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开源软件名称：robertkrimen/otto开源软件地址：https://github.com/robertkrimen/otto开源编程语言：Go 97.6%开源软件介绍：otto-- import "github.com/robertkrimen/otto"Package otto is a JavaScript parser and interpreter written natively in Go. http://godoc.org/github.com/robertkrimen/otto import (
"github.com/robertkrimen/otto"
)Run something in the VM vm := otto.New()
vm.Run(`
abc = 2 + 2;
console.log("The value of abc is " + abc); // 4
`)Get a value out of the VM if value, err := vm.Get("abc"); err == nil {
if value_int, err := value.ToInteger(); err == nil {
fmt.Printf("", value_int, err)
}
}Set a number vm.Set("def", 11)
vm.Run(`
console.log("The value of def is " + def);
// The value of def is 11
`)Set a string vm.Set("xyzzy", "Nothing happens.")
vm.Run(`
console.log(xyzzy.length); // 16
`)Get the value of an expression value, _ = vm.Run("xyzzy.length")
{
// value is an int64 with a value of 16
value, _ := value.ToInteger()
}An error happens value, err = vm.Run("abcdefghijlmnopqrstuvwxyz.length")
if err != nil {
// err = ReferenceError: abcdefghijlmnopqrstuvwxyz is not defined
// If there is an error, then value.IsUndefined() is true
...
}Set a Go function vm.Set("sayHello", func(call otto.FunctionCall) otto.Value {
fmt.Printf("Hello, %s.\n", call.Argument(0).String())
return otto.Value{}
})Set a Go function that returns something useful vm.Set("twoPlus", func(call otto.FunctionCall) otto.Value {
right, _ := call.Argument(0).ToInteger()
result, _ := vm.ToValue(2 + right)
return result
})Use the functions in JavaScript result, _ = vm.Run(`
sayHello("Xyzzy"); // Hello, Xyzzy.
sayHello(); // Hello, undefined
result = twoPlus(2.0); // 4
`)ParserA separate parser is available in the parser package if you're just interested in building an AST. http://godoc.org/github.com/robertkrimen/otto/parser Parse and return an AST filename := "" // A filename is optional
src := `
// Sample xyzzy example
(function(){
if (3.14159 > 0) {
console.log("Hello, World.");
return;
}
var xyzzy = NaN;
console.log("Nothing happens.");
return xyzzy;
})();
`
// Parse some JavaScript, yielding a *ast.Program and/or an ErrorList
program, err := parser.ParseFile(nil, filename, src, 0)ottoYou can run (Go) JavaScript from the commandline with: http://github.com/robertkrimen/otto/tree/master/otto Run JavaScript by entering some source on stdin or by giving otto a filename: underscoreOptionally include the JavaScript utility-belt library, underscore, with this import: import (
"github.com/robertkrimen/otto"
_ "github.com/robertkrimen/otto/underscore"
)
// Now every otto runtime will come loaded with underscoreFor more information: http://github.com/robertkrimen/otto/tree/master/underscore Caveat EmptorThe following are some limitations with otto: Regular Expression IncompatibilityGo translates JavaScript-style regular expressions into something that is
"regexp" compatible via Therefore, the following syntax is incompatible: A brief discussion of these limitations: "Regexp (?!re)" https://groups.google.com/forum/?fromgroups=#%21topic/golang-nuts/7qgSDWPIh_E More information about re2: https://code.google.com/p/re2/ In addition to the above, re2 (Go) has a different definition for \s: [\t\n\f\r ]. The JavaScript definition, on the other hand, also includes \v, Unicode "Separator, Space", etc. Halting ProblemIf you want to stop long running executions (like third-party code), you can use the interrupt channel to do this: package main
import (
"errors"
"fmt"
"os"
"time"
"github.com/robertkrimen/otto"
)
var halt = errors.New("Stahp")
func main() {
runUnsafe(`var abc = [];`)
runUnsafe(`
while (true) {
// Loop forever
}`)
}
func runUnsafe(unsafe string) {
start := time.Now()
defer func() {
duration := time.Since(start)
if caught := recover(); caught != nil {
if caught == halt {
fmt.Fprintf(os.Stderr, "Some code took to long! Stopping after: %v\n", duration)
return
}
panic(caught) // Something else happened, repanic!
}
fmt.Fprintf(os.Stderr, "Ran code successfully: %v\n", duration)
}()
vm := otto.New()
vm.Interrupt = make(chan func(), 1) // The buffer prevents blocking
go func() {
time.Sleep(2 * time.Second) // Stop after two seconds
vm.Interrupt <- func() {
panic(halt)
}
}()
vm.Run(unsafe) // Here be dragons (risky code)
}Where is setTimeout/setInterval? These timing functions are not actually part of the ECMA-262 specification.
Typically, they belong to the For an example of how this could be done in Go with otto, see natto: http://github.com/robertkrimen/natto Here is some more discussion of the issue: Usagevar ErrVersion = errors.New("version mismatch")type Errortype Error struct {
}An Error represents a runtime error, e.g. a TypeError, a ReferenceError, etc. func (Error) Errorfunc (err Error) Error() stringError returns a description of the error func (Error) Stringfunc (err Error) String() stringString returns a description of the error and a trace of where the error occurred. type FunctionCalltype FunctionCall struct {
This Value
ArgumentList []Value
Otto *Otto
}FunctionCall is an encapsulation of a JavaScript function call. func (FunctionCall) Argumentfunc (self FunctionCall) Argument(index int) ValueArgument will return the value of the argument at the given index. If no such argument exists, undefined is returned. type Objecttype Object struct {
}Object is the representation of a JavaScript object. func (Object) Callfunc (self Object) Call(name string, argumentList ...interface{}) (Value, error)Call a method on the object. It is essentially equivalent to: An undefined value and an error will result if: func (Object) Classfunc (self Object) Class() stringClass will return the class string of the object. The return value will (generally) be one of: func (Object) Getfunc (self Object) Get(name string) (Value, error)Get the value of the property with the given name. func (Object) Keysfunc (self Object) Keys() []stringGet the keys for the object Equivalent to calling Object.keys on the object func (Object) Setfunc (self Object) Set(name string, value interface{}) errorSet the property of the given name to the given value. An error will result if the setting the property triggers an exception (i.e. read-only), or there is an error during conversion of the given value. func (Object) Valuefunc (self Object) Value() ValueValue will return self as a value. type Ottotype Otto struct {
// Interrupt is a channel for interrupting the runtime. You can use this to halt a long running execution, for example.
// See "Halting Problem" for more information.
Interrupt chan func()
}Otto is the representation of the JavaScript runtime. Each instance of Otto has a self-contained namespace. func Newfunc New() *OttoNew will allocate a new JavaScript runtime func Runfunc Run(src interface{}) (*Otto, Value, error)Run will allocate a new JavaScript runtime, run the given source on the allocated runtime, and return the runtime, resulting value, and error (if any). src may be a string, a byte slice, a bytes.Buffer, or an io.Reader, but it MUST always be in UTF-8. src may also be a Script. src may also be a Program, but if the AST has been modified, then runtime behavior is undefined. func (Otto) Callfunc (self Otto) Call(source string, this interface{}, argumentList ...interface{}) (Value, error)Call the given JavaScript with a given this and arguments. If this is nil, then some special handling takes place to determine the proper this value, falling back to a "standard" invocation if necessary (where this is undefined). If source begins with "new " (A lowercase new followed by a space), then Call will invoke the function constructor rather than performing a function call. In this case, the this argument has no effect. // value is a String object
value, _ := vm.Call("Object", nil, "Hello, World.")
// Likewise...
value, _ := vm.Call("new Object", nil, "Hello, World.")
// This will perform a concat on the given array and return the result
// value is [ 1, 2, 3, undefined, 4, 5, 6, 7, "abc" ]
value, _ := vm.Call(`[ 1, 2, 3, undefined, 4 ].concat`, nil, 5, 6, 7, "abc")func (*Otto) Compilefunc (self *Otto) Compile(filename string, src interface{}) (*Script, error)Compile will parse the given source and return a Script value or nil and an error if there was a problem during compilation. script, err := vm.Compile("", `var abc; if (!abc) abc = 0; abc += 2; abc;`)
vm.Run(script)func (*Otto) Copyfunc (in *Otto) Copy() *OttoCopy will create a copy/clone of the runtime. Copy is useful for saving some time when creating many similar runtimes. This method works by walking the original runtime and cloning each object, scope, stash, etc. into a new runtime. Be on the lookout for memory leaks or inadvertent sharing of resources. func (Otto) Getfunc (self Otto) Get(name string) (Value, error)Get the value of the top-level binding of the given name. If there is an error (like the binding does not exist), then the value will be undefined. func (Otto) Objectfunc (self Otto) Object(source string) (*Object, error)Object will run the given source and return the result as an object. For example, accessing an existing object: object, _ := vm.Object(`Number`)Or, creating a new object: object, _ := vm.Object(`({ xyzzy: "Nothing happens." })`)Or, creating and assigning an object: object, _ := vm.Object(`xyzzy = {}`)
object.Set("volume", 11)If there is an error (like the source does not result in an object), then nil and an error is returned. func (Otto) Runfunc (self Otto) Run(src interface{}) (Value, error)Run will run the given source (parsing it first if necessary), returning the resulting value and error (if any) src may be a string, a byte slice, a bytes.Buffer, or an io.Reader, but it MUST always be in UTF-8. If the runtime is unable to parse source, then this function will return undefined and the parse error (nothing will be evaluated in this case). src may also be a Script. src may also be a Program, but if the AST has been modified, then runtime behavior is undefined. func (Otto) Setfunc (self Otto) Set(name string, value interface{}) errorSet the top-level binding of the given name to the given value. Set will automatically apply ToValue to the given value in order to convert it to a JavaScript value (type Value). If there is an error (like the binding is read-only, or the ToValue conversion fails), then an error is returned. If the top-level binding does not exist, it will be created. func (Otto) ToValuefunc (self Otto) ToValue(value interface{}) (Value, error)ToValue will convert an interface{} value to a value digestible by otto/JavaScript. type Scripttype Script struct {
}Script is a handle for some (reusable) JavaScript. Passing a Script value to a run method will evaluate the JavaScript. func (*Script) Stringfunc (self *Script) String() stringtype Valuetype Value struct {
}Value is the representation of a JavaScript value. |
