Implements helper to split command from arguments

Also tests the helper function (ofc...)

db/repl.go

@@ -118,29 +118,28 @@ func Repl(h *graph.Handle, queryLanguage string, cfg *config.Config) error {
 		}
 
 		if code == "" {
-			switch {
-			case strings.HasPrefix(line, ":debug"):
+			command, arguments := splitLine(line)
+
+			switch command {
+			case ":debug":
 				ses.ToggleDebug()
 				fmt.Println("Debug Toggled")
 				continue
 
-			case strings.HasPrefix(line, ":a "):
-				quad, err := cquads.Parse(line[3:])
-				if !quad.IsValid() {
-					if err != nil {
-						fmt.Printf("not a valid quad: %v\n", err)
-					}
+			case ":a":
+				quad, err := cquads.Parse(arguments)
+				if err != nil {
+					fmt.Printf("Error: not a valid quad: %v\n", err)
 					continue
 				}
+
 				h.QuadWriter.AddQuad(quad)
 				continue
 
-			case strings.HasPrefix(line, ":d "):
-				quad, err := cquads.Parse(line[3:])
-				if !quad.IsValid() {
-					if err != nil {
-						fmt.Printf("not a valid quad: %v\n", err)
-					}
+			case ":d":
+				quad, err := cquads.Parse(arguments)
+				if err != nil {
+					fmt.Printf("Error: not a valid quad: %v\n", err)
 					continue
 				}
 				h.QuadWriter.RemoveQuad(quad)
@@ -163,6 +162,26 @@ func Repl(h *graph.Handle, queryLanguage string, cfg *config.Config) error {
 	}
 }
 
+// Splits a line into a command and its arguments
+// e.g. ":a b c d ." will be split into ":a" and " b c d ."
+func splitLine(line string) (string, string) {
+	var command, arguments string
+
+	line = strings.TrimSpace(line)
+
+	// An empty line/a line consisting of whitespace contains neither command nor arguments
+	if len(line) > 0 {
+		command = strings.Fields(line)[0]
+
+		// A line containing only a command has no arguments
+		if len(line) > len(command) {
+			arguments = line[len(command):]
+		}
+	}
+
+	return command, arguments
+}
+
 func terminal(path string) (*liner.State, error) {
 	term := liner.NewLiner()
 

db/repl_test.go

@@ -0,0 +1,66 @@
+// Copyright 2014 The Cayley Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package db
+
+import (
+	"testing"
+)
+
+var testSplitLines = []struct {
+	line              string
+	expectedCommand   string
+	expectedArguments string
+	err               error
+}{
+	{
+		line:              ":a arg1 arg2 arg3 .",
+		expectedCommand:   ":a",
+		expectedArguments: " arg1 arg2 arg3 .",
+	},
+	{
+		line:            ":debug",
+		expectedCommand: ":debug",
+		// expectedArguments is nil
+	},
+	{
+		line: "",
+		// expectedCommand is nil
+		// expectedArguments is nil
+	},
+	{
+		line:              `:d <http://one.example/subject1> <http://one.example/predicate1> <http://one.example/object1> . # comments here`,
+		expectedCommand:   ":d",
+		expectedArguments: ` <http://one.example/subject1> <http://one.example/predicate1> <http://one.example/object1> . # comments here`,
+	},
+	{
+		line:              `  :a  subject  "predicate with spaces" object  . `,
+		expectedCommand:   ":a",
+		expectedArguments: `  subject  "predicate with spaces" object  .`,
+	},
+}
+
+func TestSplitLines(t *testing.T) {
+	for _, testcase := range testSplitLines {
+		command, arguments := splitLine(testcase.line)
+
+		if testcase.expectedCommand != command {
+			t.Errorf("Error splitting lines: got: %v expected: %v", command, testcase.expectedCommand)
+		}
+
+		if testcase.expectedArguments != arguments {
+			t.Errorf("Error splitting lines: got: %v expected: %v", arguments, testcase.expectedArguments)
+		}
+	}
+}