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Merge pull request #637 from leftibot/fix/issue-12-document-reflection

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[WIP] Issue #12 — Document reflection
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120
cheatsheet.md
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@ -593,6 +593,126 @@ use("filename") // evals file exactly once and returns value of last statement
Both `use` and `eval_file` search the 'usepaths' passed to the ChaiScript constructor
## Reflection and Introspection
ChaiScript provides built-in reflection capabilities for inspecting types, functions, and objects at runtime.
### Type Inspection
```
type_name(x) // returns the type name of a value as a string
is_type(x, "typename") // returns true if x is of the named type
type("typename") // returns a Type_Info object for the named type
// Examples
type_name(1) // "int"
type_name("hello") // "string"
is_type(1, "int") // true
is_type(1, "string") // false
```
### Object Inspection Methods
Every object in ChaiScript supports these methods:
```
x.get_type_info() // returns a Type_Info object for the value
x.is_type("string") // returns true if x is of the named type
x.is_type(string_type) // returns true if x matches the Type_Info
x.is_var_const() // returns true if x is immutable
x.is_var_null() // returns true if x is a null pointer
x.is_var_pointer() // returns true if x is stored as a pointer
x.is_var_reference() // returns true if x is stored as a reference
x.is_var_undef() // returns true if x is undefined
```
### Type_Info
`Type_Info` objects describe a type. You can get them via `type("typename")` or `x.get_type_info()`.
```
var ti = type("int")
ti.name() // ChaiScript registered name, e.g. "int"
ti.cpp_name() // mangled C++ type name
ti.cpp_bare_name() // C++ name without const/pointer/reference
ti.bare_equal(other) // true if types match ignoring const/ptr/ref
ti.is_type_const() // true if type is const
ti.is_type_reference() // true if type is a reference
ti.is_type_void() // true if type is void
ti.is_type_undef() // true if type is undefined
ti.is_type_pointer() // true if type is a pointer
ti.is_type_arithmetic() // true if type is arithmetic (int, double, etc.)
```
Built-in type constants are available: `int_type`, `double_type`, `string_type`, `bool_type`, `Object_type`, `Function_type`, `vector_type`, `map_type`.
### Function Introspection
Function objects support these introspection methods:
```
f.get_arity() // number of parameters (-1 for variadic)
f.get_param_types() // Vector of Type_Info (first element is return type)
f.get_contained_functions() // Vector of overloaded functions (empty if not a conglomerate)
f.has_guard() // true if the function has a guard condition
f.get_guard() // returns the guard function (throws if none)
f.get_annotation() // returns the annotation description
f.call([param1, param2]) // call the function with a vector of parameters
// Examples
def my_func(a, b) { return a + b; }
my_func.get_arity() // 2
my_func.has_guard() // false
def guarded(x) : x > 0 { return x; }
guarded.has_guard() // true
guarded.get_guard().get_arity() // 1
// Calling functions dynamically
`+`.call([1, 2]) // 3
```
### System Introspection
```
get_functions() // returns a Map of all registered functions (name -> function)
get_objects() // returns a Map of all scripting objects (name -> value)
function_exists("f") // returns true if a function named "f" is registered
call_exists(`f`, args) // returns true if f can be called with the given args
dump_system() // prints all registered functions to stdout
dump_object(x) // prints information about a value to stdout
// Examples
var funcs = get_functions()
funcs["print"] // the print function object
function_exists("print") // true
call_exists(`+`, 1, 2) // true
```
### Dynamic_Object Reflection
ChaiScript-defined classes are Dynamic_Objects internally. They support:
```
obj.get_type_name() // returns the ChaiScript class name (e.g. "MyClass")
obj.get_attrs() // returns a Map of all attributes
obj.has_attr("name") // returns true if the attribute exists
obj.get_attr("name") // returns the value of the attribute
obj.set_explicit(true) // disables dynamic attribute creation
obj.is_explicit() // returns true if explicit mode is enabled
// Example
class MyClass {
var x
def MyClass() { this.x = 10; }
}
var m = MyClass()
m.get_type_name() // "MyClass"
m.get_attrs() // map containing "x" -> 10
type_name(m) // "Dynamic_Object" (the underlying C++ type)
m.is_type("MyClass") // true (checks the ChaiScript class name)
```
## JSON
* `from_json` converts a JSON string into its strongly typed (map, vector, int, double, string) representations

87
include/chaiscript/language/chaiscript_prelude_docs.hpp
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@ -426,6 +426,9 @@ namespace ChaiScript_Language {
/// \brief Returns true if the type is "void"
bool is_type_void() const;
/// \brief Returns true if the type is an arithmetic type (int, double, etc.)
bool is_type_arithmetic() const;
/// \brief Returns the ChaiScript registered name for the type if one exists.
string name() const;
};
@ -764,6 +767,90 @@ namespace ChaiScript_Language {
/// \endcode
bool call_exists(Function f, ...);
/// \brief Returns the type name of the given object as a string
///
/// Example:
/// \code
/// eval> type_name(1)
/// int
/// eval> type_name("hello")
/// string
/// \endcode
///
/// \sa Type_Info::name()
/// \sa Object::get_type_info()
string type_name(Object o);
/// \brief Returns true if the object is of the named type
///
/// Example:
/// \code
/// eval> is_type(1, "int")
/// true
/// eval> is_type(1, "string")
/// false
/// \endcode
///
/// \sa Object::is_type()
bool is_type(Object o, string type_name);
/// \brief Returns true if a function with the given name is registered
///
/// Example:
/// \code
/// eval> function_exists("print")
/// true
/// eval> function_exists("nonexistent")
/// false
/// \endcode
bool function_exists(string name);
/// \brief Returns a Map of all registered functions, keyed by function name
///
/// Example:
/// \code
/// eval> var funcs = get_functions()
/// eval> funcs["print"].get_arity()
/// 1
/// \endcode
///
/// \sa Function
Map get_functions();
/// \brief Returns a Map of all scripting objects (variables), keyed by name
///
/// Example:
/// \code
/// eval> var x = 42
/// eval> var objs = get_objects()
/// eval> objs.count("x")
/// 1
/// \endcode
Map get_objects();
/// \brief Returns a Type_Info for the named type
///
/// Example:
/// \code
/// eval> type("int").name()
/// int
/// \endcode
///
/// \param type_name The name of the type to look up
/// \param throw_on_fail If true (default), throws if the type is not found
/// \sa Type_Info
Type_Info type(string type_name, bool throw_on_fail = true);
/// \brief Prints all registered functions to stdout
///
/// Useful for debugging. Outputs a list of all functions registered in the system.
void dump_system();
/// \brief Prints information about the given object to stdout
///
/// Useful for debugging. Outputs the type and value of the object.
void dump_object(Object o);
/// \brief Reverses a Range object so that the elements are accessed in reverse
Range retro(Range);

123
unittests/reflection_documentation.chai Normal file
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@ -0,0 +1,123 @@
// Tests for ChaiScript reflection / introspection capabilities
// Ensures all documented reflection functions work correctly
// --- Global reflection functions ---
// type_name: returns the type name of a value
assert_equal("int", type_name(1))
assert_equal("string", type_name("hello"))
assert_equal("bool", type_name(true))
assert_equal("double", type_name(1.0))
// is_type: checks if a value is of the given type
assert_true(is_type(1, "int"))
assert_true(is_type("hello", "string"))
assert_false(is_type(1, "string"))
// function_exists: checks if a named function is registered
assert_true(function_exists("print"))
assert_true(function_exists("type_name"))
assert_true(function_exists("function_exists"))
assert_false(function_exists("this_function_does_not_exist_xyz"))
// get_functions: returns a Map of all registered functions
var funcs = get_functions()
assert_true(funcs.size() > 0)
assert_true(funcs.count("print") > 0)
assert_true(funcs.count("type_name") > 0)
// get_objects: returns a Map of all scripting objects
var my_test_var = 42
var objs = get_objects()
assert_true(objs.size() > 0)
assert_true(objs.count("my_test_var") > 0)
// type: returns a Type_Info for a named type
var ti = type("int")
assert_equal("int", ti.name())
// call_exists: checks if a function call with given params exists
assert_true(call_exists(`+`, 1, 2))
assert_true(call_exists(`+`, "a", "b"))
// --- Object methods ---
// get_type_info: returns Type_Info for a value
var s = "hello"
assert_equal("string", s.get_type_info().name())
assert_equal("int", 1.get_type_info().name())
// is_type on objects
assert_true("hello".is_type("string"))
assert_true(1.is_type("int"))
assert_false(1.is_type("string"))
// is_type with Type_Info
assert_true("hello".is_type(string_type))
assert_true(1.is_type(int_type))
// is_var_* methods
var x = 5
assert_false(x.is_var_const())
assert_false(x.is_var_null())
assert_false(x.is_var_undef())
// --- Type_Info methods ---
var int_ti = type("int")
assert_equal("int", int_ti.name())
assert_false(int_ti.is_type_const())
assert_false(int_ti.is_type_void())
assert_false(int_ti.is_type_undef())
assert_false(int_ti.is_type_reference())
assert_false(int_ti.is_type_pointer())
// bare_equal: compares types ignoring const/pointer/reference
assert_true(int_ti.bare_equal(1.get_type_info()))
// --- Function introspection ---
def my_reflection_test_func(a, b) { return a + b; }
// get_arity
assert_equal(2, my_reflection_test_func.get_arity())
// get_param_types
var param_types = my_reflection_test_func.get_param_types()
assert_true(param_types.size() > 0)
// get_contained_functions
assert_equal(0, my_reflection_test_func.get_contained_functions().size())
// has_guard
assert_false(my_reflection_test_func.has_guard())
// Guarded function
def my_guarded_func(x) : x > 0 { return x; }
assert_true(my_guarded_func.has_guard())
var g = my_guarded_func.get_guard()
assert_equal(1, g.get_arity())
// call: invoke a function with a vector of parameters
assert_equal(3, `+`.call([1, 2]))
// --- Dynamic_Object reflection ---
var obj = Dynamic_Object()
obj.name = "test"
obj.value = 42
var attrs = obj.get_attrs()
assert_true(attrs.count("name") > 0)
assert_true(attrs.count("value") > 0)
// --- Class reflection ---
class ReflectionTestClass {
var x
def ReflectionTestClass() { this.x = 10; }
def get_x() { return this.x; }
}
var rtc = ReflectionTestClass()
assert_equal("ReflectionTestClass", rtc.get_type_name())
assert_true(rtc.is_type("ReflectionTestClass"))
assert_equal("Dynamic_Object", type_name(rtc))
assert_equal("ReflectionTestClass", rtc.get_type_name())