> ## Documentation Index > Fetch the complete documentation index at: https://docs.somark.cn/llms.txt > Use this file to discover all available pages before exploring further. # Syntax Reference > Complete syntax guide for all SoMarkDown components with examples ## 1. Headings SoMarkDown supports six heading levels following CommonMark, using `#` symbols. ```markdown theme={null} # Heading 1 ## Heading 2 ### Heading 3 #### Heading 4 ##### Heading 5 ###### Heading 6 ``` *** ## 2. Text Styles ### Basic Styles | Effect | Syntax | | ----------------- | ------------------------ | | **Bold** | `**text**` or `__text__` | | *Italic* | `*text*` or `_text_` | | ==Highlight== | `==text==` | | Superscript | `text^sup^` | | Subscript | `text~sub~` | | ~~Strikethrough~~ | `~~text~~` | ```markdown theme={null} **bold text** *italic text* ==highlighted text== H^2^O (superscript) CO~2~ (subscript) ~~strikethrough~~ ``` ### Underline Wrap text with `++`. Every pair of `+` adds one underline level — you can stack levels by adding more `+`: ```markdown theme={null} ++underlined text++ ++++double underline++++ ``` ### Blockquote ```markdown theme={null} > Quoted text > > Multiple paragraphs supported ``` *** ## 3. Special Symbols ### Emoji Uses [markdown-it-emoji](https://github.com/markdown-it/markdown-it-emoji) syntax: `:emoji_name:` ### Copyright Symbols | Character | Syntax | | --------- | ---------------- | | © | `(c)` or `(C)` | | ® | `(r)` or `(R)` | | ™ | `(tm)` or `(TM)` | *** ## 4. Lists ### Ordered List ```markdown theme={null} 1. First item 2. Second item 3. Third item ``` ### Unordered List Any of `*`, `+`, or `-` work as list markers: ```markdown theme={null} - First item - Second item - Nested item ``` *** ## 5. Table of Contents Insert `[[TOC]]` anywhere in the document to generate an automatic table of contents based on headings. ```markdown theme={null} [[TOC]] ``` Reference: [markdown-it-table-of-contents](https://github.com/cmaas/markdown-it-table-of-contents) *** ## 6. Code Code highlighting is powered by [highlight.js](https://github.com/highlightjs/highlight.js). Use highlight.js language identifiers for the language tag. ### Inline Code ```markdown theme={null} Use the `print()` function to output text. ``` ### Code Block ````markdown theme={null} ```python def hello(): print("Hello, SoMarkDown!") ``` ```` Common language identifiers: `python`, `javascript`, `typescript`, `java`, `c`, `cpp`, `bash`, `sql`, `json`. If you want the overview and installation notes first, go back to the [SoMarkDown overview](/en/open-source-tools/somarkdown/index). See the [full list](https://github.com/highlightjs/highlight.js/blob/main/SUPPORTED_LANGUAGES.md). *** ## 7. Math Formulas Math is rendered by [KaTeX](https://katex.org) using standard LaTeX syntax. ### Inline Math ```markdown theme={null} The mass-energy equation $E = mc^2$ is a cornerstone of physics. Euler's identity: $e^{i\pi} + 1 = 0$ ``` ### Display Math ```markdown theme={null} $$ \int_{-\infty}^{\infty} e^{-x^2} dx = \sqrt{\pi} $$ ``` *** ## 8. Images ```markdown theme={null} ![semantic description](image URL) ``` SoMarkDown repurposes the Markdown alt-text field as the location for **AI-generated semantic understanding** of the image. In SoMarkDown renderers, the text in brackets is displayed as a semantic annotation. This design is backward compatible with standard Markdown. ```markdown theme={null} ![This chart shows exponential user growth from 2020 to 2024.](https://example.com/chart.png) ``` Control whether image descriptions are displayed via the `imgDescEnabled` config option: ```javascript theme={null} new SoMarkDown({ imgDescEnabled: true }) ``` *** ## 9. Tables SoMarkDown uses HTML `` tags for tables instead of the native Markdown pipe syntax. This provides full support for merged cells (`rowspan` / `colspan`). ```html theme={null}
Column A Column B Column C
Merged cell B1 C1
B2 C2
``` *** ## 10. Captions Captions can annotate a Figure or Table. They start with `: ` (colon + space). ```markdown theme={null} : Figure 1 — User growth trend ![chart](chart.png) ``` **Rules:** * Must start with `: ` (a colon followed by exactly one space) * Must be directly adjacent to the target component (above or below), with blank lines allowed but no other elements in between * If captions exist on both sides, the one above takes priority Reference: [Pandoc caption extension](https://pandoc.org/MANUAL.html#extension-table_captions) *** ## 11. Chemical Equations Chemical equations use `\ce{}` syntax rendered by [mhchem](https://mhchem.github.io/MathJax-mhchem), and must be placed inside a math environment. ### Inline ```markdown theme={null} The reaction $\ce{H2 + O2 -> H2O}$ is exothermic. ``` ### Display ```markdown theme={null} $$ \ce{CO2 + C -> 2 CO} $$ $$ \ce{2H2 + O2 ->[\text{ignition}] 2H2O} $$ ``` *** ## 12. Chemical Structures (SMILES) Chemical structures use `\smiles{}` syntax rendered by [SmilesDrawer](https://github.com/reymond-group/smilesDrawer), and must be placed inside a math environment. SoMarkDown treats SMILES notation as a special symbol within the math environment. This is because: (1) structures appear inside chemical equations; (2) like math formulas, they need both inline and display layout modes; (3) it keeps the integration consistent with chemical equations. ### Inline Structure ```markdown theme={null} Ethanol has the structure $\smiles{CCO}$. ``` ### Display Structure ```markdown theme={null} $$ \smiles{c1ccccc1} $$ ``` ### Mixed Chemical Structure Equations (mhchem + SMILES) SoMarkDown innovatively supports embedding `\smiles{}` inside `\ce{}`, merging structural and equation notation in a single expression: ```markdown theme={null} $$ \ce{\smiles{CCO} + \smiles{O} -> \smiles{CC(O)O}} $$ ``` SMILES rendering can be customized via configuration: ```javascript theme={null} new SoMarkDown({ smiles: { disableColors: false, width: 300, height: 200 } }) ``` *** ## 13. Diagrams — Mermaid (Coming Soon) Mermaid diagram support is in development. The planned syntax: ````markdown theme={null} ```mermaid graph TD A[Start] --> B{Decision} B -->|Yes| C[Execute] B -->|No| D[End] ``` ````