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interpret2.go
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interpret2.go
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package interpreter
import (
"errors"
"fmt"
"reflect"
"strconv"
"strings"
"github.com/qiniu/text/tpl"
"github.com/qiniu/text/tpl/interpreter"
"github.com/xushiwei/qlang/exec"
)
var (
ErrNotObject = errors.New("not object")
)
// -----------------------------------------------------------------------------
type Options struct {
Scanner tpl.Tokener
ScanMode tpl.ScanMode
}
type Engine struct {
*tpl.CompileRet
Interpreter *exec.Object
mute int
}
var (
optionsDef Options
typeFunc = reflect.TypeOf((*exec.Function)(nil))
)
var (
InsertSemis = &Options{ScanMode: tpl.InsertSemis}
)
func lastWord(s string) string {
idx := strings.LastIndexFunc(s, func(c rune) bool {
return c >= 'A' && c <= 'Z'
})
if idx >= 0 {
return s[idx:]
}
return ""
}
func call(estk *exec.Stack, ip *exec.Object, name string) interface{} {
if fn, ok := ip.Cls.Fns[name]; ok {
return fn.Call(estk, ip)
}
panic("method not found: " + name)
}
func callN(estk *exec.Stack, ip *exec.Object, name string, args ...interface{}) interface{} {
if fn, ok := ip.Cls.Fns[name]; ok {
args1 := make([]interface{}, 1, len(args)+1)
args1[0] = ip
return fn.Call(estk, append(args1, args...)...)
}
panic("method not found: " + name)
}
func callFn(estk *exec.Stack, stk *exec.Object, fn interface{}, arity int) {
var in []reflect.Value
if arity > 0 {
ret := reflect.ValueOf(callN(estk, stk, "popArgs", arity))
if ret.Kind() != reflect.Slice {
panic("method stack.popArgs doesn't return a slice")
}
n := ret.Len()
in = make([]reflect.Value, n)
for i := 0; i < n; i++ {
in[i] = ret.Index(i)
}
}
vfn := reflect.ValueOf(fn)
out := vfn.Call(in)
if len(out) == 0 {
callN(estk, stk, "push", nil)
} else {
callN(estk, stk, "push", out[0].Interface())
}
}
func callVfn(estk *exec.Stack, stk *exec.Object, fn *exec.Function, arity int) {
v := callN(estk, stk, "popArgs", arity)
if args, ok := v.([]interface{}); ok {
callN(estk, stk, "push", fn.Call(estk, args...))
return
}
ret := reflect.ValueOf(v)
if ret.Kind() != reflect.Slice {
panic("method stack.popArgs doesn't return a slice")
}
n := ret.Len()
in := make([]interface{}, n)
for i := 0; i < n; i++ {
in[i] = ret.Index(i).Interface()
}
callN(estk, stk, "push", fn.Call(estk, in...))
}
func New(ip interface{}, options *Options) (p *Engine, err error) {
defer func() {
if e := recover(); e != nil {
switch v := e.(type) {
case string:
err = errors.New(v)
case error:
err = v
default:
panic(e)
}
}
}()
estk := exec.NewStack()
p = newEngine(estk, ip, options)
return
}
func (p *Engine) Exec(code []byte, fname string) (err error) {
defer func() {
if e := recover(); e != nil {
switch v := e.(type) {
case string:
err = errors.New(v)
case error:
err = v
default:
panic(e)
}
}
}()
err = p.MatchExactly(code, fname)
return
}
func (p *Engine) Eval(expr string) (err error) {
return p.Exec([]byte(expr), "")
}
func newEngine(estk *exec.Stack, ip1 interface{}, options *Options) (p *Engine) {
if options == nil {
options = &optionsDef
}
ip, ok := ip1.(*exec.Object)
if !ok {
panic(ErrNotObject)
}
p = new(Engine)
vstk := call(estk, ip, "stack")
stk, ok := vstk.(*exec.Object)
if !ok {
panic("stack isn't an object")
}
vfntable := call(estk, ip, "fntable")
fntable, ok := vfntable.(map[string]interface{})
if !ok {
panic("fntable isn't a map[string]interface{} object")
}
compiler := new(tpl.Compiler)
initer := func() {
p.mute = 0 // bugfix: 语法匹配过程有可能有异常,需要通过 init 完成 mute 状态的重置
}
marker := func(g tpl.Grammar, mark string) tpl.Grammar {
fn, ok := fntable["$"+mark]
if !ok {
switch mark {
case "_mute":
return tpl.Action(g, func(tokens []tpl.Token, g tpl.Grammar) {
p.mute++
})
case "_unmute":
return tpl.Action(g, func(tokens []tpl.Token, g tpl.Grammar) {
p.mute--
})
case "_tr":
return tpl.Action(g, func(tokens []tpl.Token, g tpl.Grammar) {
println(string(tpl.Source(tokens, compiler.Scanner)))
})
default:
panic("invalid grammar mark: " + mark)
}
}
tfn := reflect.TypeOf(fn)
if tfn != typeFunc {
if tfn.Kind() != reflect.Func {
panic("function table item not a function: " + mark)
}
if tfn.IsVariadic() {
panic("invalid mark - doesn't support variadic function: " + mark)
}
n := tfn.NumIn()
if n < 1 {
panic("invalid function (no param): " + mark)
}
action := func(tokens []tpl.Token, g tpl.Grammar) {
if p.mute > 0 { // 禁止所有非 '_' 开头的 action
if mark[0] != '_' || p.mute > 1 {
return
}
}
callFn(estk, stk, fn, n)
}
return tpl.Action(g, action)
}
vfn := fn.(*exec.Function)
if vfn.Variadic {
panic("invalid mark - doesn't support variadic function: " + mark)
}
n := len(vfn.Args)
if n < 1 {
panic("invalid function (no param): " + mark)
}
kindRecvr := 0
if vfn.Cls == stk.Cls {
kindRecvr = 1
} else if vfn.Cls == ip.Cls {
kindRecvr = 2
}
if kindRecvr > 0 && n > 2 {
panic("invalid function (too many params): " + mark)
}
idxLen := 0
if mark[0] == '_' {
idxLen++
}
isLen := (mark[idxLen] >= 'A' && mark[idxLen] <= 'Z') // 用大写的mark表示取Grammar.Len()
action := func(tokens []tpl.Token, g tpl.Grammar) {
if p.mute > 0 { // 禁止所有非 '_' 开头的 action
if mark[0] != '_' || p.mute > 1 {
return
}
}
if kindRecvr > 0 {
args := make([]interface{}, n)
if kindRecvr == 1 {
args[0] = stk
} else {
args[0] = p.Interpreter
}
if n == 2 {
if isLen {
args[1] = g.Len()
} else {
switch lastWord(mark) {
case "Src":
if len(tokens) != 0 {
args[1] = tokens
}
case "Engine":
args[1] = p
case "Float":
v, err := strconv.ParseFloat(tokens[0].Literal, 64)
if err != nil {
panic(fmt.Sprintf("parse mark `%s` failed: %v", mark, err))
}
args[1] = v
case "Int":
v, err := strconv.Atoi(tokens[0].Literal)
if err != nil {
panic(fmt.Sprintf("parse mark `%s` failed: %v", mark, err))
}
args[1] = v
default:
args[1] = tokens[0].Literal
}
}
}
vfn.Call(estk, args...)
} else {
callVfn(estk, stk, vfn, n)
}
}
return tpl.Action(g, action)
}
vgrammar := call(estk, ip, "grammar")
grammar, ok := vgrammar.(string)
if !ok {
panic("grammar isn't a string object")
}
compiler.Grammar = []byte(grammar)
compiler.Scanner = options.Scanner
compiler.ScanMode = options.ScanMode
compiler.Marker = marker
compiler.Init = initer
ret, err := compiler.Cl()
if err != nil {
panic(err)
}
p.CompileRet = &ret
p.Interpreter = ip
return
}
func (p *Engine) EvalCode(fn *exec.Object, name string, src interface{}) error {
old := p.Interpreter
mute := p.mute
p.Interpreter = fn
defer func() { // 正常的 return 使用了 panic,所以需要保护
p.Interpreter = old
p.mute = mute
}()
return p.EvalSub(name, src)
}
func ClassOf(v interface{}) interface{} {
if o, ok := v.(*exec.Object); ok {
return o.Cls
}
return nil
}
func NewRuntimeError(msg string) error {
return &interpreter.RuntimeError{Err: errors.New(msg)}
}
// -----------------------------------------------------------------------------
var Exports = map[string]interface{}{
"classof": ClassOf,
"newRuntimeError": NewRuntimeError,
"interpreter": New,
"insertSemis": InsertSemis,
}
// -----------------------------------------------------------------------------