Updated Map accessors (#93)

#### Summary
fixes #89 
Maps can now be accessed both as `a.b` or `a[b]`

#### Checklist
- [x] Tests are passing: `task test`
- [x] Code style is correct: `task lint`

accessors.go

@@ -16,11 +16,18 @@ const (
 	// arrayAccesRegexString is the regex used to extract the array number
 	// from the access path
 	arrayAccesRegexString = `^(.+)\[([0-9]+)\]$`
+
+	// mapAccessRegexString is the regex used to extract the map key
+	// from the access path
+	mapAccessRegexString = `^([^\[]*)\[([^\]]+)\](.*)$`
 )
 
 // arrayAccesRegex is the compiled arrayAccesRegexString
 var arrayAccesRegex = regexp.MustCompile(arrayAccesRegexString)
 
+// mapAccessRegex is the compiled mapAccessRegexString
+var mapAccessRegex = regexp.MustCompile(mapAccessRegexString)
+
 // Get gets the value using the specified selector and
 // returns it inside a new Obj object.
 //
@@ -70,13 +77,45 @@ func getIndex(s string) (int, string) {
 	return -1, s
 }
 
+// getKey returns the key which is held in s by two brackets.
+// It also returns the next selector.
+func getKey(s string) (string, string) {
+	selSegs := strings.SplitN(s, PathSeparator, 2)
+	thisSel := selSegs[0]
+	nextSel := ""
+
+	if len(selSegs) > 1 {
+		nextSel = selSegs[1]
+	}
+
+	mapMatches := mapAccessRegex.FindStringSubmatch(s)
+	if len(mapMatches) > 0 {
+		if _, err := strconv.Atoi(mapMatches[2]); err != nil {
+			thisSel = mapMatches[1]
+			nextSel = "[" + mapMatches[2] + "]" + mapMatches[3]
+
+			if thisSel == "" {
+				thisSel = mapMatches[2]
+				nextSel = mapMatches[3]
+			}
+
+			if nextSel == "" {
+				selSegs = []string{"", ""}
+			} else if nextSel[0] == '.' {
+				nextSel = nextSel[1:]
+			}
+		}
+	}
+
+	return thisSel, nextSel
+}
+
 // access accesses the object using the selector and performs the
 // appropriate action.
 func access(current interface{}, selector string, value interface{}, isSet bool) interface{} {
-	selSegs := strings.SplitN(selector, PathSeparator, 2)
-	thisSel := selSegs[0]
-	index := -1
+	thisSel, nextSel := getKey(selector)
 
+	index := -1
 	if strings.Contains(thisSel, "[") {
 		index, thisSel = getIndex(thisSel)
 	}
@@ -88,7 +127,7 @@ func access(current interface{}, selector string, value interface{}, isSet bool)
 	switch current.(type) {
 	case map[string]interface{}:
 		curMSI := current.(map[string]interface{})
-		if len(selSegs) <= 1 && isSet {
+		if nextSel == "" && isSet {
 			curMSI[thisSel] = value
 			return nil
 		}
@@ -112,8 +151,8 @@ func access(current interface{}, selector string, value interface{}, isSet bool)
 			}
 		}
 	}
-	if len(selSegs) > 1 {
-		current = access(current, selSegs[1], value, isSet)
+	if nextSel != "" {
+		current = access(current, nextSel, value, isSet)
 	}
 	return current
 }

accessors_test.go

@@ -43,6 +43,25 @@ func TestAccessorsAccessGetDeepDeep(t *testing.T) {
 	}
 
 	assert.Equal(t, 4, m.Get("one.two.three.four").Data())
+	assert.Equal(t, 4, m.Get("one[two][three][four]").Data())
+}
+
+func TestAccessorsGetWithComplexKey(t *testing.T) {
+	m := objx.Map{
+		"domains": objx.Map{
+			"example-dot-com": objx.Map{
+				"apex": "example",
+			},
+			"example.com": objx.Map{
+				"apex": "example",
+			},
+		},
+	}
+
+	assert.Equal(t, "example", m.Get("domains.example-dot-com.apex").Data())
+
+	assert.Equal(t, "example", m.Get("domains[example.com].apex").Data())
+	assert.Equal(t, "example", m.Get("domains[example.com][apex]").Data())
 }
 
 func TestAccessorsAccessGetInsideArray(t *testing.T) {