From f914c52768c1ae16df8f466409c0f9a1a21d518d Mon Sep 17 00:00:00 2001
From: Kraemerd <Dominic_Daniel.Kraemer@Student.Reutlingen-University.de>
Date: Fri, 6 Jan 2023 06:01:55 +0100
Subject: [PATCH] improved lexter (variables can't be multiple characters)
---
src/Application.java | 2 +-
src/Lexer.java | 15 ++++++++-------
2 files changed, 9 insertions(+), 8 deletions(-)
diff --git a/src/Application.java b/src/Application.java
index 8f0b93c..b8e4e45 100644
--- a/src/Application.java
+++ b/src/Application.java
@@ -3,7 +3,7 @@ import java.util.List;
public class Application {
public static void main(String[] args) {
- List<String> test = Arrays.asList("1 + x^2 - (31 * x)");
+ List<String> test = Arrays.asList("1 + xy^2 - (31 * x)y");
for (String value: test) {
List<Lexer.Token> tokens = Lexer.lex(value);
for(Lexer.Token singleToken: tokens) {
diff --git a/src/Lexer.java b/src/Lexer.java
index 5cc07dd..250e863 100644
--- a/src/Lexer.java
+++ b/src/Lexer.java
@@ -48,15 +48,16 @@ public class Lexer {
index++;
}
else if(Character.isLetter(current)){
- int endIndex = index+1;
- if(endIndex<input.length()) {
- while(Character.isLetter(input.charAt(endIndex)) && endIndex<input.length()) {
- endIndex += 1;
+ int iterator = index;
+ while(Character.isLetter(input.charAt(iterator)) && iterator<input.length()) {
+ Token token = new Token(TokenType.VARIABLE, String.valueOf(input.charAt(iterator)));
+ result.add(token);
+ iterator += 1;
+ if(!(iterator<input.length())) {
+ break;
}
}
- Token token = new Token(TokenType.VARIABLE, input.substring(index,endIndex));
- result.add(token);
- index += endIndex - index;
+ index += iterator - index;
}
else {
Token token = new Token(TokenType.SPECIAL, String.valueOf(current));
--
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