Crate serde_ssml 

SSML Parser Library

SSML Parser

A Rust library for parsing, manipulating, and generating Speech Synthesis Markup Language (SSML) documents.

Features

• 🔍 Robust SSML parsing
• 🛠 Flexible SSML element representation
• 📝 SSML serialization and deserialization
• 🔢 Strong typing for SSML elements
• 🚀 Performance-optimized parsing

Installation

Add to your Cargo.toml:

[dependencies]
serde_ssml = "0.3"  # Replace with actual version

Quick Start

Parsing SSML

use serde_ssml::{from_str, SsmlElement};

fn main() {
    let ssml_input = r#"
    <?xml version="1.0"?>
    <speak version="1.1" xml:lang="en-US">
        <p>
            <s>This is a <emphasis level="strong">test</emphasis> sentence.</s>
        </p>
    </speak>
    "#;

    // Parse SSML into a structured representation
    let parsed_ssml = from_str(ssml_input).expect("Failed to parse SSML");

    // Traverse the parsed structure
    for element in &parsed_ssml.elements {
        match element {
            SsmlElement::Speak { version, lang, children, .. } => {
                println!("SSML Version: {}", version.as_deref().unwrap_or("Unknown"));
                println!("Language: {}", lang.as_deref().unwrap_or("Unknown"));
            }
            _ => {}
        }
    }
}

Creating SSML Programmatically

use serde_ssml::{SsmlElement, SSML, BreakStrength};
use std::time::Duration;

fn main() {
    let ssml = SSML {
        elements: vec![
            SsmlElement::Speak {
                version: Some("1.1".to_string()),
                xmlns: Some("http://www.w3.org/2001/10/synthesis".to_string()),
                lang: Some("en-US".to_string()),
                children: vec![
                    SsmlElement::Paragraph {
                        children: vec![
                            SsmlElement::Sentence {
                                children: vec![
                                    SsmlElement::Text("Welcome to ".to_string()),
                                    SsmlElement::Prosody {
                                        rate: "slow".to_string(),
                                        pitch: "low".to_string(),
                                        contour: "".to_string(),
                                        range: "".to_string(),
                                        volume: "soft".to_string(),
                                        children: vec![
                                            SsmlElement::Emphasis {
                                                level: "strong".to_string(),
                                                children: vec![
                                                    SsmlElement::Text("speech synthesis".to_string())
                                                ]
                                            }
                                        ]
                                    },
                                    SsmlElement::Text("!".to_string())
                                ]
                            }
                        ]
                    },
                    SsmlElement::Break {
                        time: Some(Duration::from_millis(500)),
                        strength: Some(BreakStrength::Medium)
                    }
                ]
            }
        ]
    };

    // Convert back to SSML
    let output = serde_ssml::to_string(&ssml);
    println!("{}", output);
}

XML Serialization and Deserialization

use serde_ssml::{to_string, from_str};

fn main() {
    let ssml_input = r#"<speak>Hello, world!</speak>"#;

    // Parse SSML
    let parsed_ssml = from_str(ssml_input).expect("Failed to parse");

    // Convert back to XML string
    let output = to_string(&parsed_ssml);
    println!("{}", output);
}

Supported SSML Elements

The library supports a wide range of SSML elements:

• <speak>: Root document element
• <voice>: Voice selection and characteristics
• <p>: Paragraph
• <s>: Sentence
• <break>: Pause control
• <emphasis>: Text emphasis
• <phoneme>: Precise pronunciation
• <say-as>: Content interpretation
• <prosody>: Speech characteristics control
• <audio>: Embedded audio
• And more…

Parsing Capabilities

• Handles nested SSML structures
• Preserves text content and attributes
• Lenient parsing with whitespace
• Optional attributes support

Limitations

• Does not validate against official SSML schemas
• Parsing based on structural recognition

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

License

Copyright (c) 2025 Ernestas Poškus

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the “Software”), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

Structs

SSML

Represents the entire SSML document structure.

Enums

BreakStrength

Represents the strength of a break in speech synthesis.

SsmlElement

Represents the various elements that can appear in an SSML (Speech Synthesis Markup Language) document.

Functions

find_and_modify_elements

Find all elements of a specific type and apply a modification

from_str

Parses a SSML (Speech Synthesis Markup Language) string into a structured representation.

to_string

Converts a structured SSML representation into a serialized SSML string.

visit_mut

Generic visitor function for finding and modifying SSML elements

Type Aliases

ParseError

Represents a parse error, containing a list of simple error tokens.