Function calling support for Kimi-K2 (ikawrakow#628)

* Implement function calling / tools for ik_llama.cpp for Kimi K2

* Implement basic tool choice

* Backport llama.cpp tool calls support

* Enhance function calls with improved chat parser and string utilities

- Add new chat.h/chat.cpp and chat-parser.h/chat-parser.cpp for better chat handling
- Improve function calls parsing with fallback to llama.cpp builder pattern
- Add string utility functions (starts_with, ends_with, find_partial_stop)
- Update README with function calls testing instructions
- Enhance Kimi K2 parser and function calls documentation
- Add comprehensive test suite for function calls
- Update CMakeLists.txt and Makefile for new components

* Enhance function calling with unified streaming and parser improvements

- Fix streaming content cleanup to prevent function syntax in output
- Unify content extraction patterns with llama.cpp approach
- Improve Kimi K2 parser robustness and partial content handling
- Add comprehensive test coverage for function call scenarios
- Optimize chat message parsing and diff computation

* Replace hardcoded values in kimi_k2_parser.hpp with named constants

- Add compile-time constants for all token format markers
- Add compile-time constants for XML format markers
- Add compile-time constants for simple format patterns
- Replace all hardcoded string literals with named constants
- Use compile-time length calculation to avoid manual counting
- Improve maintainability and reduce magic numbers throughout parser

* Fix duplicate common_chat_parse definition

- Remove duplicate implementation from chat-parser.cpp
- Keep single implementation in chat.cpp following llama.cpp patterns
- Resolves linker error: multiple definition of common_chat_parse

* Fix JSON assertion failure in function call parsing

- Add proper validation that 'function' field is an object before accessing nested keys
- Handle missing 'arguments' field gracefully with default "{}"
- Prevents crash when parsing malformed tool call JSON structures

* Add comprehensive Qwen3 XML tool calling support with unit tests

- Implement Qwen3 XML parser with <tool_call>{"name": "func", "arguments": {...}}</tool_call> format
- Add model detection and routing for Qwen3 vs Kimi-K2 formats
- Create 8 comprehensive unit tests covering parsing, streaming, error handling
- Fix token format cleaning bug in kimi_k2_parser.hpp processing order
- Remove progressive parsing code and related utilities
- Add tool injection support for Qwen3 format in server utils

* Add DeepSeek R1 function calling support with comprehensive unit tests

- Implement complete DeepSeek R1 tool call parsing in common_chat_parser.cpp
- Add DeepSeek R1 model detection and tool injection in deepseek_r1_tools.hpp
- Update function_calls.hpp with DeepSeek R1 integration and content extraction
- Update documentation to reflect support for Kimi-K2, Qwen3, and DeepSeek R1 models
- Add comprehensive unit tests for DeepSeek R1 reasoning, tool calls, and integration
- Port exact implementation patterns from original llama.cpp for compatibility

Key features:
- Native DeepSeek R1 format: <｜tool▁calls▁begin｜>function<｜tool▁sep｜>name```json{}```<｜tool▁call▁end｜><｜tool▁calls▁end｜>
- Reasoning content extraction from <think>...</think> tags
- Multiple tool calls support with separate call blocks
- Model detection for deepseek-r1, deepseek_r1 naming patterns
- Integration with incremental parsing and streaming support

* Add partial parsing support for JSON and regex

- json-partial.h/cpp: JSON partial parsing functionality
- regex-partial.h/cpp: Regex partial parsing functionality

* Add format_chat integration tests for Qwen3 tool injection

- Add test_qwen3_format_chat_integration() to validate tool injection pipeline
- Test tool injection conditions and system message enhancement
- Verify JSON formatting and anti-preamble instructions
- Add comprehensive test documentation

Tests confirm tool injection works correctly - conversational preamble
issue is not in ik_llama.cpp but likely in UI configuration.

* Fix Qwen3 tool call parsing - pass model name to parser

Server was not passing model name to parse_chat_message_incremental(),
causing Qwen3 to fall back to Kimi-K2 parser and return tool calls
as content instead of proper tool_calls array.

* Fix non-streaming path to use model-specific parsing

Non-streaming responses were hardcoded to use Kimi-K2 format,
causing Qwen3 XML tool calls to be returned as content instead
of proper tool_calls array. Now uses same model detection as
streaming path for consistency.

Author: iSevenDays

Makefile

@@ -1087,6 +1087,7 @@ ggml/src/iqk/iqk_mul_mat.o: \
 	$(CXX) $(CXXFLAGS) -c $< -o $@
 endif # GGML_NO_IQKMULMAT
 
+
 ifndef GGML_NO_LLAMAFILE
 ggml/src/llamafile/sgemm.o: \
 	ggml/src/llamafile/sgemm.cpp \

README.md

@@ -104,6 +104,20 @@ There is no single point of reference describing all new `ik_llama.cpp` features
 * [This discussion](https://github.com/ikawrakow/ik_llama.cpp/discussions/266) is about running DeepSeek-V3/R1 on a 16 x 3090 setup
 * [This discussion](https://github.com/ikawrakow/ik_llama.cpp/discussions/8) describes the new quantization types available in `ik_llama.cpp`
 
+## Testing
+
+### Function Calls Tests
+
+To run the function calls test suite:
+
+```bash
+cd build
+cmake --build . --target test-function-calls
+./bin/test-function-calls
+```
+
+The test suite covers parser functionality, streaming, error handling, content cleaning, and server integration. All tests should pass to ensure production readiness.
+
 ## Contributing
 
 Contributions in form of pull requests, issue submissions (bug reports, feature requests), or general discussions, are welcome.

common/CMakeLists.txt

@@ -54,6 +54,14 @@ add_library(${TARGET} STATIC
     base64.hpp
     common.h
     common.cpp
+    chat.h
+    chat.cpp
+    chat-parser.h
+    chat-parser.cpp
+    json-partial.h
+    json-partial.cpp
+    regex-partial.h
+    regex-partial.cpp
     sampling.h
     sampling.cpp
     console.h