From 2af9f369cf85c1dde92903430a8e419ab4482604 Mon Sep 17 00:00:00 2001
From: nitrix <me@nitrix.one>
Date: Mon, 18 Nov 2019 18:54:24 +0100
Subject: [PATCH] implement variable assignment

---
 .../antlr4/de/hsrm/compiler/Klang/Klang.g4    | 10 +++++++--
 .../hsrm/compiler/Klang/ContextAnalysis.java  |  7 +++++++
 .../nodes/statements/VariableAssignment.java  | 21 +++++++++++++++++++
 .../compiler/Klang/visitors/EvalVisitor.java  |  7 +++++++
 .../Klang/visitors/PrettyPrintVisitor.java    | 10 ++++++++-
 .../hsrm/compiler/Klang/visitors/Visitor.java |  1 +
 6 files changed, 53 insertions(+), 3 deletions(-)
 create mode 100644 src/main/java/de/hsrm/compiler/Klang/nodes/statements/VariableAssignment.java

diff --git a/src/main/antlr4/de/hsrm/compiler/Klang/Klang.g4 b/src/main/antlr4/de/hsrm/compiler/Klang/Klang.g4
index d895218..27d0b70 100644
--- a/src/main/antlr4/de/hsrm/compiler/Klang/Klang.g4
+++ b/src/main/antlr4/de/hsrm/compiler/Klang/Klang.g4
@@ -5,7 +5,7 @@ parse
   ;
 
 program
-  : functionDef* expression
+  : functionDef* expression SCOL
   ;
 
 functionDef
@@ -23,6 +23,7 @@ braced_block
 statement
   : print
   | if_statement
+  | variable_assignment
   ;
 
 print
@@ -33,6 +34,10 @@ if_statement
   : IF OPAR cond = expression CPAR then = braced_block (ELSE (alt = braced_block | elif = if_statement) )?
   ;  
 
+variable_assignment
+  : IDENT EQUAL expression SCOL
+  ;
+
 expression
   : atom MULT atom #multiplicationExpression
   | atom op=(ADD | SUB) atom #additiveExpression
@@ -43,7 +48,7 @@ expression
   ;
 
 functionCall
-  : IDENT OPAR arguments CPAR SCOL
+  : IDENT OPAR arguments CPAR
   ;
 
 arguments
@@ -66,6 +71,7 @@ CBRK: '}';
 OPAR: '(';
 CPAR: ')';
 COMMA: ',';
+EQUAL: '=';
 
 MULT: '*';
 ADD: '+';
diff --git a/src/main/java/de/hsrm/compiler/Klang/ContextAnalysis.java b/src/main/java/de/hsrm/compiler/Klang/ContextAnalysis.java
index f2a62d2..83fc6e4 100644
--- a/src/main/java/de/hsrm/compiler/Klang/ContextAnalysis.java
+++ b/src/main/java/de/hsrm/compiler/Klang/ContextAnalysis.java
@@ -52,6 +52,13 @@ public class ContextAnalysis extends KlangBaseVisitor<Node> {
     }
   }
 
+  @Override
+  public Node visitVariable_assignment(KlangParser.Variable_assignmentContext ctx) {
+    String name = ctx.IDENT().getText();
+    Expression expression = (Expression) this.visit(ctx.expression());
+    return new VariableAssignment(name, expression);
+  }
+
   @Override
   public Node visitMultiplicationExpression(KlangParser.MultiplicationExpressionContext ctx) {
     Node left = this.visit(ctx.atom(0));
diff --git a/src/main/java/de/hsrm/compiler/Klang/nodes/statements/VariableAssignment.java b/src/main/java/de/hsrm/compiler/Klang/nodes/statements/VariableAssignment.java
new file mode 100644
index 0000000..73eb851
--- /dev/null
+++ b/src/main/java/de/hsrm/compiler/Klang/nodes/statements/VariableAssignment.java
@@ -0,0 +1,21 @@
+package de.hsrm.compiler.Klang.nodes.statements;
+
+import de.hsrm.compiler.Klang.nodes.expressions.Expression;
+import de.hsrm.compiler.Klang.visitors.Visitor;
+
+public class VariableAssignment extends Statement {
+
+    public String name;
+    public Expression expression;
+
+    public VariableAssignment(String name, Expression expression) {
+        this.name = name;
+        this.expression = expression;
+    }
+
+    @Override
+    public <R> R welcome(Visitor<R> v) {
+        return v.visit(this);
+    }
+
+}
\ No newline at end of file
diff --git a/src/main/java/de/hsrm/compiler/Klang/visitors/EvalVisitor.java b/src/main/java/de/hsrm/compiler/Klang/visitors/EvalVisitor.java
index cd639a2..8b0bdda 100644
--- a/src/main/java/de/hsrm/compiler/Klang/visitors/EvalVisitor.java
+++ b/src/main/java/de/hsrm/compiler/Klang/visitors/EvalVisitor.java
@@ -85,6 +85,13 @@ public class EvalVisitor implements Visitor<Value> {
     return null;
   }
 
+  @Override
+  public Value visit(VariableAssignment e) {
+    Value result = e.expression.welcome(this);
+    this.env.put(e.name, result);
+    return result;
+  }
+
   @Override
   public Value visit(Block e) {
     Value result = null;
diff --git a/src/main/java/de/hsrm/compiler/Klang/visitors/PrettyPrintVisitor.java b/src/main/java/de/hsrm/compiler/Klang/visitors/PrettyPrintVisitor.java
index 5f655d4..96a645d 100644
--- a/src/main/java/de/hsrm/compiler/Klang/visitors/PrettyPrintVisitor.java
+++ b/src/main/java/de/hsrm/compiler/Klang/visitors/PrettyPrintVisitor.java
@@ -125,6 +125,14 @@ public class PrettyPrintVisitor implements Visitor<Void> {
         return null;
     }
 
+    @Override
+    public Void visit(VariableAssignment e) {
+        ex.write(e.name + " = ");
+        e.expression.welcome(this);
+        ex.write(";");
+        return null;
+    }
+
     @Override
     public Void visit(Block e) {
         ex.write("{");
@@ -171,7 +179,7 @@ public class PrettyPrintVisitor implements Visitor<Void> {
             }
             arg.welcome(this);
         }
-        ex.write(");");
+        ex.write(")");
         return null;
     }
 
diff --git a/src/main/java/de/hsrm/compiler/Klang/visitors/Visitor.java b/src/main/java/de/hsrm/compiler/Klang/visitors/Visitor.java
index 7c2efd8..28cbbd5 100644
--- a/src/main/java/de/hsrm/compiler/Klang/visitors/Visitor.java
+++ b/src/main/java/de/hsrm/compiler/Klang/visitors/Visitor.java
@@ -15,6 +15,7 @@ public interface Visitor<R> {
     R visit(ModuloExpression e);
     R visit(IfStatement e);
     R visit(PrintStatement e);
+    R visit(VariableAssignment e);
     R visit(Block e);
     R visit(FunctionDefinition e);
     R visit(FunctionCall e);