type system readme

src/base/type_system/README.md

@@ -0,0 +1,30 @@
+# kerep type system
+
+For using some kerep capabilities, such as generic structs, unitype, and kprint, types should be *registered*.
+
+## type id
+
+Every registered type has its own id (`ktId`), which should be declared in header file and defined in source file.  
+Example: 
+```c
+//someStruct.h
+typedef struct { } someStruct;
+ktId_declare(ktId_someStruct);
+ktId_declare(ktId_someStructPtr); // pointer to type is another type
+```
+```c
+//someStruct.c
+ktId_define(ktId_someStruct);
+ktId_define(ktId_someStructPtr);
+```
+
+## type descriptors
+
+Every registered type should have it's own descriptor (`ktDescriptor`). It's a struct, which contains some information about type and pointers to some specific functions for this type (`toString`, `freeMembers`).
+
+## type registration
+
+To finally register a type, you should call macro `kt_register()` between `ktDescriptors_beginInit()` and `ktDescriptors_endInit()`. Better do it at the start of your program. To register all types from kerep, call `ktDescriptors_initKerepTypes()`.  
+Examples:  
++ [ktDescriptors_initKerepTypes()](src/base/type_system/init.c)
++ [kerep types registration](tests/main.cpp)