tick

package
v0.2.2 Latest Latest
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Published: Dec 15, 2015 License: MIT Imports: 13 Imported by: 0

Documentation

Overview

TICKscript is a simple invocation chaining DSL.

See the examples for how its used and example syntax of the DSL.

A reflection based evaluation of an AST.

Index

Examples

Constants

This section is empty.

Variables

View Source
var ErrEmptyStack = errors.New("stack is empty")
View Source
var ErrInvalidExpr = errors.New("expression is invalid, could not evaluate")
View Source
var ErrNotFloat = errors.New("value is not a float")

Functions

func Evaluate

func Evaluate(script string, scope *Scope) (err error)

Parse and evaluate a given script for the scope. This evaluation method uses reflection to call methods on objects within the scope.

Example
package main

import (
	"fmt"

	"github.com/influxdb/kapacitor/tick"
)

type Process struct {
	Name     string
	Children []*Process
}

func (p *Process) Spawn() *Process {
	child := &Process{}
	p.Children = append(p.Children, child)
	return child
}

func (p *Process) String() string {
	return fmt.Sprintf("{%q %s}", p.Name, p.Children)
}

func main() {

	//Run a test that evaluates the DSL against the Process struct.
	script := `
//Name the parent
parent.name('parent')

// Spawn a first child
var child1 = parent.spawn()

// Name the first child
child1.name('child1')

//Spawn a grandchild and name it
child1.spawn().name('grandchild')

//Spawn a second child and name it
parent.spawn().name('child2')
`

	scope := tick.NewScope()
	parent := &Process{}
	scope.Set("parent", parent)

	err := tick.Evaluate(script, scope)
	if err != nil {
		fmt.Println(err)
	}

	fmt.Println(parent)
}
Output:

{"parent" [{"child1" [{"grandchild" []}]} {"child2" []}]}

Types

type BinaryNode

type BinaryNode struct {
	Left     Node
	Right    Node
	Operator tokenType
	// contains filtered or unexported fields
}

binaryNode holds two arguments and an operator.

func (BinaryNode) Position

func (p BinaryNode) Position() int

func (*BinaryNode) String

func (b *BinaryNode) String() string

type BoolNode

type BoolNode struct {
	Bool bool
	// contains filtered or unexported fields
}

boolNode holds one argument and an operator.

func (BoolNode) Position

func (p BoolNode) Position() int

func (*BoolNode) String

func (b *BoolNode) String() string

type DurationNode

type DurationNode struct {
	Dur time.Duration //the duration
	// contains filtered or unexported fields
}

durationNode holds a number: signed or unsigned integer or float. The value is parsed and stored under all the types that can represent the value. This simulates in a small amount of code the behavior of Go's ideal constants.

func (DurationNode) Position

func (p DurationNode) Position() int

func (*DurationNode) String

func (d *DurationNode) String() string

type Func

type Func interface {
	Reset()
	Call(...interface{}) (interface{}, error)
}

A callable function from within the expression

type Funcs

type Funcs map[string]Func

Lookup for functions

func NewFunctions

func NewFunctions() Funcs

Return set of built-in Funcs

type FunctionNode

type FunctionNode struct {
	Func string // The identifier
	Args []Node
	// contains filtered or unexported fields
}

Holds the a function call with its args

func (FunctionNode) Position

func (p FunctionNode) Position() int

func (*FunctionNode) String

func (f *FunctionNode) String() string

type IdentifierNode

type IdentifierNode struct {
	Ident string // The identifier
	// contains filtered or unexported fields
}

Holds the textual representation of an identifier

func (IdentifierNode) Position

func (p IdentifierNode) Position() int

func (*IdentifierNode) String

func (i *IdentifierNode) String() string

type LambdaNode

type LambdaNode struct {
	Node Node
	// contains filtered or unexported fields
}

Represents the begining of a lambda expression

func (LambdaNode) Position

func (p LambdaNode) Position() int

func (*LambdaNode) String

func (l *LambdaNode) String() string

type ListNode

type ListNode struct {
	Nodes []Node
	// contains filtered or unexported fields
}

Holds a function call with its args

func (*ListNode) Add

func (l *ListNode) Add(n Node)

func (ListNode) Position

func (p ListNode) Position() int

func (*ListNode) String

func (l *ListNode) String() string

type Node

type Node interface {
	String() string
	Position() int // byte position of start of node in full original input string
}

type NumberNode

type NumberNode struct {
	IsInt   bool    // Number has an integral value.
	IsFloat bool    // Number has a floating-point value.
	Int64   int64   // The integer value.
	Float64 float64 // The floating-point value.
	// contains filtered or unexported fields
}

numberNode holds a number: signed or unsigned integer or float. The value is parsed and stored under all the types that can represent the value. This simulates in a small amount of code the behavior of Go's ideal constants.

func (NumberNode) Position

func (p NumberNode) Position() int

func (*NumberNode) String

func (n *NumberNode) String() string

type ReferenceNode

type ReferenceNode struct {
	Reference string // The field reference
	// contains filtered or unexported fields
}

Holds the textual representation of an identifier

func (ReferenceNode) Position

func (p ReferenceNode) Position() int

func (*ReferenceNode) String

func (r *ReferenceNode) String() string

type RegexNode

type RegexNode struct {
	Regex *regexp.Regexp
	// contains filtered or unexported fields
}

Holds the textual representation of a regex literal

func (RegexNode) Position

func (p RegexNode) Position() int

func (*RegexNode) String

func (s *RegexNode) String() string

type Scope

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

Contains a set of variables references and their values.

func NewScope

func NewScope() *Scope

Initialize a new Scope object.

func (*Scope) Get

func (s *Scope) Get(name string) (interface{}, error)

Get returns the value of 'name'.

func (*Scope) Set

func (s *Scope) Set(name string, value interface{})

Set defines a name -> value pairing in the scope.

type StarNode

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

Represents a standalone '*' token.

func (StarNode) Position

func (p StarNode) Position() int

func (*StarNode) String

func (s *StarNode) String() string

type StatefulExpr

type StatefulExpr struct {
	Node  Node
	Funcs Funcs
}

Expression functions are stateful. Their state is updated with each call to the function. A StatefulExpr is a Node and its associated function state.

func NewStatefulExpr

func NewStatefulExpr(n Node) *StatefulExpr

func (*StatefulExpr) EvalBool

func (s *StatefulExpr) EvalBool(scope *Scope) (bool, error)

func (*StatefulExpr) EvalNum

func (s *StatefulExpr) EvalNum(scope *Scope) (float64, error)

func (*StatefulExpr) Reset

func (s *StatefulExpr) Reset()

Reset the state

type StringNode

type StringNode struct {
	Literal string // The string literal
	// contains filtered or unexported fields
}

Holds the textual representation of a string literal

func (StringNode) Position

func (p StringNode) Position() int

func (*StringNode) String

func (s *StringNode) String() string

type UnaryNode

type UnaryNode struct {
	Node     Node
	Operator tokenType
	// contains filtered or unexported fields
}

unaryNode holds one argument and an operator.

func (UnaryNode) Position

func (p UnaryNode) Position() int

func (*UnaryNode) String

func (u *UnaryNode) String() string

Directories

Path Synopsis
cmd
tickdoc
Tickdoc is a simple utility similiar to godoc that generates documentation from comments.
Tickdoc is a simple utility similiar to godoc that generates documentation from comments.

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