Comment Parsing

BSharp implements comprehensive comment parsing for both regular comments and XML documentation comments, preserving them as part of the AST for documentation generation and analysis tools.

Comment Types

1. Single-Line Comments

Standard C++ style comments:

// This is a single-line comment
int x = 5; // End-of-line comment

2. Multi-Line Comments

Traditional C-style block comments:

/*
 * This is a multi-line comment
 * that spans several lines
 */
int y = 10; /* Inline block comment */

3. XML Documentation Comments

Single-Line XML Comments

/// <summary>
/// This method calculates the sum of two integers.
/// </summary>
/// <param name="a">The first integer.</param>
/// <param name="b">The second integer.</param>
/// <returns>The sum of a and b.</returns>
public int Add(int a, int b)
{
    return a + b;
}

Multi-Line XML Comments

/**
 * <summary>
 * This is a multi-line XML documentation comment.
 * It provides detailed information about the method.
 * </summary>
 * <param name="value">The input value to process.</param>
 * <returns>The processed result.</returns>
 */
public string ProcessValue(string value) { }

XML Documentation Structure

Standard XML Tags

Summary and Description

<summary>
Brief description of the member.
</summary>

<remarks>
Detailed remarks and additional information.
</remarks>

Parameters and Returns

<param name="parameterName">Description of the parameter.</param>
<returns>Description of the return value.</returns>

Exceptions

<exception cref="ArgumentNullException">
Thrown when the parameter is null.
</exception>

Examples

<example>
This example shows how to use the method:
<code>
var result = MyMethod("input");
Console.WriteLine(result);
</code>
</example>

See References

<see cref="RelatedMethod"/>
<seealso cref="AnotherClass"/>

Generic Type Parameters

<typeparam name="T">The type parameter.</typeparam>
<typeparamref name="T"/>

Custom XML Tags

The parser supports custom XML tags:

<custom attribute="value">
Custom content with <nested>elements</nested>.
</custom>

XML Documentation Parsing

XML Element Structure

The parser represents XML elements with:

#![allow(unused)]
fn main() {
#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
pub struct XmlElement {
    pub name: Identifier,
    pub attributes: Vec<XmlAttribute>,
    pub children: Vec<XmlNode>,
}

#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
pub struct XmlAttribute {
    pub name: Identifier,
    pub value: String,
}

#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
pub enum XmlNode {
    Element(XmlElement),
    Text(String),
    CData(String),
    Comment(String),
}
}

XML Documentation Comment

#![allow(unused)]
fn main() {
#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
pub struct XmlDocumentationComment {
    pub elements: Vec<XmlNode>,
}
}

Parsing XML Attributes

The parser handles XML attributes with various syntaxes:

<param name="value">Description</param>
<see cref="MyClass.MyMethod(int, string)"/>
<exception cref="System.ArgumentException">Error description</exception>

XML Content Parsing

The parser processes mixed content:

<summary>
This method processes <paramref name="input"/> and returns
<see cref="ProcessResult"/> containing the result.
</summary>

Comment Association

Declaration Comments

Comments are associated with their following declarations:

/// <summary>Class documentation</summary>
public class MyClass
{
    /// <summary>Method documentation</summary>
    public void MyMethod() { }
}

Member Comments

Each declaration can have associated documentation:

#![allow(unused)]
fn main() {
#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
pub struct MethodDeclaration {
    pub documentation: Option<XmlDocumentationComment>,
    // ... other fields
}
}

Advanced XML Features

CDATA Sections

The parser handles CDATA sections for literal content:

<example>
<![CDATA[
if (x < y && y > z)
{
    Console.WriteLine("Complex condition");
}
]]>
</example>

Nested XML Elements

Complex nested structures are supported:

<summary>
This method handles <see cref="List{T}"/> where T is
<typeparamref name="T"/> and implements <see cref="IComparable{T}"/>.
</summary>

XML Namespaces

The parser can handle XML namespaces in documentation:

<doc:summary xmlns:doc="http://schemas.microsoft.com/developer/documentation">
Namespaced documentation content.
</doc:summary>

Comment Preservation

Comment Tokens

Comments are preserved as tokens in the AST:

#![allow(unused)]
fn main() {
#[derive(Debug, Clone, PartialEq, Eq)]
pub enum CommentToken {
    SingleLine(String),
    MultiLine(String),
    XmlDocumentation(XmlDocumentationComment),
}
}

Position Information

Comments maintain position information:

#![allow(unused)]
fn main() {
#[derive(Debug, Clone, PartialEq, Eq)]
pub struct PositionedComment {
    pub comment: CommentToken,
    pub line: usize,
    pub column: usize,
}
}

Error Handling

XML Validation

The parser validates XML structure:

• Well-formed XML: Proper opening and closing tags
• Attribute syntax: Valid attribute name-value pairs
• Nesting rules: Correct element nesting
• Character escaping: Proper XML character escaping

Error Recovery

When XML is malformed, the parser attempts recovery:

• Skip malformed elements: Continue parsing after errors
• Preserve content: Keep as much content as possible
• Error reporting: Provide detailed error locations

Integration with Analysis

Documentation Analysis

Comments are available for analysis tools:

#![allow(unused)]
fn main() {
impl XmlDocumentationComment {
    pub fn find_elements_by_name(&self, name: &str) -> Vec<&XmlElement> {
        // Find all elements with the given tag name
    }
    
    pub fn get_summary(&self) -> Option<String> {
        // Extract summary text
    }
    
    pub fn get_parameters(&self) -> Vec<(String, String)> {
        // Extract parameter documentation
    }
}
}

Documentation Generation

The parsed XML documentation can be used for:

• API documentation generation
• IntelliSense information
• Code analysis and quality checks
• Documentation coverage reports

Performance Considerations

Lazy Parsing

XML documentation can be parsed lazily when needed:

#![allow(unused)]
fn main() {
#[derive(Debug, Clone)]
pub enum DocumentationState {
    Unparsed(String),
    Parsed(XmlDocumentationComment),
    Invalid(String, ParseError),
}
}

Memory Optimization

The parser optimizes memory usage by:

• String interning: Reusing common XML tag names
• Structured storage: Efficient representation of XML structure
• On-demand parsing: Parse XML only when accessed

The comment parsing system ensures that all documentation and comments are preserved and available for analysis, while maintaining the performance characteristics needed for large codebases.