[router] restructure tool parser module folder (#9693)

sgl-router/src/tool_parser/mod.rs

 /// Tool parser module for handling function/tool calls in model outputs
 ///
 /// This module provides infrastructure for parsing tool calls from various model formats.
+// Core modules
 pub mod errors;
-pub mod json_parser;
-pub mod llama_parser;
-pub mod mistral_parser;
 pub mod partial_json;
 pub mod python_literal_parser;
-pub mod pythonic_parser;
-pub mod qwen_parser;
 pub mod registry;
 pub mod state;
 pub mod traits;
 pub mod types;
 
+// Parser implementations
+pub mod parsers;
+
 #[cfg(test)]
 mod tests;
 
 // Re-export commonly used types
 pub use errors::{ToolParserError, ToolParserResult};
-pub use json_parser::JsonParser;
-pub use llama_parser::LlamaParser;
-pub use mistral_parser::MistralParser;
-pub use pythonic_parser::PythonicParser;
-pub use qwen_parser::QwenParser;
 pub use registry::ParserRegistry;
 pub use state::{ParsePhase, ParseState};
 pub use traits::{PartialJsonParser, ToolParser};
 pub use types::{FunctionCall, PartialToolCall, StreamResult, TokenConfig, ToolCall};
+
+// Re-export parsers for convenience
+pub use parsers::{JsonParser, LlamaParser, MistralParser, PythonicParser, QwenParser};

sgl-router/src/tool_parser/json_parser.rs → sgl-router/src/tool_parser/parsers/json_parser.rs

@@ -291,7 +291,8 @@ impl ToolParser for JsonParser {
                         // Clear buffer since we consumed everything
                         state.buffer.clear();
 
-                        // Return the first tool as complete (simplified for Phase 2)
+                        // Return the first tool as complete
+                        // TODO simplified version, address more complex version
                         if let Some(tool) = tools.into_iter().next() {
                             return Ok(StreamResult::ToolComplete(tool));
                         }
@@ -299,7 +300,7 @@ impl ToolParser for JsonParser {
                 } else {
                     // Partial JSON, try to extract tool name
                     if let Some(name) = value.get("name").and_then(|v| v.as_str()) {
-                        // Simple implementation for Phase 2
+                        // TODO simplified version, address more complex version
                         // Just return the tool name once we see it
                         if !state.in_string {
                             state.in_string = true; // Use as a flag for "name sent"
@@ -430,12 +431,12 @@ mod tests {
 
     #[tokio::test]
     async fn test_streaming_parse() {
-        // Phase 2 simplified streaming test
         // Just verify that streaming eventually produces a complete tool call
         let parser = JsonParser::new();
         let mut state = ParseState::new();
 
-        // Send complete JSON in one go (simplified for Phase 2)
+        // Send complete JSON in one go
+        // TODO simplified version, address more complex version
         let full_json = r#"{"name": "get_weather", "arguments": {"location": "SF"}}"#;
 
         let result = parser

sgl-router/src/tool_parser/llama_parser.rs → sgl-router/src/tool_parser/parsers/llama_parser.rs

 use async_trait::async_trait;
 
+use super::json_parser::JsonParser;
 use crate::tool_parser::{
     errors::ToolParserResult,
-    json_parser::JsonParser,
     state::ParseState,
     traits::ToolParser,
     types::{StreamResult, TokenConfig, ToolCall},

sgl-router/src/tool_parser/parsers/mod.rs

+/// Parser implementations for different model formats
+///
+/// This module contains concrete parser implementations for various model-specific
+/// tool/function call formats.
+// Individual parser modules
+pub mod json_parser;
+pub mod llama_parser;
+pub mod mistral_parser;
+pub mod pythonic_parser;
+pub mod qwen_parser;
+
+pub use json_parser::JsonParser;
+pub use llama_parser::LlamaParser;
+pub use mistral_parser::MistralParser;
+pub use pythonic_parser::PythonicParser;
+pub use qwen_parser::QwenParser;

sgl-router/src/tool_parser/registry.rs

-use crate::tool_parser::json_parser::JsonParser;
-use crate::tool_parser::llama_parser::LlamaParser;
-use crate::tool_parser::mistral_parser::MistralParser;
-use crate::tool_parser::pythonic_parser::PythonicParser;
-use crate::tool_parser::qwen_parser::QwenParser;
+use crate::tool_parser::parsers::{
+    JsonParser, LlamaParser, MistralParser, PythonicParser, QwenParser,
+};
 use crate::tool_parser::traits::ToolParser;
 use std::collections::HashMap;
 use std::sync::Arc;

sgl-router/src/tool_parser/tests.rs

 use super::*;
-use crate::tool_parser::json_parser::JsonParser;
+use crate::tool_parser::parsers::JsonParser;
 use crate::tool_parser::partial_json::{
     compute_diff, find_common_prefix, is_complete_json, PartialJson,
 };
@@ -387,11 +387,10 @@ fn test_json_parser_format_detection() {
 
 #[tokio::test]
 async fn test_json_parser_streaming() {
-    // Phase 2 simplified streaming test
     let parser = JsonParser::new();
     let mut state = ParseState::new();
 
-    // Test with complete JSON (simplified for Phase 2)
+    // Test with complete JSON
     let full_json = r#"{"name": "get_weather", "arguments": {"location": "San Francisco"}}"#;
 
     let result = parser
@@ -739,7 +738,7 @@ mod edge_cases {
             _ => panic!("Expected ToolComplete for complete JSON"),
         }
 
-        // Test 3: Partial JSON with name - Phase 2 behavior
+        // Test 3: Partial JSON with name
         // The PartialJson parser can complete partial JSON by filling in missing values
         let mut state3 = ParseState::new();
         let partial_with_name = r#"{"name": "test", "argum"#;