Base class for all AST nodes in the byeol language. More...

#include <node.hpp>

Inheritance diagram for by::node:

Public Member Functions
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

Public Member Functions inherited from by::frameInteractable
void	inFrame () const

Public Attributes
T sub	name

T sub	nullptr

tpriorities< T > subAll< T >	name

priorType prioritize	it

priorType prioritize	NO_MATCH

str eval	name

Protected Member Functions
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

Detailed Description

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.

Member Function Documentation

◆ _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.

Parameters

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

Returns: The result of the evaluation as a str object.

Reimplemented in by::baseObj, and by::genericOrigin.

◆ 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.

Reimplemented in 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, and by::genericOrigin.

◆ inFrame() [1/2]

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

overridevirtual

Implements by::frameInteractable.

◆ inFrame() [2/2]

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

virtual

Implements by::frameInteractable.

◆ 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.

Reimplemented in by::origin.

◆ outFrame() [1/2]

void by::node::outFrame ( ) const

overridevirtual

Implements by::frameInteractable.

◆ outFrame() [2/2]

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

virtual

Implements by::frameInteractable.

◆ prioritize()

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

pure virtual

Implemented in by::expr, and by::retExpr.

◆ promote()

const node * by::node::promote ( const node & it ) const

Parameters

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.

Returns: 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.

Reimplemented in by::autopod, by::blockExpr, by::pod, by::arr, by::nStr, by::frame, and by::thread.

◆ 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.

Parameters

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.

Warning: 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.

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

The documentation for this class was generated from the following file:

/home/runner/work/byeol/byeol/module/core/ast/node.hpp

Public Member Functions

Public Attributes

Protected Member Functions

Friends

Detailed Description

Program Execution Tree

Fundamental Base Class

Side Functions

AST Traversal

Handling Duplicate Symbols

Evaluation

Type Inference

Type Conversion

Scripted vs Native Type Conversion

Implicit vs Explicit Conversion

Visitable Class

Frame Interaction

Message Priority

Member Function Documentation

◆ _onEvalSub()

◆ infer()

◆ inFrame() [1/2]

◆ inFrame() [2/2]

◆ isComplete()

◆ outFrame() [1/2]

◆ outFrame() [2/2]

◆ prioritize()

◆ promote()

◆ rel()

◆ subAll()

◆ subs()