Add initial String implementation

types/blob.go

@@ -4,7 +4,7 @@ import "io"
 
 type Blob interface {
 	Value
-	Len() uint64
+	ByteLen() uint64
 	Read() io.Reader
 }
 

types/flat_blob.go

@@ -16,7 +16,7 @@ func (fb flatBlob) Read() io.Reader {
 	return bytes.NewBuffer(fb.data)
 }
 
-func (fb flatBlob) Len() uint64 {
+func (fb flatBlob) ByteLen() uint64 {
 	return uint64(len(fb.data))
 }
 

types/flat_blob_test.go

@@ -21,12 +21,12 @@ func TestNewBlobIsFlatBlob(t *testing.T) {
 	assert.IsType(t, flatBlob{}, b)
 }
 
-func TestFlatBlobLen(t *testing.T) {
+func TestFlatBlobByteLen(t *testing.T) {
 	assert := assert.New(t)
 	b := NewBlob([]byte{})
-	assert.Equal(uint64(0), b.Len())
+	assert.Equal(uint64(0), b.ByteLen())
 	b = NewBlob([]byte{0x01})
-	assert.Equal(uint64(1), b.Len())
+	assert.Equal(uint64(1), b.ByteLen())
 }
 
 func TestFlatBlobEquals(t *testing.T) {

types/flat_string.go

@@ -0,0 +1,9 @@
+package types
+
+type flatString struct {
+	flatBlob
+}
+
+func (fs flatString) String() string {
+	return string(fs.data)
+}

types/flat_string_test.go

@@ -0,0 +1,43 @@
+package types
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestNewStringIsFlatString(t *testing.T) {
+	assert := assert.New(t)
+	s := NewString("foo")
+	assert.IsType(s, flatString{})
+}
+
+func TestFlatStringLen(t *testing.T) {
+	assert := assert.New(t)
+	s1 := NewString("foo")
+	s2 := NewString("⌘")
+	assert.Equal(uint64(3), uint64(s1.ByteLen()))
+	assert.Equal(uint64(3), uint64(s2.ByteLen()))
+}
+
+func TestFlatStringEquals(t *testing.T) {
+	assert := assert.New(t)
+	s1 := NewString("foo")
+	s2 := NewString("foo")
+	s3 := s2
+	s4 := NewString("bar")
+	assert.True(s1.Equals(s2))
+	assert.True(s2.Equals(s1))
+	assert.True(s1.Equals(s3))
+	assert.True(s3.Equals(s1))
+	assert.False(s1.Equals(s4))
+	assert.False(s4.Equals(s1))
+}
+
+func TestFlatStringString(t *testing.T) {
+	assert := assert.New(t)
+	s1 := NewString("")
+	s2 := NewString("foo")
+	assert.Equal("", s1.String())
+	assert.Equal("foo", s2.String())
+}

types/string.go

@@ -0,0 +1,16 @@
+package types
+
+type String interface {
+	Blob
+
+	// Slurps the entire string into memory. You obviously don't want to do this if the string might be large.
+	String() string
+}
+
+func NewString(s string) String {
+	return flatString{flatBlob{[]byte(s)}}
+}
+
+func StringFromBytes(b []byte) String {
+	return flatString{flatBlob{b}}
+}