Changelog of @hackage/pandoc-filter-indent 0.3.3.1

Changelog for pandoc-filter-indent

0.3.3.1 Nov 17 2025

Documentation

  • Improve Hackage package page presentation
    • Split documentation into README.md and DESCRIPTION.md
    • README.md: Concise, user-friendly quick-start guide
    • DESCRIPTION.md: Full academic documentation with YAML metadata
    • Fix incomplete code block example in package description
    • Resolves YAML frontmatter display issue on Hackage

Packaging

  • Relax lower bounds to support older LTS snapshots
    • Tested with LTS 20.15 (GHC 9.2.7) and LTS 24.20 (GHC 9.10.3)
    • Widens compatibility while maintaining PVP-compliant upper bounds

0.3.3.0 Nov 17 2025

Unicode and Operator Support

  • Add comprehensive support for GHC UnicodeSyntax extension operators
    • Unicode lambda (λ) now correctly renders as \lambda
    • All GHC UnicodeSyntax operators now supported: ∷, ⇒, →, ←, ⤚, ⤙, ⤜, ⤛, ★, ∀, ⦇, ⦈, ⟦, ⟧, ⊸
    • ASCII and Unicode versions of operators produce identical LaTeX output
  • Fix unicode lambda (λ) character handling in both Haskell and Skylighting tokenizers
    • Add splitUnicodeLambda to handle tokens like "λx" → ["λ", "x"]
  • Fix lambda expressions rendering in LaTeX math mode
  • Fix backslash operators (, \, /, /, etc.) rendering
  • Add preprocessing for Skylighting tokenizer to handle split backslash operators
  • Add fixBracketOperators to merge GHC bracket operators: (|, |), [|, |]

  • < as Cartesian product (\times)

  • :-> as \longmapsto
  • Design choice: * renders as \times (multiplication) since modern Haskell uses Type for kinds
    • Unicode ★ renders as \star for legacy kind annotations
    • Tokenizers cannot distinguish between kind and multiplication contexts
    • TODO: Make this configurable for projects with legacy kind syntax

Tokenizer Differences and Solutions

  • Root cause identified: Haskell and Skylighting tokenizers produce different token types
    • Haskell tokenizer: most operators → TOther
    • Skylighting tokenizer: some operators → TOperator (e.g., *, >-, -<, >>-, -<<)
    • Unicode ∀: TKeyword (Haskell) vs TOther (Skylighting)
    • Unicode λ: TVar (Haskell) vs TOther (Skylighting)
  • Solution: Introduced OpOrOther pattern synonym using PatternSynonyms extension
    • Eliminates code duplication when handling same operator from both tokenizers
    • Cleaner syntax: formatToken (OpOrOther "->") = mathop "to"

Bug Fixes

  • Fix extraColumns and tableColumns deduplication mismatch
    • Both now use text column position deduplication to avoid gaps in table column indices
    • Fixes prop_tableColumns test failure on inputs like "\n a"
  • Rename subscripts to subAndSuperscripts with proper superscript support

Testing

  • Add comprehensive test suite for lambda expressions and backslash operators
  • Add unit tests for all GHC UnicodeSyntax operators (UnicodeOperatorSpec)
    • Tests verify ASCII and Unicode versions produce identical LaTeX output
    • Tests now fail on error instead of just warning (enforced with error function)
  • Add tokenizer comparison tests (TokenizerTest)
  • Refactor test suite: extract common test pattern into helper function
  • Improve test readability: reduce code duplication in property tests

Code Quality

  • Code cleanup: remove unused LANGUAGE pragmas, add missing pragmas
  • Code cleanup: use newtype for single-field records, use concatMap and elemIndex
  • Code cleanup: remove redundant $ operators and brackets
  • Code cleanup: fix pattern matching style (otherwise -> _)
  • Code cleanup: use hPrint instead of hPutStrLn . show

Documentation

  • Add UNICODE_OPERATORS.md explaining Unicode operator support, design decisions, and limitations
  • Document tokenizer differences and solutions
  • Document the * vs ★ rendering choice with rationale

Release history

0.3.2.0 Sep 29 2021

  • stacked subscripts
  • lambda in Haskell tokenizer
  • greek letters for special variable names: eps, pi, rho
  • automatically append required LaTeX packages (broken for Beamer output)
  • Mapsto for |=>

0.3.1.0 Jan 15 2021

  • Slightly improved formatting with SkyLighting and LaTeX

0.3.0.0 Jan 15 2021

  • Support default syntaxes from skylighting.

0.2.3.0 Jan 12 2021

  • fixed minor issue that disabled inline rendering.

0.2.2.0 Jan 12 2021

  • Fixed problem with declaring too few columns in LaTeX
  • Inline code formatting
  • Removed indent marks from parenthesised operators: "(+)"
  • Removed indent marks from functions promoted to operators like "mappend"
  • Fixed rendering of indent mark at the start of the column

0.1.0.0 Dec 1 2020

  • Initial release supporting LaTeX and HTML output

0.2.0.0 Dec 2 2020

  • Preliminary support for Tikzmarks
  • Updated README

0.2.1.0 Dec 2 2020

  • Extended code documentation
  • Cleanups