Add support for single quotes and escape double quotes (#96)

* Add support for single quotes and escape double quotes

Signed-off-by: Flipez <code@brauser.io>

* add single quote test

Signed-off-by: Flipez <code@brauser.io>

* please the linter

Signed-off-by: Flipez <code@brauser.io>

* update tests and docs

Signed-off-by: Flipez <code@brauser.io>

docs/content/docs/literals/string.md

@@ -39,6 +39,13 @@ puts(s)
 "ef"
 "bcd"
 "abCdEf"
+
+// you can also use single quotes
+'test "string" with doublequotes'
+
+// and you can scape a double quote in a double quote string
+"te\"st" == 'te"st'
+
 ```
 
 ## Literal Specific Methods

docs/generate.go

@@ -57,7 +57,14 @@ puts(s)
 "cdef"
 "ef"
 "bcd"
-"abCdEf"`,
+"abCdEf"
+
+// you can also use single quotes
+'test "string" with doublequotes'
+
+// and you can scape a double quote in a double quote string
+"te\"st" == 'te"st'
+`,
 		LiteralMethods: string_methods,
 		DefaultMethods: default_methods}
 	create_doc("docs/templates/literal.md", "docs/content/docs/literals/string.md", tempData)

lexer/lexer.go

@@ -139,7 +139,10 @@ func (l *Lexer) NextToken() token.Token {
 		tok.Type = token.EOF
 	case '"':
 		tok.Type = token.STRING
-		tok.Literal = l.readString()
+		tok.Literal = l.readDoubleQuoteString()
+	case '\'':
+		tok.Type = token.STRING
+		tok.Literal = l.readSingleQuoteString()
 	default:
 		if isLetter(l.ch) {
 			tok.Literal = l.readIdentifier()
@@ -177,11 +180,29 @@ func (l *Lexer) NextToken() token.Token {
 	return tok
 }
 
-func (l *Lexer) readString() string {
+func (l *Lexer) readDoubleQuoteString() string {
+	var escapedString string
+
+	for {
+		l.readChar()
+
+		if l.ch == '\\' && l.peekChar() == '"' {
+			l.readChar()
+		} else if l.ch == '"' || l.ch == 0 {
+			break
+		}
+
+		escapedString += string(l.ch)
+	}
+
+	return escapedString
+}
+
+func (l *Lexer) readSingleQuoteString() string {
 	position := l.position + 1
 	for {
 		l.readChar()
-		if l.ch == '"' || l.ch == 0 {
+		if l.ch == '\'' || l.ch == 0 {
 			break
 		}
 	}

object/string.go

@@ -317,7 +317,20 @@ func init() {
 }
 
 func (s *String) Type() ObjectType { return STRING_OBJ }
-func (s *String) Inspect() string  { return `"` + s.Value + `"` }
+func (s *String) Inspect() string {
+	var output string
+
+	for _, char := range s.Value {
+		if char == '"' {
+			output += string('\\')
+		}
+
+		output += string(char)
+	}
+
+	return `"` + output + `"`
+}
+
 func (s *String) InvokeMethod(method string, env Environment, args ...Object) Object {
 	return objectMethodLookup(s, method, env, args)
 }

object/string_test.go

@@ -88,6 +88,10 @@ func TestStringObjectMethods(t *testing.T) {
 		{`2 * "test"`, "testtest"},
 		{`"test".to_json()`, `"test"`},
 		{`{"test": HTTP.new()}.to_json()`, `Error while marshal value: json: error calling MarshalJSON for type *object.Hash: unable to serialize value: "test"`},
+		{`"te\nst".size()`, 6},
+		{`"te\"st".size()`, 5},
+		{`'te\"st'.size()`, 6},
+		{`"te\"st" == 'te"st'`, true},
 	}
 
 	testInput(t, tests)