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lexer.dart
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lexer.dart
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import '../core/errors/lexer_exceptions.dart';
import 'position.dart';
import 'tokens.dart';
class Lexer {
String fileContent;
Cursor cursor = Cursor();
bool isEndOfFile = false;
late String currentCharacter;
Lexer(this.fileContent);
List<Token> tokenize() {
fileContent = fileContent.trim();
List<Token> tokens = [];
advanceCursor();
while (!isEndOfFile) {
skipWhitespaces();
switch (currentCharacter) {
case "[":
{
tokens.add(
consumeToken(TokenKind.openingSquareBracket, currentCharacter));
break;
}
case "]":
{
tokens.add(
consumeToken(TokenKind.closingSquareBracket, currentCharacter));
break;
}
case ":":
{
tokens.add(consumeToken(TokenKind.colon, currentCharacter));
break;
}
case "\"":
{
String issueName = "";
advanceCursor();
while (currentCharacter != "\"" && !isEndOfFile) {
issueName += currentCharacter;
advanceCursor();
}
advanceCursor();
tokens.add(Token(TokenKind.issueText, issueName));
break;
}
case "~":
{
tokens.add(consumeToken(TokenKind.tilde, currentCharacter));
break;
}
case ";":
{
tokens.add(consumeToken(TokenKind.semicolon, currentCharacter));
break;
}
case ",":
{
tokens.add(consumeToken(TokenKind.comma, currentCharacter));
break;
}
case "{":
{
tokens.add(
consumeToken(TokenKind.openingCurlyBrace, currentCharacter));
break;
}
case "}":
{
tokens.add(
consumeToken(TokenKind.closingCurlyBrace, currentCharacter));
break;
}
default:
throw UnknownToken(currentCharacter);
}
}
return tokens;
}
Token consumeToken(TokenKind kind, String lexeme) {
Token token = Token(kind, lexeme);
advanceCursor();
return token;
}
bool isDigit(String currentChar) {
return double.tryParse(currentChar) != null;
}
void skipWhitespaces() {
while (currentCharacter.trim().isEmpty) {
advanceCursor();
}
}
void advanceCursor() {
if (cursor.position < fileContent.length) {
currentCharacter = fileContent[cursor.position];
} else {
isEndOfFile = true;
}
if (currentCharacter == '\n') {
cursor.line++;
}
cursor.position++;
}
}