parser

type Grammar interface {
	// Parse parses the source text according to the grammar.
	Parse(source string) (*Result, error)
	// Source returns the text source of the grammar description.
	Source() string
}

type Node struct {
	// Label determines the type of the node, usually corresponding
	// to the rule name (LHS of the parser rule).
	Label string
	// Text is a captured text, if a rule defines a capture region.
	Text string
	// Content is a complete text that was consumed during parsing of this
	// element.  Maybe nil if the content was not recorded during parsing, or for
	// nodes that were programmatically generated.  If not nil, len(Content)
	// should be len(Children) + 1 When present, concatenating node Content in
	// order with children content results in exactly the parser input.
	// NOTE: this is not computed during parsing, but at a later stage.
	Content []string
	// The byte posittion of the first character consumed by this node rule
	// during parsing in the buffer that was passed to parser.
	Pos int
	// The number of bytes consumed by this node rule.
	Len int
	// The line number of the first character consumed by this node. 1-based.
	Row int
	// The column number of the first character consumed by this node. 0-based.
	Col int
	// The children of this node.
	Children []*Node
	// Err caches the error that resulted from application of some parsing rule at some position.
	Err error
	// Annotations stores some string-form annotations.
	Annotations map[string]string
	// TreeAnnotations stores some tree-form annotations (aka labelled children).
	TreeAnnotations map[string]*Node
	// Private fields.
	// Start is used by the bootstrap parser to implement captures. Parser generator or main parser
	// do not need it, but they also set it for compatibility with node drop/keep heuristics.
	// TODO(salikh): Remove after deprecating the bootstrap parser.
	Start int
}

type NodeStack []*Node

type Result struct {
	G      *grammar
	Source string
	Memo   map[int]map[*rule]*Node
	Level  int
	// Final AST.
	Tree *Node
	NodeStack
}