From 173e3dee3690df4a562cea4255b9721206caa9b9 Mon Sep 17 00:00:00 2001
From: Kraemerd <Dominic_Daniel.Kraemer@Student.Reutlingen-University.de>
Date: Mon, 9 Jan 2023 16:17:49 +0100
Subject: [PATCH] advanced the project structure & implemented the lexer test
class
---
expressions.txt | 2 +-
src/Exceptions/LexerException.java | 7 +++
src/{ => Exceptions}/ParserException.java | 2 +
src/{ => main}/ASTPrinter.java | 2 +
src/{ => main}/Application.java | 53 +++++++++++++-------
src/{ => main}/Evaluator.java | 3 ++
src/{ => main}/Lexer.java | 16 ++++--
src/{ => main}/Parser.java | 8 +++
src/{ => main}/SwingFunctionPlotter.java | 2 +
src/{ => main}/Visitor.java | 2 +
src/test/LexerTest.java | 59 +++++++++++++++++++++++
src/test/ParserTest.java | 4 ++
12 files changed, 138 insertions(+), 22 deletions(-)
create mode 100644 src/Exceptions/LexerException.java
rename src/{ => Exceptions}/ParserException.java (85%)
rename src/{ => main}/ASTPrinter.java (98%)
rename src/{ => main}/Application.java (51%)
rename src/{ => main}/Evaluator.java (97%)
rename src/{ => main}/Lexer.java (90%)
rename src/{ => main}/Parser.java (98%)
rename src/{ => main}/SwingFunctionPlotter.java (98%)
rename src/{ => main}/Visitor.java (94%)
create mode 100644 src/test/LexerTest.java
create mode 100644 src/test/ParserTest.java
diff --git a/expressions.txt b/expressions.txt
index 956089d..74f9b71 100644
--- a/expressions.txt
+++ b/expressions.txt
@@ -1,2 +1,2 @@
1+(x^2)-(3*x)
-2*x+0.5*(x^2)-1
\ No newline at end of file
+2*x+0.5*(x^2+4)-1
\ No newline at end of file
diff --git a/src/Exceptions/LexerException.java b/src/Exceptions/LexerException.java
new file mode 100644
index 0000000..28ac422
--- /dev/null
+++ b/src/Exceptions/LexerException.java
@@ -0,0 +1,7 @@
+package Exceptions;
+
+public class LexerException extends Exception {
+ public LexerException(String message) {
+ super(message);
+ }
+}
diff --git a/src/ParserException.java b/src/Exceptions/ParserException.java
similarity index 85%
rename from src/ParserException.java
rename to src/Exceptions/ParserException.java
index ef36000..d3e5195 100644
--- a/src/ParserException.java
+++ b/src/Exceptions/ParserException.java
@@ -1,3 +1,5 @@
+package Exceptions;
+
public class ParserException extends Exception{
public ParserException(String message) {
super(message);
diff --git a/src/ASTPrinter.java b/src/main/ASTPrinter.java
similarity index 98%
rename from src/ASTPrinter.java
rename to src/main/ASTPrinter.java
index 8983653..10669f2 100644
--- a/src/ASTPrinter.java
+++ b/src/main/ASTPrinter.java
@@ -1,3 +1,5 @@
+package main;
+
public class ASTPrinter implements Visitor<String>{
@Override
public String visit(final Parser.BinaryOperation binaryOP) {
diff --git a/src/Application.java b/src/main/Application.java
similarity index 51%
rename from src/Application.java
rename to src/main/Application.java
index b25cd9f..f65d712 100644
--- a/src/Application.java
+++ b/src/main/Application.java
@@ -1,4 +1,10 @@
+package main;
+
+import Exceptions.LexerException;
+import Exceptions.ParserException;
+
import java.io.BufferedReader;
+import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.util.LinkedList;
@@ -6,34 +12,47 @@ import java.util.List;
public class Application {
public static void main(String[] args) {
+ //A list that will contain a String for each line of the "expressions.txt" file
List<String> expressions = new LinkedList<>();
- //Reads the file "expressions.txt" and adds its values to a list
+ //Reads the file "expressions.txt" and adds its values to the list expressions
BufferedReader reader;
- String dataPath = "expressions.txt";
+ String datapath = "expressions.txt";
try {
System.out.println("Reading the file...\n");
- reader = new BufferedReader(new FileReader(dataPath));
- String line = reader.readLine();
- while(line != null) {
- expressions.add(line);
- line = reader.readLine();
+ reader = new BufferedReader(new FileReader(datapath));
+ String currentLine = reader.readLine();
+ while(currentLine !=null) {
+ expressions.add(currentLine);
+ currentLine = reader.readLine();
}
reader.close();
}
- catch (IOException e ) {
+ catch(IOException e) {
e.printStackTrace();
}
+ //Iterate through every String
+ for (String expression: expressions) {
+ System.out.println("Expression: " + expression);
+ //Usage of the lexer, parser & evaluator
+ try {
+ //Create a list of tokens with the lexer
+ List<Lexer.Token> tokens = Lexer.lex(expression);
+ System.out.println("Lexer created tokens:");
+ //prints out each token to the console
+ for(Lexer.Token token: tokens) {
+ System.out.println(token.toString());
+ }
+ }
+ catch (Exception e) {
+ e.printStackTrace();
+ }
+
+ }
+
+ /*
//Iterates through every String and parses them into multiple tokens
for (String value: expressions) {
- System.out.println(value);
- //creates a list of tokens out of the String
- List<Lexer.Token> tokens = Lexer.lex(value);
-
- //prints each token out (with .toString())
- for(Lexer.Token singleToken: tokens) {
- System.out.println(singleToken.toString());
- }
Parser parser = new Parser();
try {
Parser.Expression exp = parser.parse(tokens);
@@ -48,6 +67,6 @@ public class Application {
System.out.println(e.getMessage());
}
System.out.println();
- }
+ }*/
}
}
diff --git a/src/Evaluator.java b/src/main/Evaluator.java
similarity index 97%
rename from src/Evaluator.java
rename to src/main/Evaluator.java
index b9979c7..7f51f3c 100644
--- a/src/Evaluator.java
+++ b/src/main/Evaluator.java
@@ -1,3 +1,5 @@
+package main;
+
public class Evaluator implements Visitor<Double>{
@Override
@@ -16,6 +18,7 @@ public class Evaluator implements Visitor<Double>{
result -= rOperand;
break;
case '*':
+ rOperand *= rOperand;
result *= rOperand;
break;
case '/':
diff --git a/src/Lexer.java b/src/main/Lexer.java
similarity index 90%
rename from src/Lexer.java
rename to src/main/Lexer.java
index c380695..d84a782 100644
--- a/src/Lexer.java
+++ b/src/main/Lexer.java
@@ -1,3 +1,7 @@
+package main;
+
+import Exceptions.LexerException;
+
import java.util.LinkedList;
import java.util.List;
@@ -9,7 +13,7 @@ public class Lexer {
}
//tokens with a TokenType that represents their type and a String with the actual data
- //has for both values a getter method and overrides toString with it's fitting values
+ //has for both values a getter method and overrides toString with its fitting values
public static class Token {
protected TokenType type;
protected String data;
@@ -33,15 +37,19 @@ public class Lexer {
}
//creates a list of tokens from a given String
- public static List<Token> lex(String input) {
+ public static List<Token> lex(String input) throws Exception{
+ if(input.isEmpty()) {
+ throw new LexerException("SyntaxError: lexer received empty String");
+ }
+
//the list that will be returned at the end
List<Token> result = new LinkedList<Token>();
//for-loop that iterates through each character of the String
for(int index=0; index < input.length();) {
char current = input.charAt(index);
- //checks if a character is a digit, then creates a token with one or multiple numbers
- //with TokenType=NUMBER
+ //checks if a character is a digit, then creates a token with one or multiple
+ //numbers with TokenType=NUMBER
if(Character.isDigit(current)) {
int endIndex = index;
if(endIndex<input.length()) {
diff --git a/src/Parser.java b/src/main/Parser.java
similarity index 98%
rename from src/Parser.java
rename to src/main/Parser.java
index 527d628..ca46fc9 100644
--- a/src/Parser.java
+++ b/src/main/Parser.java
@@ -1,3 +1,7 @@
+package main;
+
+import Exceptions.ParserException;
+
import java.util.LinkedList;
import java.util.List;
@@ -21,6 +25,10 @@ public class Parser {
public <T> T accept(Visitor<T> visitor) {
return visitor.visit(this);
}
+
+ public <T> T accept(Visitor<T> vistor, String operator) {
+ return vistor.visit(this);
+ }
}
public class Variable extends Expression {
diff --git a/src/SwingFunctionPlotter.java b/src/main/SwingFunctionPlotter.java
similarity index 98%
rename from src/SwingFunctionPlotter.java
rename to src/main/SwingFunctionPlotter.java
index 110dc61..d433aee 100644
--- a/src/SwingFunctionPlotter.java
+++ b/src/main/SwingFunctionPlotter.java
@@ -1,3 +1,5 @@
+package main;
+
import com.mindfusion.charting.FunctionSeries;
import com.mindfusion.charting.swing.LineChart;
diff --git a/src/Visitor.java b/src/main/Visitor.java
similarity index 94%
rename from src/Visitor.java
rename to src/main/Visitor.java
index 4e925c9..88d87ae 100644
--- a/src/Visitor.java
+++ b/src/main/Visitor.java
@@ -1,3 +1,5 @@
+package main;
+
public interface Visitor<T>{
public T visit(final Parser.BinaryOperation binOp);
public T visit(final Parser.Variable variable);
diff --git a/src/test/LexerTest.java b/src/test/LexerTest.java
new file mode 100644
index 0000000..54356a6
--- /dev/null
+++ b/src/test/LexerTest.java
@@ -0,0 +1,59 @@
+package test;
+
+import org.junit.Test;
+import main.*;
+
+import java.io.IOException;
+import java.util.LinkedList;
+import java.util.List;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+class LexerTest {
+
+ @Test
+ void disassembleFirstStringWithLexer() {
+ String s = "3+x*(2^4)";
+ List<Lexer.Token> tokens = new LinkedList<>();
+ tokens.add(new Lexer.Token(Lexer.TokenType.NUMBER,"3"));
+ tokens.add(new Lexer.Token(Lexer.TokenType.SPECIAL,"+"));
+ tokens.add(new Lexer.Token(Lexer.TokenType.VARIABLE,"x"));
+ tokens.add(new Lexer.Token(Lexer.TokenType.SPECIAL,"*"));
+ tokens.add(new Lexer.Token(Lexer.TokenType.SPECIAL,"("));
+ tokens.add(new Lexer.Token(Lexer.TokenType.NUMBER,"2"));
+ tokens.add(new Lexer.Token(Lexer.TokenType.SPECIAL,"^"));
+ tokens.add(new Lexer.Token(Lexer.TokenType.NUMBER,"4"));
+ tokens.add(new Lexer.Token(Lexer.TokenType.SPECIAL,")"));
+ try {
+ assertEquals(Lexer.lex(s),tokens);
+ }
+ catch(Exception e) {
+ e.printStackTrace();
+ }
+ }
+
+ @Test
+ void disassembleSecondStringWithLexer() {
+ String s = "1 + (x^2 )- (3*x)";
+ List<Lexer.Token> tokens = new LinkedList<>();
+ tokens.add(new Lexer.Token(Lexer.TokenType.NUMBER,"1"));
+ tokens.add(new Lexer.Token(Lexer.TokenType.SPECIAL,"+"));
+ tokens.add(new Lexer.Token(Lexer.TokenType.SPECIAL,"("));
+ tokens.add(new Lexer.Token(Lexer.TokenType.VARIABLE,"x"));
+ tokens.add(new Lexer.Token(Lexer.TokenType.SPECIAL,"^"));
+ tokens.add(new Lexer.Token(Lexer.TokenType.NUMBER,"2"));
+ tokens.add(new Lexer.Token(Lexer.TokenType.SPECIAL,")"));
+ tokens.add(new Lexer.Token(Lexer.TokenType.SPECIAL,"-"));
+ tokens.add(new Lexer.Token(Lexer.TokenType.SPECIAL,"("));
+ tokens.add(new Lexer.Token(Lexer.TokenType.NUMBER,"3"));
+ tokens.add(new Lexer.Token(Lexer.TokenType.SPECIAL,"*"));
+ tokens.add(new Lexer.Token(Lexer.TokenType.VARIABLE,"x"));
+ tokens.add(new Lexer.Token(Lexer.TokenType.SPECIAL,")"));
+ try {
+ assertEquals(Lexer.lex(s),tokens);
+ }
+ catch(Exception e) {
+ e.printStackTrace();
+ }
+ }
+}
\ No newline at end of file
diff --git a/src/test/ParserTest.java b/src/test/ParserTest.java
new file mode 100644
index 0000000..0be7f64
--- /dev/null
+++ b/src/test/ParserTest.java
@@ -0,0 +1,4 @@
+package test;
+
+public class ParserTest {
+}
--
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