Struct Engine

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pub struct Engine { /* private fields */ }

Implementations§

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impl Engine

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pub fn new() -> Self

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pub fn with_fixed_today(self, today: Option<NaiveDate>) -> Self

Overrides the “today” value used by diagrams that depend on local time (e.g. Gantt).

This exists primarily to make fixture snapshots deterministic. By default, Mermaid uses the current local date.

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pub fn with_fixed_local_offset_minutes( self, offset_minutes: Option<i32>, ) -> Self

Overrides the local timezone offset (in minutes) used by diagrams that depend on local time semantics (notably Gantt).

This exists primarily to make fixture snapshots deterministic across CI runners. When None, the system local timezone is used.

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pub fn parse_metadata_sync( &self, text: &str, options: ParseOptions, ) -> Result<Option<ParseMetadata>>

Synchronous variant of Engine::parse_metadata.

This is useful for UI render pipelines that are synchronous (e.g. immediate-mode UI), where introducing an async executor would be awkward. The parsing work is CPU-bound and does not perform I/O.

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pub fn parse_metadata_as_sync( &self, diagram_type: &str, text: &str, options: ParseOptions, ) -> Result<Option<ParseMetadata>>

Parses metadata for an already-known diagram type (skips type detection).

This is intended for integrations that already know the diagram type, e.g. Markdown fences like ````mermaid/ flowchart` / ` sequenceDiagram`.

§Example (Markdown fence)

use merman_core::{Engine, ParseOptions};

let engine = Engine::new();

// Your markdown parser provides the fence info string (e.g. "flowchart", "sequenceDiagram").
let fence = "sequenceDiagram";
let diagram = r#"sequenceDiagram
  Alice->>Bob: Hello
"#;

// Map fence info strings to merman's internal diagram ids.
let diagram_type = match fence {
    "sequenceDiagram" => "sequence",
    "flowchart" | "graph" => "flowchart-v2",
    "stateDiagram" | "stateDiagram-v2" => "stateDiagram",
    other => other,
};

let meta = engine
    .parse_metadata_as_sync(diagram_type, diagram, ParseOptions::strict())?
    .expect("diagram detected");

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pub async fn parse_metadata( &self, text: &str, options: ParseOptions, ) -> Result<Option<ParseMetadata>>

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pub async fn parse_metadata_as( &self, diagram_type: &str, text: &str, options: ParseOptions, ) -> Result<Option<ParseMetadata>>

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pub fn parse_diagram_sync( &self, text: &str, options: ParseOptions, ) -> Result<Option<ParsedDiagram>>

Synchronous variant of Engine::parse_diagram.

Note: callers that want “always returns a diagram” behavior can set ParseOptions::suppress_errors to true to get an error diagram on parse failures.

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pub async fn parse_diagram( &self, text: &str, options: ParseOptions, ) -> Result<Option<ParsedDiagram>>

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pub fn parse_diagram_for_render_sync( &self, text: &str, options: ParseOptions, ) -> Result<Option<ParsedDiagram>>

Parses a diagram for layout/render pipelines.

Compared to Engine::parse_diagram_sync, this may omit semantic-model keys that are not required by merman’s layout/SVG renderers (e.g. embedding the full effective config into the returned model). This keeps the public parse_diagram* APIs stable while allowing render pipelines to avoid paying large JSON clone costs.

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pub async fn parse_diagram_for_render( &self, text: &str, options: ParseOptions, ) -> Result<Option<ParsedDiagram>>

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pub fn parse_diagram_for_render_model_sync( &self, text: &str, options: ParseOptions, ) -> Result<Option<ParsedDiagramRender>>

Parses a diagram into a typed semantic model optimized for headless layout + SVG rendering.

Unlike Engine::parse_diagram_for_render_sync, this avoids constructing large serde_json::Value object trees for some high-impact diagrams (currently stateDiagram and mindmap) and instead returns typed semantic structs that the renderer can consume directly.

Callers that need the semantic JSON model should continue using Engine::parse_diagram_sync or Engine::parse_diagram_for_render_sync.

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pub async fn parse_diagram_for_render_model( &self, text: &str, options: ParseOptions, ) -> Result<Option<ParsedDiagramRender>>

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pub fn parse_diagram_for_render_model_as_sync( &self, diagram_type: &str, text: &str, options: ParseOptions, ) -> Result<Option<ParsedDiagramRender>>

Parses a diagram into a typed semantic render model when the diagram type is already known (skips type detection).

This is the preferred entrypoint for Markdown renderers and editors that already know the diagram type from the code fence info string. It avoids the detection pass and can reduce a small fixed overhead in tight render loops.

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pub async fn parse_diagram_for_render_model_as( &self, diagram_type: &str, text: &str, options: ParseOptions, ) -> Result<Option<ParsedDiagramRender>>

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pub fn parse_diagram_as_sync( &self, diagram_type: &str, text: &str, options: ParseOptions, ) -> Result<Option<ParsedDiagram>>

Parses a diagram when the diagram type is already known (skips type detection).

This is the preferred entrypoint for Markdown renderers and editors that already know the diagram type from the code fence info string. It avoids the detection pass and can reduce a small fixed overhead in tight render loops.

§Example

use merman_core::{Engine, ParseOptions};

let engine = Engine::new();
let input = "flowchart TD; A-->B;";

let parsed = engine
    .parse_diagram_as_sync("flowchart-v2", input, ParseOptions::strict())?
    .expect("diagram detected");

assert_eq!(parsed.meta.diagram_type, "flowchart-v2");

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