Golang Context.Config方法代码示例

// Run runs the parser/evaluator until EOF or error.
// The return value says whether we completed without error. If the return
// value is true, it means we ran out of data (EOF) and the run was successful.
// Typical execution is therefore to loop calling Run until it succeeds.
// Error details are reported to the configured error output stream.
func Run(p *parse.Parser, context value.Context, interactive bool) (success bool) {
	conf := context.Config()
	writer := conf.Output()
	defer func() {
		if conf.Debug("panic") {
			return
		}
		err := recover()
		if err == nil {
			return
		}
		p.FlushToNewline()
		if err, ok := err.(value.Error); ok {
			fmt.Fprintf(conf.ErrOutput(), "%s%s\n", p.Loc(), err)
			if interactive {
				fmt.Fprintln(writer)
			}
			success = false
			return
		}
		panic(err)
	}()
	for {
		if interactive {
			fmt.Fprint(writer, conf.Prompt())
		}
		exprs, ok := p.Line()
		var values []value.Value
		if exprs != nil {
			if interactive {
				start := time.Now()
				values = context.Eval(exprs)
				conf.SetCPUTime(time.Now().Sub(start))
			} else {
				values = context.Eval(exprs)
			}
		}
		if printValues(conf, writer, values) {
			context.Assign("_", values[len(values)-1])
		}
		if !ok {
			return true
		}
		if interactive {
			if exprs != nil && conf.Debug("cpu") && conf.CPUTime() != 0 {
				fmt.Printf("(%s)\n", conf.PrintCPUTime())
			}
			fmt.Fprintln(writer)
		}
	}
}

// runFromFile executes the contents of the named file.
func (p *Parser) runFromFile(context value.Context, name string) {
	runDepth++
	if runDepth > 10 {
		p.errorf("get %q nested too deep", name)
	}
	defer func() {
		runDepth--
		err := recover()
		if err == nil {
			return
		}
		if err, ok := err.(value.Error); ok {
			fmt.Fprintf(p.context.Config().ErrOutput(), "%s%s\n", p.Loc(), err)
			return
		}
		panic(err)
	}()
	fd, err := os.Open(name)
	if err != nil {
		p.errorf("%s", err)
	}
	scanner := scan.New(context, name, bufio.NewReader(fd))
	parser := NewParser(name, scanner, p.context)
	out := p.context.Config().Output()
	for {
		exprs, ok := parser.Line()
		for _, expr := range exprs {
			val := expr.Eval(p.context)
			if val == nil {
				continue
			}
			if _, ok := val.(Assignment); ok {
				continue
			}
			fmt.Fprintf(out, "%v\n", val.Sprint(context.Config()))
		}
		if !ok {
			return
		}
	}
}

// eval runs until EOF or error. It prints every value but the last, and returns the last.
// By last we mean the last expression of the last evaluation.
// (Expressions are separated by ; in the input.)
// It is always called from (somewhere below) run, so if it errors out the recover in
// run will catch it.
func eval(p *parse.Parser, context value.Context) value.Value {
	conf := context.Config()
	writer := conf.Output()
	var prevValues []value.Value
	for {
		exprs, ok := p.Line()
		var values []value.Value
		if exprs != nil {
			values = context.Eval(exprs)
		}
		if !ok {
			if len(prevValues) == 0 {
				return nil
			}
			printValues(conf, writer, prevValues[:len(prevValues)-1])
			return prevValues[len(prevValues)-1]
		}
		printValues(conf, writer, prevValues)
		prevValues = values
	}
}