Loop variable 'it' tracks the repetition count in the scope closing #5,…

… also closes #4

src/main/antlr/MellowDParser.g4

@@ -190,7 +190,7 @@ value
 //Each mapping is put into the compiler's symbol table. Adding a `*` after the assignment token
 //parses the value as if it was inside a percussion block.
 varDeclaration
-    :   IDENTIFIER ASSIGNMENT STAR? value
+    :   identifier ASSIGNMENT STAR? value
     ;
 
 //Dynamics are what change the velocity of a note. Mellow D supports the main dynamic identifiers

src/main/java/cas/cs4tb3/mellowd/intermediate/executable/statements/RepeatedCodeBlock.java

@@ -2,9 +2,12 @@
 
 import cas.cs4tb3.mellowd.intermediate.Output;
 import cas.cs4tb3.mellowd.intermediate.executable.expressions.Expression;
+import cas.cs4tb3.mellowd.intermediate.variables.Memory;
 import cas.cs4tb3.mellowd.parser.ExecutionEnvironment;
 
 public class RepeatedCodeBlock extends CodeBlock {
+    public static final String IMPLICIT_LOOP_COUNTER_ID = "it";
+
     protected final Expression<Number> repetitions;
 
     public RepeatedCodeBlock(Expression<Number> repetitions) {
@@ -15,10 +18,16 @@ public RepeatedCodeBlock(Expression<Number> repetitions) {
     @Override
     public void execute(ExecutionEnvironment environment, Output output) {
         int repetitions = this.repetitions.evaluate(environment).intValue();
+        Memory memory = environment.getMemory();
+        Object old = memory.get(IMPLICIT_LOOP_COUNTER_ID);
+
         for (int i = 0; i < repetitions; i++) {
+            memory.set(IMPLICIT_LOOP_COUNTER_ID, i);
             for (Statement stmt : super.statements) {
                 stmt.execute(environment, output);
             }
         }
+
+        memory.set(IMPLICIT_LOOP_COUNTER_ID, old);
     }
 }

src/main/java/cas/cs4tb3/mellowd/parser/MellowDCompiler.java

@@ -111,7 +111,7 @@ public Integer visitNumber(MellowDParser.NumberContext ctx) {
     @Override
     public Expression<Integer> visitNumberOrId(MellowDParser.NumberOrIdContext ctx) {
         MellowDParser.IdentifierContext idCtx = ctx.identifier();
-        if (idCtx != null) return lookupIdentifier(idCtx, Integer.class);
+        if (idCtx != null) return new RuntimeNullCheck<>(idCtx.getText(), lookupIdentifier(idCtx, Integer.class), idCtx);
         return new Constant<>(visitNumber(ctx.number()));
     }
 
@@ -416,9 +416,11 @@ public Expression<?> visitValue(MellowDParser.ValueContext ctx) {
     public Statement visitVarDeclaration(MellowDParser.VarDeclarationContext ctx, boolean isField) {
         boolean percussionToggle = ctx.STAR() != null;
 
+        Identifier identifier = visitIdentifier(ctx.identifier());
+
         Expression<?> valueExpr = visitValue(ctx.value());
 
-        return new AssignmentStatement(new String[0], ctx.IDENTIFIER().getText(), valueExpr, isField, percussionToggle);
+        return new AssignmentStatement(identifier.qualifier, identifier.name, valueExpr, isField, percussionToggle);
     }
 
     @Override