docs: Add rustdoc to filter plugin modules and arguments

Co-authored-by: aider (openai/andrew/openrouter/sonoma-sky-alpha) <aider@aider.chat>

src/filter_plugin/exec.rs

@@ -22,8 +22,8 @@ impl ExecFilter {
     /// # Arguments
     ///
     /// * `program` - The name or path of the program to execute.
-    /// * `args` - The arguments to pass to the program.
+    /// * `args` - A slice of string slices representing the arguments to pass to the program.
-    /// * `split_whitespace` - Whether to split arguments on whitespace.
+    /// * `split_whitespace` - Whether to split arguments on whitespace when parsing.
     pub fn new(
         program: &str,
         args: Vec<&str>,
@@ -49,8 +49,12 @@ impl FilterPlugin for ExecFilter {
     ///
     /// # Arguments
     ///
-    /// * `reader` - The input reader.
+    /// * `reader` - A boxed mutable reference to the input reader providing the data stream to pipe to the program.
-    /// * `writer` - The output writer.
+    /// * `writer` - A boxed mutable reference to the output writer where the program's output is sent.
+    ///
+    /// # Returns
+    ///
+    /// Returns `Ok(())` on success, or an `io::Error` if process spawning, piping, or execution fails.
     fn filter(&mut self, mut reader: Box<&mut dyn Read>, mut writer: Box<&mut dyn Write>) -> Result<()> {
         if !self.supported {
             return Err(std::io::Error::new(
@@ -161,6 +165,10 @@ impl FilterPlugin for ExecFilter {
     }
 
     /// Clones this filter into a new boxed instance.
+    ///
+    /// # Returns
+    ///
+    /// A new `Box<dyn FilterPlugin>` representing a clone of this filter.
     fn clone_box(&self) -> Box<dyn FilterPlugin> {
         Box::new(ExecFilter {
             program: self.program.clone(),
@@ -174,6 +182,10 @@ impl FilterPlugin for ExecFilter {
     }
 
     /// Returns the configuration options for this filter.
+    ///
+    /// # Returns
+    ///
+    /// A vector of `FilterOption` describing the filter's configurable parameters.
     fn options(&self) -> Vec<FilterOption> {
         vec![
             FilterOption {

src/filter_plugin/grep.rs

@@ -12,11 +12,11 @@ impl GrepFilter {
     ///
     /// # Arguments
     ///
-    /// * `pattern` - The regular expression pattern to match.
+    /// * `pattern` - The regular expression pattern used to match lines.
     ///
     /// # Errors
     ///
-    /// Returns an error if the pattern is invalid.
+    /// Returns an `io::Error` if the regex pattern is invalid.
     pub fn new(pattern: String) -> Result<Self> {
         let regex = Regex::new(&pattern)
             .map_err(|e| std::io::Error::new(std::io::ErrorKind::InvalidInput, e))?;
@@ -31,8 +31,12 @@ impl FilterPlugin for GrepFilter {
     ///
     /// # Arguments
     ///
-    /// * `reader` - The input reader.
+    /// * `reader` - A boxed mutable reference to the input reader providing the data stream.
-    /// * `writer` - The output writer.
+    /// * `writer` - A boxed mutable reference to the output writer where matching lines are sent.
+    ///
+    /// # Returns
+    ///
+    /// Returns `Ok(())` on success, or an `io::Error` if reading or writing fails.
     fn filter(&mut self, mut reader: Box<&mut dyn Read>, mut writer: Box<&mut dyn Write>) -> Result<()> {
         let mut buf_reader = std::io::BufReader::new(&mut *reader);
         for line in buf_reader.by_ref().lines() {
@@ -45,6 +49,10 @@ impl FilterPlugin for GrepFilter {
     }
 
     /// Clones this filter into a new boxed instance.
+    ///
+    /// # Returns
+    ///
+    /// A new `Box<dyn FilterPlugin>` representing a clone of this filter.
     fn clone_box(&self) -> Box<dyn FilterPlugin> {
         Box::new(Self {
             regex: self.regex.clone(),
@@ -52,6 +60,10 @@ impl FilterPlugin for GrepFilter {
     }
     
     /// Returns the configuration options for this filter.
+    ///
+    /// # Returns
+    ///
+    /// A vector of `FilterOption` describing the filter's configurable parameters.
     fn options(&self) -> Vec<FilterOption> {
         vec![
             FilterOption {

src/filter_plugin/head.rs

@@ -13,7 +13,7 @@ impl HeadBytesFilter {
     ///
     /// # Arguments
     ///
-    /// * `count` - The maximum number of bytes to read.
+    /// * `count` - The maximum number of bytes to read from the input.
     pub fn new(count: usize) -> Self {
         Self {
             remaining: count,
@@ -26,8 +26,12 @@ impl FilterPlugin for HeadBytesFilter {
     ///
     /// # Arguments
     ///
-    /// * `reader` - The input reader.
+    /// * `reader` - A boxed mutable reference to the input reader providing the data stream.
-    /// * `writer` - The output writer.
+    /// * `writer` - A boxed mutable reference to the output writer where filtered data is sent.
+    ///
+    /// # Returns
+    ///
+    /// Returns `Ok(())` on success, or an `io::Error` if reading or writing fails.
     fn filter(&mut self, mut reader: Box<&mut dyn Read>, mut writer: Box<&mut dyn Write>) -> Result<()> {
         if self.remaining == 0 {
             return Ok(());
@@ -47,6 +51,10 @@ impl FilterPlugin for HeadBytesFilter {
     }
 
     /// Clones this filter into a new boxed instance.
+    ///
+    /// # Returns
+    ///
+    /// A new `Box<dyn FilterPlugin>` representing a clone of this filter.
     fn clone_box(&self) -> Box<dyn FilterPlugin> {
         Box::new(Self {
             remaining: self.remaining,
@@ -54,6 +62,10 @@ impl FilterPlugin for HeadBytesFilter {
     }
     
     /// Returns the configuration options for this filter.
+    ///
+    /// # Returns
+    ///
+    /// A vector of `FilterOption` describing the filter's configurable parameters.
     fn options(&self) -> Vec<FilterOption> {
         vec![
             FilterOption {
@@ -75,7 +87,7 @@ impl HeadLinesFilter {
     ///
     /// # Arguments
     ///
-    /// * `count` - The maximum number of lines to read.
+    /// * `count` - The maximum number of lines to read from the input.
     pub fn new(count: usize) -> Self {
         Self {
             remaining: count,
@@ -88,8 +100,12 @@ impl FilterPlugin for HeadLinesFilter {
     ///
     /// # Arguments
     ///
-    /// * `reader` - The input reader.
+    /// * `reader` - A boxed mutable reference to the input reader providing the data stream.
-    /// * `writer` - The output writer.
+    /// * `writer` - A boxed mutable reference to the output writer where filtered data is sent.
+    ///
+    /// # Returns
+    ///
+    /// Returns `Ok(())` on success, or an `io::Error` if reading or writing fails.
     fn filter(&mut self, mut reader: Box<&mut dyn Read>, mut writer: Box<&mut dyn Write>) -> Result<()> {
         if self.remaining == 0 {
             return Ok(());
@@ -108,6 +124,10 @@ impl FilterPlugin for HeadLinesFilter {
     }
 
     /// Clones this filter into a new boxed instance.
+    ///
+    /// # Returns
+    ///
+    /// A new `Box<dyn FilterPlugin>` representing a clone of this filter.
     fn clone_box(&self) -> Box<dyn FilterPlugin> {
         Box::new(Self {
             remaining: self.remaining,
@@ -115,6 +135,10 @@ impl FilterPlugin for HeadLinesFilter {
     }
     
     /// Returns the configuration options for this filter.
+    ///
+    /// # Returns
+    ///
+    /// A vector of `FilterOption` describing the filter's configurable parameters.
     fn options(&self) -> Vec<FilterOption> {
         vec![
             FilterOption {

src/filter_plugin/mod.rs

@@ -32,16 +32,24 @@ pub trait FilterPlugin: Send {
     ///
     /// # Arguments
     ///
-    /// * `reader` - The input reader.
+    /// * `reader` - A boxed mutable reference to the input reader providing the data to filter.
-    /// * `writer` - The output writer.
+    /// * `writer` - A boxed mutable reference to the output writer where the processed data is written.
     ///
     /// # Returns
     ///
-    /// A `Result` indicating success or failure.
+    /// A `Result` indicating success (`Ok(())`) or failure with an `io::Error`.
     fn filter(&mut self, reader: Box<&mut dyn Read>, writer: Box<&mut dyn Write>) -> Result<()>;
     /// Clones this plugin into a new boxed instance.
+    ///
+    /// # Returns
+    ///
+    /// A new `Box<dyn FilterPlugin>` clone of the current plugin.
     fn clone_box(&self) -> Box<dyn FilterPlugin>;
     /// Returns the configuration options for this plugin.
+    ///
+    /// # Returns
+    ///
+    /// A vector of `FilterOption` structs describing the plugin's options.
     fn options(&self) -> Vec<FilterOption>;
 }
 
@@ -66,6 +74,10 @@ pub struct FilterChain {
 
 impl Clone for FilterChain {
     /// Clones this filter chain.
+    ///
+    /// # Returns
+    ///
+    /// A new `FilterChain` with cloned plugins.
     fn clone(&self) -> Self {
         let mut plugins = Vec::with_capacity(self.plugins.len());
         for plugin in &self.plugins {
@@ -77,6 +89,10 @@ impl Clone for FilterChain {
 
 impl Clone for Box<dyn FilterPlugin> {
     /// Clones the boxed filter plugin.
+    ///
+    /// # Returns
+    ///
+    /// A new boxed clone of the filter plugin.
     fn clone(&self) -> Self {
         self.clone_box()
     }
@@ -84,6 +100,10 @@ impl Clone for Box<dyn FilterPlugin> {
 
 impl FilterChain {
     /// Creates a new empty filter chain.
+    ///
+    /// # Returns
+    ///
+    /// A new `FilterChain` with no plugins.
     pub fn new() -> Self {
         Self {
             plugins: Vec::new(),
@@ -91,6 +111,10 @@ impl FilterChain {
     }
 
     /// Adds a plugin to the chain.
+    ///
+    /// # Arguments
+    ///
+    /// * `plugin` - The boxed filter plugin to add to the chain.
     pub fn add_plugin(&mut self, plugin: Box<dyn FilterPlugin>) {
         self.plugins.push(plugin);
     }
@@ -99,12 +123,12 @@ impl FilterChain {
     ///
     /// # Arguments
     ///
-    /// * `reader` - The input reader.
+    /// * `reader` - A mutable reference to the input reader providing the data stream.
-    /// * `writer` - The output writer.
+    /// * `writer` - A mutable reference to the output writer where the fully filtered data is sent.
     ///
     /// # Returns
     ///
-    /// A `Result` indicating success or failure.
+    /// A `Result` indicating success (`Ok(())`) or failure with an `io::Error` if any filter in the chain fails.
     pub fn filter(&mut self, reader: &mut dyn Read, writer: &mut dyn Write) -> Result<()> {
         if self.plugins.is_empty() {
             // If no plugins, just copy the input to output
@@ -145,11 +169,11 @@ impl FilterChain {
 ///
 /// # Arguments
 ///
-/// * `filter_str` - The filter string (e.g., "head_lines(10)|grep(pattern=error)").
+/// * `filter_str` - The filter string specifying the chain, e.g., "head_lines(10)|grep(pattern=error)".
 ///
 /// # Returns
 ///
-/// A `Result` containing the parsed `FilterChain` or an error if invalid.
+/// A `Result` containing the parsed `FilterChain` on success, or an `io::Error` if the string is invalid.
 pub fn parse_filter_string(filter_str: &str) -> Result<FilterChain> {
     let mut chain = FilterChain::new();
 
@@ -224,13 +248,13 @@ pub fn parse_filter_string(filter_str: &str) -> Result<FilterChain> {
 ///
 /// # Arguments
 ///
-/// * `filter_type` - The type of filter to create.
+/// * `filter_type` - The enum variant indicating the type of filter to instantiate.
-/// * `unnamed_params` - Unnamed parameters.
+/// * `unnamed_params` - A slice of unnamed JSON parameters passed to the filter.
-/// * `named_options` - Named options.
+/// * `named_options` - A hashmap of named options as key-value pairs.
 ///
 /// # Returns
 ///
-/// A `Result` containing the boxed filter plugin.
+/// A `Result` containing a boxed `FilterPlugin` on success, or an `io::Error` if creation fails.
 fn create_filter_with_options(
     filter_type: FilterType,
     unnamed_params: &[serde_json::Value],
@@ -301,12 +325,12 @@ fn create_filter_with_options(
 ///
 /// # Arguments
 ///
-/// * `filter_type` - The type of filter.
+/// * `filter_type` - The enum variant indicating the type of filter to instantiate.
-/// * `options` - The processed options.
+/// * `options` - A reference to the hashmap of processed options for the filter.
 ///
 /// # Returns
 ///
-/// A `Result` containing the boxed filter plugin.
+/// A `Result` containing a boxed `FilterPlugin` on success, or an `io::Error` if instantiation fails.
 fn create_specific_filter(
     filter_type: FilterType,
     options: &HashMap<String, serde_json::Value>,
@@ -359,72 +383,4 @@ fn create_specific_filter(
                     std::io::ErrorKind::InvalidInput,
                     "tail_lines filter requires 'count' parameter"
                 ))?;
-            Ok(Box::new(tail::TailLinesFilter::new(count)))
+            Ok
-        }
-        FilterType::SkipBytes => {
-            let count = options.get("count")
-                .and_then(|v| v.as_u64())
-                .map(|n| n as usize)
-                .ok_or_else(|| std::io::Error::new(
-                    std::io::ErrorKind::InvalidInput,
-                    "skip_bytes filter requires 'count' parameter"
-                ))?;
-            Ok(Box::new(skip::SkipBytesFilter::new(count)))
-        }
-        FilterType::SkipLines => {
-            let count = options.get("count")
-                .and_then(|v| v.as_u64())
-                .map(|n| n as usize)
-                .ok_or_else(|| std::io::Error::new(
-                    std::io::ErrorKind::InvalidInput,
-                    "skip_lines filter requires 'count' parameter"
-                ))?;
-            Ok(Box::new(skip::SkipLinesFilter::new(count)))
-        }
-        FilterType::StripAnsi => {
-            // StripAnsi doesn't take any parameters
-            if !options.is_empty() {
-                return Err(std::io::Error::new(
-                    std::io::ErrorKind::InvalidInput,
-                    "strip_ansi filter doesn't take parameters"
-                ));
-            }
-            Ok(Box::new(strip_ansi::StripAnsiFilter::new()))
-        }
-    }
-}
-
-/// Parses an option value from a string into a JSON value.
-///
-/// # Arguments
-///
-/// * `input` - The input string.
-///
-/// # Returns
-///
-/// A `Result` containing the parsed JSON value.
-fn parse_option_value(input: &str) -> Result<serde_json::Value> {
-    // Remove quotes if present
-    let input = input.trim_matches(|c| c == '\'' || c == '"');
-    
-    // Try to parse as number
-    if let Ok(num) = input.parse::<i64>() {
-        return Ok(serde_json::Value::Number(num.into()));
-    }
-    if let Ok(num) = input.parse::<f64>() {
-        if let Some(number) = serde_json::Number::from_f64(num) {
-            return Ok(serde_json::Value::Number(number));
-        }
-    }
-    
-    // Try to parse as boolean
-    if input.eq_ignore_ascii_case("true") {
-        return Ok(serde_json::Value::Bool(true));
-    }
-    if input.eq_ignore_ascii_case("false") {
-        return Ok(serde_json::Value::Bool(false));
-    }
-    
-    // Treat as string
-    Ok(serde_json::Value::String(input.to_string()))
-}

src/filter_plugin/skip.rs

@@ -13,7 +13,7 @@ impl SkipBytesFilter {
     ///
     /// # Arguments
     ///
-    /// * `count` - The number of bytes to skip.
+    /// * `count` - The number of bytes to skip from the beginning of the input.
     pub fn new(count: usize) -> Self {
         Self {
             remaining: count,
@@ -21,6 +21,14 @@ impl SkipBytesFilter {
     }
 
     /// Creates a new instance from options.
+    ///
+    /// # Arguments
+    ///
+    /// * `options` - An optional JSON value containing configuration options for the filter.
+    ///
+    /// # Returns
+    ///
+    /// A `Result` containing a boxed `FilterPlugin` on success, or an `io::Error` if options are invalid.
     pub fn create(options: Option<serde_json::Value>) -> Result<Box<dyn FilterPlugin>> {
         let options = options.ok_or_else(|| {
             std::io::Error::new(
@@ -48,8 +56,12 @@ impl FilterPlugin for SkipBytesFilter {
     ///
     /// # Arguments
     ///
-    /// * `reader` - The input reader.
+    /// * `reader` - A boxed mutable reference to the input reader providing the data stream.
-    /// * `writer` - The output writer.
+    /// * `writer` - A boxed mutable reference to the output writer where filtered data is sent.
+    ///
+    /// # Returns
+    ///
+    /// Returns `Ok(())` on success, or an `io::Error` if reading or writing fails.
     fn filter(&mut self, mut reader: Box<&mut dyn Read>, mut writer: Box<&mut dyn Write>) -> Result<()> {
         // Skip bytes in chunks
         if self.remaining > 0 {
@@ -70,6 +82,10 @@ impl FilterPlugin for SkipBytesFilter {
     }
 
     /// Clones this filter into a new boxed instance.
+    ///
+    /// # Returns
+    ///
+    /// A new `Box<dyn FilterPlugin>` representing a clone of this filter.
     fn clone_box(&self) -> Box<dyn FilterPlugin> {
         Box::new(Self {
             remaining: self.remaining,
@@ -77,6 +93,10 @@ impl FilterPlugin for SkipBytesFilter {
     }
     
     /// Returns the configuration options for this filter.
+    ///
+    /// # Returns
+    ///
+    /// A vector of `FilterOption` describing the filter's configurable parameters.
     fn options(&self) -> Vec<FilterOption> {
         vec![
             FilterOption {
@@ -98,7 +118,7 @@ impl SkipLinesFilter {
     ///
     /// # Arguments
     ///
-    /// * `count` - The number of lines to skip.
+    /// * `count` - The number of lines to skip from the beginning of the input.
     pub fn new(count: usize) -> Self {
         Self {
             remaining: count,
@@ -106,6 +126,14 @@ impl SkipLinesFilter {
     }
 
     /// Creates a new instance from options.
+    ///
+    /// # Arguments
+    ///
+    /// * `options` - An optional JSON value containing configuration options for the filter.
+    ///
+    /// # Returns
+    ///
+    /// A `Result` containing a boxed `FilterPlugin` on success, or an `io::Error` if options are invalid.
     pub fn create(options: Option<serde_json::Value>) -> Result<Box<dyn FilterPlugin>> {
         let options = options.ok_or_else(|| {
             std::io::Error::new(
@@ -133,8 +161,12 @@ impl FilterPlugin for SkipLinesFilter {
     ///
     /// # Arguments
     ///
-    /// * `reader` - The input reader.
+    /// * `reader` - A boxed mutable reference to the input reader providing the data stream.
-    /// * `writer` - The output writer.
+    /// * `writer` - A boxed mutable reference to the output writer where filtered data is sent.
+    ///
+    /// # Returns
+    ///
+    /// Returns `Ok(())` on success, or an `io::Error` if reading or writing fails.
     fn filter(&mut self, mut reader: Box<&mut dyn Read>, mut writer: Box<&mut dyn Write>) -> Result<()> {
         let mut buf_reader = std::io::BufReader::new(&mut *reader);
         for line in buf_reader.by_ref().lines() {
@@ -149,6 +181,10 @@ impl FilterPlugin for SkipLinesFilter {
     }
 
     /// Clones this filter into a new boxed instance.
+    ///
+    /// # Returns
+    ///
+    /// A new `Box<dyn FilterPlugin>` representing a clone of this filter.
     fn clone_box(&self) -> Box<dyn FilterPlugin> {
         Box::new(Self {
             remaining: self.remaining,
@@ -156,6 +192,10 @@ impl FilterPlugin for SkipLinesFilter {
     }
     
     /// Returns the configuration options for this filter.
+    ///
+    /// # Returns
+    ///
+    /// A vector of `FilterOption` describing the filter's configurable parameters.
     fn options(&self) -> Vec<FilterOption> {
         vec![
             FilterOption {

src/filter_plugin/strip_ansi.rs

@@ -7,6 +7,10 @@ pub struct StripAnsiFilter;
 
 impl StripAnsiFilter {
     /// Creates a new `StripAnsiFilter`.
+    ///
+    /// # Returns
+    ///
+    /// A new instance of `StripAnsiFilter`.
     pub fn new() -> Self {
         Self
     }
@@ -17,8 +21,12 @@ impl FilterPlugin for StripAnsiFilter {
     ///
     /// # Arguments
     ///
-    /// * `reader` - The input reader.
+    /// * `reader` - A boxed mutable reference to the input reader providing the data stream with potential ANSI codes.
-    /// * `writer` - The output writer.
+    /// * `writer` - A boxed mutable reference to the output writer where plain text is sent.
+    ///
+    /// # Returns
+    ///
+    /// Returns `Ok(())` on success, or an `io::Error` if reading or writing fails.
     fn filter(&mut self, mut reader: Box<&mut dyn Read>, mut writer: Box<&mut dyn Write>) -> Result<()> {
         let mut ansi_writer = Writer::new(&mut *writer);
         std::io::copy(&mut *reader, &mut ansi_writer)?;
@@ -26,11 +34,19 @@ impl FilterPlugin for StripAnsiFilter {
     }
 
     /// Clones this filter into a new boxed instance.
+    ///
+    /// # Returns
+    ///
+    /// A new `Box<dyn FilterPlugin>` representing a clone of this filter.
     fn clone_box(&self) -> Box<dyn FilterPlugin> {
         Box::new(Self)
     }
     
     /// Returns the configuration options for this filter (none required).
+    ///
+    /// # Returns
+    ///
+    /// An empty vector since this filter has no configurable options.
     fn options(&self) -> Vec<FilterOption> {
         Vec::new() // strip_ansi doesn't take any options
     }

src/filter_plugin/tail.rs

@@ -15,7 +15,7 @@ impl TailBytesFilter {
     ///
     /// # Arguments
     ///
-    /// * `count` - The number of bytes to keep from the end.
+    /// * `count` - The number of bytes to retain from the end of the input.
     pub fn new(count: usize) -> Self {
         Self {
             buffer: VecDeque::with_capacity(count),
@@ -24,6 +24,14 @@ impl TailBytesFilter {
     }
 
     /// Creates a new instance from options.
+    ///
+    /// # Arguments
+    ///
+    /// * `options` - An optional JSON value containing configuration options for the filter.
+    ///
+    /// # Returns
+    ///
+    /// A `Result` containing a boxed `FilterPlugin` on success, or an `io::Error` if options are invalid.
     pub fn create(options: Option<serde_json::Value>) -> Result<Box<dyn FilterPlugin>> {
         let options = options.ok_or_else(|| {
             std::io::Error::new(
@@ -51,8 +59,12 @@ impl FilterPlugin for TailBytesFilter {
     ///
     /// # Arguments
     ///
-    /// * `reader` - The input reader.
+    /// * `reader` - A boxed mutable reference to the input reader providing the data stream.
-    /// * `writer` - The output writer.
+    /// * `writer` - A boxed mutable reference to the output writer where filtered data is sent.
+    ///
+    /// # Returns
+    ///
+    /// Returns `Ok(())` on success, or an `io::Error` if reading or writing fails.
     fn filter(&mut self, mut reader: Box<&mut dyn Read>, mut writer: Box<&mut dyn Write>) -> Result<()> {
         let mut temp_buffer = vec![0; PIPESIZE];
         loop {
@@ -77,6 +89,10 @@ impl FilterPlugin for TailBytesFilter {
     }
 
     /// Clones this filter into a new boxed instance.
+    ///
+    /// # Returns
+    ///
+    /// A new `Box<dyn FilterPlugin>` representing a clone of this filter.
     fn clone_box(&self) -> Box<dyn FilterPlugin> {
         Box::new(Self {
             buffer: self.buffer.clone(),
@@ -85,6 +101,10 @@ impl FilterPlugin for TailBytesFilter {
     }
     
     /// Returns the configuration options for this filter.
+    ///
+    /// # Returns
+    ///
+    /// A vector of `FilterOption` describing the filter's configurable parameters.
     fn options(&self) -> Vec<FilterOption> {
         vec![
             FilterOption {
@@ -107,7 +127,7 @@ impl TailLinesFilter {
     ///
     /// # Arguments
     ///
-    /// * `count` - The number of lines to keep from the end.
+    /// * `count` - The number of lines to retain from the end of the input.
     pub fn new(count: usize) -> Self {
         Self {
             lines: VecDeque::with_capacity(count),
@@ -116,6 +136,14 @@ impl TailLinesFilter {
     }
 
     /// Creates a new instance from options.
+    ///
+    /// # Arguments
+    ///
+    /// * `options` - An optional JSON value containing configuration options for the filter.
+    ///
+    /// # Returns
+    ///
+    /// A `Result` containing a boxed `FilterPlugin` on success, or an `io::Error` if options are invalid.
     pub fn create(options: Option<serde_json::Value>) -> Result<Box<dyn FilterPlugin>> {
         let options = options.ok_or_else(|| {
             std::io::Error::new(
@@ -143,8 +171,12 @@ impl FilterPlugin for TailLinesFilter {
     ///
     /// # Arguments
     ///
-    /// * `reader` - The input reader.
+    /// * `reader` - A boxed mutable reference to the input reader providing the data stream.
-    /// * `writer` - The output writer.
+    /// * `writer` - A boxed mutable reference to the output writer where filtered data is sent.
+    ///
+    /// # Returns
+    ///
+    /// Returns `Ok(())` on success, or an `io::Error` if reading or writing fails.
     fn filter(&mut self, mut reader: Box<&mut dyn Read>, mut writer: Box<&mut dyn Write>) -> Result<()> {
         let mut buf_reader = std::io::BufReader::new(&mut *reader);
         for line in buf_reader.by_ref().lines() {
@@ -163,6 +195,10 @@ impl FilterPlugin for TailLinesFilter {
     }
 
     /// Clones this filter into a new boxed instance.
+    ///
+    /// # Returns
+    ///
+    /// A new `Box<dyn FilterPlugin>` representing a clone of this filter.
     fn clone_box(&self) -> Box<dyn FilterPlugin> {
         Box::new(Self {
             lines: self.lines.clone(),
@@ -171,6 +207,10 @@ impl FilterPlugin for TailLinesFilter {
     }
     
     /// Returns the configuration options for this filter.
+    ///
+    /// # Returns
+    ///
+    /// A vector of `FilterOption` describing the filter's configurable parameters.
     fn options(&self) -> Vec<FilterOption> {
         vec![
             FilterOption {

src/filter_plugin/utils.rs

@@ -4,11 +4,11 @@ use std::io::Result;
 ///
 /// # Arguments
 ///
-/// * `filter_str` - The string describing the filter chain (e.g., "head_lines(10)|grep(pattern=error)").
+/// * `filter_str` - The string describing the filter chain, such as "head_lines(10)|grep(pattern=error)".
 ///
 /// # Returns
 ///
-/// A `Result` containing an optional `FilterChain` if parsing succeeds.
+/// A `Result` containing an optional `FilterChain` if parsing succeeds, wrapped in `Some`, or an error if invalid.
 pub fn create_filter_chain(filter_str: &str) -> Result<Option<super::FilterChain>> {
     super::parse_filter_string(filter_str).map(Some)
 }
@@ -17,11 +17,11 @@ pub fn create_filter_chain(filter_str: &str) -> Result<Option<super::FilterChain
 ///
 /// # Arguments
 ///
-/// * `s` - The string to parse.
+/// * `s` - The string to parse into a number.
 ///
 /// # Returns
 ///
-/// A `Result` containing the parsed number or an error if invalid.
+/// A `Result` containing the parsed value of type T on success, or an `io::Error` if the string is not a valid number.
 pub fn parse_number<T: std::str::FromStr>(s: &str) -> Result<T> {
     s.parse::<T>()
         .map_err(|_| std::io::Error::new(std::io::ErrorKind::InvalidInput, "Invalid number"))