[~] First totaly functional Calculator, reorganised the files, verified and added error messages

12 files changed, 67 insertions, 63 deletions

diff --git a/calculator-java/src/main/java/ch/bfh/Main.java b/calculator-java/src/main/java/ch/bfh/Main.java
index 5dc8a91..ea01185 100644
--- a/calculator-java/src/main/java/ch/bfh/Main.java
+++ b/calculator-java/src/main/java/ch/bfh/Main.java
@@ -1,7 +1,8 @@
 package ch.bfh;
 
+import ch.bfh.lexer.LexerException;
+import ch.bfh.parser.ParserException;
 import ch.bfh.parser.StatementParser;
-
 import java.util.Scanner;
 
 public class Main {
@@ -16,8 +17,8 @@ public class Main {
 
             try {
                 sp.parseStatement(expression);
-                System.out.println(sp.getValue());
-            } catch (Exception e) {
+                System.out.println("Result: " + sp.getValue());
+            } catch (LexerException | ParserException e) {
                 System.out.println(e.getMessage());
             }
         }
diff --git a/calculator-java/src/main/java/ch/bfh/exceptions/ParserException.java b/calculator-java/src/main/java/ch/bfh/exceptions/ParserException.java
deleted file mode 100644
index ca6d037..0000000
--- a/calculator-java/src/main/java/ch/bfh/exceptions/ParserException.java
+++ /dev/null
@@ -1,5 +0,0 @@
-package ch.bfh.exceptions;
-
-public class ParserException extends RuntimeException {
-    public ParserException(String s) { super(s); }
-}
\ No newline at end of file
diff --git a/calculator-java/src/main/java/ch/bfh/CalculatorLexer.java b/calculator-java/src/main/java/ch/bfh/lexer/CalculatorLexer.java
index 48d009e..0ba9535 100644
--- a/calculator-java/src/main/java/ch/bfh/CalculatorLexer.java
+++ b/calculator-java/src/main/java/ch/bfh/lexer/CalculatorLexer.java
@@ -1,5 +1,4 @@
-package ch.bfh;
-import ch.bfh.exceptions.LexerException;
+package ch.bfh.lexer;
 
 // Lexer for classical arithmetic expressions with identifiers and assignments.
 // Scans a source string char by char.
diff --git a/calculator-java/src/main/java/ch/bfh/exceptions/LexerException.java b/calculator-java/src/main/java/ch/bfh/lexer/LexerException.java
index 082beee..c5f8671 100644
--- a/calculator-java/src/main/java/ch/bfh/exceptions/LexerException.java
+++ b/calculator-java/src/main/java/ch/bfh/lexer/LexerException.java
@@ -1,4 +1,4 @@
-package ch.bfh.exceptions;
+package ch.bfh.lexer;
 
 public class LexerException extends RuntimeException {
     public LexerException(String s) { super(s); }
diff --git a/calculator-java/src/main/java/ch/bfh/Token.java b/calculator-java/src/main/java/ch/bfh/lexer/Token.java
index 93d4d02..b021075 100644
--- a/calculator-java/src/main/java/ch/bfh/Token.java
+++ b/calculator-java/src/main/java/ch/bfh/lexer/Token.java
@@ -1,4 +1,4 @@
-package ch.bfh;
+package ch.bfh.lexer;
 
 // Various Tokens for arithmetic expressions based on integers
 // with identifiers and assignments
@@ -8,16 +8,16 @@ public class Token {
   public double value;               // numerical value for NUM
   public String str;                 // token string
 
-  public static final int EOL=0;     // End Of Line
-  public static final int PAL=1;     // Left Parenthesis
-  public static final int PAR=2;     // Right Parenthesis
-  public static final int ADD=3;     // operators
-  public static final int SUB=4;
+  public static final int EOL=0;//     // End Of Line
+  public static final int PAL=1;//     // Left Parenthesis
+  public static final int PAR=2;//     // Right Parenthesis
+  public static final int ADD=3;//     // operators
+  public static final int SUB=4;//
   public static final int MUL=5;
   public static final int DIV=6;
-  public static final int NUM=7;     // number
+  public static final int NUM=7;//     // number
   public static final int EQU=8;     // equal 
   public static final int LET=9;     // let
-  public static final int ID=10;     // identifier
+  public static final int ID=10;//     // identifier
   public static final int END=11;    // exit
-}
+}
\ No newline at end of file
diff --git a/calculator-java/src/main/java/ch/bfh/parser/ExpressionParser.java b/calculator-java/src/main/java/ch/bfh/parser/ExpressionParser.java
index 3ec0194..e68983b 100644
--- a/calculator-java/src/main/java/ch/bfh/parser/ExpressionParser.java
+++ b/calculator-java/src/main/java/ch/bfh/parser/ExpressionParser.java
@@ -1,22 +1,15 @@
 package ch.bfh.parser;
 
-import ch.bfh.CalculatorLexer;
-import ch.bfh.Token;
-import ch.bfh.exceptions.ParserException;
-
+import ch.bfh.lexer.CalculatorLexer;
+import ch.bfh.lexer.Token;
 import java.util.ArrayList;
 
-public class ExpressionParser extends Parser {
+class ExpressionParser extends Parser {
 
     protected ArrayList<Parser> parsers = new ArrayList<>();
     protected ArrayList<Token> ops = new ArrayList<>();
     private boolean isParenthesised = false;
 
-    public ExpressionParser(CalculatorLexer cl) {
-        this.cl = cl;
-        parse();
-    }
-
     protected ExpressionParser(CalculatorLexer cl, Token lastToken, boolean isParenthesised) {
         this.cl = cl;
         this.lastToken = lastToken;
@@ -31,8 +24,8 @@ public class ExpressionParser extends Parser {
             token = lastToken;
         else
             token = cl.nextToken();
-        Parser l = null;
-        Parser r = null; // left and right expressions
+        TermParser l = null;
+        TermParser r = null; // left and right Terms
         Token op = null; // operation of the current l and right expressions
 
         loop:
@@ -48,9 +41,9 @@ public class ExpressionParser extends Parser {
                         op = token;
                         this.ops.add(op);
                     }else if (l == null)
-                        throw new ParserException("Factor cannot start with '+'.");
+                        throw new ParserException("Redundant use of '+' is forbidden.");
                     else
-                        throw new ParserException("Invalid use of '+' was found in the Expression.");
+                        throw new ParserException(token, "repetition of operator -> a term was expected.");
                     break;
                 case Token.SUB:
                     if (l != null && op == null) { // if the '-' sign is between two term (op)
@@ -82,14 +75,19 @@ public class ExpressionParser extends Parser {
                         break loop;
                     } else
                         throw new ParserException("No matching opening parenthesis were found.");
-                default:
-                    //TODO - Replace default by each individual case
-                    throw new ParserException("Malformed Expression.");
+                case Token.MUL:
+                case Token.DIV:
+                    throw new ParserException(token,"a term was expected.");
+                case Token.EQU:
+                case Token.LET:
+                    throw new ParserException("The inputted token '"+token.str+"' can only be placed in a variable declaration context (let var = Expression).");
+                case Token.END:
+                    throw new ParserException("The keyword 'exit' can only be placed at the beginning of an expression.");
             }
             token = cl.nextToken();
         }
         if (op != null && r == null)
-            throw new ParserException("Missing expression after last operation '"+op.str+"'");
+            throw new ParserException("Missing term after the last operator '"+op.str+"'.");
     }
 
     @Override
@@ -111,4 +109,4 @@ public class ExpressionParser extends Parser {
         }
         return result;
     }
-}
+}
\ No newline at end of file
diff --git a/calculator-java/src/main/java/ch/bfh/parser/FactorParser.java b/calculator-java/src/main/java/ch/bfh/parser/FactorParser.java
index 8bb5ef7..fd54cf4 100644
--- a/calculator-java/src/main/java/ch/bfh/parser/FactorParser.java
+++ b/calculator-java/src/main/java/ch/bfh/parser/FactorParser.java
@@ -1,8 +1,7 @@
 package ch.bfh.parser;
 
-import ch.bfh.CalculatorLexer;
-import ch.bfh.Token;
-import ch.bfh.exceptions.ParserException;
+import ch.bfh.lexer.CalculatorLexer;
+import ch.bfh.lexer.Token;
 
 class FactorParser extends Parser {
 
@@ -72,9 +71,11 @@ class FactorParser extends Parser {
                         lastToken = token;
                     else throw new ParserException("Missing expression before closing the parenthesis.");
                     break loop;
-                default:
-                    //TODO - Replace default by each individual case
-                    throw new ParserException("Malformed Expression.");
+                case Token.EQU:
+                case Token.LET:
+                    throw new ParserException("The inputted token '"+token.str+"' can only be placed in a variable declaration context (let var = Expression).");
+                case Token.END:
+                    throw new ParserException("The keyword 'exit' can only be placed at the beginning of an expression.");
             }
             token = cl.nextToken();
         }
@@ -91,4 +92,4 @@ class FactorParser extends Parser {
             return value * (-1);
         return value;
     }
-}
+}
\ No newline at end of file
diff --git a/calculator-java/src/main/java/ch/bfh/parser/Parser.java b/calculator-java/src/main/java/ch/bfh/parser/Parser.java
index 333b942..6a03fe1 100644
--- a/calculator-java/src/main/java/ch/bfh/parser/Parser.java
+++ b/calculator-java/src/main/java/ch/bfh/parser/Parser.java
@@ -1,14 +1,13 @@
 package ch.bfh.parser;
 
-import ch.bfh.CalculatorLexer;
-import ch.bfh.Token;
-
+import ch.bfh.lexer.CalculatorLexer;
+import ch.bfh.lexer.Token;
 import java.util.HashMap;
 import java.util.Map;
 
 abstract class Parser{
 
-    protected static Map<String, ExpressionParser> variables = new HashMap<>(); //'Persisted' Expressions when 'let' token was specified
+    protected static Map<String, ExpressionParser> variables = new HashMap<>(); //Persisted Expressions aka variables
 
     protected CalculatorLexer cl;
     protected Token lastToken;
diff --git a/calculator-java/src/main/java/ch/bfh/parser/ParserException.java b/calculator-java/src/main/java/ch/bfh/parser/ParserException.java
new file mode 100644
index 0000000..a85e3b2
--- /dev/null
+++ b/calculator-java/src/main/java/ch/bfh/parser/ParserException.java
@@ -0,0 +1,8 @@
+package ch.bfh.parser;
+
+import ch.bfh.lexer.Token;
+
+public class ParserException extends RuntimeException {
+    public ParserException(String s) { super(s); }
+    public ParserException(Token token, String s) { super("Last read token: '"+token.str+"', "+s); }
+}
\ No newline at end of file
diff --git a/calculator-java/src/main/java/ch/bfh/parser/StatementParser.java b/calculator-java/src/main/java/ch/bfh/parser/StatementParser.java
index c85398b..482ef34 100644
--- a/calculator-java/src/main/java/ch/bfh/parser/StatementParser.java
+++ b/calculator-java/src/main/java/ch/bfh/parser/StatementParser.java
@@ -1,8 +1,7 @@
 package ch.bfh.parser;
 
-import ch.bfh.CalculatorLexer;
-import ch.bfh.Token;
-import ch.bfh.exceptions.ParserException;
+import ch.bfh.lexer.CalculatorLexer;
+import ch.bfh.lexer.Token;
 
 public class StatementParser extends Parser{
 
@@ -27,15 +26,15 @@ public class StatementParser extends Parser{
             switch (token.type) {
                 case Token.LET:
                     if (lastToken != null)
-                        throw new ParserException("The keyword 'let' cannot be placed anywhere else than at the beginning of an expression.");
+                        throw new ParserException("The keyword 'let' can only be placed at the beginning of an expression.");
                     break;
                 case Token.EQU:
                     if (lastToken == null || lastToken.type != Token.LET || variableName == null)
-                        throw new ParserException("The inputted token '=' can only be placed in a variable declaration context (let variable = Expression).");
+                        throw new ParserException("The token '=' can only be placed in a variable declaration context (let var = Expression).");
                     break;
                 case Token.END:
                     if (lastToken != null)
-                        throw new ParserException("The keyword 'exit' cannot be placed anywhere else than at the beginning of an expression.");
+                        throw new ParserException("The keyword 'exit' can only be placed at the beginning of an expression.");
                     else
                         System.exit(0);
                 case Token.ID:
@@ -58,7 +57,7 @@ public class StatementParser extends Parser{
         if (lastToken == null)
             return;
         if (lastToken.type == Token.LET || lastToken.type == Token.EQU)
-            throw new ParserException("Incomplete variable declaration");
+            throw new ParserException("Incomplete variable declaration. Expected: let var = Expression.");
     }
 
     @Override
diff --git a/calculator-java/src/main/java/ch/bfh/parser/TermParser.java b/calculator-java/src/main/java/ch/bfh/parser/TermParser.java
index 9a97659..9e49fa8 100644
--- a/calculator-java/src/main/java/ch/bfh/parser/TermParser.java
+++ b/calculator-java/src/main/java/ch/bfh/parser/TermParser.java
@@ -1,8 +1,7 @@
 package ch.bfh.parser;
 
-import ch.bfh.CalculatorLexer;
-import ch.bfh.Token;
-import ch.bfh.exceptions.ParserException;
+import ch.bfh.lexer.CalculatorLexer;
+import ch.bfh.lexer.Token;
 
 class TermParser extends ExpressionParser {
 
@@ -61,9 +60,11 @@ class TermParser extends ExpressionParser {
                 case Token.PAR:  // Going as high as possible --> possibly the end of an expression created by a Factor :)
                     lastToken = token;
                     break loop;
-                default:
-                    //TODO - Replace default by each individual case
-                    throw new ParserException("Malformed Expression.");
+                case Token.EQU:
+                case Token.LET:
+                    throw new ParserException("The inputted token '"+token.str+"' can only be placed in a variable declaration context (let var = Expression).");
+                case Token.END:
+                    throw new ParserException("The keyword 'exit' can only be placed at the beginning of an expression.");
             }
             token = cl.nextToken();
         }
diff --git a/calculator-java/src/test/java/StatementParserTest.java b/calculator-java/src/test/java/StatementParserTest.java
index 8c2db59..ee4ab6b 100644
--- a/calculator-java/src/test/java/StatementParserTest.java
+++ b/calculator-java/src/test/java/StatementParserTest.java
@@ -111,6 +111,9 @@ public class StatementParserTest {
         sp.parseStatement("b/a");
         assertEquals(50.0, sp.getValue(), 0.0);
 
+        sp.parseStatement("b--a");
+        assertEquals(255.0, sp.getValue(), 0.0);
+
         sp.parseStatement("b+a/2");
         assertEquals(252.5, sp.getValue(), 0.0);