parsley

README

🥬 Parsley

Documentation

Overview

Package parsley a parser/tokeniser used to evaluate expressions

Index

• Constants
• func ToBool(e any) (bool, error)
• func ToFloat64(input any) (float64, error)
• func TypesMatch(a, b any) bool
• type BinaryNodeFunc
• type Function
• type Node
• type Parser
  • func NewParser(withCache bool) (m *Parser, err error)
  • func (m *Parser) Close()
  • func (m *Parser) ParseAsAny(str string, data map[string]any) (any, error)
  • func (m *Parser) ParseAsBool(str string, data map[string]any) (bool, error)
  • func (m *Parser) ParseAsFloat(str string, data map[string]any) (float64, error)
  • func (m *Parser) ParseAsString(str string, data map[string]any) (string, error)
  • func (p *Parser) RegisterBinaryNode(token string, fun BinaryNodeFunc)
  • func (p *Parser) RegisterFunction(name string, fun Function)
  • func (p *Parser) RegisterUnaryNode(token string, fun UnaryNodeFunc)
• type UnaryNodeFunc

Constants

const ErrCacheSetup = cache.ErrCacheSetup

ErrCacheSetup is returned when setting up the cache fails

const ErrComparisonFailed = nodes.ErrComparisonFailed

ErrComparisonFailed is returned when the comparison of two values fails

const ErrFunctionNotFound = helpers.ConstError("function not found")

ErrFunctionNotFound is returned when an unrecognised function is found

const ErrNodeEvalFailed = nodes.ErrNodeEvalFailed

ErrNodeEvalFailed is returned when a node failed to evaluate correctly

Functions

func ToBool

func ToBool(e any) (bool, error)

ToBool converts the input value in to a bool.

- If the type is a number then any value over 0 will return true - Strings will be checked against known values - Strings not matching a known value will attempt to parse as a float

func ToFloat64

func ToFloat64(input any) (float64, error)

ToFloat64 attempts to convert the input value in to a float64. It will cast int/uint/flaot types, and attempt to parse strings as floats

func TypesMatch

func TypesMatch(a, b any) bool

TypesMatch check if the types of the two values are the same

Types

type BinaryNodeFunc

type BinaryNodeFunc func(left, right Node) Node

BinaryNodeFunc is a constructor for a binary node

type Function

type Function func(args ...any) (any, error)

Function defines the shape of a function that can be called inside an expression

type Node

type Node = nodes.Node

Node defines the interface for new nodes to adhere

type Parser

type Parser struct {
	Registry *registry
	// contains filtered or unexported fields
}

Parser provides parsing and evaluation functionality

func NewParser

func NewParser(withCache bool) (m *Parser, err error)

NewParser configures a new parser. If a cache it required one will be set up using github.com/dgraph-io/ristretto/v2

func (*Parser) Close

func (m *Parser) Close()

Close releases the underlying resources

func (*Parser) ParseAsAny

func (m *Parser) ParseAsAny(str string, data map[string]any) (any, error)

ParseAsAny will parse and evaluate the expression provided. Returning the result as a whichever type is most appropriate

func (*Parser) ParseAsBool

func (m *Parser) ParseAsBool(str string, data map[string]any) (bool, error)

ParseAsBool is used to test whether the incoming data matches the given expression. Any numeric value over 0, or strings evaluating to true will match

func (*Parser) ParseAsFloat

func (m *Parser) ParseAsFloat(str string, data map[string]any) (float64, error)

ParseAsFloat will parse and evaluate the expression provided. Returning the result as a float64

func (*Parser) ParseAsString

func (m *Parser) ParseAsString(str string, data map[string]any) (string, error)

ParseAsString will parse and evaluate the expression provided. Returning the result as a string, if the expression results in any other type it will be printed as a string

func (*Parser) RegisterBinaryNode

func (p *Parser) RegisterBinaryNode(token string, fun BinaryNodeFunc)

RegisterBinaryNode adds a new binary node to the registry

func (*Parser) RegisterFunction

func (p *Parser) RegisterFunction(name string, fun Function)

RegisterFunction registers a new function in the available set. Repeated calls will result in the latest one being registered

func (*Parser) RegisterUnaryNode

func (p *Parser) RegisterUnaryNode(token string, fun UnaryNodeFunc)

RegisterUnaryNode adds a new unary node to the registry

type UnaryNodeFunc

type UnaryNodeFunc func(right Node) Node

UnaryNodeFunc is a constructor for a unary node