Merge branch 'feature/variable-declaration' into 'master'

Feature/variable declaration

See merge request mkais001/klang!3

src/main/antlr4/de/hsrm/compiler/Klang/Klang.g4

@@ -23,6 +23,7 @@ braced_block
 statement
   : print
   | if_statement
+  | variable_declaration
   | variable_assignment
   | return_statement
   ;
@@ -35,6 +36,10 @@ if_statement
   : IF OPAR cond = expression CPAR then = braced_block (ELSE (alt = braced_block | elif = if_statement) )?
   ; 
 
+variable_declaration
+  : LET IDENT (EQUAL expression)? SCOL
+  ;
+
 variable_assignment
   : IDENT EQUAL expression SCOL
   ;
@@ -72,6 +77,7 @@ IF: 'if';
 ELSE: 'else';
 FUNC: 'function';
 RETURN: 'return';
+LET: 'let';
 
 SCOL: ';';
 OBRK: '{';

src/main/java/de/hsrm/compiler/Klang/ContextAnalysis.java

@@ -1,11 +1,16 @@
 package de.hsrm.compiler.Klang;
 
+import java.util.Set;
+import java.util.HashSet;
+
 import de.hsrm.compiler.Klang.nodes.*;
 import de.hsrm.compiler.Klang.nodes.expressions.*;
 import de.hsrm.compiler.Klang.nodes.statements.*;
 import de.hsrm.compiler.Klang.types.Type;
 
 public class ContextAnalysis extends KlangBaseVisitor<Node> {
+  Set<String> vars = new HashSet<>();
+
   @Override
   public Node visitProgram(KlangParser.ProgramContext ctx) {
     FunctionDefinition[] funcs = new FunctionDefinition[ctx.functionDef().size()];
@@ -52,9 +57,31 @@ public class ContextAnalysis extends KlangBaseVisitor<Node> {
     }
   }
 
+  @Override
+  public Node visitVariable_declaration(KlangParser.Variable_declarationContext ctx) {
+    String name = ctx.IDENT().getText();
+
+    if (this.vars.contains(name)) {
+      throw new RuntimeException("Redeclaration of variable with name \"" + name +"\".");
+    }
+
+    this.vars.add(name);
+
+    if (ctx.expression() != null) {
+      return new VariableDeclaration(name, (Expression) this.visit(ctx.expression()));
+    } else {
+      return new VariableDeclaration(name);
+    }
+  }
+
   @Override
   public Node visitVariable_assignment(KlangParser.Variable_assignmentContext ctx) {
     String name = ctx.IDENT().getText();
+
+    if (!this.vars.contains(name)) {
+      throw new RuntimeException("Variable with name \"" + name + "\" not defined.");
+    }
+
     Expression expression = (Expression) this.visit(ctx.expression());
     return new VariableAssignment(name, expression);
   }
@@ -97,6 +124,12 @@ public class ContextAnalysis extends KlangBaseVisitor<Node> {
 
   @Override
   public Node visitVariable(KlangParser.VariableContext ctx) {
+    String name = ctx.IDENT().getText();
+
+    if (!this.vars.contains(name)) {
+      throw new RuntimeException("Variable with name \"" + name + "\" not defined.");
+    }
+
     return new Variable(ctx.IDENT().getText());
   }
 
@@ -115,9 +148,16 @@ public class ContextAnalysis extends KlangBaseVisitor<Node> {
   @Override
   public Node visitFunctionDef(KlangParser.FunctionDefContext ctx) {
     String name = ctx.funcName.getText();
+
+    // Create a new set for the variables of the current function
+    // this will be filled in the variable declaration visitor aswell
+    this.vars = new HashSet<>();
+
     String[] params = new String[ctx.parameters().IDENT().size()];
     for (int i = 0; i < ctx.parameters().IDENT().size(); i++) {
-      params[i] = ctx.parameters().IDENT(i).getText();
+      String paramName = ctx.parameters().IDENT(i).getText();
+      params[i] = paramName;
+      this.vars.add(paramName); // add the param as a variable
     }
     Node block = this.visit(ctx.braced_block());
     return new FunctionDefinition(name, params, (Block) block);

src/main/java/de/hsrm/compiler/Klang/nodes/statements/VariableDeclaration.java

@@ -0,0 +1,23 @@
+package de.hsrm.compiler.Klang.nodes.statements;
+
+import de.hsrm.compiler.Klang.nodes.expressions.Expression;
+import de.hsrm.compiler.Klang.visitors.Visitor;
+
+public class VariableDeclaration extends Statement {
+    public String name;
+    public Expression expression;
+
+    public VariableDeclaration(String name, Expression expression) {
+        this.name = name;
+        this.expression = expression;
+    }
+
+    public VariableDeclaration(String name) {
+        this(name, null);
+    }
+
+    @Override
+    public <R> R welcome(Visitor<R> v) {
+        return v.visit(this);
+    }
+}

src/main/java/de/hsrm/compiler/Klang/visitors/EvalVisitor.java

@@ -101,6 +101,17 @@ public class EvalVisitor implements Visitor<Value> {
     return null;
   }
 
+  @Override
+  public Value visit(VariableDeclaration e) {
+    Value initialValue = null;
+    if (e.expression != null) {
+      initialValue = e.expression.welcome(this);
+    }
+
+    this.env.put(e.name, initialValue);
+    return null;
+  }
+
   @Override
   public Value visit(VariableAssignment e) {
     Value result = e.expression.welcome(this);

src/main/java/de/hsrm/compiler/Klang/visitors/GenASM.java

@@ -162,6 +162,18 @@ public class GenASM implements Visitor<Void> {
     throw new RuntimeException("Das machen wir mal nicht, ne?!");
   }
 
+  @Override
+  public Void visit(VariableDeclaration e) {
+    // If there is an initialization present,
+    // push it to the location of the local var
+    if (e.expression != null) {
+      e.expression.welcome(this);
+      int offset = this.env.get(e.name);
+      this.ex.write("    movq %rax, " + offset + "(%rbp)\n");
+    }
+    return null;
+  }
+
   @Override
   public Void visit(VariableAssignment e) {
     e.expression.welcome(this);

src/main/java/de/hsrm/compiler/Klang/visitors/GetVars.java

@@ -84,8 +84,13 @@ class GetVars implements Visitor<Void> {
   }
 
   @Override
-  public Void visit(VariableAssignment e) {
+  public Void visit(VariableDeclaration e) {
     vars.add(e.name);
+    return null;
+  }
+
+  @Override
+  public Void visit(VariableAssignment e) {
     e.expression.welcome(this);
     return null;
   }

src/main/java/de/hsrm/compiler/Klang/visitors/PrettyPrintVisitor.java

@@ -153,6 +153,18 @@ public class PrettyPrintVisitor implements Visitor<Void> {
         return null;
     }
 
+    @Override
+    public Void visit(VariableDeclaration e) {
+        ex.write("let " + e.name);
+
+        if (e.expression != null) {
+            ex.write(" = " + e.expression.welcome(this));
+        }
+
+        ex.write(";");
+        return null;
+    }
+
     @Override
     public Void visit(VariableAssignment e) {
         ex.write(e.name + " = ");

src/main/java/de/hsrm/compiler/Klang/visitors/Visitor.java

@@ -17,6 +17,7 @@ public interface Visitor<R> {
     R visit(NegateExpression e);
     R visit(IfStatement e);
     R visit(PrintStatement e);
+    R visit(VariableDeclaration e);
     R visit(VariableAssignment e);
     R visit(ReturnStatement e);
     R visit(Block e);