.LHS File Extension
Literate Haskell Script
| Developer | N/A |
| Popularity | |
| Category | Developer Files |
| Format | .LHS |
| Cross Platform | Update Soon |
What is an LHS file?
The .LHS file extension stands for Literate Haskell Script. Haskell, a purely functional programming language, uses these files to combine documentation and code in a way that is easy to read and understand.
Literate Haskell allows developers to write programs that can be more easily understood by humans while still being executable by computers.
This blend of human-readable text and machine-readable code makes .LHS files are particularly useful for teaching, documentation, and collaborative development projects.
More Information.
The initial purpose of .LHS files were to make Haskell programs easier to understand, modify, and maintain. By integrating documentation directly into the source code, developers could ensure that their code was well-explained and accessible to others.
This was particularly important in academic and research settings, where the ability to share and explain complex algorithms and processes is crucial.
Over time, the use of .LHS files have expanded to include various other applications, including teaching materials, tutorials, and collaborative software development projects.
Origin Of This File.
The concept of literate programming was introduced by Donald Knuth in the early 1980s. Literate programming is a methodology that combines a program’s source code with its documentation.
The goal is to create a comprehensive and comprehensible narrative that explains the logic, design decisions, and functionality of the code.
Haskell, developed in the late 1980s and early 1990s, adopted this approach and provided support for literate programming through .LHS files.
File Structure Technical Specification.
.LHS files follow a structure that combines documentation and Haskell code. There are two main styles of organizing .LHS files:
Bird Track Style:
- In this style, each line of Haskell code is preceded by a greater-than sign (
>). - The documentation can be written in plain text, with Haskell code interspersed throughout.
- This style is straightforward and easy to read, making it suitable for small to medium-sized projects.
TeX Style:
- TeX-style .LHS files use LaTeX markup for documentation and code.
- Haskell code is enclosed within specific environments recognized by LaTeX, such as
\begin{code}and\end{code}. - This style provides more flexibility in formatting documentation but may be more complex for beginners.
Technical Specification
.LHS files are plain text files with the extension “.lhs”. They do not have any specific binary format. The structure and content of .LHS files adhere to the rules of literate programming, where the emphasis is on human readability and comprehension.
How to Convert the File?
Converting .LHS files to standard Haskell (.HS) files can be done manually or using specialized tools. Here are the steps for conversion:
Manual Conversion:
- Manually extract the Haskell code from the .LHS file, removing any documentation or markup.
- Save the extracted code into a new file with the “.hs” extension.
Using lhs2TeX:
- Install lhs2TeX, a preprocessor for literate Haskell documents.
- Run lhs2TeX with appropriate options to generate a LaTeX document or plain Haskell code from the .LHS file.
- Save the output as a .TEX or .HS file, depending on the desired format.
Using Pandoc:
- Install Pandoc, a universal document converter.
- Use Pandoc to convert the .LHS file to a desired format, such as LaTeX or Markdown.
- Extract the Haskell code from the converted document and save it as a .HS file.
By following these methods, developers can convert .LHS files to standard Haskell format, enabling seamless integration into existing workflows and toolchains.
Advantages And Disadvantages.
Advantages
- Enhanced Readability: Combining documentation with code improves readability and understanding.
- Better Documentation: Encourages thorough documentation practices.
- Educational Utility: Ideal for teaching programming concepts and Haskell.
- Collaboration: Facilitates easier code sharing and collaboration.
- Maintenance: Easier to maintain and update due to integrated documentation.
Disadvantages
- Complexity: Can become complex with large codebases.
- Tool Support: Limited support in some development environments.
- Learning Curve: Requires learning the specific syntax for literate programming.
- Performance: Parsing and compiling can be slower due to the additional processing of documentation.
How to Open LHS?
Open In Windows
- Visual Studio Code (VSCode): With the Haskell extension, VSCode can handle .LHS files effectively.
- Notepad++: While more basic, Notepad++ can open and edit .LHS files with syntax highlighting.
Open In Linux
- Emacs: With the Haskell mode, Emacs can edit and interact with .LHS files.
- Vim: Configured with Haskell plugins, Vim is a flexible choice for editing .LHS files.
Open In MAC
- Visual Studio Code (VSCode): Similarly, VSCode with the Haskell extension is a robust choice.
- TextMate: A powerful text editor for macOS that can handle .LHS files.
