parser

type DefaulSyntaxTreeBuilder struct {
	// contains filtered or unexported fields
}

type Grammar interface {
	// InitialState returns the initial state of a parser.
	InitialState() int

	// StartProduction returns the start production of grammar.
	StartProduction() int

	// Action returns an ACTION entry corresponding to a (state, terminal symbol) pair.
	Action(state int, terminal int) int

	// GoTo returns a GOTO entry corresponding to a (state, non-terminal symbol) pair.
	GoTo(state int, lhs int) int

	// ErrorTrapperState returns true when a state can shift the error symbol.
	ErrorTrapperState(state int) bool

	// LHS returns a LHS symbol of a production.
	LHS(prod int) int

	// AlternativeSymbolCount returns a symbol count of p production.
	AlternativeSymbolCount(prod int) int

	// RecoverProduction returns true when a production has the recover directive.
	RecoverProduction(prod int) bool

	// NonTerminal retuns a string representaion of a non-terminal symbol.
	NonTerminal(nonTerminal int) string

	// TerminalCount returns a terminal symbol count of grammar.
	TerminalCount() int

	// SkipTerminal returns true when a terminal symbol must be skipped on syntax analysis.
	SkipTerminal(terminal int) bool

	// EOF returns the EOF symbol.
	EOF() int

	// Error returns the error symbol.
	Error() int

	// Terminal retuns a string representaion of a terminal symbol.
	Terminal(terminal int) string

	// ASTAction returns an AST action entries.
	ASTAction(prod int) []int
}

type Node struct {
	Type     NodeType
	KindName string
	Text     string
	Row      int
	Col      int
	Children []*Node
}

type NodeType int

type Parser struct {
	// contains filtered or unexported fields
}

type ParserOption func(p *Parser) error

type SemanticActionSet interface {
	// Shift runs when the parser shifts a symbol onto a state stack. `tok` is a token corresponding to the symbol.
	// When the parser recovered from an error state by shifting the token, `recovered` is true.
	Shift(tok VToken, recovered bool)

	// Reduce runs when the parser reduces an RHS of a production to its LHS. `prodNum` is a number of the production.
	// When the parser recovered from an error state by reducing the production, `recovered` is true.
	Reduce(prodNum int, recovered bool)

	// Accept runs when the parser accepts an input.
	Accept()

	// TrapAndShiftError runs when the parser traps a syntax error and shifts a error symbol onto the state stack.
	// `cause` is a token that caused a syntax error. `popped` is the number of frames that the parser discards
	// from the state stack.
	// Unlike `Shift` function, this function doesn't take a token to be shifted as an argument because a token
	// corresponding to the error symbol doesn't exist.
	TrapAndShiftError(cause VToken, popped int)

	// MissError runs when the parser fails to trap a syntax error. `cause` is a token that caused a syntax error.
	MissError(cause VToken)
}

type SyntaxError struct {
	Row               int
	Col               int
	Message           string
	Token             VToken
	ExpectedTerminals []string
}

type SyntaxTreeActionSet struct {
	// contains filtered or unexported fields
}

type SyntaxTreeBuilder interface {
	Shift(kindName string, text string, row, col int) SyntaxTreeNode
	ShiftError(kindName string) SyntaxTreeNode
	Reduce(kindName string, children []SyntaxTreeNode) SyntaxTreeNode
	Accept(f SyntaxTreeNode)
}

type SyntaxTreeNode interface {
	// ChildCount returns a child count of a node. A parser calls this method to know the child count to be expanded by an `#ast`
	// directive with `...` operator.
	ChildCount() int

	// ExpandChildren returns children of a node. A parser calls this method to fetch the children to be expanded by an `#ast`
	// directive with `...` operator.
	ExpandChildren() []SyntaxTreeNode
}

type TokenStream interface {
	Next() (VToken, error)
}

type VToken interface {
	// TerminalID returns a terminal ID.
	TerminalID() int

	// Lexeme returns a lexeme.
	Lexeme() []byte

	// EOF returns true when a token represents EOF.
	EOF() bool

	// Invalid returns true when a token is invalid.
	Invalid() bool

	// Position returns (row, column) pair.
	Position() (int, int)
}