by::node 클래스 참조

Base class for all AST nodes in the byeol language 더 자세히 ...

#include <node.hpp>

by::node에 대한 상속 다이어그램 :

Public 멤버 함수
me &	operator[] (const std::string &name)
const me &	operator[] (const std::string &name) const BY_CONST_FUNC(operator[](name))
me &	operator[] (const std::string *it)
const me &	operator[] (const std::string *it) const BY_CONST_FUNC(operator[](it))
me &	operator[] (const nchar *name)
const me &	operator[] (const nchar *name) const BY_CONST_FUNC(operator[](name))
nbool	in (const node &elem) const
nbool	in (const node *elem) const
virtual scope &	subs ()=0
const scope &	subs () const BY_CONST_FUNC(subs()) virtual tstr< nbicontainer > mySubs() const
	Returns a tstr to a container of immediate sub-nodes (excluding inherited or chained ones).
const node *	promote (const node &it) const
const node *	promote (const node *it) const BY_SIDE_FUNC(promote)
template<typename T >
T *	sub (std::function< nbool(const std::string &, const T &)> l)
template<typename T >
const T *	sub (std::function< nbool(const std::string &, const T &)> l) const BY_CONST_FUNC(sub< T >(l)) template< typename T
template<typename T = me>
const T *	sub () const BY_CONST_FUNC(sub< T >()) template< typename T
template<typename T = me>
T *	sub (const std::string *it) BY_SIDE_FUNC(sub)
template<typename T = me>
const T *	sub (const std::string &name) const BY_CONST_FUNC(sub< T >(name)) template< typename T
template<typename T = me>
T *	sub (const std::string *name, const args &a) BY_SIDE_FUNC(name
template<typename T = me>
const T *	sub (const std::string &name, const args &a) const BY_CONST_FUNC(sub< T >(name
template<typename T = me>
const T a const T *	sub (const std::string *name, const args &a) const BY_CONST_FUNC(sub< T >(name
template<typename T >
const T a const T a tnarr< T, strTactic >	subAll (std::function< nbool(const std::string &, const T &)> l) const
template<typename T = me>
tnarr< T, strTactic >	subAll () const
template<typename T = me>
tpriorities< T >	subAll (const std::string &name) const
template<typename T = me>
tpriorities< T >	subAll (const std::string *it) const BY_SIDE_FUNC(subAll< T >) template< typename T
template<typename T = me>
tpriorities< T >	subAll (const std::string &name, const args &a) const
template<typename T = me>
tpriorities< T >	subAll (const std::string *name, const args *a) const BY_SIDE_FUNC(name
tpriorities< T > subAll< T >	tpriorities ())
template<typename T = me>
tpriorities< T >	subAll (const std::string *name, const args &a) const BY_SIDE_FUNC(name
tpriorities< T > subAll< T >	tpriorities ())
bool	canEval (const args &a) const
virtual priorType	prioritize (const args &a) const =0
priorType	prioritize (const args *it) const BY_SIDE_FUNC(it
virtual str	eval (const args &a)=0
str	eval (const args *it) BY_SIDE_FUNC(eval)
str	eval (const std::string &name, const args &a)
str	eval (const std::string &name, const args *a) BY_SIDE_FUNC(a
str	eval (name, a)
str	str ())
str	eval (const std::string *name, const args &a) BY_SIDE_FUNC(name
str eval	str ())
str	eval (const std::string *name, const args *a) BY_SIDE_FUNC(name &&a
str eval	str ())
str	eval (const std::string &name)
str	eval (const std::string *it) BY_SIDE_FUNC(eval)
str	eval ()
virtual void	rel ()
template<typename T >
nbool	is () const
nbool	is (const typeProvidable &to) const
nbool	is (const typeProvidable *it) const BY_SIDE_FUNC(is)
nbool	is (const type &to) const
nbool	is (const type *it) const BY_SIDE_FUNC(is)
template<typename T >
tstr< T >	as () const
str	as (const typeProvidable &to) const
str	as (const typeProvidable *it) const BY_SIDE_FUNC(as)
str	as (const type &to) const
str	as (const type *it) const BY_SIDE_FUNC(as)
template<typename T >
nbool	isImpli () const
virtual nbool	isImpli (const type &to) const
nbool	isImpli (const typeProvidable &to) const
nbool	isImpli (const typeProvidable *it) const BY_SIDE_FUNC(isImpli)
template<typename T >
tstr< T >	asImpli () const
virtual str	asImpli (const type &to) const
str	asImpli (const typeProvidable &to) const
str	asImpli (const typeProvidable *it) const BY_SIDE_FUNC(asImpli)
virtual const src &	getSrc () const
virtual nbool	isComplete () const
virtual str	infer () const
virtual void	accept (const visitInfo &i, visitor &v)
void	inFrame (const bicontainable *args) const override
void	outFrame () const override
virtual const modifier &	getModifier () const
virtual void	inFrame (const bicontainable *args) const=0
void	inFrame () const
virtual void	outFrame () const=0
by::frameInteractable(으)로부터 상속된 Public 멤버 함수
void	inFrame () const

Public 속성
T sub	name
T sub	nullptr
tpriorities< T > subAll< T >	name
priorType prioritize	it
priorType prioritize	NO_MATCH
str eval	name

Protected 멤버 함수
virtual str	_onEvalSub (node &sub, const args &a)
	Protected virtual method for evaluating a sub-node.
virtual void	_setSrc (const src &s)
void	_setSrc (const src *it) BY_SIDE_FUNC(_setSrc)

Friends
class	coreInternal

상세한 설명

Base class for all AST nodes in the byeol language

The most fundamental class in the core module. Unlike traditional AST (Abstract Syntax Tree) implementations, byeol executes programs while maintaining the AST structure, making it more akin to a Program Execution Tree (PET). Provides comprehensive APIs for AST structure manipulation, node evaluation, child node traversal, and type conversion.

Program Execution Tree

Unlike typical programming languages, byeol executes programs while maintaining the AST structure intact. In most languages, the AST is merely an intermediate representation of grammatical structure, but in byeol, the AST serves as the final executable output. Because execution is considered from the start, the class provides not only tree-based program structure representation but also APIs for type conversion and node evaluation.

Fundamental Base Class

Each node must be executable, so a node can be a function, an object, or an operator like +. The evaluation function is provided as eval(const args&) to execute and evaluate values.

Side Functions

As the core base class of the byeol project, node provides numerous side functions for various operations.

AST Traversal

Due to AST characteristics, a node can contain objects of other node-derived classes. Like a DOM tree, it uses the composition pattern, and various functions are provided to traverse this tree. In byeol, this tree is called scope and is map-based. Classes like blockExpr contain statement blocks as arrays while also being nodes. Therefore, the overall AST structure is a mix of maps and arrays. The scope uses each node's name as a key, where the parser defines appropriate names as keys when adding instances.

Common traversal functions: operator[], sub(), subs(), in(), subAll()

const node& root = getRoot();
root.sub("name1");             // Find node named name1 in root (unknown if function or object)
root.sub<func>("name1");       // Get symbol named name1 only if it's a function
 
// Find all nodes named name2 that take one int argument
tnarr found = root.subAll("name2", args(narr(*new nInt())));
 
const scope& subs = root.subs(); // Can utilize all tbicontainable APIs
                                 // Supports for loops, iterators, lambda filtering, etc.
subs.len();                      // Returns number of child nodes root has

Handling Duplicate Symbols

Byeol doesn't allow duplicate symbols within the same scope, but this doesn't mean two pairs with the same key cannot exist. Functions with the same name but different parameter counts or types are different symbols. Simple string comparison cannot determine duplication, so the scope class is based on multimap rather than map.

Evaluation

A node can be a function, object, or expression. eval(const args&) returns the execution result of such nodes. (Byeol has no class concept; objects replace this role. Objects can be executed like functions, equivalent to calling a constructor.) The args object containing required arguments is passed to eval(). If the node's expected parameters differ in count or type from args, an empty str may be returned. Some node functions take a name parameter along with eval(), which finds child nodes matching the node's name and passes args to evaluate them—essentially dispatching a message.

Type Inference

infer() performs type inference. It doesn't return the exact runtime value but the type determined at verification stage. For example:

// In byeol language, `2 + 3.5` is represented as:
FBOExpr e = FBOExpr(FBOExpr::SYMBOL_ADD, *new nInt(2), *nFlt(3.5));
 
str infered = e.infer();       // What type results from adding int 2 and flt 3.5?
infered->cast<nFlt>() != nullptr; // true: answer is flt

This creates an expression like 2 + 3.5 by putting nInt and nFlt objects into FBOExpr. Calling infer() yields nFlt due to type promotion (int + flt = flt). Type inference for an expression requires recursively calling type inference on child nodes, unlike getType() which returns immediately. The AST must be traversed to calculate type information. Note that type inference focuses on quickly determining types and doesn't compute values. In the example above, the nFlt value in infered contains the default value—use eval() for accurate values.

Type Conversion

Node provides as() for explicit type conversion and is() to check conversion possibility:

// The following byeol code translated to C++:
//  foo(val int) void
//      if val is flt
//          doSomething(val as flt)
 
void foo(const nInt& val) {
    if(val.is<nFlt>()) {
        str isFlt = val.as<nFlt>();
        nflt converted = isFlt->get();
        doSomething(converted);
    }
}

as() and is() provide various side functions, enabling generic functions:

str convertIfPossible(const node& it, const node& toThisType) {
    // getType() retrieves type information (C++ class type or user-defined byeol type)
    // See type and ntype classes for details
    if(!it.is(toThisType.getType())) return str();
    return it.as(toThisType.getType());
}

This example is verbose for clarity. Real code uses WHEN for brevity. Rewriting foo():

void foo(const nInt& val) {
    tstr<nFlt> converted = val OR.ret(); // early-return pattern + WHEN + OR macro
    doSomething(converted->get());
}

Scripted vs Native Type Conversion

The as() and is() functions handle type conversion in the byeol language environment. For example, nInt is the C++ class representing byeol's int. It inherits from node because int can be an AST instance in byeol. Calling is<nFlt>() on nInt is allowed, but this doesn't mean nInt converts to nFlt in C++ code. In C++, implicit conversion is generally only allowed when nInt is a parent class of nFlt.

To check if nFlt is a kind of node, use the meta module's type conversion via cast(). The meta module manages native environment types in C++ code. Thus, two type conversion systems exist: one for native (C++) and one for script (byeol language):

// Simplified inheritance relationship of nFlt and nInt:
class nFlt : public obj {};
class nInt : public obj {};
class obj : public node {};
 
nInt val1;
nFlt val2;
 
// Native type conversion:
nFlt* cast1 = dynamic_cast<nFlt>(val1);  // nullptr: disallowed conversion
nFlt* cast2 = val1.cast<val2>();          // nullptr: same, using meta module conversion
node* isNode = val1.cast<node>();         // != nullptr: upcasting allowed
isNode->cast<nFlt>();                     // nullptr
&val1 == isNode->cast<nInt>();            // true
 
// Scripted type conversion:
val1.is<nFlt>(); // true: byeol supports explicit int <-> flt conversion

The core module often implements the same concept separately for native and byeol runtime environments. Get familiar with this pattern. See ases and asable for type conversion flow details.

Implicit vs Explicit Conversion

Implicit conversion is provided via impliAs() and impliIs(). Rarely called directly by external code; mostly invoked by AST classes like expr and baseFunc. User-defined type conversions are naturally excluded from implicit conversion, hence the distinction.

Visitable Class

AST traversal occurs for various purposes, not just eval() but also for debugging output. To separate traversal methods from node processing, the visitor pattern must be applied to nodes. accept() is used by the visitor class, and each class header requires the VISIT macro. See visitor for details.

Frame Interaction

frame manages the currently executing scope and registered symbols. Since node forms the AST base, if a node is an object or function, it must register or unregister owned functions or properties with the frame. inFrame() and outFrame() handle this. See frame for details.

Message Priority

Byeol supports function overloading, so an object may have multiple functions with the same name but different parameters. Some functions match args exactly, while others may require type conversion. Node uses prioritize() to determine how well child nodes match given args. Derived node classes return EXACT_MATCH for precise matches and NO_MATCH otherwise. See tprior and priorType for detailed criteria and algorithms.

멤버 함수 문서화

_onEvalSub()

virtual str by::node::_onEvalSub ( node & sub, const args & a )

protectedvirtual

Protected virtual method for evaluating a sub-node.

This method is a crucial part of the evaluation mechanism, allowing derived classes to define how a specific sub-node is evaluated within the context of the current node.

매개변수

sub	The sub-node to be evaluated.
a	The arguments for evaluation.

반환값

The result of the evaluation as a str object.

by::baseObj, by::genericOrigin에서 재구현되었습니다.

infer()

virtual str by::node::infer ( ) const

virtual

getType() returns what it is. opposite to it, this returns what this class will represents after evaluation.

for example, the expr class has derived from this node class. and if an user call the funcs to get type of it, class 'ntype' of 'expr' will be returned. but if that user call the 'infer()' then the 'expr' object evaluate its terms and returns it as a node from the output. it could be an integer if it was addExpr and all terms are constructed with integers.

and also this func requires frames. means that you have to interact frame first before call this func.

Remarks

some derived class of node may require to call this function first by verifier. if you call this function without calling verifier previously will damage then process.

by::baseCtor, by::ctor, by::asExpr, by::assignExpr, by::blockExpr, by::defArrayExpr, by::defAssignExpr, by::defSeqExpr, by::defVarExpr, by::endExpr, by::evalExpr, by::FBOExpr, by::getExpr, by::ifExpr, by::isExpr, by::loopExpr, by::retExpr, by::genericOrigin에서 재구현되었습니다.

inFrame() [1/2]

void by::node::inFrame ( const bicontainable * args ) const

overridevirtual

by::frameInteractable를 구현.

inFrame() [2/2]

virtual void by::frameInteractable::inFrame ( const bicontainable * args ) const

virtual

by::frameInteractable를 구현.

isComplete()

virtual nbool by::node::isComplete ( ) const

virtual

returns whether this instance is complete or not. if some instance is incomplete, it means that it's not accessible on byeolang source codes.

by::origin에서 재구현되었습니다.

outFrame() [1/2]

void by::node::outFrame ( ) const

overridevirtual

by::frameInteractable를 구현.

outFrame() [2/2]

virtual void by::frameInteractable::outFrame ( ) const

virtual

by::frameInteractable를 구현.

prioritize()

virtual priorType by::node::prioritize ( const args & a ) const

pure virtual

by::expr, by::retExpr에서 구현되었습니다.

promote()

const node * by::node::promote

(

const node &

it

)

const

매개변수

r	type to be promoted to this type. if a type is null, it means that there is no type specified. it's complete different to 'void' type.

반환값

null if it's not relative between l & r.

rel()

virtual void by::node::rel ( )

inlinevirtual

Release all held resources and prepare for termination.

Remarks

Some classes won't be able to reinitialize after rel() is called.

by::autopod, by::blockExpr, by::pod, by::arr, by::nStr, by::frame, by::thread에서 재구현되었습니다.

subAll()

template<typename T = me>

tpriorities< T > by::node::subAll

(

const std::string *

it

)

const

finds subnodes of this node, allowing implicit conversion based on name and arguments.

매개변수

a	if you pass this as a nullptr, the argument will be ignored and all names that are the same will be considered to meet the condition.

경고

if you pass the argument as args(), it will be considered to meet the condition only if there are no parameters and the names are the same, so the two have completely different meanings.

subs()

const scope & by::node::subs

(

)

const

Returns a tstr to a container of immediate sub-nodes (excluding inherited or chained ones).

This method provides direct access to the immediate children owned by this node, distinguishing them from children accessible via chained scopes or inheritance.

반환값

A tstr to a container holding the immediate sub-nodes.

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