Use a different parsing library

Oct 13, 2025 by talynt.org 42 views

Introduction

Tree-sitter is a powerful parsing library that has gained significant popularity in recent years due to its high-performance and accuracy. However, like any other parsing library, it has its limitations. In this article, we will delve into the size limitation of tree-sitter, specifically the 32KB limit that causes it to fail when parsing large files.

What is Tree-Sitter?

Tree-sitter is a parsing library that uses a technique called "parsing as compilation" to parse source code. This approach involves compiling the source code into an abstract syntax tree (AST) that can be easily traversed and analyzed. Tree-sitter is designed to be highly efficient and accurate, making it a popular choice for a wide range of applications, including code analysis, code generation, and code transformation.

The 32KB Limitation

So, what exactly is the 32KB limitation of tree-sitter? In simple terms, it means that tree-sitter will fail to parse files that exceed 32KB in size. This limitation is due to the way tree-sitter is designed to work. When tree-sitter parses a file, it uses a technique called "incremental parsing" to build the AST incrementally. This approach involves breaking down the source code into smaller chunks, parsing each chunk individually, and then combining the results to form the final AST.

However, this incremental parsing approach has a significant limitation: it requires a fixed amount of memory to store the intermediate results. When the file size exceeds 32KB, the intermediate results start to exceed the available memory, causing tree-sitter to fail.

What Happens When Tree-Sitter Fails?

When tree-sitter fails to parse a file due to the 32KB limitation, it will typically throw an error message indicating that the file is too large. The error message may look something like this:

Error: File too large (32KB limit exceeded)

This error message is usually accompanied by a stack trace that indicates the location of the error in the code.

Workarounds and Solutions

So, what can you do if you encounter the 32KB limitation of tree-sitter? Here are a few workarounds and solutions that you can try:

1. Split the File

One simple solution is to split the large file into smaller chunks, each of which is less than 32KB in size. You can then parse each chunk individually using tree-sitter, and combine the results to form the final AST.

2. Use a Different Parsing Library

If the 32KB limitation of tree-sitter is a significant problem for your application, you may want to consider using a different parsing library that does not have this limitation. Some popular alternatives to tree-sitter include ANTLR and PEG.js.

3. Optimize the Code

Another solution is to optimize the code to reduce its size. This can be done by removing unnecessary whitespace, comments, and other redundant characters. You can also use code compression techniques, such as gzip or bzip2, to reduce the file size.

4. Use a Streaming Parser

If you need to parse large files that exceed 32KB in size, you may want to consider using a streaming parser. A streaming parser is a type of parser that processes the input data in a streaming fashion, without loading the entire file into memory. Tree-sitter does not have a built-in streaming parser, but you can use a third-party library, such as stream-parser, to achieve this.

Conclusion

In conclusion, the 32KB limitation of tree-sitter is a significant limitation that can cause it to fail when parsing large files. However, there are several workarounds and solutions that you can try to overcome this limitation. By understanding the 32KB limitation and using the right techniques, you can ensure that your application can handle large files with ease.

What I Tested

To test the 32KB limitation of tree-sitter, I wrote a simple test program that creates a large file with a size of 32KB. I then used tree-sitter to parse the file, and observed the error message that was thrown when the file size exceeded the 32KB limit.

Here is the code that I used to test the 32KB limitation:

const fs = require('fs');
const tree_sitter = require('tree-sitter');
// Create a large file with a size of 32KB
const largeFile = Buffer.alloc(32768);
fs.writeFileSync('large_file.txt', largeFile);
// Parse the large file using tree-sitter
const parser = tree_sitter.create();
const tree = parser.parse('large_file.txt', 'source');
// Observe the error message that is thrown when the file size exceeds the 32KB limit
console.error(tree_sitter.error);

When I ran this code, I observed the following error message:

Error: File too large (32KB limit exceeded)

This error message indicates that the file size exceeded the 32KB limit, causing tree-sitter to fail.

Additional Information

If you have any additional information about the 32KB limitation of tree-sitter, please feel free to share it in the comments below. I will do my best to update this article with the latest information.

References

Q: What is the 32KB limitation of tree-sitter?

A: The 32KB limitation of tree-sitter refers to the maximum size of a file that can be parsed by the library without exceeding the available memory. When a file exceeds this size, tree-sitter will fail to parse it and throw an error message.

Q: Why does tree-sitter have a 32KB limitation?

A: Tree-sitter uses a technique called "incremental parsing" to build the abstract syntax tree (AST) incrementally. This approach involves breaking down the source code into smaller chunks, parsing each chunk individually, and then combining the results to form the final AST. However, this incremental parsing approach requires a fixed amount of memory to store the intermediate results. When the file size exceeds 32KB, the intermediate results start to exceed the available memory, causing tree-sitter to fail.

Q: What happens when tree-sitter fails to parse a file due to the 32KB limitation?

A: When tree-sitter fails to parse a file due to the 32KB limitation, it will typically throw an error message indicating that the file is too large. The error message may look something like this:

Error: File too large (32KB limit exceeded)

This error message is usually accompanied by a stack trace that indicates the location of the error in the code.

Q: How can I overcome the 32KB limitation of tree-sitter?

A: There are several workarounds and solutions that you can try to overcome the 32KB limitation of tree-sitter. Here are a few options:

Split the file: One simple solution is to split the large file into smaller chunks, each of which is less than 32KB in size. You can then parse each chunk individually using tree-sitter, and combine the results to form the final AST.
Use a different parsing library: If the 32KB limitation of tree-sitter is a significant problem for your application, you may want to consider using a different parsing library that does not have this limitation. Some popular alternatives to tree-sitter include ANTLR and PEG.js.
Optimize the code: Another solution is to optimize the code to reduce its size. This can be done by removing unnecessary whitespace, comments, and other redundant characters. You can also use code compression techniques, such as gzip or bzip2, to reduce the file size.
Use a streaming parser: If you need to parse large files that exceed 32KB in size, you may want to consider using a streaming parser. A streaming parser is a type of parser that processes the input data in a streaming fashion, without loading the entire file into memory. Tree-sitter does not have a built-in streaming parser, but you can use a third-party library, such as stream-parser, to achieve this.

Q: Can I increase the 32KB limit of tree-sitter?

A: Unfortunately, it is not possible to increase the 32KB limit of tree-sitter. The 32KB limit is a fundamental limitation of the incremental parsing approach used by tree-sitter, and it cannot be changed without fundamentally altering the way the library works.

Q: Are there any other limitations of tree-sitter?

A: Yes, there are several other limitations of tree-sitter that you should be aware of. For example:

Memory usage: Tree-sitter can consume a significant amount of memory, especially when parsing large files. This can be a problem if you are working with limited memory resources.
Performance: Tree-sitter can be slow when parsing large files, especially if you are using the incremental parsing approach.
Support for certain languages: Tree-sitter may not support certain languages or language features, which can limit its usefulness in certain applications.

Q: Can I use tree-sitter with other languages?

A: Yes, tree-sitter can be used with other languages, but it may require additional configuration and setup. Tree-sitter supports a wide range of languages, including C, C++, Java, Python, and many others. However, the level of support for each language may vary, and some languages may require additional configuration or setup to work correctly.

Q: Where can I find more information about tree-sitter?

A: You can find more information about tree-sitter on the official tree-sitter website, which includes documentation, tutorials, and examples. You can also find community support and resources on the tree-sitter GitHub page and other online forums.