Create a JqRepl struct to encapsualte state

This is the main guts of our repl and provides us a place to start
adding methods and features.

jqrepl.go

@@ -0,0 +1,114 @@
+package jqrepl
+
+import (
+	"fmt"
+	"io"
+
+	"github.com/ashb/jqrepl/jq"
+	"gopkg.in/chzyer/readline.v1"
+)
+
+type JqRepl struct {
+	programCounter int
+	promptTemplate string
+	reader         *readline.Instance
+	libJq          *jq.Jq
+	input          *jq.Jv
+}
+
+func New() (*JqRepl, error) {
+	repl := JqRepl{
+		promptTemplate: "\033[0;36m%3d »\033[0m",
+	}
+	var err error
+	repl.reader, err = readline.New(repl.currentPrompt())
+	if err != nil {
+		return nil, err
+	}
+
+	repl.libJq, err = jq.New()
+	if err != nil {
+		repl.reader.Close()
+		return nil, err
+	}
+
+	return &repl, nil
+}
+
+func (repl *JqRepl) Close() {
+	repl.reader.Close()
+	repl.libJq.Close()
+	if repl.input != nil {
+		repl.input.Free()
+	}
+}
+
+func (repl *JqRepl) currentPrompt() string {
+	return fmt.Sprintf(repl.promptTemplate, repl.programCounter)
+}
+
+// JvInput returns the current input the JQ program will operate on
+func (repl *JqRepl) JvInput() *jq.Jv {
+	return repl.input
+}
+
+func (repl *JqRepl) SetJvInput(input *jq.Jv) {
+	if repl.input != nil {
+		repl.input.Free()
+	}
+	repl.input = input
+}
+
+func (repl *JqRepl) Loop() {
+	for {
+		repl.reader.SetPrompt(repl.currentPrompt())
+
+		line, err := repl.reader.Readline()
+		if err == io.EOF {
+			break
+		} else if err == readline.ErrInterrupt {
+			// Stop the streaming of any results - if we were
+			continue
+		} else if err != nil {
+			panic(fmt.Errorf("%#v", err))
+		}
+
+		repl.programCounter++
+		repl.RunProgram(line)
+	}
+}
+
+func (repl *JqRepl) Error(err error) {
+	fmt.Fprintf(repl.reader.Stderr(), "\033[0;31m%s\033[0m\n", err)
+}
+
+func (repl *JqRepl) Output(o *jq.Jv) {
+	fmt.Fprintln(repl.reader.Stdout(), o.Dump(jq.JvPrintPretty|jq.JvPrintSpace1|jq.JvPrintColour))
+}
+
+func (repl *JqRepl) RunProgram(program string) {
+	chanIn, chanOut, chanErr := repl.libJq.Start(program)
+	inCopy := repl.JvInput().Copy()
+
+	// Run until the channels are closed
+	for chanErr != nil && chanOut != nil {
+		select {
+		case e, ok := <-chanErr:
+			if !ok {
+				chanErr = nil
+			} else {
+				repl.Error(e)
+			}
+		case o, ok := <-chanOut:
+			if !ok {
+				chanOut = nil
+			} else {
+				repl.Output(o)
+			}
+		case chanIn <- inCopy:
+			// We've sent our input, close the channel to tell Jq we're done
+			close(chanIn)
+			chanIn = nil
+		}
+	}
+}

main.go

@@ -3,82 +3,35 @@
 package main
 
 import (
-	"fmt"
-	"io"
-
+	"github.com/ashb/jqrepl"
 	"github.com/ashb/jqrepl/jq"
-
-	"gopkg.in/chzyer/readline.v1"
 )
 
 func main() {
-	prompt := "\033[0;36m»\033[0m "
-	l, err := readline.New(prompt)
+	repl, err := jqrepl.New()
 
 	if err != nil {
 		// TODO: don't use panic
 		panic(err)
 	}
 
-	libjq, err := jq.New()
-	if err != nil {
-		// TODO: don't use panic
-		panic(err)
-	}
-	defer libjq.Close()
+	defer repl.Close()
 
 	input, err := jq.JvFromJSONString(`
 		{ "simple": 123,
 			"nested": {
 				"a": [1,2,"a"],
 				"b": true,
 				"c": null
-			}
+			},
+			"non_printable": "\ud83c\uddec\ud83c\udde7"
 		}`)
 	if err != nil {
 		// TODO: don't use panic
 		panic(err)
 	}
 
-	defer input.Free()
-
-	for {
-		line, err := l.Readline()
-		if err == io.EOF {
-			break
-		} else if err == readline.ErrInterrupt {
-			// Stop the streaming.
-			continue
-		} else if err != nil {
-			panic(fmt.Errorf("%#v", err))
-		}
-
-		chanIn, chanOut, chanErr := libjq.Start(line)
-		inCopy := input.Copy()
-
-		// Run until the channels are closed
-		for chanErr != nil && chanOut != nil {
-			select {
-			case e, ok := <-chanErr:
-				if !ok {
-					chanErr = nil
-				} else {
-					fmt.Printf("\033[0;31m%s\033[0m\n", e)
-				}
-			case o, ok := <-chanOut:
-				if !ok {
-					chanOut = nil
-				} else {
-					fmt.Printf("// Read from output %v %#v\n", o.Kind(), ok)
-					fmt.Println(o.ToGoVal())
-				}
-			case chanIn <- inCopy:
-				// We've sent our input, close the channel to tell Jq we're done
-				close(chanIn)
-				chanIn = nil
-			}
-		}
-	}
+	repl.SetJvInput(input)
 
-	libjq.Close()
+	repl.Loop()
 }