script

package module
v0.0.0-...-3558dc3 Latest Latest
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 Go to latest Published: Nov 17, 2021 License: MIT Imports: 31 Imported by: 0

README

script is a simple script engine written in golang with Lua-like syntax.

(If you are looking for a Lua 5.2 compatible engine, refer to tag v0.2)

Differ from Lua

  • Functions should be declared in the topmost scope:
    • do function foo() ... end end is invalid.
    • function foo() function bar() ... end end is invalid.
  • Use lambda to declare anonymous functions:
    • local foo = lambda(x) ... end.
    • Last return can be omitted: lambda (x) x=x+1; x end <=> lambda (x) x=x+1; return x end.
  • Syntax of calling functions strictly requires no spaces between callee and '(':
    • print(1) is the only right way of calling a function.
    • print (1) literally means two things: 1) get value of print and discard it, 2) evaluate (1).
  • To write variadic functions:
    • function foo(a, b...) end.
    • args = {1, 2, 3}; foo(args...).
  • Simple keyword arguments syntax sugar:
    • foo(a, b=2, c=3) will be converted to foo(a, { b=2, c=3 }).
    • There is no REAL keyword argument in script, e.g.: function foo(a) return type(a) end:
      • foo(1) returns "number".
      • foo(a=1) <=> foo({a=1}) returns "table".
  • Returning multiple arguments will be translated into returning a table, e.g.:
    • function f() return 1, 2 end; local a, b = f().
    • function f() return {1, 2} end; local tmp = f(); local a, b = tmp[0], tmp[1].
    • local a, b, c = d <=> local a, b, c = d[0], d[1], d[2].
  • Everything starts at ZERO. For-loops start inclusively and end exclusively, e.g.:
    • a={1, 2}; assert(a[0] == 1).
    • for i=0,n do ... end.
    • for i=n-1,-1,-1 do ... end.
  • Functions loaded from table will have a self-like argument at first, to not-to-have it, use : operator, e.g.:
    • a={foo=lambda(this) print(this.v) end, v=1} a.foo() will print 1.
    • a={foo=lambda(this) print(this) end} a:foo() will print nil.
    • That's to say, you should call most lib functions using :.
  • You can define up to 32000 variables (varies depending on the number of temporal variables generated by interpreter) in a function.
  • Numbers are int64 + float64 internally, interpreter may promote it to float64 when needed and downgrade it to int64 when possible.
  • You can return anywhere inside functions, continue inside for-loops, goto any label within the same function.

Run

program, err := script.LoadString("return 1")
v, err := program.Run() // v == 1

Global Values

script.AddGlobalValue("G", func() int { return 1 })

program, _ := script.LoadString("return G() + 1")
v, err := program.Run() // v == 2

program, _ = script.LoadString("return G() + 2")
v, err = program.Run() // v == 3

program, _ = script.LoadString("return G + 2", &CompileOptions{
	GlobalKeyValues: {
		"G": 10, // override the global 'G'
	},
})
v, err = program.Run() // v == 12

Benchmarks

Refer to here.

Documentation

Index

Constants

View Source 
const (
	ValueSize = unsafe.Sizeof(Value{})
)
View Source 
const Version int64 = 327

Variables

View Source 
var (
	ReaderProto = Map(Str("__name"), Str("reader"),
		Str("read"), Func2("read", func(rx, n Value) Value {
			f := rx.Table().GetString("_f").Interface().(io.Reader)
			switch n.Type() {
			case typ.Number:
				p := make([]byte, n.MaybeInt(0))
				rn, err := f.Read(p)
				if err == nil || rn > 0 {
					return Bytes(p[:rn])
				}
				if err == io.EOF {
					return Nil
				}
				panic(err)
			default:
				buf, err := ioutil.ReadAll(f)
				panicErr(err)
				return Bytes(buf)
			}
		}, "read() string", "\tread all bytes, return nil if EOF reached", "read(n: int) string", "\tread n bytes"),
		Str("readbuf"), Func2("readbuf", func(rx, n Value) Value {
			rn, err := rx.Table().GetString("_f").Interface().(io.Reader).Read(n.Interface().([]byte))
			return Array(Int(int64(rn)), Val(err))
		}, "$f(buf: bytes) array", "\tread into buf and return { bytes_read, error } in Go style"),
		Str("readlines"), Func2("readlines", func(rx, cb Value) Value {
			f := rx.Table().GetString("_f").Interface().(io.Reader)
			delim := rx.Table().GetString("delim").MaybeStr("\n")
			if cb == Nil {
				buf, err := ioutil.ReadAll(f)
				if err != nil {
					panic(err)
				}
				parts := bytes.Split(buf, []byte(delim))
				var res []Value
				for i, line := range parts {
					if i < len(parts)-1 {
						line = append(line, delim...)
					}
					res = append(res, Bytes(line))
				}
				return Array(res...)
			}
			for rd := bufio.NewReader(f); ; {
				line, err := rd.ReadString(delim[0])
				if len(line) > 0 {
					if v, err := cb.MustFunc("callback").Call(Str(line)); err != nil {
						panic(err)
					} else if v != Nil {
						return v
					}
				}
				if err != nil {
					if err != io.EOF {
						panic(err)
					}
					break
				}
			}
			return Nil
		},
			"readlines() array", "\tread the whole file and return lines as a table array",
			"readlines(f: function)", "\tfor every line read, f(line) will be called", "\tto exit the reading, return anything other than nil in f",
		),
	).Table()

	WriterProto = Map(Str("__name"), Str("writer"),
		Str("write"), Func2("write", func(rx, buf Value) Value {
			f := rx.Table().GetString("_f").Interface().(io.Writer)
			wn, err := f.Write([]byte(buf.MustStr("")))
			panicErr(err)
			return Int(int64(wn))
		}, "$f({w}: value, buf: string) int", "\twrite buf to w"),
		Str("pipe"), Func3("pipe", func(dest, src, n Value) Value {
			var wn int64
			var err error
			if n := n.MaybeInt(0); n > 0 {
				wn, err = io.CopyN(NewWriter(dest), NewReader(src), n)
			} else {
				wn, err = io.Copy(NewWriter(dest), NewReader(src))
			}
			panicErr(err)
			return Int(wn)
		}, "$f({w}: value, r: value) int", "\tcopy bytes from r to w, return number of bytes copied",
			"$f({w}: value, r: value, n: int) int", "\tcopy at most n bytes from r to w"),
	).Table()

	SeekerProto = Map(Str("__name"), Str("seeker"),
		Str("seek"), Func3("seek", func(rx, off, where Value) Value {
			f := rx.Table().GetString("_f").Interface().(io.Seeker)
			wn, err := f.Seek(off.MustInt("offset"), int(where.MustInt("where")))
			panicErr(err)
			return Int(int64(wn))
		}, "")).Table()

	CloserProto = Map(Str("__name"), Str("closer"),
		Str("close"), Func1("close", func(rx Value) Value {
			panicErr(rx.Table().GetString("_f").Interface().(io.Closer).Close())
			return Nil
		}, "")).Table()

	ReadWriterProto = ReaderProto.Copy().Merge(WriterProto, Str("__name"), Str("readwriter"))

	ReadCloserProto = ReaderProto.Copy().Merge(CloserProto, Str("__name"), Str("readcloser"))

	WriteCloserProto = WriterProto.Copy().Merge(CloserProto, Str("__name"), Str("writecloser"))

	ReadWriteCloserProto = ReadWriterProto.Copy().Merge(CloserProto, Str("__name"), Str("readwritecloser"))

	ReadWriteSeekCloserProto = ReadWriteCloserProto.Copy().Merge(SeekerProto, Str("__name"), Str("readwriteseekcloser"))
)
View Source 
var (
	Nil     = Value{}
	Zero    = Int(0)
	NullStr = Str("")
	False   = Bool(false)
	True    = Bool(true)
)

Functions

func AddGlobalValue 

func AddGlobalValue(k string, v interface{}, doc ...string)

func NewCloser 

func NewCloser(v Value) io.Closer

NewCloser creates an io.Closer from value if possible

func NewReader 

func NewReader(v Value) io.Reader

NewReader creates an io.Reader from value if possible

func NewWriter 

func NewWriter(v Value) io.Writer

NewWriter creates an io.Writer from value if possible

func RemoveGlobalValue 

func RemoveGlobalValue(k string)

func Stringify 

func Stringify(v interface{}) string

func WebREPLHandler 

func WebREPLHandler(opt *CompileOptions, cb func(*Program)) func(w http.ResponseWriter, r *http.Request)

Types

type CompileOptions 

type CompileOptions struct {
	GlobalKeyValues map[string]interface{}
}

type Env 

type Env struct {
	Global *Program
	A      Value

	// Debug info for native functions to read
	IP         uint32
	CS         *Function
	Stacktrace []stacktrace
	// contains filtered or unexported fields
}

Env is the environment for a function to run within. stack contains arguments used by the execution and is a global shared value, local can only use stack[stackOffset:] A stores the result of the execution

func (*Env) B 

func (env *Env) B(index int) Value

B is an alias of Get

func (*Env) Clear 

func (env *Env) Clear()

Clear clears the current stack

func (*Env) CopyStack 

func (env *Env) CopyStack() []Value

func (*Env) Get 

func (env *Env) Get(index int) Value

Get gets a value from the current stack

func (*Env) Prepend 

func (env *Env) Prepend(v Value)

func (*Env) Push 

func (env *Env) Push(v Value)

Push pushes a value into the current stack

func (*Env) PushVararg 

func (env *Env) PushVararg(v []Value)

func (*Env) Set 

func (env *Env) Set(index int, value Value)

Set sets a value in the current stack

func (*Env) Size 

func (env *Env) Size() int

func (*Env) Stack 

func (env *Env) Stack() []Value

func (*Env) String 

func (env *Env) String() string

type ExecError 

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

ExecError represents the runtime error

func (*ExecError) Error 

func (e *ExecError) Error() string

func (*ExecError) GetRootPanic 

func (e *ExecError) GetRootPanic() interface{}

type FuncBody 

type FuncBody struct {
	Code       packet
	Name       string
	DocString  string
	StackSize  uint16
	NumParams  uint16
	Variadic   bool
	Native     func(env *Env)
	LoadGlobal *Program
	Locals     []string
}

type Function 

type Function struct {
	*FuncBody
	Receiver Value
}

func (*Function) Call 

func (c *Function) Call(args ...Value) (v1 Value, err error)

func (*Function) CallVal 

func (c *Function) CallVal(args ...interface{}) (v1 interface{}, err error)

func (*Function) Copy 

func (f *Function) Copy() *Function

func (*Function) EmergStop 

func (c *Function) EmergStop()

EmergStop terminates the execution of Func After calling, Func will become unavailable for any further operations

func (*Function) PrettyCode 

func (c *Function) PrettyCode() string

func (*Function) Pure 

func (f *Function) Pure() *Function

func (*Function) String 

func (c *Function) String() string

func (*Function) Value 

func (c *Function) Value() Value

type Program 

type Program struct {
	Top          *Function
	Symbols      map[string]*symbol
	MaxStackSize int64
	Stack        *[]Value
	Functions    []*Function
	Stdout       io.Writer
	Stderr       io.Writer
	Stdin        io.Reader
}

func LoadFile 

func LoadFile(path string, opt *CompileOptions) (*Program, error)

func LoadString 

func LoadString(code string, opt *CompileOptions) (*Program, error)

func (*Program) EmergStop 

func (p *Program) EmergStop()

EmergStop terminates the execution of program After calling, program will become unavailable for any further operations

func (*Program) Get 

func (p *Program) Get(k string) (v Value, ok bool)

func (*Program) PrettyCode 

func (p *Program) PrettyCode() string

func (*Program) Run 

func (p *Program) Run() (v1 Value, err error)

func (*Program) Set 

func (p *Program) Set(k string, v Value) (ok bool)

type Table 

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

func NewTable 

func NewTable(size int) *Table

func (*Table) ArrayLen 

func (m *Table) ArrayLen() int

func (*Table) ArrayPart 

func (m *Table) ArrayPart() []Value

func (*Table) Clear 

func (m *Table) Clear()

Clear clears the table, where already allocated memory will be reused.

func (*Table) ClearArray 

func (m *Table) ClearArray()

func (*Table) ClearMap 

func (m *Table) ClearMap()

func (*Table) Contains 

func (m *Table) Contains(k Value) bool

func (*Table) Copy 

func (m *Table) Copy() *Table

func (*Table) Foreach 

func (m *Table) Foreach(f func(k, v Value) bool)

func (*Table) Get 

func (m *Table) Get(k Value) (v Value)

Get retrieves the value for a given key.

func (*Table) GetString 

func (m *Table) GetString(k string) (v Value)

func (*Table) Len 

func (m *Table) Len() int

func (*Table) MapLen 

func (m *Table) MapLen() int

func (*Table) MapPart 

func (m *Table) MapPart() map[Value]Value

func (*Table) Merge 

func (m *Table) Merge(src *Table, kvs ...Value) *Table

func (*Table) Name 

func (m *Table) Name() string

func (*Table) New 

func (m *Table) New() *Table

func (*Table) Next 

func (m *Table) Next(k Value) (Value, Value)

func (*Table) Parent 

func (m *Table) Parent() *Table

func (*Table) RawGet 

func (m *Table) RawGet(k Value) (v Value)

func (*Table) RawSet 

func (m *Table) RawSet(k, v Value) (prev Value)

func (*Table) Set 

func (m *Table) Set(k, v Value) (prev Value)

Set inserts or updates a key/val pair into the Map. If val == Nil, then key will get deleted

func (*Table) SetFirstParent 

func (m *Table) SetFirstParent(m2 *Table)

func (*Table) SetParent 

func (m *Table) SetParent(m2 *Table)

func (*Table) SetString 

func (m *Table) SetString(k string, v Value) (prev Value)

func (*Table) Size 

func (m *Table) Size() int

func (*Table) String 

func (m *Table) String() string

func (*Table) Value 

func (m *Table) Value() Value

type Value 

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

Value is the basic data type used by the intepreter, an empty Value naturally represent nil 

var (
	StrLib   Value
	MathLib  Value
	TableLib Value
	OSLib    Value
	IOLib    Value
)

func Array 

func Array(m ...Value) Value

Array creates an array consists of given arguments

func Bool 

func Bool(v bool) Value

Bool creates a boolean value

func Byte 

func Byte(s byte) Value

Byte creates a one-byte string value

func Bytes 

func Bytes(b []byte) Value

Bytes creates a string value from bytes

func Float 

func Float(f float64) Value

Float creates a number value

func Func 

func Func(name string, f func(env *Env), doc ...string) Value

Func creates a function

func Func1 

func Func1(name string, f func(Value) Value, doc ...string) Value

func Func2 

func Func2(name string, f func(Value, Value) Value, doc ...string) Value

func Func3 

func Func3(name string, f func(Value, Value, Value) Value, doc ...string) Value

func Int 

func Int(i int64) Value

Int creates a number value

func Map 

func Map(kvs ...Value) Value

Map creates a map from `kvs`, which should be laid out as: key1, value1, key2, value2, ...

func MustRun 

func MustRun(p *Program, err error) Value

func Run 

func Run(p *Program, err error) (Value, error)

func Rune 

func Rune(r rune) Value

Rune creates a one-rune string value encoded in UTF-8

func Str 

func Str(s string) Value

Str creates a string value

func TableMerge 

func TableMerge(dst Value, src Value, kvs ...Value) Value

TableMerge merges key-value pairs from `src` and `kvs` into `dst`

func TableProto 

func TableProto(p *Table, kvs ...Value) Value

TableProto creates a table whose parent will be set to `p`

func Val 

func Val(i interface{}) Value

Val creates a `Value` from golang `interface{}` `slice`, `array` and `map` will be left as is (except []Value), to convert them recursively, use ValRec instead

func ValRec 

func ValRec(v interface{}) Value

func (Value) Bool 

func (v Value) Bool() bool

Bool returns value as a boolean without checking Type()

func (Value) Equal 

func (v Value) Equal(r Value) bool

Equal tests whether two values are equal

func (Value) Float 

func (v Value) Float() float64

Float returns value as a float without checking Type()

func (Value) Func 

func (v Value) Func() *Function

Func returns value as a function without checking Type()

func (Value) HashCode 

func (v Value) HashCode() uint64

func (Value) Int 

func (v Value) Int() int64

Int returns value as an int without checking Type()

func (Value) Interface 

func (v Value) Interface() interface{}

Interface returns value as an interface{}

func (Value) IsFalse 

func (v Value) IsFalse() bool

IsFalse tests whether value is falsy: nil, false, empty string or 0

func (Value) IsInt 

func (v Value) IsInt() bool

IsInt tests whether value is an integer number

func (Value) IsValue 

func (v Value) IsValue(parser.Node)

Reverse-reference in 'parser' package

func (Value) JSONString 

func (v Value) JSONString() string

func (Value) MarshalJSON 

func (v Value) MarshalJSON() ([]byte, error)

func (Value) MaybeFloat 

func (v Value) MaybeFloat(d float64) float64

func (Value) MaybeInt 

func (v Value) MaybeInt(d int64) int64

func (Value) MaybeStr 

func (v Value) MaybeStr(d string) string

func (Value) MaybeTableGetString 

func (v Value) MaybeTableGetString(key string) Value

func (Value) MustBool 

func (v Value) MustBool(msg string) bool

func (Value) MustFloat 

func (v Value) MustFloat(msg string) float64

func (Value) MustFunc 

func (v Value) MustFunc(msg string) *Function

func (Value) MustInt 

func (v Value) MustInt(msg string) int64

func (Value) MustNum 

func (v Value) MustNum(msg string) Value

func (Value) MustStr 

func (v Value) MustStr(msg string) string

func (Value) MustTable 

func (v Value) MustTable(msg string) *Table

func (Value) ReflectValue 

func (v Value) ReflectValue(t reflect.Type) reflect.Value

ReflectValue returns value as a reflect.Value based on reflect.Type

func (Value) Str 

func (v Value) Str() string

Str returns value as a string without checking Type()

func (Value) StrLen 

func (v Value) StrLen() int

StrLen returns the length of string without checking Type()

func (Value) String 

func (v Value) String() string

func (Value) Table 

func (v Value) Table() *Table

Table returns value as a table without checking Type()

func (Value) Type 

func (v Value) Type() typ.ValueType

Type returns the type of value

type ValueIO 

type ValueIO Value

func (ValueIO) Close 

func (m ValueIO) Close() error

func (ValueIO) Read 

func (m ValueIO) Read(p []byte) (int, error)

func (ValueIO) Write 

func (m ValueIO) Write(p []byte) (int, error)

Source Files

View all Source files

Directories

Path Synopsis
cmd
script
Modified upon: yuin/gopher-lua
 Modified upon: yuin/gopher-lua
tests
bench

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