Notes on Haskell Programming (Part 161): From token streams to structured AST document

Generated by NotebookLM based on this blog post: https://www.kianmeng.org/2026/06/note... This technical guide documents a transition in Haskell development from a disordered token stream to a structured Abstract Syntax Tree (AST) for document parsing. By moving away from flat lists of tokens, the author introduces a hierarchical model that explicitly separates metadata from content blocks, thereby eliminating the need for inefficient list manipulation during conversion. This architectural shift ensures that information like titles or headers is immediately accessible, resulting in a cleaner separation of concerns between data extraction and final transformation. Ultimately, this refactoring enhances computational performance and prepares the codebase for future integration with the Pandoc engine.