vm

package
v0.0.7 Latest Latest
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 Go to latest Published: Dec 19, 2018 License: MIT Imports: 11 Imported by: 0

Documentation

Overview

Package vm implements virtual-machine for anko.

Example (VmArrays) 
package main

import (
	"fmt"
	"log"

	"github.com/mattn/anko/vm"
)

func main() {
	env := vm.NewEnv()

	err := env.Define("println", fmt.Println)
	if err != nil {
		log.Fatalf("define error: %v\n", err)
	}

	script := `
a = [1, 2]
println(a)

a += 3
println(a)

a = []
// this automatically appends to array
a[0] = 1
println(a)

println("")

a = []
// this would give an index out of range error
// a[1] = 1

a = [1, 2]
b = [3, 4]
c = a + b
println(c)

c = [1, 2] + [3, 4]
println(c)

println("")

c = [a] + b
println(c)

c = [a] + [b]
println(c)

c = [[1, 2]] + [[3, 4]]
println(c)

println("")

a = [1, 2]

println(len(a))

println(a[1])
`

	_, err = env.Execute(script)
	if err != nil {
		log.Fatalf("execute error: %v\n", err)
	}

}

Output:

[1 2]
[1 2 3]
[1]

[1 2 3 4]
[1 2 3 4]

[[1 2] 3 4]
[[1 2] [3 4]]
[[1 2] [3 4]]

2
2
Example (VmBasicOperators) 
package main

import (
	"fmt"
	"log"

	"github.com/mattn/anko/vm"
)

func main() {
	env := vm.NewEnv()

	err := env.Define("println", fmt.Println)
	if err != nil {
		log.Fatalf("define error: %v\n", err)
	}

	script := `
a = nil
println(a)
a = true
println(a)

println("")

a = 2 + 1
println(a)
a = 2 - 1
println(a)
a = 2 * 1
println(a)
a = 4 / 2
println(a)

println("")

a = 1
a++
println(a)
a--
println(a)

println("")

a = 1
a += 1
println(a)
a -= 1
println(a)
a *= 4
println(a)
a /= 2
println(a)

println("")

a = 2 ** 3
println(a)
a = 1 & 3
println(a)
a = 1 | 2
println(a) 

println("")

a = 2 << 3
println(a)
a = 8 >> 2
println(a)
a = 7 % 3
println(a)

println("")

a = 2 - (-2)
println(a)
a = ^2
println(a)
a = "a" * 4
println(a)
a = !true
println(a)

`

	_, err = env.Execute(script)
	if err != nil {
		log.Fatalf("execute error: %v\n", err)
	}

}

Output:

<nil>
true

3
1
2
2

2
1

2
1
4
2

8
1
3

16
2
1

4
-3
aaaa
false
Example (VmChannels) 
package main

import (
	"fmt"
	"log"

	"github.com/mattn/anko/vm"
)

func main() {
	env := vm.NewEnv()

	err := env.Define("println", fmt.Println)
	if err != nil {
		log.Fatalf("define error: %v\n", err)
	}

	script := `
a = make(chan string, 1)
a <- "a"
println(<- a)

a = make(chan string)
go func() {
	a <- "a"
}()
println(<- a)


`

	_, err = env.Execute(script)
	if err != nil {
		log.Fatalf("execute error: %v\n", err)
	}

}

Output:

a
a
Example (VmComparisonOperators) 
package main

import (
	"fmt"
	"log"

	"github.com/mattn/anko/vm"
)

func main() {
	env := vm.NewEnv()

	err := env.Define("println", fmt.Println)
	if err != nil {
		log.Fatalf("define error: %v\n", err)
	}

	script := `
a = nil == nil
println(a)
a = "a" != "a" 
println(a)
a = 1 == 1.0
println(a)
a = !true
println(a)

println("")

a = 1 < 2
println(a)
a = 1 > 3
println(a)
a = 2 <= 2
println(a)
a = 2 >= 3
println(a)

println("")
a = 1 == 2 && 1 == 1
println(a)
a = 1 == 2 || 1 == 1
println(a)
`

	_, err = env.Execute(script)
	if err != nil {
		log.Fatalf("execute error: %v\n", err)
	}

}

Output:

true
false
true
false

true
false
true
false

false
true
Example (VmForLoops) 
package main

import (
	"fmt"
	"log"

	"github.com/mattn/anko/vm"
)

func main() {
	env := vm.NewEnv()

	err := env.Define("println", fmt.Println)
	if err != nil {
		log.Fatalf("define error: %v\n", err)
	}

	script := `
i = 0
for {
	println(i)
	i++
	if i > 1 {
		break
	}
}

println("")

for i in [0, 1] {
	println(i)
}

println("")

for key, value in {"a": "b"} {
	println(key, value)
}

println("")

i = 0
for i < 2 {
	println(i)
	i++
}

println("")

for i = 0; i < 2; i++ {
	println(i)
}

println("")


for i = 0; i < 10; i++ {
	println(i)
	if i < 1 {
		continue
	}
	break
}

`

	_, err = env.Execute(script)
	if err != nil {
		log.Fatalf("execute error: %v\n", err)
	}

}

Output:

0
1

0
1

a b

0
1

0
1

0
1
Example (VmFunctions) 
package main

import (
	"fmt"
	"log"

	"github.com/mattn/anko/vm"
)

func main() {
	env := vm.NewEnv()

	err := env.Define("println", fmt.Println)
	if err != nil {
		log.Fatalf("define error: %v\n", err)
	}

	script := `
func a(b) {
	println(b)
}
a("b")

a = func(b) {
	println(b)
}
a("b")

func(b) {
	println(b)
}("b")

func a() {
	return "a"
}
println(a())

println("")


func fib(n) {
	if (n <= 1) {
		return n
	}
	return fib(n - 1) + fib(n - 2) 
}

println(fib(8))
 
 func sum(n...) {
	 t = 0
	 for a in n {
		 t += a
	 }
	 return t
 }
println(sum(1, 2, 3, 4))

func add(a, b) {
	return a + b
} 
println(add([1, 2]...))
`

	_, err = env.Execute(script)
	if err != nil {
		log.Fatalf("execute error: %v\n", err)
	}

}

Output:

b
b
b
a

21
10
3
Example (VmFunctionsOutside) 
package main

import (
	"fmt"
	"log"

	"github.com/mattn/anko/vm"
)

func testFunc1(a interface{}) int {
	b, ok := a.([]interface{})
	if ok {
		return len(b)
	}
	return 0
}

func main() {

	/*
	   // the following function would be uncommented
	   func testFunc1(a interface{}) int {
	   	b, ok := a.([]interface{})
	   	if ok {
	   		return len(b)
	   	}
	   	return 0
	   }
	*/

	env := vm.NewEnv()

	err := env.Define("println", fmt.Println)
	if err != nil {
		log.Fatalf("define error: %v\n", err)
	}
	err = env.Define("addString", func(a string, b string) string { return a + b })
	if err != nil {
		log.Fatalf("define error: %v\n", err)
	}
	// uses the function that would be declared above
	err = env.Define("aFunc", testFunc1)
	if err != nil {
		log.Fatalf("define error: %v\n", err)
	}

	script := `
a = addString("a", "b")
println(a)

a = aFunc([1, 2, 3])
println(a) 
`

	_, err = env.Execute(script)
	if err != nil {
		log.Fatalf("execute error: %v\n", err)
	}

}

Output:

ab
3
Example (VmFunctionsScope) 
package main

import (
	"fmt"
	"log"

	"github.com/mattn/anko/vm"
)

func main() {
	env := vm.NewEnv()

	err := env.Define("println", fmt.Println)
	if err != nil {
		log.Fatalf("define error: %v\n", err)
	}

	script := `
a = 1
func () {
	a = 2
}()
println(a)

var a = 1
func () {
	a = 2
}()
println(a)

a = 1
func () {
	var a = 2
}()
println(a)

var a = 1
func () {
	var a = 2
}()
println(a)
`

	_, err = env.Execute(script)
	if err != nil {
		log.Fatalf("execute error: %v\n", err)
	}

}

Output:

2
2
1
1
Example (VmHelloWorld) 
package main

import (
	"fmt"
	"log"

	"github.com/mattn/anko/vm"
)

func main() {
	env := vm.NewEnv()

	err := env.Define("println", fmt.Println)
	if err != nil {
		log.Fatalf("define error: %v\n", err)
	}

	script := `
println("Hello World :)")
`

	_, err = env.Execute(script)
	if err != nil {
		log.Fatalf("execute error: %v\n", err)
	}

}

Output:

Hello World :)
Example (VmHttp) 
package main

import (
	"log"

	"github.com/mattn/anko/packages"
	"github.com/mattn/anko/vm"
)

func main() {
	env := vm.NewEnv()
	packages.DefineImport(env)

	script := `
fmt = import("fmt")
io = import("io")
ioutil = import("io/ioutil")
net = import("net")
http = import("net/http")
time = import("time")

func handlerRoot(responseWriter, request) {
	io.WriteString(responseWriter, "Hello World :)")
}

serveMux = http.NewServeMux()
serveMux.HandleFunc("/", handlerRoot)
listener, err = net.Listen("tcp", ":8080")
if err != nil {
	fmt.Println(err)
	return
}
go http.Serve(listener, serveMux)

client = http.DefaultClient

response, err = client.Get("http://localhost:8080/")
if err != nil {
	fmt.Println(err)
	return
}

body, err = ioutil.ReadAll(response.Body)
if err != nil {
	fmt.Println(err)
}
response.Body.Close()

fmt.Printf("%s\n", body)
`

	_, err := env.Execute(script)
	if err != nil {
		log.Fatalf("execute error: %v\n", err)
	}

}

Output:

Hello World :)
Example (VmIfOperators) 
package main

import (
	"fmt"
	"log"

	"github.com/mattn/anko/vm"
)

func main() {
	env := vm.NewEnv()

	err := env.Define("println", fmt.Println)
	if err != nil {
		log.Fatalf("define error: %v\n", err)
	}

	script := `
a = 1
b = 2

if a == 1 {
	println(a)
}

if b == 1 {
	println(a)
} else {
	println(b)
}

if a == 3 {
	println(a)
} else if b == 3 {
	println(b)
} else {
	println(a + b)
}

println("")

if a == 2 || b == 2 {
	println(4)
}

if a == 1 && b == 2 {
	println(5)
}
`

	_, err = env.Execute(script)
	if err != nil {
		log.Fatalf("execute error: %v\n", err)
	}

}

Output:

1
2
3

4
5
Example (VmMaps) 
package main

import (
	"fmt"
	"log"

	"github.com/mattn/anko/vm"
)

func main() {
	env := vm.NewEnv()

	err := env.Define("println", fmt.Println)
	if err != nil {
		log.Fatalf("define error: %v\n", err)
	}

	script := `
a = {}
println(a)

a.b = 1
println(a)
println(a.b)

println("")

a = {}
a["b"] = 1
println(a)
println(a["b"])

println("")

b, ok = a["b"]
println(b)
println(ok)

delete(a, "b")
_, ok = a["b"]
println(ok)

println("")

a = {"a": 1}
println(len(a))

`

	_, err = env.Execute(script)
	if err != nil {
		log.Fatalf("execute error: %v\n", err)
	}

}

Output:

map[]
map[b:1]
1

map[b:1]
1

1
true
false

1
Example (VmModules) 
package main

import (
	"fmt"
	"log"

	"github.com/mattn/anko/vm"
)

func main() {
	env := vm.NewEnv()

	err := env.Define("println", fmt.Println)
	if err != nil {
		log.Fatalf("define error: %v\n", err)
	}

	script := `
module rectangle {
	_length = 1
	_width = 1
	
	func setLength (length) {
		if length <= 0 {
			return
		}
		_length = length
	}
	
	func setWidth (width) {
		if width <= 0 {
			return
		}
		_width = width
	}
	
	func area () {
		return _length * _width
	}
	
	func perimeter () {
		return 2 * (_length + _width)
	}
 }

rectangle1 = rectangle

rectangle1.setLength(4)
rectangle1.setWidth(5)

println(rectangle1.area())
println(rectangle1.perimeter())

rectangle2 = rectangle

rectangle2.setLength(2)
rectangle2.setWidth(4)

println(rectangle2.area())
println(rectangle2.perimeter())
`

	_, err = env.Execute(script)
	if err != nil {
		log.Fatalf("execute error: %v\n", err)
	}

}

Output:

20
18
8
12
Example (VmQuickStart) 
package main

import (
	"fmt"
	"log"

	"github.com/mattn/anko/vm"
)

func main() {
	env := vm.NewEnv()

	err := env.Define("println", fmt.Println)
	if err != nil {
		log.Fatalf("define error: %v\n", err)
	}

	script := `
// declare variables
x = 1
y = x + 1

// print using outside the script defined println function
println(x + y) // 3

// if else statement
if x < 1 || y < 1 {
	println(x)
} else if x < 1 && y < 1 {
	println(y)
} else {
	println(x + y)
}

// array
a = [1, 2, 3]
println(a) // [1 2 3]
println(a[0]) // 1

// map
a = {"x": 1}
println(a) // map[x:1]
a.b = 2
a["c"] = 3
println(a["b"]) // 2
println(a.c) // 3

// function
func a (x) {
	println(x + 1)
}
a(3) // 4
`

	_, err = env.Execute(script)
	if err != nil {
		log.Fatalf("execute error: %v\n", err)
	}

}

Output:

3
3
[1 2 3]
1
map[x:1]
2
3
4
Example (VmRegexp) 
package main

import (
	"log"

	"github.com/mattn/anko/packages"
	"github.com/mattn/anko/vm"
)

func main() {
	env := vm.NewEnv()
	packages.DefineImport(env)

	script := `
fmt = import("fmt")
regexp = import("regexp")

re = regexp.MustCompile("^simple$")
result = re.MatchString("simple")
fmt.Println(result)
fmt.Println("")

re = regexp.MustCompile("simple")
result = re.FindString("This is a simple sentence")
fmt.Println(result)
fmt.Println("")

re = regexp.MustCompile(",")
result = re.Split("a,b,c", -1)
fmt.Println(result)
fmt.Println("")

re = regexp.MustCompile("foo")
result = re.ReplaceAllString("foo", "bar")
fmt.Println(result)
`

	_, err := env.Execute(script)
	if err != nil {
		log.Fatalf("execute error: %v\n", err)
	}

}

Output:

true

simple

[a b c]

bar
Example (VmSlices) 
package main

import (
	"fmt"
	"log"

	"github.com/mattn/anko/vm"
)

func main() {
	env := vm.NewEnv()

	err := env.Define("println", fmt.Println)
	if err != nil {
		log.Fatalf("define error: %v\n", err)
	}

	script := `
a = "abc"
println(a[1:])
println(a[:2])
println(a[1:2])

println("")

a = [1, 2, 3]
println(a[1:])
println(a[:2])
println(a[1:2])
`

	_, err = env.Execute(script)
	if err != nil {
		log.Fatalf("execute error: %v\n", err)
	}

}

Output:

bc
ab
b

[2 3]
[1 2]
[2]
Example (VmSort) 
package main

import (
	"log"

	"github.com/mattn/anko/packages"
	"github.com/mattn/anko/vm"
)

func main() {
	env := vm.NewEnv()
	packages.DefineImport(env)

	script := `
fmt = import("fmt")
sort = import("sort")
a = [5, 1.1, 3, "f", "2", "4.4"]
sortFuncs = make(sort.SortFuncsStruct)
sortFuncs.LenFunc = func() { return len(a) }
sortFuncs.LessFunc = func(i, j) { return a[i] < a[j] }
sortFuncs.SwapFunc = func(i, j) { temp = a[i]; a[i] = a[j]; a[j] = temp }
sort.Sort(sortFuncs)
fmt.Println(a)
`

	_, err := env.Execute(script)
	if err != nil {
		log.Fatalf("execute error: %v\n", err)
	}

}

Output:

[f 1.1 2 3 4.4 5]

Index

Examples

Constants

This section is empty.

Variables

View Source 
var (

	// ErrBreak when there is an unexpected break statement
	ErrBreak = errors.New("unexpected break statement")
	// ErrContinue when there is an unexpected continue statement
	ErrContinue = errors.New("unexpected continue statement")
	// ErrReturn when there is an unexpected return statement
	ErrReturn = errors.New("unexpected return statement")
	// ErrInterrupt when execution has been interrupted
	ErrInterrupt = errors.New("execution interrupted")
)

Functions

func ClearInterrupt 

func ClearInterrupt(env *Env)

ClearInterrupt removes the interrupt flag from specified environment. This includes all parent & child environments.

func Interrupt 

func Interrupt(env *Env)

Interrupt interrupts the execution of any running statements in the specified environment. This includes all parent & child environments. Note that the execution is not instantly aborted: after a call to Interrupt, the current running statement will finish, but the next statement will not run, and instead will return a nilValue and an ErrInterrupt.

Example 
package main

import (
	"fmt"
	"log"
	"sync"
	"time"

	"github.com/mattn/anko/vm"
)

func main() {
	var waitGroup sync.WaitGroup
	waitGroup.Add(1)
	waitChan := make(chan struct{}, 1)

	env := vm.NewEnv()
	sleepMillisecond := func() { time.Sleep(time.Millisecond) }

	err := env.Define("println", fmt.Println)
	if err != nil {
		log.Fatalf("define error: %v\n", err)
	}
	err = env.Define("sleep", sleepMillisecond)
	if err != nil {
		log.Fatalf("define error: %v\n", err)
	}

	script := `
# sleep for 10 seconds
for i = 0; i < 10000; i++ {
	sleep()
}
# Should interrupt before printing the next line
println("this line should not be printed")
`

	go func() {
		close(waitChan)
		v, err := env.Execute(script)
		fmt.Println(v, err)
		waitGroup.Done()
	}()

	<-waitChan
	vm.Interrupt(env)

	waitGroup.Wait()

}

Output:

<nil> execution interrupted

func Run 

func Run(stmts []ast.Stmt, env *Env) (interface{}, error)

Run executes statements in the specified environment.

func RunSingleStmt 

func RunSingleStmt(stmt ast.Stmt, env *Env) (interface{}, error)

RunSingleStmt executes one statement in the specified environment.

func ValueEqual 

func ValueEqual(v1 interface{}, v2 interface{}) bool

ValueEqual checks the values and returns true if equal If passed function, does extra checks otherwise just doing reflect.DeepEqual

Types

type Env 

type Env struct {
	sync.RWMutex
	// contains filtered or unexported fields
}

Env provides interface to run VM. This mean function scope and blocked-scope. If stack goes to blocked-scope, it will make new Env.

func NewEnv 

func NewEnv() *Env

NewEnv creates new global scope.

func NewPackage 

func NewPackage(n string) *Env

NewPackage creates a new env with a name

func (*Env) AddPackage 

func (e *Env) AddPackage(name string, methods map[string]interface{}, types map[string]interface{}) (*Env, error)

AddPackage creates a new env with a name that has methods and types in it. Created under the parent env

func (*Env) Addr 

func (e *Env) Addr(k string) (reflect.Value, error)

Addr returns pointer value which specified symbol. It goes to upper scope until found or returns error.

func (*Env) Copy 

func (e *Env) Copy() *Env

Copy the state of the virtual machine environment

func (*Env) DeepCopy 

func (e *Env) DeepCopy() *Env

DeepCopy copy recursively the state of the virtual machine environment

func (*Env) Define 

func (e *Env) Define(k string, v interface{}) error

Define defines symbol in current scope.

Example 
package main

import (
	"fmt"
	"log"

	"github.com/mattn/anko/vm"
)

func main() {
	env := vm.NewEnv()
	env.SetName("myName")

	err := env.Define("println", fmt.Println)
	if err != nil {
		log.Fatalf("define error: %v\n", err)
	}

	err = env.Define("a", true)
	if err != nil {
		log.Fatalf("define error: %v\n", err)
	}
	err = env.Define("b", int64(1))
	if err != nil {
		log.Fatalf("define error: %v\n", err)
	}
	err = env.Define("c", float64(1.1))
	if err != nil {
		log.Fatalf("define error: %v\n", err)
	}
	err = env.Define("d", "d")
	if err != nil {
		log.Fatalf("define error: %v\n", err)
	}
	err = env.Define("e", []interface{}{true, int64(1), float64(1.1), "d"})
	if err != nil {
		log.Fatalf("define error: %v\n", err)
	}
	err = env.Define("f", map[string]interface{}{"a": true})
	if err != nil {
		log.Fatalf("define error: %v\n", err)
	}

	script := `
println(a)
println(b)
println(c)
println(d)
println(e)
println(f)
`

	_, err = env.Execute(script)
	if err != nil {
		log.Fatalf("execute error: %v\n", err)
	}

}

Output:

true
1
1.1
d
[true 1 1.1 d]
map[a:true]

func (*Env) DefineGlobal 

func (e *Env) DefineGlobal(k string, v interface{}) error

DefineGlobal defines symbol in global scope.

func (*Env) DefineGlobalReflectType 

func (e *Env) DefineGlobalReflectType(k string, t reflect.Type) error

DefineGlobalReflectType defines type in global scope.

func (*Env) DefineGlobalType 

func (e *Env) DefineGlobalType(k string, t interface{}) error

DefineGlobalType defines type in global scope.

func (*Env) DefineReflectType 

func (e *Env) DefineReflectType(k string, t reflect.Type) error

DefineReflectType defines type in current scope.

func (*Env) DefineType 

func (e *Env) DefineType(k string, t interface{}) error

DefineType defines type in current scope.

func (*Env) Delete 

func (e *Env) Delete(k string) error

Delete deletes symbol in current scope.

func (*Env) DeleteGlobal 

func (e *Env) DeleteGlobal(k string) error

DeleteGlobal deletes the first matching symbol found in current or parent scope.

func (*Env) Dump 

func (e *Env) Dump()

Dump show symbol values in the scope.

Example 
package main

import (
	"log"

	"github.com/mattn/anko/vm"
)

func main() {
	env := vm.NewEnv()
	env.SetName("myName")

	err := env.Define("a", "a")
	if err != nil {
		log.Fatalf("define error: %v\n", err)
	}

	_, err = env.Get("a")
	if err != nil {
		log.Fatalf("get error: %v\n", err)
	}

	env.Dump()

}

Output:

Name: myName
Has parent: false
a = "a"

func (*Env) Execute 

func (e *Env) Execute(src string) (interface{}, error)

Execute parses and runs source in current scope.

func (*Env) Get 

func (e *Env) Get(k string) (interface{}, error)

Get returns value which specified symbol. It goes to upper scope until found or returns error.

func (*Env) GetName 

func (e *Env) GetName() string

GetName returns module name.

func (*Env) NewEnv 

func (e *Env) NewEnv() *Env

NewEnv creates new child scope.

func (*Env) NewModule 

func (e *Env) NewModule(n string) *Env

NewModule creates new module scope as global.

func (*Env) NewPackage 

func (e *Env) NewPackage(n string) *Env

NewPackage creates a new env with a name under the parent env

func (*Env) Run 

func (e *Env) Run(stmts []ast.Stmt) (interface{}, error)

Run runs statements in current scope.

func (*Env) Set 

func (e *Env) Set(k string, v interface{}) error

Set modifies value which specified as symbol. It goes to upper scope until found or returns error.

func (*Env) SetExternal 

func (e *Env) SetExternal(res EnvResolver)

SetExternal sets an external resolver

func (*Env) SetName 

func (e *Env) SetName(n string)

SetName sets a name of the scope. This means that the scope is module.

func (*Env) String 

func (e *Env) String() string

String return the name of current scope.

func (*Env) Type 

func (e *Env) Type(k string) (reflect.Type, error)

Type returns type which specified symbol. It goes to upper scope until found or returns error.

type EnvResolver 

type EnvResolver interface {
	Get(string) (reflect.Value, error)
	Type(string) (reflect.Type, error)
}

EnvResolver provides an interface for extrenal values and types

type Error 

type Error struct {
	Message string
	Pos     ast.Position
}

Error provides a convenient interface for handling runtime error. It can be Error interface with type cast which can call Pos().

func (*Error) Error 

func (e *Error) Error() string

Error returns the error message.

Source Files

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