Added comments (#1)

Comments start with a `#` and continue until a new line or the end of the program is reached. The comment may be on its own line or at the end of a sentence.

Author: elliotchance

.gitignore

@@ -1,2 +1,3 @@
 /.idea
 /bento
+/gh-md-toc

README.md

@@ -1,5 +1,12 @@
 # 🍱 bento
 
+   * [Example Use Case](#example-use-case)
+   * [Language](#language)
+      * [Sentences](#sentences)
+      * [Comments](#comments)
+   * [Examples](#examples)
+      * [Hello, World!](#hello-world)
+
 bento is a
 [forth-generation programming language](https://en.wikipedia.org/wiki/Fourth-generation_programming_language)
 that is English-based. It is designed to separate orchestration from
@@ -77,6 +84,28 @@ Did you mean this instead?
 Hopefully, they will be able to adjust the script accordingly and resolve it
 immediately. Hooray!
 
+# Language
+
+## Sentences
+
+A sentence contains a collection of words and values and it is terminated by a
+new line. For example:
+
+```
+display "Hello"
+```
+
+## Comments
+
+Comments start with a `#` and continue until a new line or the end of the
+program is reached. The comment may be on its own line or at the end of a
+sentence.
+
+```
+# A comment looks like this.
+display "Hello" # It can also be here
+```
+
 # Examples
 
 ## Hello, World!

examples/hello-world.bento

@@ -1 +1,3 @@
+# Comments start with a hash.
+
 display "Hello, World!"

token.go

@@ -28,6 +28,14 @@ func Tokenize(r io.Reader) (tokens []Token, err error) {
 
 	for i := 0; i < len(entire); i++ {
 		switch entire[i] {
+		case '#':
+			tokens = appendEndline(tokens)
+			for ; i < len(entire); i++ {
+				if entire[i] == '\n' {
+					break
+				}
+			}
+
 		case '\n':
 			tokens = appendWord(tokens, &word)
 			tokens = appendEndline(tokens)

token_test.go

@@ -13,7 +13,7 @@ func TestTokenize(t *testing.T) {
 		expected []Token
 	}{
 		"Empty": {
-			bento: "",
+			bento:    "",
 			expected: nil,
 		},
 		"Word": {
@@ -99,7 +99,27 @@ func TestTokenize(t *testing.T) {
 				{TokenKindEndline, ""},
 			},
 		},
-	}{
+		"Comment1": {
+			bento:    "# comment",
+			expected: nil,
+		},
+		"Comment2": {
+			bento: "# comment\ndisplay",
+			expected: []Token{
+				{TokenKindWord, "display"},
+				{TokenKindEndline, ""},
+			},
+		},
+		"Comment3": {
+			bento: "display #comment\ndisplay",
+			expected: []Token{
+				{TokenKindWord, "display"},
+				{TokenKindEndline, ""},
+				{TokenKindWord, "display"},
+				{TokenKindEndline, ""},
+			},
+		},
+	} {
 		t.Run(testName, func(t *testing.T) {
 			actual, err := Tokenize(strings.NewReader(test.bento))
 			require.NoError(t, err)