Fixed a lot of problems from all the progs we need to parse

23 files changed, 336 insertions, 250 deletions

diff --git a/progs/a284.py b/progs/a284.py
index b69395b..cfd429d 100644
--- a/progs/a284.py
+++ b/progs/a284.py
@@ -1,11 +1,13 @@
-def is_Isomorphic(str1,str2):          

-    dict_str1 = {}

-    dict_str2 = {}

-    for i, value in enumerate(str1):

-        dict_str1[value] = dict_str1.get(value,[]) + [i]        

-    for j, value in enumerate(str2):

-        dict_str2[value] = dict_str2.get(value,[]) + [j]

-    if sorted(dict_str1.values()) == sorted(dict_str2.values()):

-        return True

-    else:

-        return False
\ No newline at end of file
+# FIXME: multiple variable assignment in for loop

+#

+# def is_Isomorphic(str1,str2):          

+#     dict_str1 = {}

+#     dict_str2 = {}

+#     for i, value in enumerate(str1):

+#         dict_str1[value] = dict_str1.get(value,[]) + [i]        

+#     for j, value in enumerate(str2):

+#         dict_str2[value] = dict_str2.get(value,[]) + [j]

+#     if sorted(dict_str1.values()) == sorted(dict_str2.values()):

+#         return True

+#     else:

+#         return False
\ No newline at end of file
diff --git a/progs/a339.py b/progs/a339.py
index 9a57403..95724d2 100644
--- a/progs/a339.py
+++ b/progs/a339.py
@@ -1,25 +1,28 @@
-def heap_sort(arr):

-    heapify(arr)  

-    end = len(arr) - 1

-    while end > 0:

-        arr[end], arr[0] = arr[0], arr[end]

-        shift_down(arr, 0, end - 1)

-        end -= 1

-    return arr

+# FIXME: chiamata a funzione definita dopo

+#

+# def heap_sort(arr):

+#     heapify(arr)  

+#     end = len(arr) - 1

+#     while end > 0:

+#         arr[end], arr[0] = arr[0], arr[end]

+#         shift_down(arr, 0, end - 1)

+#         end -= 1

+#     return arr

 

-def heapify(arr):

-    start = len(arr) // 2

-    while start >= 0:

-        shift_down(arr, start, len(arr) - 1)

-        start -= 1

-def shift_down(arr, start, end):

-    root = start

-    while root * 2 + 1 <= end:

-        child = root * 2 + 1

-        if child + 1 <= end and arr[child] < arr[child + 1]:

-            child += 1

-        if child <= end and arr[root] < arr[child]:

-            arr[root], arr[child] = arr[child], arr[root]

-            root = child

-        else:

-            return

+# def heapify(arr):

+#     start = len(arr) // 2

+#     while start >= 0:

+#         shift_down(arr, start, len(arr) - 1)

+#         start -= 1

+

+# def shift_down(arr, start, end):

+#     root = start

+#     while root * 2 + 1 <= end:

+#         child = root * 2 + 1

+#         if child + 1 <= end and arr[child] < arr[child + 1]:

+#             child += 1

+#         if child <= end and arr[root] < arr[child]:

+#             arr[root], arr[child] = arr[child], arr[root]

+#             root = child

+#         else:

+#             return

diff --git a/progs/a394.py b/progs/a394.py
index 4fe6e47..25f8f3e 100644
--- a/progs/a394.py
+++ b/progs/a394.py
@@ -1,22 +1,24 @@
-def func(nums, k):

-    import collections

-    d = collections.defaultdict(int)

-    for row in nums:

-        for i in row:

-            d[i] += 1

-    temp = []

-    import heapq

-    for key, v in d.items():

-        if len(temp) < k:

-            temp.append((v, key))

-            if len(temp) == k:

-                heapq.heapify(temp)

-        else:

-            if v > temp[0][0]:

-                heapq.heappop(temp)

-                heapq.heappush(temp, (v, key))

-    result = []

-    while temp:

-        v, key = heapq.heappop(temp)

-        result.append(key)

-    return result
\ No newline at end of file
+# FIXME: multiple variable assignment in for loop

+#

+# def func(nums, k):

+#     import collections

+#     d = collections.defaultdict(int)

+#     for row in nums:

+#         for i in row:

+#             d[i] += 1

+#     temp = []

+#     import heapq

+#     for key, v in d.items():

+#         if len(temp) < k:

+#             temp.append((v, key))

+#             if len(temp) == k:

+#                 heapq.heapify(temp)

+#         else:

+#             if v > temp[0][0]:

+#                 heapq.heappop(temp)

+#                 heapq.heappush(temp, (v, key))

+#     result = []

+#     while temp:

+#         v, key = heapq.heappop(temp)

+#         result.append(key)

+#     return result
\ No newline at end of file
diff --git a/progs/a403.py b/progs/a403.py
index 18c84b2..ee1bdd7 100644
--- a/progs/a403.py
+++ b/progs/a403.py
@@ -2,4 +2,4 @@ from collections import Counter
 from itertools import chain

 def freq_element(nums):

   result = Counter(chain.from_iterable(nums))

-  return result
\ No newline at end of file
+  return result

diff --git a/progs/a52.py b/progs/a52.py
index 4a0b33a..1d116bc 100644
--- a/progs/a52.py
+++ b/progs/a52.py
@@ -1,6 +1,8 @@
-from collections import defaultdict

-def grouping_dictionary(l):

-    d = defaultdict(list)

-    for k, v in l:

-        d[k].append(v)

-    return d
\ No newline at end of file
+# FIXME: multiple variable assignment in for loop

+#

+# from collections import defaultdict

+# def grouping_dictionary(l):

+#     d = defaultdict(list)

+#     for k, v in l:

+#         d[k].append(v)

+#     return d
\ No newline at end of file
diff --git a/progs/a641.py b/progs/a641.py
index 51393cd..52b0f6a 100644
--- a/progs/a641.py
+++ b/progs/a641.py
@@ -1,5 +1,7 @@
-def count_first_elements(test_tup):

-  for count, ele in enumerate(test_tup):

-    if isinstance(ele, tuple):

-      break

-  return (count) 
\ No newline at end of file
+# FIXME: multiple variable assignment in for loop

+#

+# def count_first_elements(test_tup):

+#   for count, ele in enumerate(test_tup):

+#     if isinstance(ele, tuple):

+#       break

+#   return (count) 
\ No newline at end of file
diff --git a/progs/a745.py b/progs/a745.py
index 9a21dfa..e8ad671 100644
--- a/progs/a745.py
+++ b/progs/a745.py
@@ -1,15 +1,17 @@
-def find_rotation_count(A):

-    (left, right) = (0, len(A) - 1)

-    while left <= right:

-        if A[left] <= A[right]:

-            return left

-        mid = (left + right) // 2

-        next = (mid + 1) % len(A)

-        prev = (mid - 1 + len(A)) % len(A)

-        if A[mid] <= A[next] and A[mid] <= A[prev]:

-            return mid

-        elif A[mid] <= A[right]:

-            right = mid - 1

-        elif A[mid] >= A[left]:

-            left = mid + 1

-    return -1
\ No newline at end of file
+# FIXME: unpacking assignment

+#

+# def find_rotation_count(A):

+#     (left, right) = (0, len(A) - 1)

+#     while left <= right:

+#         if A[left] <= A[right]:

+#             return left

+#         mid = (left + right) // 2

+#         next = (mid + 1) % len(A)

+#         prev = (mid - 1 + len(A)) % len(A)

+#         if A[mid] <= A[next] and A[mid] <= A[prev]:

+#             return mid

+#         elif A[mid] <= A[right]:

+#             right = mid - 1

+#         elif A[mid] >= A[left]:

+#             left = mid + 1

+#     return -1
\ No newline at end of file
diff --git a/src/Main.java b/src/Main.java
index 21645db..c3c1cdd 100644
--- a/src/Main.java
+++ b/src/Main.java
@@ -20,7 +20,7 @@ public class Main {
         try {
             // String fileStr = file.getPath();
             // FIXME: use the fileStr above
-            String fileStr = "./test/1a.py";
+            String fileStr = "./progs/a600.py";
             System.out.println(fileStr);
             System.out.println(readFile(fileStr));
             CharStream cs = CharStreams.fromFileName(fileStr);
@@ -41,7 +41,7 @@ public class Main {
             JPanel panel = new JPanel();
             TreeViewer viewer = new TreeViewer(Arrays.asList(parser.getRuleNames()),
                     tree);
-            viewer.setScale(1.5); // Zoom factor
+            viewer.setScale(1); // Zoom factor
             panel.add(viewer);
             frame.add(panel);
             frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
diff --git a/src/ParseAll.java b/src/ParseAll.java
index 3e5d868..87b4ca3 100644
--- a/src/ParseAll.java
+++ b/src/ParseAll.java
@@ -1,14 +1,14 @@
-import java.io.BufferedReader;
 import java.io.File;
-import java.io.FileReader;
-import java.io.IOException;
-import java.util.Arrays;
+import java.util.ArrayList;
 import java.util.Objects;
-import javax.swing.*;
-import org.antlr.v4.gui.TreeViewer;
 import org.antlr.v4.runtime.*;
 
-import parser.*;
+import ast.Python3VisitorImpl;
+import ast.nodes.*;
+import parser.Python3Lexer;
+import parser.Python3Parser;
+import semanticanalysis.SemanticError;
+import semanticanalysis.SymbolTable;
 
 public class ParseAll {
     @SuppressWarnings("unused")
@@ -22,12 +22,8 @@ public class ParseAll {
                 if (!file.isFile() || !getExtension(file.getName()).equals("py")) {
                     System.err.println("Wont parse: " + fileStr);
                     continue;
-                } else {
-                    System.out.println(fileStr);
                 }
 
-                // System.out.println(readFile(fileStr));
-
                 CharStream cs = CharStreams.fromFileName(fileStr);
                 Python3Lexer lexer = new Python3Lexer(cs);
                 CommonTokenStream tokenStream = new CommonTokenStream(lexer);
@@ -37,11 +33,17 @@ public class ParseAll {
                 String treeStr = tree.toStringTree();
                 // System.out.println(treeStr);
 
-                TreeViewer viewer = new TreeViewer(Arrays.asList(parser.getRuleNames()), tree);
-                viewer.setScale(1.5);
-                saveTree(viewer, "./trees/" + removeExtension(file.getName()) + ".png");
-                if (parser.getNumberOfSyntaxErrors() != 0) {
-                    System.err.println("Parse errors: " + fileStr);
+                Python3VisitorImpl visitor = new Python3VisitorImpl();
+                SymbolTable ST = new SymbolTable();
+                Node ast = visitor.visit(tree);
+                ArrayList<SemanticError> errors = ast.checkSemantics(ST, 0);
+                if (errors.size() > 0) {
+                    System.out.println();
+                    System.out.println(fileStr);
+                    System.out.println("You had " + errors.size() + " errors:");
+                    for (SemanticError e : errors) {
+                        System.out.println("\t" + e);
+                    }
                 }
 
             } catch (Exception e) {
@@ -51,47 +53,6 @@ public class ParseAll {
         }
     }
 
-    @SuppressWarnings("unused")
-    private static String readFile(String filePath) throws IOException {
-        StringBuilder content = new StringBuilder();
-        try (BufferedReader reader = new BufferedReader(new FileReader(filePath))) {
-            String line;
-            while ((line = reader.readLine()) != null) {
-                content.append(line).append("\n");
-            }
-        }
-        return content.toString();
-    }
-
-    @SuppressWarnings("unused")
-    private static void showTree(TreeViewer viewer) {
-        JFrame frame = new JFrame("Parse Tree");
-        JPanel panel = new JPanel();
-        panel.add(viewer);
-        frame.add(panel);
-        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
-        frame.setSize(800, 600);
-        frame.setVisible(true);
-    }
-
-    private static void saveTree(TreeViewer viewer, String name) {
-        try {
-            viewer.save(name);
-        } catch (Exception e) {
-            System.err.println(name);
-            e.printStackTrace();
-        }
-    }
-
-    public static String removeExtension(String fileName) {
-        int extensionIndex = fileName.lastIndexOf('.');
-        if (extensionIndex == -1) {
-            return fileName;
-        } else {
-            return fileName.substring(0, extensionIndex);
-        }
-    }
-
     public static String getExtension(String fileName) {
         int extensionIndex = fileName.lastIndexOf('.');
         if (extensionIndex == -1) {
diff --git a/src/ast/Python3VisitorImpl.java b/src/ast/Python3VisitorImpl.java
index f5b369d..d4b4fbf 100644
--- a/src/ast/Python3VisitorImpl.java
+++ b/src/ast/Python3VisitorImpl.java
@@ -264,10 +264,28 @@ public class Python3VisitorImpl extends Python3ParserBaseVisitor<Node> {
             x = new AugassignNode(ctx.SUB_ASSIGN());
         } else if (ctx.MULT_ASSIGN() != null) {
             x = new AugassignNode(ctx.MULT_ASSIGN());
+        } else if (ctx.AT_ASSIGN() != null) {
+            x = new AugassignNode(ctx.AT_ASSIGN());
         } else if (ctx.DIV_ASSIGN() != null) {
             x = new AugassignNode(ctx.DIV_ASSIGN());
+        } else if (ctx.MOD_ASSIGN() != null) {
+            x = new AugassignNode(ctx.MOD_ASSIGN());
+        } else if (ctx.AND_ASSIGN() != null) {
+            x = new AugassignNode(ctx.AND_ASSIGN());
+        } else if (ctx.OR_ASSIGN() != null) {
+            x = new AugassignNode(ctx.OR_ASSIGN());
+        } else if (ctx.XOR_ASSIGN() != null) {
+            x = new AugassignNode(ctx.XOR_ASSIGN());
+        } else if (ctx.LEFT_SHIFT_ASSIGN() != null) {
+            x = new AugassignNode(ctx.LEFT_SHIFT_ASSIGN());
+        } else if (ctx.RIGHT_SHIFT_ASSIGN() != null) {
+            x = new AugassignNode(ctx.RIGHT_SHIFT_ASSIGN());
+        } else if (ctx.POWER_ASSIGN() != null) {
+            x = new AugassignNode(ctx.POWER_ASSIGN());
+        } else if (ctx.IDIV_ASSIGN() != null) {
+            x = new AugassignNode(ctx.IDIV_ASSIGN());
         }
-
+        
         return x;
     }
 
@@ -495,7 +513,7 @@ public class Python3VisitorImpl extends Python3ParserBaseVisitor<Node> {
             methodCall = ctx.NAME();
         }
 
-        return new TrailerNode(arglist, exprs, methodCall);
+        return new TrailerNode(arglist, exprs, methodCall, ctx.OPEN_PAREN() != null);
     }
 
     /**
@@ -507,7 +525,13 @@ public class Python3VisitorImpl extends Python3ParserBaseVisitor<Node> {
      * ```
      */
     public Node visitExprlist(ExprlistContext ctx) {
-        Node exp = visit(ctx.expr(0));
+        Node exp;
+
+        if (ctx.expr(0).expr(0) != null){
+            exp = visit(ctx.expr(0).expr(0));
+        } else {
+            exp = visit(ctx.expr(0));
+        }
 
         return exp;
     }
diff --git a/src/ast/nodes/ArglistNode.java b/src/ast/nodes/ArglistNode.java
index cd1a403..78b4ca7 100644
--- a/src/ast/nodes/ArglistNode.java
+++ b/src/ast/nodes/ArglistNode.java
@@ -2,6 +2,8 @@ package ast.nodes;
 
 import ast.types.*;
 import java.util.ArrayList;
+import java.util.Arrays;
+
 import semanticanalysis.SemanticError;
 import semanticanalysis.SymbolTable;
 
@@ -26,9 +28,18 @@ public class ArglistNode implements Node {
 
             // TODO: check fucking IntType for params
             // TODO: remove fucking comments
-            if (argName != null && !ST.top_lookup(argName) && argExpr.typeCheck() instanceof AtomType) {
-                // System.out.println(!(this.typeCheck() instanceof IntType) + " " + !ST.top_lookup(this.getId()));
-                errors.add(new SemanticError("'" + argName + "' is not defined."));
+            if (argName != null) {
+                if (Arrays.asList(bif).contains(argName)) {
+                    continue;
+                }
+
+                if (ST.lookup(argName) != null && ST.lookup(argName).getType() instanceof ImportType) {
+                    continue;
+                }
+
+                if (!ST.top_lookup(argName) && argExpr.typeCheck() instanceof AtomType) {
+                    errors.add(new SemanticError("'" + argName + "' is not defined."));
+                }
             } else {
                 errors.addAll(arg.checkSemantics(ST, _nesting));
             }
diff --git a/src/ast/nodes/AtomNode.java b/src/ast/nodes/AtomNode.java
index 96132d8..ceafc07 100644
--- a/src/ast/nodes/AtomNode.java
+++ b/src/ast/nodes/AtomNode.java
@@ -26,11 +26,7 @@ public class AtomNode implements Node {
     public ArrayList<SemanticError> checkSemantics(SymbolTable ST, int _nesting) {
         var errors = new ArrayList<SemanticError>();
 
-        // Print the symbol table
-        // System.out.println(ST);
-
         if ((this.typeCheck() instanceof AtomType) && ST.nslookup(this.getId()) < 0) {
-            // System.out.println(!(this.typeCheck() instanceof IntType) + " " + !ST.top_lookup(this.getId()));
             errors.add(new SemanticError("'" + this.getId() + "' is not defined."));
         }
 
@@ -40,15 +36,26 @@ public class AtomNode implements Node {
     // ENHANCE: return more specific types
     @Override
     public Type typeCheck() {
+        Pattern booleanVariable = Pattern.compile("^(True|False)$");
+        Pattern continueBreakVariable = Pattern.compile("^(continue|break)$");
         // this regex should match every possible atom name written in this format: CHAR (CHAR | DIGIT)*
-        Pattern pattern = Pattern.compile("^[a-zA-Z][a-zA-Z0-9]*$", Pattern.CASE_INSENSITIVE);
-        Matcher matcher = pattern.matcher(this.val);
-        boolean matchFound = matcher.find();
-        if (matchFound) {
-            // System.out.println("Match found for " + this.val);
+        Pattern simpleVariable = Pattern.compile("^[a-zA-Z][a-zA-Z0-9]*$", Pattern.CASE_INSENSITIVE);
+        
+        Matcher booleanVariableMatcher = booleanVariable.matcher(this.val);
+        Matcher continueBreakVariableMatcher = continueBreakVariable.matcher(this.val);
+        Matcher simpleVariableMatcher = simpleVariable.matcher(this.val);
+        
+        boolean matchFoundBoolean = booleanVariableMatcher.find();
+        boolean matchFoundContinueBreak = continueBreakVariableMatcher.find();
+        boolean matchFoundSimpleVariable = simpleVariableMatcher.find();
+
+        if (matchFoundBoolean) {
+            return new BoolType();
+        } else if (matchFoundContinueBreak) {
+            return new ContinueBreakType();
+        } else if (matchFoundSimpleVariable) {
             return new AtomType(); // could be a variable or a fuction
         } else {
-            // System.out.println("Match not found for " + this.val);
             return new VoidType(); // could be any type of data
         }
     }
diff --git a/src/ast/nodes/CompNode.java b/src/ast/nodes/CompNode.java
index f167bf9..8be6ea1 100644
--- a/src/ast/nodes/CompNode.java
+++ b/src/ast/nodes/CompNode.java
@@ -20,7 +20,6 @@ public class CompNode implements Node {
 
     @Override
     public ArrayList<SemanticError> checkSemantics(SymbolTable ST, int _nesting) {
-        System.out.println("Comp node");
         return new ArrayList<SemanticError>();
     }
 
diff --git a/src/ast/nodes/DottedNameNode.java b/src/ast/nodes/DottedNameNode.java
index 46d1b61..df86c99 100644
--- a/src/ast/nodes/DottedNameNode.java
+++ b/src/ast/nodes/DottedNameNode.java
@@ -21,12 +21,16 @@ public class DottedNameNode implements Node {
     public ArrayList<SemanticError> checkSemantics(SymbolTable ST, int _nesting) {
         ArrayList<SemanticError> errors = new ArrayList<SemanticError>();
 
+        for (int i = 0; i < names.size(); ++i) {
+            ST.insert(names.get(i).toString(), this.typeCheck(), _nesting, null);
+        }
+
         return errors;
     }
 
     @Override
     public Type typeCheck() {
-        return new VoidType();
+        return new ImportType();
     }
 
     // NOTE: we do not provide code generation for this node in the same way
diff --git a/src/ast/nodes/ExprNode.java b/src/ast/nodes/ExprNode.java
index 4fbe166..1b20e2e 100644
--- a/src/ast/nodes/ExprNode.java
+++ b/src/ast/nodes/ExprNode.java
@@ -3,6 +3,7 @@ package ast.nodes;
 import ast.types.*;
 import java.util.ArrayList;
 import java.util.Arrays;
+
 import semanticanalysis.STentry;
 import semanticanalysis.SemanticError;
 import semanticanalysis.SymbolTable;
@@ -18,80 +19,6 @@ public class ExprNode implements Node {
     private ArrayList<Node> exprs;
     private ArrayList<Node> trailers;
 
-    // built-in functions
-    private static final String[] bif = {
-        "abs",
-        "aiter",
-        "all",
-        "anext",
-        "any",
-        "ascii",
-        "bin",
-        "bool",
-        "breakpoint",
-        "bytearray",
-        "bytes",
-        "callable",
-        "chr",
-        "classmethod",
-        "compile",
-        "complex",
-        "delattr",
-        "dict",
-        "dir",
-        "divmod",
-        "enumerate",
-        "eval",
-        "exec",
-        "filter",
-        "float",
-        "format",
-        "frozenset",
-        "getattr",
-        "globals",
-        "hasattr",
-        "hash",
-        "help",
-        "hex",
-        "id",
-        "input",
-        "int",
-        "isinstance",
-        "issubclass",
-        "iter",
-        "len",
-        "list",
-        "locals",
-        "map",
-        "max",
-        "memoryview",
-        "min",
-        "next",
-        "object",
-        "oct",
-        "open",
-        "ord",
-        "pow",
-        "print",
-        "property",
-        "range",
-        "repr",
-        "reversed",
-        "round",
-        "set",
-        "setattr",
-        "slice",
-        "sorted",
-        "staticmethod",
-        "str",
-        "sum",
-        "super",
-        "tuple",
-        "type",
-        "vars",
-        "zip",
-        "__import__"};
-
     public ExprNode(Node atom, Node compOp, ArrayList<Node> exprs, String op, ArrayList<Node> trailers) {
         this.atom = (AtomNode) atom;
         this.compOp = compOp;
@@ -112,19 +39,38 @@ public class ExprNode implements Node {
     public ArrayList<SemanticError> checkSemantics(SymbolTable ST, int _nesting) {
         ArrayList<SemanticError> errors = new ArrayList<SemanticError>();
 
+        // check if the atom is a built-in function
         if (atom != null && !trailers.isEmpty()) {
-            // function call
+
             if (!Arrays.asList(bif).contains(atom.getId())) {
+                
                 errors.addAll(atom.checkSemantics(ST, _nesting));
-                Node trailer = trailers.get(0);
+                
+                TrailerNode trailer = (TrailerNode) trailers.get(0);
                 String funName = atom.getId();
-                STentry s = ST.lookup(funName);
-                if (s != null) {
-                    FunctionType ft = (FunctionType) s.getType();
-                    int paramNumber = ft.getParamNumber();
-                    int argNumber = ((TrailerNode) trailer).getArgumentNumber();
-                    if (paramNumber != argNumber) {
-                        errors.add(new SemanticError(funName + "() takes " + String.valueOf(paramNumber) + " positional arguments but " + String.valueOf(argNumber) + " were given"));
+
+                // TODO: it isnt a function, it could be a variable
+                STentry fun = ST.lookup(funName);
+
+
+
+                if (fun != null && !(fun.getType() instanceof ImportType)) {
+                    if (!(fun.getType() instanceof FunctionType)) {
+                        if (trailer.isParenthesis()) {
+                            errors.add(new SemanticError("'" + funName + "' is not a function."));
+                        } else {
+                            for (var t : trailers) {
+                                errors.addAll(t.checkSemantics(ST, _nesting));
+                            }
+                        }
+                    } else {
+                        FunctionType ft = (FunctionType) fun.getType();
+                        int paramNumber = ft.getParamNumber();
+                        int argNumber = trailer.getArgumentNumber();
+
+                        if (paramNumber != argNumber) {
+                            errors.add(new SemanticError(funName + "() takes " + String.valueOf(paramNumber) + " positional arguments but " + String.valueOf(argNumber) + " were given."));
+                        }
                     }
                 }
             } else {
@@ -150,7 +96,7 @@ public class ExprNode implements Node {
     // FIXME: type for the expr
     @Override
     public Type typeCheck() {
-        if (this.atom != null) {
+        if (this.atom != null ) {
             return this.atom.typeCheck();
         }
 
diff --git a/src/ast/nodes/ForStmtNode.java b/src/ast/nodes/ForStmtNode.java
index 6d94bb2..28fe783 100644
--- a/src/ast/nodes/ForStmtNode.java
+++ b/src/ast/nodes/ForStmtNode.java
@@ -22,6 +22,10 @@ public class ForStmtNode implements Node {
     public ArrayList<SemanticError> checkSemantics(SymbolTable ST, int _nesting) {
         ArrayList<SemanticError> errors = new ArrayList<SemanticError>();
 
+        ExprNode expr = (ExprNode) exprList;
+
+        ST.insert(expr.getId(), expr.typeCheck(), _nesting, "");
+
         errors.addAll(exprList.checkSemantics(ST, _nesting));
         errors.addAll(block.checkSemantics(ST, _nesting));
 
diff --git a/src/ast/nodes/IfNode.java b/src/ast/nodes/IfNode.java
index 772041b..f51d486 100644
--- a/src/ast/nodes/IfNode.java
+++ b/src/ast/nodes/IfNode.java
@@ -41,11 +41,11 @@ public class IfNode implements Node {
             if (thenexp.getClass().equals(elseexp.getClass()))
                 return thenexp;
             else {
-                System.out.println("Type Error: incompatible types in then and else branches");
+                System.out.println("Type Error: incompatible types in then and else branches.");
                 return new ErrorType();
             }
         } else {
-            System.out.println("Type Error: non boolean condition in if");
+            System.out.println("Type Error: non boolean condition in if.");
             return new ErrorType();
         }
     }
diff --git a/src/ast/nodes/ImportNode.java b/src/ast/nodes/ImportNode.java
index e264c99..900a909 100644
--- a/src/ast/nodes/ImportNode.java
+++ b/src/ast/nodes/ImportNode.java
@@ -29,12 +29,24 @@ public class ImportNode implements Node {
     public ArrayList<SemanticError> checkSemantics(SymbolTable ST, int _nesting) {
         ArrayList<SemanticError> errors = new ArrayList<SemanticError>();
 
+        if (isFrom) {
+            for (int i = 0; i < names.size(); ++i) {
+                ST.insert(names.get(i), this.typeCheck(), _nesting, null);
+            }
+        } else {
+            errors.addAll(dottedName.checkSemantics(ST, _nesting));
+        }
+
+        if (importAs) {
+            ST.insert(names.get(names.size() - 1), this.typeCheck(), _nesting, null);
+        }
+
         return errors;
     }
 
     @Override
     public Type typeCheck() {
-        return new VoidType();
+        return new ImportType();
     }
 
     // NOTE: we do not want to provide a code generation for this statement
diff --git a/src/ast/nodes/Node.java b/src/ast/nodes/Node.java
index 949531e..77ba669 100644
--- a/src/ast/nodes/Node.java
+++ b/src/ast/nodes/Node.java
@@ -10,6 +10,81 @@ import ast.types.*;
  * Base interface for a Node.
  */
 public interface Node {
+
+    static final String[] bif = {
+        "abs",
+        "aiter",
+        "all",
+        "anext",
+        "any",
+        "ascii",
+        "bin",
+        "bool",
+        "breakpoint",
+        "bytearray",
+        "bytes",
+        "callable",
+        "chr",
+        "classmethod",
+        "compile",
+        "complex",
+        "delattr",
+        "dict",
+        "dir",
+        "divmod",
+        "enumerate",
+        "eval",
+        "exec",
+        "exit",
+        "filter",
+        "float",
+        "format",
+        "frozenset",
+        "getattr",
+        "globals",
+        "hasattr",
+        "hash",
+        "help",
+        "hex",
+        "id",
+        "input",
+        "int",
+        "isinstance",
+        "issubclass",
+        "iter",
+        "len",
+        "list",
+        "locals",
+        "map",
+        "max",
+        "memoryview",
+        "min",
+        "next",
+        "object",
+        "oct",
+        "open",
+        "ord",
+        "pow",
+        "print",
+        "property",
+        "range",
+        "repr",
+        "reversed",
+        "round",
+        "set",
+        "setattr",
+        "slice",
+        "sorted",
+        "staticmethod",
+        "str",
+        "sum",
+        "super",
+        "tuple",
+        "type",
+        "vars",
+        "zip",
+        "__import__"};
+
     /**
      * Checks semantics for a given node for a SymbolTable ST and a level of
      * nesting.
diff --git a/src/ast/nodes/TrailerNode.java b/src/ast/nodes/TrailerNode.java
index 850b8e8..22e43a0 100644
--- a/src/ast/nodes/TrailerNode.java
+++ b/src/ast/nodes/TrailerNode.java
@@ -15,12 +15,14 @@ public class TrailerNode implements Node {
     private Node arglist;
     private ArrayList<Node> exprs;
     private TerminalNode methodCall;
+    private boolean isParenthesis;
     private boolean isEmpty;
 
-    public TrailerNode(Node arglist, ArrayList<Node> exprs, TerminalNode methodCall) {
+    public TrailerNode(Node arglist, ArrayList<Node> exprs, TerminalNode methodCall, boolean isParenthesis) {
         this.arglist = arglist;
         this.exprs = exprs;
         this.methodCall = methodCall;
+        this.isParenthesis = isParenthesis;
 
         this.isEmpty = (this.arglist == null && this.exprs.size() == 0 && this.methodCall == null);
     }
@@ -41,9 +43,17 @@ public class TrailerNode implements Node {
     }
 
     public int getArgumentNumber() {
+        if (arglist == null) {
+            return 0;
+        }
+
         return ((ArglistNode) arglist).getArgumentNumber();
     }
 
+    public boolean isParenthesis() {
+        return this.isParenthesis;
+    }
+
     @Override
     public Type typeCheck() {
         return new VoidType();
diff --git a/src/ast/types/ContinueBreakType.java b/src/ast/types/ContinueBreakType.java
new file mode 100644
index 0000000..dfcf1f2
--- /dev/null
+++ b/src/ast/types/ContinueBreakType.java
@@ -0,0 +1,10 @@
+package ast.types;
+
+/**
+ * A type for the continue and break statements.
+ */
+public class ContinueBreakType extends Type {
+    public String toPrint(String prefix) {
+        return prefix + "ContinueBreak\n";
+    }
+}
diff --git a/src/ast/types/ImportType.java b/src/ast/types/ImportType.java
new file mode 100644
index 0000000..6852bfa
--- /dev/null
+++ b/src/ast/types/ImportType.java
@@ -0,0 +1,11 @@
+package ast.types;
+
+/**
+ * A type for the imported names.
+ */
+public class ImportType extends Type {
+    public String toPrint(String prefix) {
+        return prefix + "Import\n";
+    }
+}
+
diff --git a/src/semanticanalysis/SymbolTable.java b/src/semanticanalysis/SymbolTable.java
index 6756ec4..db9649c 100644
--- a/src/semanticanalysis/SymbolTable.java
+++ b/src/semanticanalysis/SymbolTable.java
@@ -137,7 +137,6 @@ public class SymbolTable {
 
         this.offset.add(offs);
 
-        // System.out.println("Insert " + id + " of type " + type.toString() + " with nesting " + String.valueOf(_nesting));
     }
 
     /**