Use a string representation

Oct 13, 2025 by miodeya.com 8 views

Introduction

In this article, we will explore the behavior of the Crystal programming language when rendering Markdown with large integers. We will examine a specific scenario where a big integer raised exception occurs, and provide insights into the underlying causes and potential solutions.

The Problem

When working with Markdown in Crystal, we often encounter situations where we need to render large integers as part of the Markdown text. However, as we will see, this can lead to unexpected behavior and exceptions.

Let's consider the following example code:

require "markd"

puts Markd.to_html(
  "1212121212121"
)

This code attempts to render the string "1212121212121" as Markdown HTML using the Markd library. However, as we will see, this will result in an exception being raised.

The Exception

When we run the above code, we get the following exception:

Unhandled exception: Invalid Int32: "1212121212121" (ArgumentError)
  from /home/zw963/.asdf/installs/crystal/1.15.0/share/crystal/src/string.cr:450:5 in 'to_i32'
  from /home/zw963/.asdf/installs/crystal/1.15.0/share/crystal/src/string.cr:351:5 in 'to_i'
  from lib/markd/src/markd/rules/list.cr:106:29 in 'parse_list_marker'
  from lib/markd/src/markd/rules/list.cr:10:9 in 'match'
  from lib/markd/src/markd/parsers/block.cr:133:16 in 'process_line'
  from lib/markd/src/markd/parsers/block.cr:71:9 in 'parse_blocks'
  from lib/markd/src/markd/parsers/block.cr:58:9 in 'parse'
  from lib/markd/src/markd/parsers/block.cr:6:7 in 'parse'
  from lib/markd/src/markd/parser.cr:4:7 in 'parse'
  from lib/markd/src/markd.cr:11:3 in 'to_html'
  from lib/markd/src/markd.cr:11:3 in 'to_html'
  from 1.cr:33:6 in '__crystal_main'
  from /home/zw963/.asdf/installs/crystal/1.15.0/share/crystal/src/crystal/main.cr:118:5 in 'main_user_code'
  from /home/zw963/.asdf/installs/crystal/1.15.0/share/crystal/src/crystal/main.cr:104:7 in 'main'
  from /home/zw963/.asdf/installs/crystal/1.15.0/share/crystal/src/crystal/system/unix/main.cr:9:3 in 'main'
  from /usr/lib/libc.so.6 in '??'
  from /usr/lib/libc.so.6 in '__libc_start_main'
  from /home/zw963/.cache/crystal/crystal-run-1.tmp in '_start'
  from ???

As we can see, the exception is raised when attempting to convert the string "1212121212121" to an integer using the to_i32 method.

Understanding the Cause

The cause of this exception lies in the fact that the to_i32 method is attempting to convert a string that is too large to fit into a 32-bit integer. In Crystal, the to_i32 method is used to convert a string to a 32-bit integer, but it has a limit of 2^31-1, which is approximately 2 billion.

When we pass a string that is larger than this limit, the to_i32 method raises an ArgumentError exception, indicating that the conversion is invalid.

Potential Solutions

There are several potential solutions to this problem:

Use a larger integer type: Instead of using the to_i32 method, we can use the to_i64 method, which can handle larger integers.
Use a string representation: Instead of attempting to convert the string to an integer, we can use a string representation of the integer.
Use a custom parser: We can create a custom parser that can handle large integers and avoid the exception.

Conclusion

In this article, we explored the behavior of the Crystal programming language when rendering Markdown with large integers. We examined a specific scenario where a big integer raised exception occurs, and provided insights into the underlying causes and potential solutions.

By understanding the cause of this exception and exploring potential solutions, we can write more robust and reliable code that can handle large integers and avoid exceptions.

Recommendations

When working with large integers in Crystal, use the to_i64 method instead of to_i32 to avoid exceptions.
Use string representations of integers instead of attempting to convert them to integers.
Create custom parsers that can handle large integers and avoid exceptions.

Additional Resources

Crystal documentation: https://crystal-lang.org/docs/
Markd documentation: https://github.com/iamcco/markd
Crystal community: https://crystal-lang.org/community/
Q&A: Rendering Markdown with Large Integers in Crystal =====================================================

Q: What is the cause of the big integer raised exception in Crystal?

A: The cause of the big integer raised exception in Crystal is due to the to_i32 method attempting to convert a string that is too large to fit into a 32-bit integer. In Crystal, the to_i32 method is used to convert a string to a 32-bit integer, but it has a limit of 2^31-1, which is approximately 2 billion.

Q: How can I avoid the big integer raised exception in Crystal?

A: There are several ways to avoid the big integer raised exception in Crystal:

Use a larger integer type: Instead of using the to_i32 method, use the to_i64 method, which can handle larger integers.
Use a string representation: Instead of attempting to convert the string to an integer, use a string representation of the integer.
Use a custom parser: Create a custom parser that can handle large integers and avoid the exception.

Q: What is the difference between `to_i32` and `to_i64` in Crystal?

A: The main difference between to_i32 and to_i64 in Crystal is the size of the integer they can handle. to_i32 can handle integers up to 2^31-1 (approximately 2 billion), while to_i64 can handle integers up to 2^63-1 (approximately 9 quintillion).

Q: Can I use `to_i64` to handle large integers in Markdown rendering?

A: Yes, you can use to_i64 to handle large integers in Markdown rendering. However, keep in mind that to_i64 is a 64-bit integer, which may not be necessary for most use cases. You can also use string representations of integers or create custom parsers to handle large integers.

Q: How can I create a custom parser to handle large integers in Markdown rendering?

A: Creating a custom parser to handle large integers in Markdown rendering involves several steps:

Define the parser: Define a custom parser that can handle large integers.
Implement the parser: Implement the parser using Crystal's parser API.
Test the parser: Test the parser to ensure it works correctly.

Q: What are some best practices for handling large integers in Markdown rendering?

A: Some best practices for handling large integers in Markdown rendering include:

Use string representations: Use string representations of integers instead of attempting to convert them to integers.
Use custom parsers: Create custom parsers that can handle large integers and avoid exceptions.
Test thoroughly: Test your code thoroughly to ensure it works correctly with large integers.

Q: Can I use other libraries to handle large integers in Markdown rendering?

A: Yes, you can use other libraries to handle large integers in Markdown rendering. Some popular libraries include:

Big: A library for working with arbitrary-precision integers in Crystal.
Numeral: A library for working with numbers in Crystal.
Integer: A library for working with integers in Crystal.

Conclusion

In this Q&A article, we explored some common questions and answers related to rendering Markdown with large integers in Crystal. We covered topics such as the cause of the big integer raised exception, how to avoid the exception, and best practices for handling large integers in Markdown rendering. We also discussed some popular libraries for working with large integers in Crystal.