Added basic escape sequences to string parser

lexer/lexer_test.go

@@ -36,7 +36,7 @@ func TestTokenizeAll (test *testing.T) {
 		Token { kind: TokenKindInt, value: int64(-349820394) },
 		Token { kind: TokenKindUInt, value: uint64(932748397) },
 		Token { kind: TokenKindFloat, value: 239485.37520 },
-		Token { kind: TokenKindString, value: "hello world\n" },
+		Token { kind: TokenKindString, value: "hello world!\n" },
 		Token { kind: TokenKindRune, value: 'E' },
 		Token { kind: TokenKindName, value: "helloWorld" },
 		Token { kind: TokenKindColon },

lexer/text.go

@@ -2,6 +2,19 @@ package lexer
 
 import "github.com/sashakoshka/arf/file"
 
+var escapeSequenceMap = map[rune] rune {
+        'a':  '\x07',
+        'b':  '\x08',
+        'f':  '\x0c',
+        'n':  '\x0a',
+        'r':  '\x0d',
+        't':  '\x09',
+        'v':  '\x0b',
+        '\'': '\'',
+        '"':  '"',
+        '\\': '\\',
+}
+
 func (lexer *LexingOperation) tokenizeString (isRuneLiteral bool) (err error) {
 	err = lexer.nextRune()
 	if err != nil { return }
@@ -9,7 +22,24 @@ func (lexer *LexingOperation) tokenizeString (isRuneLiteral bool) (err error) {
 	got := ""
 
 	for {
+		// TODO: add hexadecimal escape codes
+		if lexer.char == '\\' {
+			err = lexer.nextRune()
+			if err != nil { return }
+	
+			actual, exists := escapeSequenceMap[lexer.char]
+			if exists {
+				got += string(actual)
+			} else {
+				err = file.NewError (
+					lexer.file.Location(), 1,
+					"unknown escape character " +
+					string(lexer.char), file.ErrorKindError)
+				return
+			}
+		} else {
 			got += string(lexer.char)
+		}
 		
 		err = lexer.nextRune()
 		if err != nil { return }