When working with Julia, it is common to encounter situations where you need to manipulate HTML code. One such situation is when you have raw HTML code stored in a docstring and you want to process it in some way. In this article, we will explore three different ways to solve this problem.

Option 1: Using the `HTML` package

The first option is to use the `HTML` package, which provides a convenient way to parse and manipulate HTML code in Julia. To use this package, you need to install it first by running the following command:

using Pkg
Pkg.add("HTML")

Once you have installed the `HTML` package, you can parse the raw HTML code by calling the `parsehtml` function and passing the docstring as an argument:

using HTML

html_code = """


Hello, World!


"""

parsed_html = parsehtml(html_code)

Now, you can manipulate the parsed HTML code using the functions provided by the `HTML` package. For example, you can extract specific elements using CSS selectors or modify the attributes of existing elements.

Option 2: Using the `Gumbo.jl` package

If you prefer a more low-level approach, you can use the `Gumbo.jl` package, which provides a Julia wrapper for the Gumbo HTML5 parser. This package allows you to parse HTML code and navigate the resulting parse tree using a simple API.

To use the `Gumbo.jl` package, you need to install it first by running the following command:

using Pkg
Pkg.add("Gumbo")

Once you have installed the `Gumbo.jl` package, you can parse the raw HTML code by calling the `parsehtml` function and passing the docstring as an argument:

using Gumbo

html_code = """


Hello, World!


"""

parsed_html = parsehtml(html_code)

Now, you can navigate the parse tree and manipulate the HTML code using the functions provided by the `Gumbo.jl` package. For example, you can find specific elements by tag name or modify the attributes of existing elements.

Option 3: Using regular expressions

If you prefer a more manual approach, you can use regular expressions to extract and manipulate the HTML code. While this option may require more effort and be less robust than using dedicated HTML parsing libraries, it can be useful for simple cases where you only need to perform basic operations.

To use regular expressions, you can use the `match` function provided by Julia’s `Regex` module. For example, to extract the content of a specific HTML tag, you can define a regular expression pattern and use the `match` function to find the matching substring:

html_code = """


Hello, World!


"""

pattern = r"
(.*?)
"
match_result = match(pattern, html_code)

if match_result !== nothing
    extracted_content = match_result.captures[1]
    println(extracted_content)
end

By using regular expressions, you have more control over the parsing and manipulation process. However, it is important to note that regular expressions may not be suitable for complex HTML structures or cases where the HTML code is not well-formed.

After exploring these three options, it is clear that using the `HTML` package provides the most convenient and robust solution for manipulating raw HTML code in Julia. It offers a high-level API and takes care of parsing and navigating the HTML code for you. While the `Gumbo.jl` package and regular expressions can be useful in certain scenarios, they require more manual effort and may not handle all edge cases as effectively as the `HTML` package.