About¶

1. About lext¶

lex is a plain text document format for structured documents. It combines the immediacy of plain text with the rigor of hierarchical, machine-readable markup so you can stay in the flow from first note to published artifact.

2. The Format¶

lex documents rely on indentation and a small set of markers to reveal structure. The syntax stays invisible so authors focus on ideas, not delimiters.

2.1. Core Elements¶

Session

Hierarchical sections with numbered titles.

Example

Introduction

Content indented under the title belongs to this section.

1.1. Subsection

Nested content at deeper levels.

:: text language=lex

Definition: Term; The definition follows immediately after the colon, indented one level.

:: text language=lex

Lists

Unordered item
Another item

Ordered item
Another ordered item
1. Nested alphabetical
2. Another nested

:: text language=lex

Verbatim Blocks: Example Code

function hello() {
    return "world";
}

Tables

Comparison

Format	Tables	Spanning
lex	Native	Yes
Markdown	Basic	No

Annotation

This is a single-line annotation.

This is a block annotation with multiple lines.

::

:: text language=lex

2.2. Inline Formatting¶

*bold* for strong emphasis
_italic_ for emphasis
`` code `` for inline code
#math# for mathematical notation
[reference] for links, citations, footnotes

2.3. Reference Types¶

[https://example.com] - URLs
[@author2024] - Citations
[42] - Footnotes
[::label] - Annotation references
[#2.1] - Session references
[./file.txt] - File references
[TK-placeholder] - Placeholders

3. Implementation¶

The reference implementation lives in Rust crates under the lex-fmt organization. Each crate focuses on a specific role in the toolchain:

Definition: lex-core; Parser with a five-phase pipeline.
Definition: lex-babel; Format conversion for Markdown, HTML, PDF, and more.
Definition: lex-analysis; Document analysis powering editor features.
Definition: lex-lsp; Language Server Protocol implementation.
Definition: lex-cli; Command-line interface.
Definition: lex-config; Configuration loader shared by the CLI and tools.

All crates are published to.

4. Design Principles¶

Invisible syntax: Structure emerges from indentation and textual conventions.
Graceful degradation: Unmatched constructs become paragraphs instead of errors.
Complete lifecycle: Scales from quick notes to finished documents.
Tool-friendly: Deterministic grammar for reliable parsing.
Future-proof: Plain Unicode text, no proprietary containers.

5. License¶

lex is open source. See each repository for license details.