pandoc-filter-indent

Pandoc filter that intelligently typesets code by detecting indentation boundaries and aligning operators.

Quick Start

Install via Stack:

stack install pandoc-filter-indent

Use with Pandoc:

pandoc --filter pandoc-filter-indent input.md -o output.pdf
pandoc --filter pandoc-filter-indent input.md -o output.html

What it does

Transforms code blocks into well-aligned, tabular layouts that highlight code structure. Instead of plain monospaced code, you get properly aligned operators, function signatures, and nested structures.

Input:

```{.haskell}
class Eq      a
   => Compare a where
  compare :: a -> a -> Ordering
  (>=)    :: a -> a -> Bool
```

Output: Rendered with operators vertically aligned in clean tables, using mathematical symbols (→, ⇒, ≥) in LaTeX/PDF output.

Features

• Smart alignment - Detects and aligns operators (::, =, ->, etc.) using GHC lexer
• Multiple languages - Haskell (GHC), Python, or generic indentation-based formatting
• Flexible output - LaTeX tables, HTML tables, or Pandoc native tables
• Symbol beautification - Converts operators to mathematical symbols (optional)
• Lightweight - Simple Pandoc filter, easy to integrate

Usage

Mark code blocks with language attribute:

```{.haskell}
-- your Haskell code
```

Or use alternate lexers:

```{.python}
# your Python code
```

For generic indentation-based alignment:

```{.haskell lexer=indent}
-- any indented code
```

Options

Configure via code block attributes:

• lexer=haskell - GHC lexer (default)
• lexer=python3 - Python lexer
• lexer=indent - Indent-only alignment
• lexer=spaces - Space-based alignment
• debug=true - Show column boundaries for debugging

Example:

```{.haskell debug=true}
yourCode :: Here
```

Full Documentation

For detailed algorithm explanation, implementation guide, and advanced usage, see DESCRIPTION.md.

See also: Complete Unicode operator symbol mapping for all supported operator conversions (→, ⇒, ≥, ⊥, ∅, etc.).

Links

• GitHub: https://github.com/migamake/pandoc-filter-typeset-code
• Hackage: https://hackage.haskell.org/package/pandoc-filter-indent
• Issues: https://github.com/migamake/pandoc-filter-typeset-code/issues

License

BSD3 - see LICENSE file