5 files changed, 53 insertions, 5 deletions
diff --git a/src/ast/nodes/AtomNode.java b/src/ast/nodes/AtomNode.java
index cea617f..fef72ec 100644
--- a/src/ast/nodes/AtomNode.java
+++ b/src/ast/nodes/AtomNode.java
@@ -20,6 +20,10 @@ public class AtomNode implements Node {
         this.exprlist = (TestlistCompNode) exprlist;
     }
 
+    /**
+     * Returns the identifier of the `AtomNode` if it's not `null`, otherwise
+     * returns `null`.
+     */
     public String getId() {
         return this.val;
     }
diff --git a/src/ast/nodes/ExprListNode.java b/src/ast/nodes/ExprListNode.java
index acdf679..800f4be 100644
--- a/src/ast/nodes/ExprListNode.java
+++ b/src/ast/nodes/ExprListNode.java
@@ -31,7 +31,14 @@ public class ExprListNode implements Node {
         return exprs.size();
     }
 
+    /**
+     * Returns the i-th expressions of `exprs` field. If the index is greater or
+     * equals than the size return `null`.
+     */
     public Node getElem(int i) {
+        if (i >= this.exprs.size()) {
+            return null;
+        }
         return exprs.get(i);
     }
 
@@ -48,7 +55,7 @@ public class ExprListNode implements Node {
 
     @Override
     public String toPrint(String prefix) {
-        String str = prefix + "Paramlist\n";
+        String str = prefix + "ExprList\n";
 
         prefix += "  ";
         for (var param : exprs) {
diff --git a/src/ast/nodes/ExprNode.java b/src/ast/nodes/ExprNode.java
index 591ee37..8e3b896 100644
--- a/src/ast/nodes/ExprNode.java
+++ b/src/ast/nodes/ExprNode.java
@@ -26,6 +26,10 @@ public class ExprNode implements Node {
         this.trailers = trailers;
     }
 
+    /**
+     * Returns the i-th expressions of `exprs` field. If the index is greater or
+     * equals than the size return `null`.
+     */
     public Node getExpr(int i) {
         if (i >= this.exprs.size()) {
             return null;
@@ -34,6 +38,10 @@ public class ExprNode implements Node {
         return this.exprs.get(i);
     }
 
+    /**
+     * Returns the identifier of the `AtomNode` if it's not `null`, otherwise
+     * returns `null`.
+     */
     public String getId() {
         if (atom != null) {
             return ((AtomNode) this.atom).getId();
@@ -65,6 +73,7 @@ public class ExprNode implements Node {
                         for (var t : trailers) {
                             errors.addAll(t.checkSemantics(ST, _nesting));
                         }
+
                     } else {
                         FunctionType ft = (FunctionType) fun.getType();
                         int paramNumber = ft.getParamNumber();
@@ -80,6 +89,7 @@ public class ExprNode implements Node {
                 for (var trailer : trailers) {
                     errors.addAll(trailer.checkSemantics(ST, _nesting));
                 }
+
             }
         } else if (atom != null) {
             errors.addAll(atom.checkSemantics(ST, _nesting));
@@ -126,11 +136,11 @@ public class ExprNode implements Node {
         }
 
         for (var expr : exprs) {
-            str += expr.toPrint(prefix);
+            str = expr.toPrint(prefix);
         }
 
         for (var trailer : trailers) {
-            str += trailer.toPrint(prefix);
+            str = trailer.toPrint(prefix);
         }
 
         if (op != null) {
diff --git a/src/ast/nodes/ForStmtNode.java b/src/ast/nodes/ForStmtNode.java
index c5301ee..d4c5e56 100644
--- a/src/ast/nodes/ForStmtNode.java
+++ b/src/ast/nodes/ForStmtNode.java
@@ -18,18 +18,38 @@ public class ForStmtNode implements Node {
         this.block = block;
     }
 
+    /**
+     * This methods check the semantics of the operation `for i in list: block`.
+     *
+     * After the `for` keyword, it's parsed as a list of expression. We verified
+     * that the last expression is always gonna be `expr comp_op expr`. We
+     * comp_op must be the `in` keyword. `i` could be of any lenght (e.g. `a, b,
+     * c`).
+     *
+     * In this function we define the following approch: we save in the
+     * SymbolTable every atom until the last expression in the expression's
+     * list. For the last element, we know that is in the `expr comp_op expr`
+     * format, so we take the left element and save it in the SymbolicTable as
+     * an atom.
+     */
     @Override
     public ArrayList<SemanticError> checkSemantics(SymbolTable ST, int _nesting) {
         ArrayList<SemanticError> errors = new ArrayList<SemanticError>();
 
+        // Save every atom in the expression's list, except the last one
         var l = (ExprListNode) exprList;
         for (int i = 0; i < l.getSize() - 1; ++i) {
             var e = (ExprNode) l.getElem(i);
             ST.insert(e.getId(), e.typeCheck(), _nesting, "");
         }
 
+        // Manage the last expression of expression's list
+        // Get the ExprNode
         var left = (ExprNode) l.getElem(l.getSize() - 1);
+        // Get the left side expression of the operation, that
+        // corresponds to the first element of the expression list.
         var atomLeft = (ExprNode) left.getExpr(0);
+        // ENHANCE: check that the comp_op is the `in` keyword
         ST.insert(atomLeft.getId(), atomLeft.typeCheck(), _nesting, "");
 
         errors.addAll(exprList.checkSemantics(ST, _nesting));
diff --git a/src/ast/nodes/TestlistCompNode.java b/src/ast/nodes/TestlistCompNode.java
index 4ae77c9..244f4ef 100644
--- a/src/ast/nodes/TestlistCompNode.java
+++ b/src/ast/nodes/TestlistCompNode.java
@@ -10,8 +10,8 @@ import semanticanalysis.SymbolTable;
  */
 public class TestlistCompNode implements Node {
 
-    private final ArrayList<Node> exprs;
-    private final CompForNode comp;
+    private ArrayList<Node> exprs;
+    private CompForNode comp;
 
     public TestlistCompNode(ArrayList<Node> exprs, Node comp) {
         this.exprs = exprs;
@@ -45,7 +45,14 @@ public class TestlistCompNode implements Node {
         return exprs.size();
     }
 
+    /**
+     * Returns the i-th expressions of `exprs` field. If the index is greater or
+     * equals than the size return `null`.
+     */
     public Node getElem(int i) {
+        if (i >= this.exprs.size()) {
+            return null;
+        }
         return exprs.get(i);
     }