Refactor: Restructure project package hierarchy and add initial implementation for assembler instructions, shell commands, and exception handling.

src/jvmMain/kotlin/mtmc/lang/sea/ast/Statement.java

@@ -0,0 +1,25 @@
+package mtmc.lang.sea.ast;
+
+import mtmc.lang.ParseException;
+import mtmc.lang.sea.Token;
+
+public abstract sealed class Statement extends Ast permits StatementBlock, StatementBreak, StatementContinue, StatementDoWhile, StatementExpression, StatementFor, StatementGoto, StatementIf, StatementReturn, StatementSyntaxError, StatementVar, StatementWhile
+{
+    private Token labelAnchor = null;
+
+    public Statement(Token start, Token end) {
+        super(start, end);
+    }
+
+    public void setLabelAnchor(Token labelAnchor) throws ParseException {
+        if (labelAnchor == null) return;
+        if (this.labelAnchor != null) {
+            throw new ParseException(new ParseException.Message(labelAnchor, "this statement has been labeled twice!!"));
+        }
+        this.labelAnchor = labelAnchor;
+    }
+
+    public Token getLabelAnchor() {
+        return labelAnchor;
+    }
+}