Show_parse_tree Class Reference

Holds the json parse tree being generated by the SHOW PARSE_TREE command. More...

#include <parse_tree_node_base.h>

Classes
struct	Parse_tree_comparator

Public Member Functions
	Show_parse_tree (Show_parse_tree *parent_tree=nullptr)
bool	push_level (const POS &pos, const char *typname)
	Create a json node out of the parse tree node position and type name, and push it onto the json object stack. More...
Json_object *	get_current_parent ()
	Get the current object under which new json objects are to be added as children. More...
std::string	get_parse_tree ()
	Generate the json tree text from the json tree, and return it. More...
bool	pop_level ()
	Pop out the json node pushed by push_level() and make it a child of the inner json object in the stack. More...

Private Member Functions
bool	make_child (Json_object *obj)
	Make the obj a child of the current parent object in the object stack. More...
Json_object *	pop_json_object ()
	Pop the current object in the object stack, and return it. More...

Private Attributes
std::vector< Json_object * >	m_json_obj_stack {}
Json_object_ptr	m_root_obj = nullptr
Show_parse_tree *	m_parent_show_parse_tree = nullptr
const char *	m_reference_pos = nullptr

Static Private Attributes
static constexpr Parse_tree_comparator	m_comparator = {}

Detailed Description

Holds the json parse tree being generated by the SHOW PARSE_TREE command.

The json tree gets built with the help of the two parse tree node walkers namely contextualize() and itemize(). Each contextualize() (or itemize()) creates a new json subtree. In the beginning of contextualize(), push_level() is called, where a new Json object is created and pushed to m_json_obj_stack. This object now becomes a parent json object to which all the subtrees created by the inner contextualize() calls will be added as its children. Each contextualize() will end with a call to pop_level() where the current parent will be popped out and made the child of the now-current parent object in the stack. This way the json tree is built identical to the tree of Parse_tree_node's.

Constructor & Destructor Documentation

Show_parse_tree()

Show_parse_tree::Show_parse_tree ( Show_parse_tree *  parent_tree = nullptr )

inlineexplicit

Member Function Documentation

get_current_parent()

Json_object * Show_parse_tree::get_current_parent ( )

inline

Get the current object under which new json objects are to be added as children.

Effectively, this is the outermost object in the object stack.

retval nullptr if the object stack is empty.

get_parse_tree()

std::string Show_parse_tree::get_parse_tree

(

)

Generate the json tree text from the json tree, and return it.

Return values

non-empty	success
empty	error

make_child()

bool Show_parse_tree::make_child ( Json_object *  obj )

private

Make the obj a child of the current parent object in the object stack.

If there is a current parent, assign this object as child of that parent.

Parameters

obj	Input json object resembling a parse tree node.

Return values

false

success; true: error

If there is no parent, make this object the root of this parse tree, unless there is a parent parse tree in which case make this object a child of the parent explain tree's leaf parent.

pop_json_object()

Json_object * Show_parse_tree::pop_json_object ( )

private

Pop the current object in the object stack, and return it.

pop_level()

bool Show_parse_tree::pop_level ( )

inline

Pop out the json node pushed by push_level() and make it a child of the inner json object in the stack.

Return values

false

success; true: error

push_level()

bool Show_parse_tree::push_level	(	const POS &	pos,
		const char *	typname
	)

Create a json node out of the parse tree node position and type name, and push it onto the json object stack.

Effectively, a new json stack level is created, to which json children would be added.

Parameters

pos	syntax position of the parse tree node
typname	type name of the class of the parse tree node

Return values

false	success
true	error

Member Data Documentation

m_comparator

constexpr Parse_tree_comparator Show_parse_tree::m_comparator = {}

staticconstexprprivate

m_json_obj_stack

std::vector<Json_object *> Show_parse_tree::m_json_obj_stack {}

private

m_parent_show_parse_tree

Show_parse_tree* Show_parse_tree::m_parent_show_parse_tree = nullptr

private

m_reference_pos

const char* Show_parse_tree::m_reference_pos = nullptr

private

m_root_obj

Json_object_ptr Show_parse_tree::m_root_obj = nullptr

private

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

• sql/parse_tree_node_base.h
• sql/parse_tree_node_base.cc