parser

Documentation

Index

• Constants
• type Error
  • func (e *Error) IsEOF() bool
  • func (e *Error) IsUnexpectedEnd() bool
• type Parser
  • func New(l *lexer.Lexer) *Parser
  • func (p *Parser) ParseProgram() (*ast.Program, *Error)

Constants

const (
	LOWEST int
	NORMAL
	ASSIGN
	LOGIC
	RANGE
	EQUALS
	COMPARE
	SUM
	PRODUCT
	PREFIX
	INDEX
	CALL
)

Constants for denoting precedence

const (

	// EndOfFileError represents normal EOF error
	EndOfFileError int
	// WrongTokenError means that token is not what we expected
	WrongTokenError
	// UnexpectedTokenError means that token is not expected to appear in current condition
	UnexpectedTokenError
	// UnexpectedEndError means we get unexpected "end" keyword (this is mainly created for REPL)
	UnexpectedEndError
	// MethodDefinitionError means there's an error on method definition's method name
	MethodDefinitionError
	// InvalidAssignmentError means user assigns value to wrong type of expressions
	InvalidAssignmentError
	// SyntaxError means there's a grammatical in the source code
	SyntaxError
)

const (
	NormalMode int = iota
	REPLMode
	TestMode
)

These are the enums for marking parser's mode, which decides whether it should pop unused values.

Types

type Error

type Error struct {
	// Message contains the readable message of error
	Message string
	// contains filtered or unexported fields
}

Error represents parser's parsing error

func (*Error) IsEOF

func (e *Error) IsEOF() bool

IsEOF checks if error is end of file error

func (*Error) IsUnexpectedEnd

func (e *Error) IsUnexpectedEnd() bool

IsUnexpectedEnd checks if error is unexpected "end" keyword error

type Parser

type Parser struct {
	Lexer *lexer.Lexer

	Mode int
	// contains filtered or unexported fields
}

Parser represents lexical analyzer struct

func New

func New(l *lexer.Lexer) *Parser

New initializes a parser and returns it

func (*Parser) ParseProgram

func (p *Parser) ParseProgram() (*ast.Program, *Error)

ParseProgram update program statements and return program