Difficulty 5/5 Over a week Newbie friendliness 25/100

lark-parser/lark#1437 · 4 comments · Opened Jul 8, 2024
Superfluous identical ambiguities in Earley Open

bug Earley

Difficulty 4/5 3-5 days Newbie friendliness 35/100

lark-parser/lark#1436 · 3 comments · Opened Jul 1, 2024
Post 1388 changes Open

Difficulty 5/5 Over a week Newbie friendliness 15/100

lark-parser/lark#1426 · 4 comments · Opened Jun 18, 2024
Forgiving syntax Open

enhancement

Difficulty 5/5 Over a week Newbie friendliness 28/100

lark-parser/lark#1425 · 3 comments · Opened Jun 18, 2024
Is it possible to parse parts of the input? Open

question

Difficulty 5/5 Over a week Newbie friendliness 25/100

lark-parser/lark#1424 · 12 comments · Opened Jun 17, 2024
Grammar Syntax For Unordered Groups Open

enhancement

Difficulty 5/5 Over a week Newbie friendliness 35/100

lark-parser/lark#1422 · 2 comments · Opened Jun 14, 2024
Fails to parse round-trip string objects from ruamel.yaml Open

question

Difficulty 4/5 3-5 days Newbie friendliness 35/100

lark-parser/lark_cython#36 · 4 comments · Opened May 27, 2024
Pipe in terminal regex not working as expected Open

bug

Difficulty 3/5 1-2 days Newbie friendliness 35/100

lark-parser/lark#1414 · 1 comment · Opened May 14, 2024
Incorrect start_pos / end_pos in the tree Open

discussion question

Difficulty 3/5 1-2 days Newbie friendliness 42/100

lark-parser/lark#1406 · 8 comments · Opened Apr 9, 2024
Import lark grammar written in one python project into another Open

question

Difficulty 4/5 3-5 days Newbie friendliness 35/100

lark-parser/lark#1397 · 6 comments · Opened Mar 26, 2024
__copy__ implementation missing Open

Difficulty 4/5 3-5 days Newbie friendliness 38/100

lark-parser/Lark.js#46 · 6 comments · Opened Feb 25, 2024
Enhancements to Test Suite: Improved Clarity,Debugging and Maintainability Open

enhancement

Difficulty 4/5 3-5 days Newbie friendliness 35/100

lark-parser/lark_cython#34 · 2 comments · Opened Feb 24, 2024
`isupper` bug Open

Difficulty 1/5 Under an hour Newbie friendliness 55/100

lark-parser/Lark.js#43 · 2 comments · Opened Feb 20, 2024
Bug with `interactive.accepts()` Open

Difficulty 3/5 1-2 days Newbie friendliness 45/100

lark-parser/Lark.js#39 · 8 comments · Opened Feb 18, 2024
Earley and reconstructor? Open

Difficulty 5/5 Over a week Newbie friendliness 20/100

lark-parser/Lark.js#38 · 1 comment · Opened Jan 27, 2024

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