From d2cc050cb1d1d202a7305c068a1fe5c24ec0d358 Mon Sep 17 00:00:00 2001
From: nils <github@dittberner.it>
Date: Sun, 15 Jan 2017 16:51:27 +0100
Subject: [PATCH 1/6] Use visitor for printing program

---
 src/main/java/printer/ExpressionPrinter.java | 32 +++++++++++++++++++++++++
 src/main/java/printer/ProgramPrinter.java    | 36 ++++++++++++++++++++++++++++
 2 files changed, 68 insertions(+)
 create mode 100644 src/main/java/printer/ExpressionPrinter.java
 create mode 100644 src/main/java/printer/ProgramPrinter.java

diff --git a/src/main/java/printer/ExpressionPrinter.java b/src/main/java/printer/ExpressionPrinter.java
new file mode 100644
index 0000000..4c0f649
--- /dev/null
+++ b/src/main/java/printer/ExpressionPrinter.java
@@ -0,0 +1,32 @@
+package printer;
+
+import expression.*;
+import interpreter.Visitor;
+
+public class ExpressionPrinter extends Visitor<String> {
+    private final String value;
+
+    public ExpressionPrinter(Expression expression) {
+        value = visit(expression);
+    }
+
+    public String visitAddition(Addition addition) {
+        return "(" + visit(addition.leftHandSide) + " + " + visit(addition.rightHandSide) + ")";
+    }
+
+    public String visitIdentifier(Identifier identifier) {
+        return identifier.name;
+    }
+
+    public String visitInt(Int integer) {
+        return Integer.toString(integer.value);
+    }
+
+    public String visitSubtraction(Subtraction subtraction) {
+        return "(" + visit(subtraction.leftHandSide) + " - " + visit(subtraction.rightHandSide) + ")";
+    }
+
+    public String getValue() {
+        return value;
+    }
+}
diff --git a/src/main/java/printer/ProgramPrinter.java b/src/main/java/printer/ProgramPrinter.java
new file mode 100644
index 0000000..32bf00b
--- /dev/null
+++ b/src/main/java/printer/ProgramPrinter.java
@@ -0,0 +1,36 @@
+package printer;
+
+import interpreter.Visitor;
+import program.*;
+
+public class ProgramPrinter extends Visitor<String> {
+    private final String value;
+
+    public ProgramPrinter(Program program) {
+        value = visit(program);
+    }
+
+    public String visitAssignment(Assignment assignment) {
+        ExpressionPrinter identifierPrinter = new ExpressionPrinter(assignment.identifier);
+        ExpressionPrinter expressionPrinter = new ExpressionPrinter(assignment.expression);
+        return identifierPrinter.getValue() + " := " + expressionPrinter.getValue();
+    }
+
+    public String visitComposition(Composition composition) {
+        return visit(composition.first) + " ; " + visit(composition.second);
+    }
+
+    public String visitConditional(Conditional conditional) {
+        ExpressionPrinter conditionPrinter = new ExpressionPrinter(conditional.condition);
+        return "if (" + conditionPrinter.getValue() + ") then { " + visit(conditional.thenCase) +  " } else { " + visit(conditional.elseCase) + " }";
+    }
+
+    public String visitLoop(Loop loop) {
+        ExpressionPrinter conditionPrinter = new ExpressionPrinter(loop.condition);
+        return "while (" + conditionPrinter.getValue() + ") { " + visit(loop.program) +  " }";
+    }
+
+    public String getValue() {
+        return value;
+    }
+}

From abba5450d785bd4f2cf6ab0eb56c7ce8a05bbb40 Mon Sep 17 00:00:00 2001
From: nils <github@dittberner.it>
Date: Sun, 15 Jan 2017 16:54:10 +0100
Subject: [PATCH 2/6] Removed toString methods

---
 src/main/java/expression/Addition.java    | 6 ------
 src/main/java/expression/Identifier.java  | 6 ------
 src/main/java/expression/Int.java         | 6 ------
 src/main/java/expression/Subtraction.java | 6 ------
 src/main/java/program/Assignment.java     | 6 ------
 src/main/java/program/Composition.java    | 6 ------
 src/main/java/program/Conditional.java    | 6 ------
 src/main/java/program/Loop.java           | 6 ------
 8 files changed, 48 deletions(-)

diff --git a/src/main/java/expression/Addition.java b/src/main/java/expression/Addition.java
index 0cefcd4..d0d4237 100644
--- a/src/main/java/expression/Addition.java
+++ b/src/main/java/expression/Addition.java
@@ -28,12 +28,6 @@ public class Addition extends Expression {
         this.rightHandSide = rightHandSide;
     }
 
-    /*!- String serialization */
-    @Override
-    public String toString() {
-        return "(" + leftHandSide + " + " + rightHandSide + ")";
-    }
-
     /*!- Generated equals implementation */
     @Override
     public boolean equals(Object o) {
diff --git a/src/main/java/expression/Identifier.java b/src/main/java/expression/Identifier.java
index c175498..7b2f85b 100644
--- a/src/main/java/expression/Identifier.java
+++ b/src/main/java/expression/Identifier.java
@@ -17,12 +17,6 @@ public class Identifier extends Expression {
         this.name = name;
     }
 
-    /*!- String serialization */
-    @Override
-    public String toString() {
-        return name;
-    }
-
     /*!- generated equals implementation */
     @Override
     public boolean equals(Object o) {
diff --git a/src/main/java/expression/Int.java b/src/main/java/expression/Int.java
index 942a014..7f38973 100644
--- a/src/main/java/expression/Int.java
+++ b/src/main/java/expression/Int.java
@@ -22,12 +22,6 @@ public class Int extends Expression {
         this.value = value;
     }
 
-    /*!- String serialization */
-    @Override
-    public String toString() {
-        return Integer.toString(value);
-    }
-
     /*!- generated equals implementation */
     @Override
     public boolean equals(Object o) {
diff --git a/src/main/java/expression/Subtraction.java b/src/main/java/expression/Subtraction.java
index 8de951a..4493577 100644
--- a/src/main/java/expression/Subtraction.java
+++ b/src/main/java/expression/Subtraction.java
@@ -28,12 +28,6 @@ public class Subtraction extends Expression {
         this.rightHandSide = rightHandSide;
     }
 
-    /*!- String serialization */
-    @Override
-    public String toString() {
-        return "(" + leftHandSide + " - " + rightHandSide + ")";
-    }
-
     /*!- generated equals implementation */
     @Override
     public boolean equals(Object o) {
diff --git a/src/main/java/program/Assignment.java b/src/main/java/program/Assignment.java
index 81d9915..7b22ee0 100644
--- a/src/main/java/program/Assignment.java
+++ b/src/main/java/program/Assignment.java
@@ -32,12 +32,6 @@ public class Assignment extends Program {
         this.expression = expression;
     }
 
-    /*!- String serialization */
-    @Override
-    public String toString() {
-        return identifier + " := " + expression;
-    }
-
     /*!- generated equals method */
     @Override
     public boolean equals(Object o) {
diff --git a/src/main/java/program/Composition.java b/src/main/java/program/Composition.java
index fae9d75..4da49dc 100644
--- a/src/main/java/program/Composition.java
+++ b/src/main/java/program/Composition.java
@@ -19,12 +19,6 @@ public class Composition extends Program {
         this.second = second;
     }
 
-    /*!- String serialization */
-    @Override
-    public String toString() {
-        return first + " ; " + second;
-    }
-
     /*!- generated equals implementation */
     @Override
     public boolean equals(Object o) {
diff --git a/src/main/java/program/Conditional.java b/src/main/java/program/Conditional.java
index edfd477..5ea732e 100644
--- a/src/main/java/program/Conditional.java
+++ b/src/main/java/program/Conditional.java
@@ -36,10 +36,4 @@ public class Conditional extends Program {
         return elseCase.equals(that.elseCase);
 
     }
-
-    /*!- String serialization */
-    @Override
-    public String toString() {
-        return "if (" + condition + ") then { " + thenCase +  " } else { " + elseCase + " }";
-    }
 }
diff --git a/src/main/java/program/Loop.java b/src/main/java/program/Loop.java
index e3ae27d..2826a7a 100644
--- a/src/main/java/program/Loop.java
+++ b/src/main/java/program/Loop.java
@@ -21,12 +21,6 @@ public class Loop extends Program {
         this.program = program;
     }
 
-    /*!- String serialization */
-    @Override
-    public String toString() {
-        return "while (" + condition + ") { " + program +  " }";
-    }
-
     /*!- generated equals implementation */
     @Override
     public boolean equals(Object o) {

From 0dfd7b7271bad5797bee7c077f42ec7dca9ab0b0 Mon Sep 17 00:00:00 2001
From: nils <github@dittberner.it>
Date: Sun, 15 Jan 2017 17:20:30 +0100
Subject: [PATCH 3/6] Added tests, fixed brackets issue

---
 src/main/java/printer/ExpressionPrinter.java     |  4 +-
 src/test/java/printer/ExpressionPrinterTest.java | 49 ++++++++++++++++++++
 src/test/java/printer/ProgramPrinterTest.java    | 58 ++++++++++++++++++++++++
 3 files changed, 109 insertions(+), 2 deletions(-)
 create mode 100644 src/test/java/printer/ExpressionPrinterTest.java
 create mode 100644 src/test/java/printer/ProgramPrinterTest.java

diff --git a/src/main/java/printer/ExpressionPrinter.java b/src/main/java/printer/ExpressionPrinter.java
index 4c0f649..2ed5997 100644
--- a/src/main/java/printer/ExpressionPrinter.java
+++ b/src/main/java/printer/ExpressionPrinter.java
@@ -11,7 +11,7 @@ public class ExpressionPrinter extends Visitor<String> {
     }
 
     public String visitAddition(Addition addition) {
-        return "(" + visit(addition.leftHandSide) + " + " + visit(addition.rightHandSide) + ")";
+        return visit(addition.leftHandSide) + " + " + visit(addition.rightHandSide);
     }
 
     public String visitIdentifier(Identifier identifier) {
@@ -23,7 +23,7 @@ public class ExpressionPrinter extends Visitor<String> {
     }
 
     public String visitSubtraction(Subtraction subtraction) {
-        return "(" + visit(subtraction.leftHandSide) + " - " + visit(subtraction.rightHandSide) + ")";
+        return visit(subtraction.leftHandSide) + " - " + visit(subtraction.rightHandSide);
     }
 
     public String getValue() {
diff --git a/src/test/java/printer/ExpressionPrinterTest.java b/src/test/java/printer/ExpressionPrinterTest.java
new file mode 100644
index 0000000..a639995
--- /dev/null
+++ b/src/test/java/printer/ExpressionPrinterTest.java
@@ -0,0 +1,49 @@
+package printer;
+
+import expression.*;
+import org.junit.Test;
+
+import static org.junit.Assert.*;
+
+/**
+ * Created by nils on 15.01.2017.
+ */
+public class ExpressionPrinterTest {
+    final String identifierCode = "a";
+    final Identifier identifier = new Identifier(identifierCode);
+
+    final String integerCode = "42";
+    final Int integer = new Int(42);
+
+    final String additionCode = "a + 42";
+    final Addition addition = new Addition(new Identifier("a"), new Int(42));
+
+    final String subtractionCode = "1 - a";
+    final Subtraction subtraction = new Subtraction(new Int(1), new Identifier("a"));
+
+
+    @Test
+    public void testVisitAddition() {
+        ExpressionPrinter printer = new ExpressionPrinter(addition);
+        assertEquals(additionCode, printer.getValue());
+    }
+
+    @Test
+    public void testVisitIdentifier() {
+        ExpressionPrinter printer = new ExpressionPrinter(identifier);
+        assertEquals(identifierCode, printer.getValue());
+    }
+
+    @Test
+    public void testVisitInt() {
+        ExpressionPrinter printer = new ExpressionPrinter(integer);
+        assertEquals(integerCode, printer.getValue());
+    }
+
+    @Test
+    public void testVisitSubtraction() {
+        ExpressionPrinter printer = new ExpressionPrinter(subtraction);
+        assertEquals(subtractionCode, printer.getValue());
+    }
+
+}
\ No newline at end of file
diff --git a/src/test/java/printer/ProgramPrinterTest.java b/src/test/java/printer/ProgramPrinterTest.java
new file mode 100644
index 0000000..9a3c4c9
--- /dev/null
+++ b/src/test/java/printer/ProgramPrinterTest.java
@@ -0,0 +1,58 @@
+package printer;
+
+import expression.Addition;
+import expression.Identifier;
+import expression.Int;
+import expression.Subtraction;
+import org.junit.Test;
+import program.*;
+
+import static org.junit.Assert.*;
+
+public class ProgramPrinterTest {
+    final String loopCode = "while (a) { r := r + b ; a := a - 1 }";
+    final Loop loop = new Loop(new Identifier("a"), new Composition(new Assignment(new Identifier("r"), new Addition(new Identifier("r"), new Identifier("b"))), new Assignment(new Identifier("a"), new Subtraction(new Identifier("a"), new Int(1)))));
+
+    final String assignmentCode = "a := 2";
+    final Assignment assignment = new Assignment(new Identifier("a"), new Int(2));
+
+    final String compositionCode = assignmentCode + " ; b := bar";
+    final Composition composition = new Composition(assignment, new Assignment(new Identifier("b"), new Identifier("bar")));
+
+    final String conditionalCode = "if (foo - bar) then { x := 5 } else { x := x }";
+    final Conditional conditional = new Conditional(new Subtraction(new Identifier("foo"), new Identifier("bar")), new Assignment(new Identifier("x"), new Int(5)), new Assignment(new Identifier("x"), new Identifier("x")));
+
+    final String programCode = compositionCode + " ; " + loopCode + " ; " + conditionalCode;
+    final Program program = new Composition(new Composition(composition, loop), conditional);
+
+    @Test
+    public void testVisitAssignment() {
+        ProgramPrinter printer = new ProgramPrinter(assignment);
+        assertEquals(assignmentCode, printer.getValue());
+    }
+
+    @Test
+    public void testVisitComposition() {
+        ProgramPrinter printer = new ProgramPrinter(composition);
+        assertEquals(compositionCode, printer.getValue());
+    }
+
+    @Test
+    public void testVisitConditional() {
+        ProgramPrinter printer = new ProgramPrinter(conditional);
+        assertEquals(conditionalCode, printer.getValue());
+    }
+
+    @Test
+    public void testVisitLoop() {
+        ProgramPrinter printer = new ProgramPrinter(loop);
+        assertEquals(loopCode, printer.getValue());
+    }
+
+    @Test
+    public void testVisitProgram() {
+        ProgramPrinter printer = new ProgramPrinter(program);
+        assertEquals(programCode, printer.getValue());
+    }
+
+}
\ No newline at end of file

From bb996551918ce4b90db231cae2989fa946c4137d Mon Sep 17 00:00:00 2001
From: nils <github@dittberner.it>
Date: Sun, 15 Jan 2017 23:56:21 +0100
Subject: [PATCH 4/6] Removed program/expression variable from printer,
 adjusted tests, added a bit of docco

---
 src/main/java/printer/ExpressionPrinter.java     | 29 +++++++++++-----
 src/main/java/printer/ProgramPrinter.java        | 42 +++++++++++++++---------
 src/test/java/printer/ExpressionPrinterTest.java | 19 +++++------
 src/test/java/printer/ProgramPrinterTest.java    | 20 +++++------
 4 files changed, 66 insertions(+), 44 deletions(-)

diff --git a/src/main/java/printer/ExpressionPrinter.java b/src/main/java/printer/ExpressionPrinter.java
index 2ed5997..38e9c41 100644
--- a/src/main/java/printer/ExpressionPrinter.java
+++ b/src/main/java/printer/ExpressionPrinter.java
@@ -1,15 +1,24 @@
+/*!! Printer */
+
+/*!
+ExpressionPrinter
+=================
+
+The `ExpressionPrinter` is used for string serialization of a given `Expression`.
+*/
+
+/*!- Header */
 package printer;
 
 import expression.*;
 import interpreter.Visitor;
 
+/*!
+The `ExpressionPrinter` implements the string serialization with the help of the
+[Visitor](${basePath}/src/main/java/interpreter/Visitor.java.html).
+*/
 public class ExpressionPrinter extends Visitor<String> {
-    private final String value;
-
-    public ExpressionPrinter(Expression expression) {
-        value = visit(expression);
-    }
-
+    /*!- Visit functions */
     public String visitAddition(Addition addition) {
         return visit(addition.leftHandSide) + " + " + visit(addition.rightHandSide);
     }
@@ -26,7 +35,11 @@ public class ExpressionPrinter extends Visitor<String> {
         return visit(subtraction.leftHandSide) + " - " + visit(subtraction.rightHandSide);
     }
 
-    public String getValue() {
-        return value;
+    /*!
+    The `getValue` function takes an `Expression` instance as an argument and returns
+    the string serialisation of the given expression.
+    */
+    public String getValue(Expression expression) {
+        return visit(expression);
     }
 }
diff --git a/src/main/java/printer/ProgramPrinter.java b/src/main/java/printer/ProgramPrinter.java
index 32bf00b..d8529e4 100644
--- a/src/main/java/printer/ProgramPrinter.java
+++ b/src/main/java/printer/ProgramPrinter.java
@@ -1,19 +1,27 @@
+/*!! Printer */
+
+/*!
+ProgramPrinter
+==============
+
+The `ProgramPrinter` is used for string serialization of a given `Program`.
+*/
+
+/*!- Header */
 package printer;
 
 import interpreter.Visitor;
 import program.*;
 
+/*!
+The `ProgramPrinter` implements the string serialization with the help of the
+[Visitor](${basePath}/src/main/java/interpreter/Visitor.java.html).
+*/
 public class ProgramPrinter extends Visitor<String> {
-    private final String value;
-
-    public ProgramPrinter(Program program) {
-        value = visit(program);
-    }
-
+    /*!- Visit functions */
     public String visitAssignment(Assignment assignment) {
-        ExpressionPrinter identifierPrinter = new ExpressionPrinter(assignment.identifier);
-        ExpressionPrinter expressionPrinter = new ExpressionPrinter(assignment.expression);
-        return identifierPrinter.getValue() + " := " + expressionPrinter.getValue();
+        ExpressionPrinter printer = new ExpressionPrinter();
+        return printer.getValue(assignment.identifier) + " := " + printer.getValue(assignment.expression);
     }
 
     public String visitComposition(Composition composition) {
@@ -21,16 +29,20 @@ public class ProgramPrinter extends Visitor<String> {
     }
 
     public String visitConditional(Conditional conditional) {
-        ExpressionPrinter conditionPrinter = new ExpressionPrinter(conditional.condition);
-        return "if (" + conditionPrinter.getValue() + ") then { " + visit(conditional.thenCase) +  " } else { " + visit(conditional.elseCase) + " }";
+        ExpressionPrinter printer = new ExpressionPrinter();
+        return "if (" + printer.getValue(conditional.condition) + ") then { " + visit(conditional.thenCase) +  " } else { " + visit(conditional.elseCase) + " }";
     }
 
     public String visitLoop(Loop loop) {
-        ExpressionPrinter conditionPrinter = new ExpressionPrinter(loop.condition);
-        return "while (" + conditionPrinter.getValue() + ") { " + visit(loop.program) +  " }";
+        ExpressionPrinter printer = new ExpressionPrinter();
+        return "while (" + printer.getValue(loop.condition) + ") { " + visit(loop.program) +  " }";
     }
 
-    public String getValue() {
-        return value;
+    /*!
+    The `getValue` function takes a `Program` instance as an argument and returns
+    the string serialisation of the given program.
+    */
+    public String getValue(Program program) {
+        return visit(program);
     }
 }
diff --git a/src/test/java/printer/ExpressionPrinterTest.java b/src/test/java/printer/ExpressionPrinterTest.java
index a639995..d4bfa2d 100644
--- a/src/test/java/printer/ExpressionPrinterTest.java
+++ b/src/test/java/printer/ExpressionPrinterTest.java
@@ -5,9 +5,6 @@ import org.junit.Test;
 
 import static org.junit.Assert.*;
 
-/**
- * Created by nils on 15.01.2017.
- */
 public class ExpressionPrinterTest {
     final String identifierCode = "a";
     final Identifier identifier = new Identifier(identifierCode);
@@ -24,26 +21,26 @@ public class ExpressionPrinterTest {
 
     @Test
     public void testVisitAddition() {
-        ExpressionPrinter printer = new ExpressionPrinter(addition);
-        assertEquals(additionCode, printer.getValue());
+        ExpressionPrinter printer = new ExpressionPrinter();
+        assertEquals(additionCode, printer.getValue(addition));
     }
 
     @Test
     public void testVisitIdentifier() {
-        ExpressionPrinter printer = new ExpressionPrinter(identifier);
-        assertEquals(identifierCode, printer.getValue());
+        ExpressionPrinter printer = new ExpressionPrinter();
+        assertEquals(identifierCode, printer.getValue(identifier));
     }
 
     @Test
     public void testVisitInt() {
-        ExpressionPrinter printer = new ExpressionPrinter(integer);
-        assertEquals(integerCode, printer.getValue());
+        ExpressionPrinter printer = new ExpressionPrinter();
+        assertEquals(integerCode, printer.getValue(integer));
     }
 
     @Test
     public void testVisitSubtraction() {
-        ExpressionPrinter printer = new ExpressionPrinter(subtraction);
-        assertEquals(subtractionCode, printer.getValue());
+        ExpressionPrinter printer = new ExpressionPrinter();
+        assertEquals(subtractionCode, printer.getValue(subtraction));
     }
 
 }
\ No newline at end of file
diff --git a/src/test/java/printer/ProgramPrinterTest.java b/src/test/java/printer/ProgramPrinterTest.java
index 9a3c4c9..107f5e2 100644
--- a/src/test/java/printer/ProgramPrinterTest.java
+++ b/src/test/java/printer/ProgramPrinterTest.java
@@ -27,32 +27,32 @@ public class ProgramPrinterTest {
 
     @Test
     public void testVisitAssignment() {
-        ProgramPrinter printer = new ProgramPrinter(assignment);
-        assertEquals(assignmentCode, printer.getValue());
+        ProgramPrinter printer = new ProgramPrinter();
+        assertEquals(assignmentCode, printer.getValue(assignment));
     }
 
     @Test
     public void testVisitComposition() {
-        ProgramPrinter printer = new ProgramPrinter(composition);
-        assertEquals(compositionCode, printer.getValue());
+        ProgramPrinter printer = new ProgramPrinter();
+        assertEquals(compositionCode, printer.getValue(composition));
     }
 
     @Test
     public void testVisitConditional() {
-        ProgramPrinter printer = new ProgramPrinter(conditional);
-        assertEquals(conditionalCode, printer.getValue());
+        ProgramPrinter printer = new ProgramPrinter();
+        assertEquals(conditionalCode, printer.getValue(conditional));
     }
 
     @Test
     public void testVisitLoop() {
-        ProgramPrinter printer = new ProgramPrinter(loop);
-        assertEquals(loopCode, printer.getValue());
+        ProgramPrinter printer = new ProgramPrinter();
+        assertEquals(loopCode, printer.getValue(loop));
     }
 
     @Test
     public void testVisitProgram() {
-        ProgramPrinter printer = new ProgramPrinter(program);
-        assertEquals(programCode, printer.getValue());
+        ProgramPrinter printer = new ProgramPrinter();
+        assertEquals(programCode, printer.getValue(program));
     }
 
 }
\ No newline at end of file

From ca4bbab971f67ce290586fd71a398862965c867a Mon Sep 17 00:00:00 2001
From: Malte Schmitz <malte@schmitz-sh.de>
Date: Mon, 16 Jan 2017 17:54:49 +0100
Subject: [PATCH 5/6] Minor simplifications

---
 src/main/java/printer/ExpressionPrinter.java     |  7 +++----
 src/main/java/printer/ProgramPrinter.java        | 18 ++++++++----------
 src/test/java/printer/ExpressionPrinterTest.java | 13 +++++--------
 src/test/java/printer/ProgramPrinterTest.java    | 17 +++++++----------
 4 files changed, 23 insertions(+), 32 deletions(-)

diff --git a/src/main/java/printer/ExpressionPrinter.java b/src/main/java/printer/ExpressionPrinter.java
index 38e9c41..1801a2a 100644
--- a/src/main/java/printer/ExpressionPrinter.java
+++ b/src/main/java/printer/ExpressionPrinter.java
@@ -18,7 +18,6 @@ The `ExpressionPrinter` implements the string serialization with the help of the
 [Visitor](${basePath}/src/main/java/interpreter/Visitor.java.html).
 */
 public class ExpressionPrinter extends Visitor<String> {
-    /*!- Visit functions */
     public String visitAddition(Addition addition) {
         return visit(addition.leftHandSide) + " + " + visit(addition.rightHandSide);
     }
@@ -36,10 +35,10 @@ public class ExpressionPrinter extends Visitor<String> {
     }
 
     /*!
-    The `getValue` function takes an `Expression` instance as an argument and returns
-    the string serialisation of the given expression.
+    The `print` function takes an `Expression` instance as an argument and returns
+    the string serialization of the given expression.
     */
-    public String getValue(Expression expression) {
+    public String print(Expression expression) {
         return visit(expression);
     }
 }
diff --git a/src/main/java/printer/ProgramPrinter.java b/src/main/java/printer/ProgramPrinter.java
index d8529e4..33a4ad9 100644
--- a/src/main/java/printer/ProgramPrinter.java
+++ b/src/main/java/printer/ProgramPrinter.java
@@ -18,10 +18,10 @@ The `ProgramPrinter` implements the string serialization with the help of the
 [Visitor](${basePath}/src/main/java/interpreter/Visitor.java.html).
 */
 public class ProgramPrinter extends Visitor<String> {
-    /*!- Visit functions */
+    private final ExpressionPrinter printer = new ExpressionPrinter();
+
     public String visitAssignment(Assignment assignment) {
-        ExpressionPrinter printer = new ExpressionPrinter();
-        return printer.getValue(assignment.identifier) + " := " + printer.getValue(assignment.expression);
+        return printer.print(assignment.identifier) + " := " + printer.print(assignment.expression);
     }
 
     public String visitComposition(Composition composition) {
@@ -29,20 +29,18 @@ public class ProgramPrinter extends Visitor<String> {
     }
 
     public String visitConditional(Conditional conditional) {
-        ExpressionPrinter printer = new ExpressionPrinter();
-        return "if (" + printer.getValue(conditional.condition) + ") then { " + visit(conditional.thenCase) +  " } else { " + visit(conditional.elseCase) + " }";
+        return "if (" + printer.print(conditional.condition) + ") then { " + visit(conditional.thenCase) +  " } else { " + visit(conditional.elseCase) + " }";
     }
 
     public String visitLoop(Loop loop) {
-        ExpressionPrinter printer = new ExpressionPrinter();
-        return "while (" + printer.getValue(loop.condition) + ") { " + visit(loop.program) +  " }";
+        return "while (" + printer.print(loop.condition) + ") { " + visit(loop.program) +  " }";
     }
 
     /*!
-    The `getValue` function takes a `Program` instance as an argument and returns
-    the string serialisation of the given program.
+    The `print` function takes a `Program` instance as an argument and returns
+    the string serialization of the given program.
     */
-    public String getValue(Program program) {
+    public String print(Program program) {
         return visit(program);
     }
 }
diff --git a/src/test/java/printer/ExpressionPrinterTest.java b/src/test/java/printer/ExpressionPrinterTest.java
index d4bfa2d..b457766 100644
--- a/src/test/java/printer/ExpressionPrinterTest.java
+++ b/src/test/java/printer/ExpressionPrinterTest.java
@@ -18,29 +18,26 @@ public class ExpressionPrinterTest {
     final String subtractionCode = "1 - a";
     final Subtraction subtraction = new Subtraction(new Int(1), new Identifier("a"));
 
+    final ExpressionPrinter printer = new ExpressionPrinter();
 
     @Test
     public void testVisitAddition() {
-        ExpressionPrinter printer = new ExpressionPrinter();
-        assertEquals(additionCode, printer.getValue(addition));
+        assertEquals(additionCode, printer.print(addition));
     }
 
     @Test
     public void testVisitIdentifier() {
-        ExpressionPrinter printer = new ExpressionPrinter();
-        assertEquals(identifierCode, printer.getValue(identifier));
+        assertEquals(identifierCode, printer.print(identifier));
     }
 
     @Test
     public void testVisitInt() {
-        ExpressionPrinter printer = new ExpressionPrinter();
-        assertEquals(integerCode, printer.getValue(integer));
+        assertEquals(integerCode, printer.print(integer));
     }
 
     @Test
     public void testVisitSubtraction() {
-        ExpressionPrinter printer = new ExpressionPrinter();
-        assertEquals(subtractionCode, printer.getValue(subtraction));
+        assertEquals(subtractionCode, printer.print(subtraction));
     }
 
 }
\ No newline at end of file
diff --git a/src/test/java/printer/ProgramPrinterTest.java b/src/test/java/printer/ProgramPrinterTest.java
index 107f5e2..866c6a8 100644
--- a/src/test/java/printer/ProgramPrinterTest.java
+++ b/src/test/java/printer/ProgramPrinterTest.java
@@ -25,34 +25,31 @@ public class ProgramPrinterTest {
     final String programCode = compositionCode + " ; " + loopCode + " ; " + conditionalCode;
     final Program program = new Composition(new Composition(composition, loop), conditional);
 
+    final ProgramPrinter printer = new ProgramPrinter();
+
     @Test
     public void testVisitAssignment() {
-        ProgramPrinter printer = new ProgramPrinter();
-        assertEquals(assignmentCode, printer.getValue(assignment));
+        assertEquals(assignmentCode, printer.print(assignment));
     }
 
     @Test
     public void testVisitComposition() {
-        ProgramPrinter printer = new ProgramPrinter();
-        assertEquals(compositionCode, printer.getValue(composition));
+        assertEquals(compositionCode, printer.print(composition));
     }
 
     @Test
     public void testVisitConditional() {
-        ProgramPrinter printer = new ProgramPrinter();
-        assertEquals(conditionalCode, printer.getValue(conditional));
+        assertEquals(conditionalCode, printer.print(conditional));
     }
 
     @Test
     public void testVisitLoop() {
-        ProgramPrinter printer = new ProgramPrinter();
-        assertEquals(loopCode, printer.getValue(loop));
+        assertEquals(loopCode, printer.print(loop));
     }
 
     @Test
     public void testVisitProgram() {
-        ProgramPrinter printer = new ProgramPrinter();
-        assertEquals(programCode, printer.getValue(program));
+        assertEquals(programCode, printer.print(program));
     }
 
 }
\ No newline at end of file

From 271a93f6df0f2d031303a438bf2f2b2b8c942c96 Mon Sep 17 00:00:00 2001
From: Malte Schmitz <malte@schmitz-sh.de>
Date: Mon, 16 Jan 2017 18:12:20 +0100
Subject: [PATCH 6/6] Add option --print to CLI

---
 src/main/java/Main.java | 26 +++++++++++++++++++++++---
 1 file changed, 23 insertions(+), 3 deletions(-)

diff --git a/src/main/java/Main.java b/src/main/java/Main.java
index 4dfd0e5..6cb9697 100644
--- a/src/main/java/Main.java
+++ b/src/main/java/Main.java
@@ -3,6 +3,7 @@ import interpreter.InterpreterException;
 import parser.Parser;
 import parser.SyntaxException;
 import program.Program;
+import printer.ProgramPrinter;
 
 import java.io.IOException;
 import java.nio.charset.StandardCharsets;
@@ -14,12 +15,20 @@ public class Main {
     public static void main(String[] args) {
         if (args.length == 0) {
             System.err.println("No file given");
-        } else if (args.length > 1) {
-            System.err.println("Too many arguments");
         } else {
             try {
                 String code = readFile(args[0]);
-                run(code);
+                if (args.length == 2) {
+                  if ("--print".equals(args[1])) {
+                    print(code);
+                  } else {
+                    System.err.println("Invalid argument " + args[1]);
+                  }
+                } else if (args.length == 1) {
+                  run(code);
+                } else {
+                  System.err.println("Too many arguments");
+                }
             } catch (IOException e) {
                 e.printStackTrace();
             }
@@ -31,6 +40,17 @@ public class Main {
         return new String(encoded, StandardCharsets.UTF_8);
     }
 
+    private static void print(String code) {
+        try {
+            Parser parser = new Parser(code);
+            Program program = parser.parse();
+            ProgramPrinter printer = new ProgramPrinter();
+            System.out.println(printer.print(program));
+        } catch (SyntaxException se) {
+            System.err.println(se);
+        }
+    }
+
     private static void run(String code) {
         try {
             Parser parser = new Parser(code);