left, right = 1, 2 assignment covered

sfaccimm ho fatto refactoring dell exprlist

8 files changed, 262 insertions, 122 deletions

diff --git a/src/ast/Python3VisitorImpl.java b/src/ast/Python3VisitorImpl.java
index d4b4fbf..5b812ea 100644
--- a/src/ast/Python3VisitorImpl.java
+++ b/src/ast/Python3VisitorImpl.java
@@ -12,20 +12,19 @@ import org.antlr.v4.runtime.tree.TerminalNode;
  * Overrides each `visitNODE` method from the base class.
  */
 public class Python3VisitorImpl extends Python3ParserBaseVisitor<Node> {
+
     /**
      * Since a root can be a simple_stmts or a compound_stmt, this method
      * returns a new `RootNode` with a list of them.
      *
-     * ```
-     * root : NEWLINE* (simple_stmts | compound_stmt)* EOF;
-     * ```
+     * ``` root : NEWLINE* (simple_stmts | compound_stmt)* EOF; ```
      */
     public Node visitRoot(RootContext ctx) {
         ArrayList<Node> childs = new ArrayList<Node>();
-        
-        for (int i = 0; i < ctx.getChildCount(); i++){
+
+        for (int i = 0; i < ctx.getChildCount(); i++) {
             var child = ctx.getChild(i);
-            
+
             if (child instanceof Simple_stmtsContext) {
                 childs.add(visit((Simple_stmtsContext) child));
             } else if (child instanceof Compound_stmtContext) {
@@ -39,9 +38,7 @@ public class Python3VisitorImpl extends Python3ParserBaseVisitor<Node> {
     /**
      * Returns a `SimpleStmtsNode`, made by an array of SimpleStmtNode
      *
-     * ```
-     * simple_stmts : simple_stmt (';' simple_stmt)* ';'? NEWLINE ;
-     * ```
+     * ``` simple_stmts : simple_stmt (';' simple_stmt)* ';'? NEWLINE ; ```
      */
     public Node visitSimple_stmts(Simple_stmtsContext ctx) {
         ArrayList<Node> stmts = new ArrayList<Node>();
@@ -57,9 +54,7 @@ public class Python3VisitorImpl extends Python3ParserBaseVisitor<Node> {
      * Returns a `CompoundNode`. It can be built by a different kind of
      * statements, so only one of theme won't be null.
      *
-     * ```
-     * compound_stmt : if_stmt | while_stmt | for_stmt | funcdef ;
-     * ```
+     * ``` compound_stmt : if_stmt | while_stmt | for_stmt | funcdef ; ```
      */
     public Node visitCompound_stmt(Compound_stmtContext ctx) {
         Node ifStmt = null;
@@ -90,9 +85,7 @@ public class Python3VisitorImpl extends Python3ParserBaseVisitor<Node> {
      * Returns a `SimpleStmtNode`. It can be built by a different kind of
      * statements, so only one of theme won't be null.
      *
-     * ```
-     * simple_stmt : assignment | expr | return_stmt | import_stm ;
-     * ```
+     * ``` simple_stmt : assignment | expr | return_stmt | import_stm ; ```
      */
     public Node visitSimple_stmt(Simple_stmtContext ctx) {
         Node assignment = null;
@@ -122,10 +115,8 @@ public class Python3VisitorImpl extends Python3ParserBaseVisitor<Node> {
     /**
      * Returns an `AssignmentNode`. It's made by left side, an assignment and a
      * right side.
-     * 
-     * ```
-     * assignment : exprlist augassign exprlist ;
-     * ```
+     *
+     * ``` assignment : exprlist augassign exprlist ; ```
      */
     public Node visitAssignment(AssignmentContext ctx) {
         Node lhr = visit(ctx.exprlist(0));
@@ -138,9 +129,7 @@ public class Python3VisitorImpl extends Python3ParserBaseVisitor<Node> {
     /**
      * Returns a `ReturnStmtNode`. The returned exprlist can be null.
      *
-     * ```
-     * return_stmt : 'return' exprlist? ;
-     * ```
+     * ``` return_stmt : 'return' exprlist? ; ```
      */
     public Node visitReturn_stmt(Return_stmtContext ctx) {
         Node exprList = null;
@@ -155,10 +144,8 @@ public class Python3VisitorImpl extends Python3ParserBaseVisitor<Node> {
      * Returns a `ImportNode`. An import can be made in different ways so we
      * check the way in a module is imported (by from, by alias or by star).
      *
-     * ```
-     * import_stm : 'import' dotted_name ('as' NAME)?
-     * | 'from' dotted_name 'import' (NAME (',' NAME)* | '*') ;
-     * ```
+     * ``` import_stm : 'import' dotted_name ('as' NAME)? | 'from' dotted_name
+     * 'import' (NAME (',' NAME)* | '*') ; ```
      */
     public Node visitImport_stm(Import_stmContext ctx) {
         boolean isFrom = ctx.FROM() != null;
@@ -179,9 +166,7 @@ public class Python3VisitorImpl extends Python3ParserBaseVisitor<Node> {
     /**
      * Returns a `DottedNameNode` used in `import_stm`.
      *
-     * ```
-     * dotted_name : NAME ('.' NAME)* ;
-     * ```
+     * ``` dotted_name : NAME ('.' NAME)* ; ```
      */
     public Node visitDotted_name(Dotted_nameContext ctx) {
         ArrayList<TerminalNode> names = new ArrayList<TerminalNode>();
@@ -196,9 +181,7 @@ public class Python3VisitorImpl extends Python3ParserBaseVisitor<Node> {
     /**
      * Returns a `FuncdefNode`. A paramlist can be null.
      *
-     * ```
-     * funcdef : 'def' NAME '(' paramlist? ')' ':' block ;
-     * ```
+     * ``` funcdef : 'def' NAME '(' paramlist? ')' ':' block ; ```
      */
     public Node visitFuncdef(FuncdefContext ctx) {
         Node paramlist = null;
@@ -216,9 +199,8 @@ public class Python3VisitorImpl extends Python3ParserBaseVisitor<Node> {
      * Returns a `ParamlistNode`. We ignore the paramdef with default values
      * (eg: is_used=False) because there is no test which uses this feature.
      *
-     * ```
-     * paramlist : paramdef ('=' expr)? (',' paramdef ('=' expr)?)* ;
-     * 
+     * ``` paramlist : paramdef ('=' expr)? (',' paramdef ('=' expr)?)* ;
+     *
      * ```
      */
     public Node visitParamlist(ParamlistContext ctx) {
@@ -235,9 +217,7 @@ public class Python3VisitorImpl extends Python3ParserBaseVisitor<Node> {
      * Returns a `ParamdefNode`. We ignore the paramdef with type annotation
      * (eg: x : int) because there is no test which uses this feature.
      *
-     * ```
-     * paramdef : NAME (':' expr)? ;
-     * ```
+     * ``` paramdef : NAME (':' expr)? ; ```
      */
     public Node visitParamdef(ParamdefContext ctx) {
         return new ParamdefNode(ctx.NAME().toString());
@@ -247,11 +227,8 @@ public class Python3VisitorImpl extends Python3ParserBaseVisitor<Node> {
      * Returns an `AugassignNode`. We don't provide all kinds of assignment
      * below.
      *
-     * ```
-     * augassign : '=' | '+=' | '-=' | '*=' | '@=' | '/=' | '%=' | '&=' | '|=' |
-     * '^=' | '<<=' | '>>=' | '**=' | '//='
-     * ;
-     * ```
+     * ``` augassign : '=' | '+=' | '-=' | '*=' | '@=' | '/=' | '%=' | '&=' |
+     * '|=' | '^=' | '<<=' | '>>=' | '**=' | '//=' ; ```
      */
     public Node visitAugassign(AugassignContext ctx) {
         Node x = null;
@@ -285,17 +262,15 @@ public class Python3VisitorImpl extends Python3ParserBaseVisitor<Node> {
         } else if (ctx.IDIV_ASSIGN() != null) {
             x = new AugassignNode(ctx.IDIV_ASSIGN());
         }
-        
+
         return x;
     }
 
     /**
-     * Returns a `IfNode`.
-     * FIXME: add support for elif statement.
+     * Returns a `IfNode`. FIXME: add support for elif statement.
      *
-     * ```
-     * if_stmt : 'if' expr ':' block ('elif' expr ':' block)* ('else' ':' block)? ;
-     * ```
+     * ``` if_stmt : 'if' expr ':' block ('elif' expr ':' block)* ('else' ':'
+     * block)? ; ```
      */
     public Node visitIf_stmt(If_stmtContext ctx) {
         var blocks = ctx.block();
@@ -312,9 +287,7 @@ public class Python3VisitorImpl extends Python3ParserBaseVisitor<Node> {
     /**
      * Returns a `WhileStmtNode`. We do not provide 'else' branch.
      *
-     * ```
-     * while_stmt : 'while' expr ':' block ('else' ':' block)? ;
-     * ```
+     * ``` while_stmt : 'while' expr ':' block ('else' ':' block)? ; ```
      */
     public Node visitWhile_stmt(While_stmtContext ctx) {
         Node expr = visit(ctx.expr());
@@ -328,9 +301,7 @@ public class Python3VisitorImpl extends Python3ParserBaseVisitor<Node> {
     /**
      * Returns a `ForSmtNode`. We do not provide 'else' branch.
      *
-     * ```
-     * for_stmt : 'for' exprlist ':' block ('else' ':' block)? ;
-     * ```
+     * ``` for_stmt : 'for' exprlist ':' block ('else' ':' block)? ; ```
      */
     public Node visitFor_stmt(For_stmtContext ctx) {
         Node exprList = visit(ctx.exprlist());
@@ -345,17 +316,15 @@ public class Python3VisitorImpl extends Python3ParserBaseVisitor<Node> {
      * Returns a `BlockNode`. A block can be be a simple_stmts or a list of
      * simple_stms and/or compound_stmt, so we just use a list for each kind.
      *
-     * ```
-     * block : simple_stmts
-     * | NEWLINE INDENT (simple_stmts | compound_stmt)+ DEDENT ;
-     * ```
+     * ``` block : simple_stmts | NEWLINE INDENT (simple_stmts | compound_stmt)+
+     * DEDENT ; ```
      */
     public Node visitBlock(BlockContext ctx) {
         ArrayList<Node> childs = new ArrayList<Node>();
 
-        for (int i = 0; i < ctx.getChildCount(); i++){
+        for (int i = 0; i < ctx.getChildCount(); i++) {
             var child = ctx.getChild(i);
-            
+
             if (child instanceof Simple_stmtsContext) {
                 childs.add(visit((Simple_stmtsContext) child));
             } else if (child instanceof Compound_stmtContext) {
@@ -369,10 +338,8 @@ public class Python3VisitorImpl extends Python3ParserBaseVisitor<Node> {
     /**
      * Returns a `CompNode`. It should never be null.
      *
-     * ```
-     * comp_op : '<' | '>' | '==' | '>=' | '<=' | '<>' | '!=' | 'in' | 'not' 'in' |
-     * 'is' | 'is' 'not' ;
-     * ```
+     * ``` comp_op : '<' | '>' | '==' | '>=' | '<=' | '<>' | '!=' | 'in' | 'not'
+     * 'in' | 'is' | 'is' 'not' ; ```
      */
     public Node visitComp_op(Comp_opContext ctx) {
         Node comp = null;
@@ -404,13 +371,11 @@ public class Python3VisitorImpl extends Python3ParserBaseVisitor<Node> {
      * Returns an `ExprNode`. An expession can be a different kind of
      * sub-expression. We do not provide all kinds of expr(s).
      *
-     * ```
-     * expr : atom trailer* | expr '**' expr | ('+' | '-' | '~')+ expr | expr ('*' |
-     * '@' | '/' | '%' | '//') expr | expr ('+' | '-') expr | expr ('<<' | '>>')
-     * expr | expr '&' expr | expr '^' expr | expr '|' expr | 'not' expr | expr
-     * comp_op expr | expr 'and' expr | expr 'or' expr | expr 'if' expr 'else' expr
-     * ;
-     * ```
+     * ``` expr : atom trailer* | expr '**' expr | ('+' | '-' | '~')+ expr |
+     * expr ('*' | '@' | '/' | '%' | '//') expr | expr ('+' | '-') expr | expr
+     * ('<<' | '>>') expr | expr '&' expr | expr '^' expr | expr '|' expr |
+     * 'not' expr | expr comp_op expr | expr 'and' expr | expr 'or' expr | expr
+     * 'if' expr 'else' expr ; ```
      */
     public Node visitExpr(ExprContext ctx) {
         Node atom = null;
@@ -459,42 +424,52 @@ public class Python3VisitorImpl extends Python3ParserBaseVisitor<Node> {
     }
 
     /**
-     * Returns an `AtomNode`.
-     * FIXME: add support for testlist_comp
+     * Returns an `AtomNode`. FIXME: add support for testlist_comp
      *
-     * ```
-     * atom : '(' testlist_comp? ')' | '[' testlist_comp? ']' | '{' testlist_comp?
-     * '}' | NAME | NUMBER | STRING+ | '...' | 'None' | 'True' | 'False' ;
-     * ```
+     * ``` atom : '(' testlist_comp? ')' | '[' testlist_comp? ']' | '{'
+     * testlist_comp? '}' | NAME | NUMBER | STRING+ | '...' | 'None' | 'True' |
+     * 'False' ; ```
      */
     public Node visitAtom(AtomContext ctx) {
+        Testlist_compContext tlc = ctx.testlist_comp();
         if (ctx.NUMBER() != null) {
-            return new AtomNode(ctx.NUMBER().toString());
+            return new AtomNode(ctx.NUMBER().toString(), null);
         } else if (ctx.TRUE() != null) {
-            return new AtomNode(ctx.TRUE().toString());
+            return new AtomNode(ctx.TRUE().toString(), null);
         } else if (ctx.FALSE() != null) {
-            return new AtomNode(ctx.FALSE().toString());
+            return new AtomNode(ctx.FALSE().toString(), null);
         } else if (ctx.NAME() != null) {
-            return new AtomNode(ctx.NAME().toString());
-        } else if (ctx.STRING() != null) {
-
+            return new AtomNode(ctx.NAME().toString(), null);
+        } else if (!ctx.STRING().isEmpty()) {
             var varName = "";
             for (var x : ctx.STRING()) {
                 varName += x;
             }
+            return new AtomNode(varName, null);
+        } else if (ctx.OPEN_BRACE() != null && ctx.CLOSE_BRACE() != null) {
+            return manageTlc(tlc);
+        } else if (ctx.OPEN_BRACK() != null && ctx.CLOSE_BRACK() != null) {
+            return manageTlc(tlc);
+        } else if (ctx.OPEN_PAREN() != null && ctx.CLOSE_PAREN() != null) {
+            return manageTlc(tlc);
+        }
+        return new AtomNode(ctx.NONE().toString(), null);
+    }
 
-            return new AtomNode(varName);
+    public AtomNode manageTlc(Testlist_compContext tlc) {
+        if (tlc != null) {
+            Node testlist_comp = visit(tlc);
+            return new AtomNode(null, testlist_comp);
+        } else {
+            return new AtomNode(null, null);
         }
-        return new AtomNode(ctx.NONE().toString());
     }
 
     /**
      * Returns an `TrailerNode`.
      *
-     * ```
-     * trailer : '(' arglist? ')' | '[' expr (',' expr)* ','? ']' | '.' NAME | '['
-     * expr? ':' expr? (':' expr? )? ']' ;
-     * ```
+     * ``` trailer : '(' arglist? ')' | '[' expr (',' expr)* ','? ']' | '.' NAME
+     * | '[' expr? ':' expr? (':' expr? )? ']' ; ```
      */
     public Node visitTrailer(TrailerContext ctx) {
         Node arglist = null;
@@ -517,31 +492,24 @@ public class Python3VisitorImpl extends Python3ParserBaseVisitor<Node> {
     }
 
     /**
-     * Returns a `Node`.
-     * FIXME: what to do in case of list??
+     * Returns a `Node`. FIXME: what to do in case of list??
      *
-     * ```
-     * exprlist : expr (',' expr )* ','? ;
-     * ```
+     * ``` exprlist : expr (',' expr )* ','? ; ```
      */
     public Node visitExprlist(ExprlistContext ctx) {
-        Node exp;
+        ArrayList<Node> exprlist = new ArrayList<Node>();
 
-        if (ctx.expr(0).expr(0) != null){
-            exp = visit(ctx.expr(0).expr(0));
-        } else {
-            exp = visit(ctx.expr(0));
+        for (ExprContext c : ctx.expr()) {
+            exprlist.add(visit(c));
         }
 
-        return exp;
+        return new ExprListNode(exprlist);
     }
 
     /**
      * Returns a `ArglistNode`.
      *
-     * ```
-     * arglist : argument (',' argument)* ','? ;
-     * ```
+     * ``` arglist : argument (',' argument)* ','? ; ```
      */
     public Node visitArglist(ArglistContext ctx) {
         ArrayList<Node> arguments = new ArrayList<Node>();
@@ -552,4 +520,20 @@ public class Python3VisitorImpl extends Python3ParserBaseVisitor<Node> {
 
         return new ArglistNode(arguments);
     }
+
+    /**
+     * Returns a `TestlistCompNode`.
+     *
+     * ``` testlist_comp : expr (comp_for | (',' expr)* ','?) ; ```
+     */
+    public Node visitTestlist_comp(Testlist_compContext ctx) {
+        // TODO: implement comp_for
+        ArrayList<Node> exprlist = new ArrayList<Node>();
+
+        for (ExprContext c : ctx.expr()) {
+            exprlist.add(visit(c));
+        }
+
+        return new TestlistCompNode(exprlist);
+    }
 }
diff --git a/src/ast/nodes/AssignmentNode.java b/src/ast/nodes/AssignmentNode.java
index 3d597ef..07966c3 100644
--- a/src/ast/nodes/AssignmentNode.java
+++ b/src/ast/nodes/AssignmentNode.java
@@ -10,14 +10,14 @@ import semanticanalysis.SymbolTable;
  */
 public class AssignmentNode implements Node {
 
-    private ExprNode lhr;
+    private ExprListNode lhr;
     private Node assign;
-    private ExprNode rhr;
+    private ExprListNode rhr;
 
     public AssignmentNode(Node lhr, Node assign, Node rhr) {
-        this.lhr = (ExprNode) lhr;
+        this.lhr = (ExprListNode) lhr;
         this.assign = assign;
-        this.rhr = (ExprNode) rhr;
+        this.rhr = (ExprListNode) rhr;
     }
 
     @Override
@@ -28,7 +28,18 @@ public class AssignmentNode implements Node {
         errors.addAll(assign.checkSemantics(ST, _nesting));
         errors.addAll(rhr.checkSemantics(ST, _nesting));
 
-        ST.insert(lhr.getId(), rhr.typeCheck(), _nesting, "");
+        int lsize = lhr.getSize();
+        int rsize = rhr.getSize();
+
+        if (lsize == rsize) {
+            for (int i = 0; i < lsize; i++) {
+                ExprNode latom = (ExprNode) lhr.getElem(i);
+                ExprNode ratom = (ExprNode) rhr.getElem(i);
+                ST.insert(latom.getId(), ratom.typeCheck(), _nesting, "");
+            }
+        } else {
+            errors.add(new SemanticError("ValueError: different size of left or right side assignment"));
+        }
 
         return errors;
     }
diff --git a/src/ast/nodes/AtomNode.java b/src/ast/nodes/AtomNode.java
index 3c2b1eb..592aac4 100644
--- a/src/ast/nodes/AtomNode.java
+++ b/src/ast/nodes/AtomNode.java
@@ -13,9 +13,11 @@ import semanticanalysis.SymbolTable;
 public class AtomNode implements Node {
 
     protected String val;
+    protected TestlistCompNode exprlist;
 
-    public AtomNode(String val) {
+    public AtomNode(String val, Node exprlist) {
         this.val = val;
+        this.exprlist = (TestlistCompNode) exprlist;
     }
 
     public String getId() {
@@ -26,10 +28,16 @@ public class AtomNode implements Node {
     public ArrayList<SemanticError> checkSemantics(SymbolTable ST, int _nesting) {
         var errors = new ArrayList<SemanticError>();
 
-        if ((this.typeCheck() instanceof AtomType) && ST.nslookup(this.getId()) < 0) {
-            errors.add(new SemanticError("name '" + this.getId() + "' is not defined."));
-        } else {
-            // System.out.println("exist " + this.getId());
+        if (val != null) {
+            if ((this.typeCheck() instanceof AtomType) && ST.nslookup(this.getId()) < 0) {
+                errors.add(new SemanticError("name '" + this.getId() + "' is not defined."));
+            } else {
+                // System.out.println("exist " + this.typeCheck());
+            }
+        }
+
+        if (exprlist != null) {
+            errors.addAll(exprlist.checkSemantics(ST, _nesting));
         }
 
         return errors;
@@ -38,6 +46,10 @@ public class AtomNode implements Node {
     // ENHANCE: return more specific types
     @Override
     public Type typeCheck() {
+        if (this.val == null) {
+            return new VoidType();
+        }
+
         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)*
diff --git a/src/ast/nodes/ExprListNode.java b/src/ast/nodes/ExprListNode.java
new file mode 100644
index 0000000..c1a2ebc
--- /dev/null
+++ b/src/ast/nodes/ExprListNode.java
@@ -0,0 +1,61 @@
+package ast.nodes;
+
+import ast.types.*;
+import java.util.ArrayList;
+import semanticanalysis.SemanticError;
+import semanticanalysis.SymbolTable;
+
+/**
+ * Node for the `expr_list` statement of the grammar.
+ */
+public class ExprListNode implements Node {
+
+    private final ArrayList<Node> exprs;
+
+    public ExprListNode(ArrayList<Node> _exprs) {
+        this.exprs = _exprs;
+    }
+
+    @Override
+    public ArrayList<SemanticError> checkSemantics(SymbolTable ST, int _nesting) {
+        ArrayList<SemanticError> errors = new ArrayList();
+
+        for (var param : exprs) {
+            errors.addAll(param.checkSemantics(ST, _nesting));
+        }
+
+        return errors;
+    }
+
+    public int getSize() {
+        return exprs.size();
+    }
+
+    public Node getElem(int i) {
+        return exprs.get(i);
+    }
+
+    @Override
+    public Type typeCheck() {
+        return new VoidType();
+    }
+
+    // TODO: code generation for expr list
+    @Override
+    public String codeGeneration() {
+        return "";
+    }
+
+    @Override
+    public String toPrint(String prefix) {
+        String str = prefix + "Paramlist\n";
+
+        prefix += "  ";
+        for (var param : exprs) {
+            str += param.toPrint(prefix);
+        }
+
+        return str;
+    }
+
+}
diff --git a/src/ast/nodes/ForStmtNode.java b/src/ast/nodes/ForStmtNode.java
index 28fe783..610d0a0 100644
--- a/src/ast/nodes/ForStmtNode.java
+++ b/src/ast/nodes/ForStmtNode.java
@@ -1,20 +1,20 @@
 package ast.nodes;
 
+import ast.types.*;
 import java.util.ArrayList;
-
 import semanticanalysis.SemanticError;
 import semanticanalysis.SymbolTable;
-import ast.types.*;
 
 /**
  * Node for the `for_stmt` statement of the grammar.
  */
 public class ForStmtNode implements Node {
-    private Node exprList;
+
+    private ExprListNode exprList;
     private Node block;
 
     public ForStmtNode(Node exprList, Node block) {
-        this.exprList = exprList;
+        this.exprList = (ExprListNode) exprList;
         this.block = block;
     }
 
@@ -22,9 +22,7 @@ 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, "");
+        // ST.insert(expr.getId(), expr.typeCheck(s), _nesting, "");
 
         errors.addAll(exprList.checkSemantics(ST, _nesting));
         errors.addAll(block.checkSemantics(ST, _nesting));
diff --git a/src/ast/nodes/ParamdefNode.java b/src/ast/nodes/ParamdefNode.java
index 5164537..adadf72 100644
--- a/src/ast/nodes/ParamdefNode.java
+++ b/src/ast/nodes/ParamdefNode.java
@@ -12,7 +12,7 @@ import semanticanalysis.SymbolTable;
 public class ParamdefNode extends AtomNode {
 
     public ParamdefNode(String val) {
-        super(val);
+        super(val, null);
     }
 
     @Override
diff --git a/src/ast/nodes/TestlistCompNode.java b/src/ast/nodes/TestlistCompNode.java
new file mode 100644
index 0000000..070b1a1
--- /dev/null
+++ b/src/ast/nodes/TestlistCompNode.java
@@ -0,0 +1,61 @@
+package ast.nodes;
+
+import ast.types.*;
+import java.util.ArrayList;
+import semanticanalysis.SemanticError;
+import semanticanalysis.SymbolTable;
+
+/**
+ * Node for the `testlist_comp` statement of the grammar.
+ */
+public class TestlistCompNode implements Node {
+
+    private final ArrayList<Node> exprs;
+
+    public TestlistCompNode(ArrayList<Node> _exprs) {
+        this.exprs = _exprs;
+    }
+
+    @Override
+    public ArrayList<SemanticError> checkSemantics(SymbolTable ST, int _nesting) {
+        ArrayList<SemanticError> errors = new ArrayList();
+
+        for (var param : exprs) {
+            errors.addAll(param.checkSemantics(ST, _nesting));
+        }
+
+        return errors;
+    }
+
+    public int getSize() {
+        return exprs.size();
+    }
+
+    public Node getElem(int i) {
+        return exprs.get(i);
+    }
+
+    @Override
+    public Type typeCheck() {
+        return new VoidType();
+    }
+
+    // TODO: code generation for expr list
+    @Override
+    public String codeGeneration() {
+        return "";
+    }
+
+    @Override
+    public String toPrint(String prefix) {
+        String str = prefix + "Testlist_comp\n";
+
+        prefix += "  ";
+        for (var param : exprs) {
+            str += param.toPrint(prefix);
+        }
+
+        return str;
+    }
+
+}
diff --git a/test/trailers.py b/test/trailers.py
new file mode 100644
index 0000000..278a2d4
--- /dev/null
+++ b/test/trailers.py
@@ -0,0 +1,13 @@
+
+def mult(nums):
+    ret = []
+    for a, b in nums:
+        ret.append(a * b)
+    return ret
+
+print(mult([(2, 4), (5, 2)]))
+
+
+# left, right = 1, 2
+# print(left)
+# print(right)