At parse time set a flag on index and field expressions when we detec…

parser/src/main/java/com/compilerprogramming/ezlang/parser/AST.java

@@ -372,9 +372,14 @@ public void accept(ASTVisitor visitor) {
     public static class ArrayIndexExpr extends Expr {
         public final Expr array;
         public final Expr expr;
+        public final boolean loading;
         public ArrayIndexExpr(Expr array, Expr expr) {
+            this(array, expr, true);
+        }
+        public ArrayIndexExpr(Expr array, Expr expr, boolean loading) {
             this.array = array;
             this.expr = expr;
+            this.loading = loading;
         }
         @Override
         public StringBuilder toStr(StringBuilder sb) {
@@ -398,9 +403,14 @@ public void accept(ASTVisitor visitor) {
     public static class FieldExpr extends Expr {
         public final Expr object;
         public final String fieldName;
+        public final boolean loading;
         public FieldExpr(Expr object, String fieldName) {
+            this(object, fieldName, true);
+        }
+        public FieldExpr(Expr object, String fieldName, boolean loading) {
             this.object = object;
             this.fieldName = fieldName;
+            this.loading = loading;
         }
         @Override
         public StringBuilder toStr(StringBuilder sb) {

parser/src/main/java/com/compilerprogramming/ezlang/parser/Parser.java

@@ -246,7 +246,19 @@ private AST.Stmt parseAssign(Lexer lexer) {
         testPunctuation(lexer, ";");
         if (rhs == null)
             return new AST.ExprStmt(lhs);
-        return new AST.AssignStmt(lhs, rhs);
+        return new AST.AssignStmt(storing(lhs), rhs);
+    }
+
+    private AST.Expr storing(AST.Expr lhs) {
+        if (lhs instanceof AST.ArrayIndexExpr arrayIndexExpr &&
+            arrayIndexExpr.loading) {
+            return new AST.ArrayIndexExpr(arrayIndexExpr.array, arrayIndexExpr.expr, false);
+        }
+        else if (lhs instanceof AST.FieldExpr fieldExpr &&
+                fieldExpr.loading) {
+            return new AST.FieldExpr(fieldExpr.object, fieldExpr.fieldName, false);
+        }
+        return lhs;
     }
 
     private AST.Expr parseBool(Lexer lexer) {