Add increment/decrement

crates/ruff_linter/src/rules/ruff/rules/invalid_formatter_suppression_comment.rs

@@ -141,15 +141,15 @@ impl<'src, 'loc> UselessSuppressionComments<'src, 'loc> {
         if comment.kind == SuppressionKind::Off || comment.kind == SuppressionKind::On {
             if let Some(
                 AnyNodeRef::StmtClassDef(StmtClassDef {
-                    name,
-                    decorator_list,
-                    ..
-                })
+                                             name,
+                                             decorator_list,
+                                             ..
+                                         })
                 | AnyNodeRef::StmtFunctionDef(StmtFunctionDef {
-                    name,
-                    decorator_list,
-                    ..
-                }),
+                                                  name,
+                                                  decorator_list,
+                                                  ..
+                                              }),
             ) = comment.enclosing
             {
                 if comment.line_position.is_own_line() && comment.range.start() < name.start() {
@@ -196,7 +196,7 @@ impl<'src, 'loc> UselessSuppressionComments<'src, 'loc> {
         self.captured.sort_by_key(|(t, _)| t.start());
     }
 
-    fn ignored_comments(&self) -> impl Iterator<Item = (TextRange, IgnoredReason)> + '_ {
+    fn ignored_comments(&self) -> impl Iterator<Item=(TextRange, IgnoredReason)> + '_ {
         self.captured.iter().map(|(r, i)| (*r, *i))
     }
 }
@@ -276,7 +276,8 @@ const fn is_valid_enclosing_node(node: AnyNodeRef) -> bool {
         | AnyNodeRef::StmtIpyEscapeCommand(_)
         | AnyNodeRef::ExceptHandlerExceptHandler(_)
         | AnyNodeRef::MatchCase(_)
-        | AnyNodeRef::ElifElseClause(_) => true,
+        | AnyNodeRef::ElifElseClause(_)
+        | AnyNodeRef::StmtCrement(_) => true,
 
         AnyNodeRef::ExprBoolOp(_)
         | AnyNodeRef::ExprNamed(_)

crates/ruff_python_ast/src/comparable.rs

@@ -1543,6 +1543,9 @@ impl<'a> From<&'a ast::Stmt> for ComparableStmt<'a> {
             ast::Stmt::Pass(_) => Self::Pass,
             ast::Stmt::Break(_) => Self::Break,
             ast::Stmt::Continue(_) => Self::Continue,
+            ast::Stmt::Crement(_) => {
+                todo!()
+            }
         }
     }
 }

crates/ruff_python_ast/src/helpers.rs

@@ -432,6 +432,7 @@ pub fn any_over_stmt(stmt: &Stmt, func: &dyn Fn(&Expr) -> bool) -> bool {
         Stmt::AugAssign(ast::StmtAugAssign { target, value, .. }) => {
             any_over_expr(target, func) || any_over_expr(value, func)
         }
+        Stmt::Crement(ast::StmtCrement { target, .. }) => any_over_expr(target, func),
         Stmt::AnnAssign(ast::StmtAnnAssign {
             target,
             annotation,

crates/ruff_python_ast/src/node.rs

@@ -36,6 +36,7 @@ pub enum AnyNode {
     StmtTypeAlias(ast::StmtTypeAlias),
     StmtAssign(ast::StmtAssign),
     StmtAugAssign(ast::StmtAugAssign),
+    StmtCrement(ast::StmtCrement),
     StmtAnnAssign(ast::StmtAnnAssign),
     StmtFor(ast::StmtFor),
     StmtWhile(ast::StmtWhile),
@@ -130,6 +131,7 @@ impl AnyNode {
             AnyNode::StmtTypeAlias(node) => Some(Stmt::TypeAlias(node)),
             AnyNode::StmtAssign(node) => Some(Stmt::Assign(node)),
             AnyNode::StmtAugAssign(node) => Some(Stmt::AugAssign(node)),
+            AnyNode::StmtCrement(node) => Some(Stmt::Crement(node)),
             AnyNode::StmtAnnAssign(node) => Some(Stmt::AnnAssign(node)),
             AnyNode::StmtFor(node) => Some(Stmt::For(node)),
             AnyNode::StmtWhile(node) => Some(Stmt::While(node)),
@@ -262,6 +264,7 @@ impl AnyNode {
             | AnyNode::StmtTypeAlias(_)
             | AnyNode::StmtAssign(_)
             | AnyNode::StmtAugAssign(_)
+            | AnyNode::StmtCrement(_)
             | AnyNode::StmtAnnAssign(_)
             | AnyNode::StmtFor(_)
             | AnyNode::StmtWhile(_)
@@ -327,6 +330,7 @@ impl AnyNode {
             | AnyNode::StmtTypeAlias(_)
             | AnyNode::StmtAssign(_)
             | AnyNode::StmtAugAssign(_)
+            | AnyNode::StmtCrement(_)
             | AnyNode::StmtAnnAssign(_)
             | AnyNode::StmtFor(_)
             | AnyNode::StmtWhile(_)
@@ -432,6 +436,7 @@ impl AnyNode {
             | AnyNode::StmtTypeAlias(_)
             | AnyNode::StmtAssign(_)
             | AnyNode::StmtAugAssign(_)
+            | AnyNode::StmtCrement(_)
             | AnyNode::StmtAnnAssign(_)
             | AnyNode::StmtFor(_)
             | AnyNode::StmtWhile(_)
@@ -522,6 +527,7 @@ impl AnyNode {
             | AnyNode::StmtTypeAlias(_)
             | AnyNode::StmtAssign(_)
             | AnyNode::StmtAugAssign(_)
+            | AnyNode::StmtCrement(_)
             | AnyNode::StmtAnnAssign(_)
             | AnyNode::StmtFor(_)
             | AnyNode::StmtWhile(_)
@@ -637,6 +643,7 @@ impl AnyNode {
             Self::StmtTypeAlias(node) => AnyNodeRef::StmtTypeAlias(node),
             Self::StmtAssign(node) => AnyNodeRef::StmtAssign(node),
             Self::StmtAugAssign(node) => AnyNodeRef::StmtAugAssign(node),
+            Self::StmtCrement(node) => AnyNodeRef::StmtCrement(node),
             Self::StmtAnnAssign(node) => AnyNodeRef::StmtAnnAssign(node),
             Self::StmtFor(node) => AnyNodeRef::StmtFor(node),
             Self::StmtWhile(node) => AnyNodeRef::StmtWhile(node),
@@ -1125,6 +1132,48 @@ impl AstNode for ast::StmtAugAssign {
         visitor.visit_expr(value);
     }
 }
+impl AstNode for ast::StmtCrement {
+    fn cast(kind: AnyNode) -> Option<Self>
+    where
+        Self: Sized,
+    {
+        if let AnyNode::StmtCrement(node) = kind {
+            Some(node)
+        } else {
+            None
+        }
+    }
+
+    fn cast_ref(kind: AnyNodeRef) -> Option<&Self> {
+        if let AnyNodeRef::StmtCrement(node) = kind {
+            Some(node)
+        } else {
+            None
+        }
+    }
+
+    fn as_any_node_ref(&self) -> AnyNodeRef {
+        AnyNodeRef::from(self)
+    }
+
+    fn into_any_node(self) -> AnyNode {
+        AnyNode::from(self)
+    }
+
+    fn visit_preorder<'a, V>(&'a self, visitor: &mut V)
+    where
+        V: PreorderVisitor<'a> + ?Sized,
+    {
+        let ast::StmtCrement {
+            target,
+            op: _,
+            range: _,
+        } = self;
+
+        visitor.visit_expr(target);
+        // TODO(konstin): visitor.visit_operator(op);
+    }
+}
 impl AstNode for ast::StmtAnnAssign {
     fn cast(kind: AnyNode) -> Option<Self>
     where
@@ -4538,6 +4587,7 @@ impl From<Stmt> for AnyNode {
             Stmt::Break(node) => AnyNode::StmtBreak(node),
             Stmt::Continue(node) => AnyNode::StmtContinue(node),
             Stmt::IpyEscapeCommand(node) => AnyNode::StmtIpyEscapeCommand(node),
+            Stmt::Crement(node) => AnyNode::StmtCrement(node),
         }
     }
 }
@@ -4676,6 +4726,12 @@ impl From<ast::StmtAugAssign> for AnyNode {
     }
 }
 
+impl From<ast::StmtCrement> for AnyNode {
+    fn from(node: ast::StmtCrement) -> Self {
+        AnyNode::StmtCrement(node)
+    }
+}
+
 impl From<ast::StmtAnnAssign> for AnyNode {
     fn from(node: ast::StmtAnnAssign) -> Self {
         AnyNode::StmtAnnAssign(node)
@@ -5251,6 +5307,7 @@ impl Ranged for AnyNode {
             AnyNode::StringLiteral(node) => node.range(),
             AnyNode::BytesLiteral(node) => node.range(),
             AnyNode::ElifElseClause(node) => node.range(),
+            AnyNode::StmtCrement(node) => node.range(),
         }
     }
 }
@@ -5266,6 +5323,7 @@ pub enum AnyNodeRef<'a> {
     StmtTypeAlias(&'a ast::StmtTypeAlias),
     StmtAssign(&'a ast::StmtAssign),
     StmtAugAssign(&'a ast::StmtAugAssign),
+    StmtCrement(&'a ast::StmtCrement),
     StmtAnnAssign(&'a ast::StmtAnnAssign),
     StmtFor(&'a ast::StmtFor),
     StmtWhile(&'a ast::StmtWhile),
@@ -5444,6 +5502,7 @@ impl<'a> AnyNodeRef<'a> {
             AnyNodeRef::StringLiteral(node) => NonNull::from(*node).cast(),
             AnyNodeRef::BytesLiteral(node) => NonNull::from(*node).cast(),
             AnyNodeRef::ElifElseClause(node) => NonNull::from(*node).cast(),
+            AnyNodeRef::StmtCrement(node) => NonNull::from(*node).cast(),
         }
     }
 
@@ -5546,6 +5605,7 @@ impl<'a> AnyNodeRef<'a> {
             AnyNodeRef::StringLiteral(_) => NodeKind::StringLiteral,
             AnyNodeRef::BytesLiteral(_) => NodeKind::BytesLiteral,
             AnyNodeRef::ElifElseClause(_) => NodeKind::ElifElseClause,
+            AnyNodeRef::StmtCrement(_) => NodeKind::StmtCrement,
         }
     }
 
@@ -5558,6 +5618,7 @@ impl<'a> AnyNodeRef<'a> {
             | AnyNodeRef::StmtTypeAlias(_)
             | AnyNodeRef::StmtAssign(_)
             | AnyNodeRef::StmtAugAssign(_)
+            | AnyNodeRef::StmtCrement(_)
             | AnyNodeRef::StmtAnnAssign(_)
             | AnyNodeRef::StmtFor(_)
             | AnyNodeRef::StmtWhile(_)
@@ -5690,6 +5751,7 @@ impl<'a> AnyNodeRef<'a> {
             | AnyNodeRef::StmtTypeAlias(_)
             | AnyNodeRef::StmtAssign(_)
             | AnyNodeRef::StmtAugAssign(_)
+            | AnyNodeRef::StmtCrement(_)
             | AnyNodeRef::StmtAnnAssign(_)
             | AnyNodeRef::StmtFor(_)
             | AnyNodeRef::StmtWhile(_)
@@ -5754,6 +5816,7 @@ impl<'a> AnyNodeRef<'a> {
             | AnyNodeRef::StmtTypeAlias(_)
             | AnyNodeRef::StmtAssign(_)
             | AnyNodeRef::StmtAugAssign(_)
+            | AnyNodeRef::StmtCrement(_)
             | AnyNodeRef::StmtAnnAssign(_)
             | AnyNodeRef::StmtFor(_)
             | AnyNodeRef::StmtWhile(_)
@@ -5859,6 +5922,7 @@ impl<'a> AnyNodeRef<'a> {
             | AnyNodeRef::StmtTypeAlias(_)
             | AnyNodeRef::StmtAssign(_)
             | AnyNodeRef::StmtAugAssign(_)
+            | AnyNodeRef::StmtCrement(_)
             | AnyNodeRef::StmtAnnAssign(_)
             | AnyNodeRef::StmtFor(_)
             | AnyNodeRef::StmtWhile(_)
@@ -5949,6 +6013,7 @@ impl<'a> AnyNodeRef<'a> {
             | AnyNodeRef::StmtTypeAlias(_)
             | AnyNodeRef::StmtAssign(_)
             | AnyNodeRef::StmtAugAssign(_)
+            | AnyNodeRef::StmtCrement(_)
             | AnyNodeRef::StmtAnnAssign(_)
             | AnyNodeRef::StmtFor(_)
             | AnyNodeRef::StmtWhile(_)
@@ -6058,6 +6123,7 @@ impl<'a> AnyNodeRef<'a> {
             AnyNodeRef::StmtTypeAlias(node) => node.visit_preorder(visitor),
             AnyNodeRef::StmtAssign(node) => node.visit_preorder(visitor),
             AnyNodeRef::StmtAugAssign(node) => node.visit_preorder(visitor),
+            AnyNodeRef::StmtCrement(node) => node.visit_preorder(visitor),
             AnyNodeRef::StmtAnnAssign(node) => node.visit_preorder(visitor),
             AnyNodeRef::StmtFor(node) => node.visit_preorder(visitor),
             AnyNodeRef::StmtWhile(node) => node.visit_preorder(visitor),
@@ -6372,6 +6438,12 @@ impl<'a> From<&'a ast::StmtAugAssign> for AnyNodeRef<'a> {
     }
 }
 
+impl<'a> From<&'a ast::StmtCrement> for AnyNodeRef<'a> {
+    fn from(node: &'a ast::StmtCrement) -> Self {
+        AnyNodeRef::StmtCrement(node)
+    }
+}
+
 impl<'a> From<&'a ast::StmtAnnAssign> for AnyNodeRef<'a> {
     fn from(node: &'a ast::StmtAnnAssign) -> Self {
         AnyNodeRef::StmtAnnAssign(node)
@@ -6837,6 +6909,7 @@ impl<'a> From<&'a Stmt> for AnyNodeRef<'a> {
             Stmt::Break(node) => AnyNodeRef::StmtBreak(node),
             Stmt::Continue(node) => AnyNodeRef::StmtContinue(node),
             Stmt::IpyEscapeCommand(node) => AnyNodeRef::StmtIpyEscapeCommand(node),
+            Stmt::Crement(node) => AnyNodeRef::StmtCrement(node),
         }
     }
 }
@@ -7073,6 +7146,7 @@ impl Ranged for AnyNodeRef<'_> {
             AnyNodeRef::FString(node) => node.range(),
             AnyNodeRef::StringLiteral(node) => node.range(),
             AnyNodeRef::BytesLiteral(node) => node.range(),
+            AnyNodeRef::StmtCrement(node) => node.range(),
         }
     }
 }
@@ -7173,4 +7247,5 @@ pub enum NodeKind {
     FString,
     StringLiteral,
     BytesLiteral,
+    StmtCrement,
 }

crates/ruff_python_ast/src/nodes.rs

@@ -101,6 +101,8 @@ pub enum Stmt {
     // Jupyter notebook specific
     #[is(name = "ipy_escape_command_stmt")]
     IpyEscapeCommand(StmtIpyEscapeCommand),
+    #[is(name = "crement_stmt")]
+    Crement(StmtCrement),
 }
 
 /// An AST node used to represent a IPython escape command at the statement level.
@@ -297,6 +299,26 @@ impl From<StmtAugAssign> for Stmt {
     }
 }
 
+#[derive(Clone, Debug, PartialEq)]
+pub enum CrementKind {
+    Increment,
+    Decrement,
+}
+
+/// `++` or `--`
+#[derive(Clone, Debug, PartialEq)]
+pub struct StmtCrement {
+    pub range: TextRange,
+    pub target: Box<Expr>,
+    pub op: CrementKind,
+}
+
+impl From<StmtCrement> for Stmt {
+    fn from(payload: StmtCrement) -> Self {
+        Stmt::Crement(payload)
+    }
+}
+
 /// See also [AnnAssign](https://docs.python.org/3/library/ast.html#ast.AnnAssign)
 #[derive(Clone, Debug, PartialEq)]
 pub struct StmtAnnAssign {
@@ -3693,6 +3715,11 @@ impl Ranged for crate::nodes::StmtAugAssign {
         self.range
     }
 }
+impl Ranged for crate::nodes::StmtCrement {
+    fn range(&self) -> TextRange {
+        self.range
+    }
+}
 impl Ranged for crate::nodes::StmtAnnAssign {
     fn range(&self) -> TextRange {
         self.range
@@ -3816,6 +3843,7 @@ impl Ranged for crate::Stmt {
             Self::Break(node) => node.range(),
             Self::Continue(node) => node.range(),
             Stmt::IpyEscapeCommand(node) => node.range(),
+            Stmt::Crement(node) => node.range(),
         }
     }
 }

crates/ruff_python_ast/src/visitor.rs

@@ -203,6 +203,14 @@ pub fn walk_stmt<'a, V: Visitor<'a> + ?Sized>(visitor: &mut V, stmt: &'a Stmt) {
             visitor.visit_operator(op);
             visitor.visit_expr(target);
         }
+        Stmt::Crement(ast::StmtCrement {
+            target,
+            op: _,
+            range: _,
+        }) => {
+            // TODO(konstin): visitor.visit_operator(op);
+            visitor.visit_expr(target);
+        }
         Stmt::AnnAssign(ast::StmtAnnAssign {
             target,
             annotation,

crates/ruff_python_ast/src/visitor/preorder.rs

@@ -209,6 +209,7 @@ where
             Stmt::TypeAlias(stmt) => stmt.visit_preorder(visitor),
             Stmt::Assign(stmt) => stmt.visit_preorder(visitor),
             Stmt::AugAssign(stmt) => stmt.visit_preorder(visitor),
+            Stmt::Crement(stmt) => stmt.visit_preorder(visitor),
             Stmt::AnnAssign(stmt) => stmt.visit_preorder(visitor),
             Stmt::For(stmt) => stmt.visit_preorder(visitor),
             Stmt::While(stmt) => stmt.visit_preorder(visitor),

crates/ruff_python_ast/src/visitor/transformer.rs

@@ -306,6 +306,7 @@ pub fn walk_stmt<V: Transformer + ?Sized>(visitor: &V, stmt: &mut Stmt) {
         Stmt::Nonlocal(_) => {}
         Stmt::Expr(ast::StmtExpr { value, range: _ }) => visitor.visit_expr(value),
         Stmt::Pass(_) | Stmt::Break(_) | Stmt::Continue(_) | Stmt::IpyEscapeCommand(_) => {}
+        Stmt::Crement(_) => {}
     }
 }
 

crates/ruff_python_codegen/src/generator.rs

@@ -4,10 +4,10 @@ use std::ops::Deref;
 
 use ruff_python_ast::str::Quote;
 use ruff_python_ast::{
-    self as ast, Alias, ArgOrKeyword, BoolOp, CmpOp, Comprehension, ConversionFlag, DebugText,
-    ExceptHandler, Expr, Identifier, MatchCase, Operator, Parameter, Parameters, Pattern,
-    Singleton, Stmt, Suite, TypeParam, TypeParamParamSpec, TypeParamTypeVar, TypeParamTypeVarTuple,
-    WithItem,
+    self as ast, Alias, ArgOrKeyword, BoolOp, CmpOp, Comprehension, ConversionFlag, CrementKind,
+    DebugText, ExceptHandler, Expr, Identifier, MatchCase, Operator, Parameter, Parameters,
+    Pattern, Singleton, Stmt, Suite, TypeParam, TypeParamParamSpec, TypeParamTypeVar,
+    TypeParamTypeVarTuple, WithItem,
 };
 use ruff_python_ast::{ParameterWithDefault, TypeParams};
 use ruff_python_literal::escape::{AsciiEscape, Escape, UnicodeEscape};
@@ -345,6 +345,20 @@ impl<'a> Generator<'a> {
                     self.unparse_expr(value, precedence::AUG_ASSIGN);
                 });
             }
+            Stmt::Crement(ast::StmtCrement {
+                target,
+                op,
+                range: _,
+            }) => {
+                statement!({
+                    self.unparse_expr(target, precedence::AUG_ASSIGN);
+                    self.p(" ");
+                    self.p(match op {
+                        CrementKind::Increment => "+= 1",
+                        CrementKind::Decrement => "-= 1",
+                    });
+                });
+            }
             Stmt::AnnAssign(ast::StmtAnnAssign {
                 target,
                 annotation,

crates/ruff_python_formatter/src/range.rs

@@ -706,7 +706,8 @@ impl Format<PyFormatContext<'_>> for FormatEnclosingNode<'_> {
             | AnyNodeRef::TypeParamTypeVar(_)
             | AnyNodeRef::TypeParamTypeVarTuple(_)
             | AnyNodeRef::TypeParamParamSpec(_)
-            | AnyNodeRef::BytesLiteral(_) => {
+            | AnyNodeRef::BytesLiteral(_)
+            | AnyNodeRef::StmtCrement(_) => {
                 panic!("Range formatting only supports formatting logical lines")
             }
         }

crates/ruff_python_formatter/src/statement/mod.rs

@@ -45,6 +45,19 @@ impl FormatRule<Stmt, PyFormatContext<'_>> for FormatStmt {
             Stmt::Delete(x) => x.format().fmt(f),
             Stmt::Assign(x) => x.format().fmt(f),
             Stmt::AugAssign(x) => x.format().fmt(f),
+            Stmt::Crement(x) => {
+                x.target.format().fmt(f)?;
+                use ruff_formatter::prelude::*;
+                match x.op {
+                    ruff_python_ast::CrementKind::Increment => {
+                        ruff_formatter::write!(f, [space(), text("+="), space(), text("1")])?;
+                    }
+                    ruff_python_ast::CrementKind::Decrement => {
+                        ruff_formatter::write!(f, [space(), text("-="), space(), text("1")])?;
+                    }
+                }
+                Ok(())
+            }
             Stmt::AnnAssign(x) => x.format().fmt(f),
             Stmt::For(x) => x.format().fmt(f),
             Stmt::While(x) => x.format().fmt(f),

crates/ruff_python_parser/src/lexer.rs

@@ -1079,7 +1079,9 @@ impl<'source> Lexer<'source> {
                 }
             }
             '+' => {
-                if self.cursor.eat_char('=') {
+                if self.cursor.eat_char('+') {
+                    Tok::Increment
+                } else if self.cursor.eat_char('=') {
                     Tok::PlusEqual
                 } else {
                     Tok::Plus
@@ -1166,7 +1168,9 @@ impl<'source> Lexer<'source> {
                 }
             }
             '-' => {
-                if self.cursor.eat_char('=') {
+                if self.cursor.eat_char('-') {
+                    Tok::Increment
+                } else if self.cursor.eat_char('=') {
                     Tok::MinusEqual
                 } else if self.cursor.eat_char('>') {
                     Tok::Rarrow

crates/ruff_python_parser/src/python.lalrpop

@@ -110,6 +110,16 @@ DelStatement: ast::Stmt = {
 };
 
 ExpressionStatement: ast::Stmt = {
+    <location:@L> <target:TestOrStarExprList> <op:Crement> <end_location:@R> =>? {
+        invalid::assignment_target(&target.expr)?;
+        Ok(ast::Stmt::Crement(
+            ast::StmtCrement {
+                target: Box::new(set_context(target.into(), ast::ExprContext::Store)),
+                op,
+                range: (location..end_location).into()
+            },
+        ))
+    },
     <location:@L> <expression:TestOrStarExprList> <suffix:AssignSuffix*> <end_location:@R> =>? {
         // Just an expression, no assignment:
         if suffix.is_empty() {
@@ -204,6 +214,11 @@ AugAssign: ast::Operator = {
     "//=" => ast::Operator::FloorDiv,
 };
 
+Crement: ast::CrementKind = {
+    "++" => ast::CrementKind::Increment,
+    "--" => ast::CrementKind::Decrement,
+};
+
 FlowStatement: ast::Stmt = {
     <location:@L> "break" <end_location:@R> => {
 
@@ -2033,6 +2048,8 @@ extern {
         ">" => token::Tok::Greater,
         ">=" => token::Tok::GreaterEqual,
         "->" => token::Tok::Rarrow,
+        "++" => token::Tok::Increment,
+        "--" => token::Tok::Decrement,
         "and" => token::Tok::And,
         "as" => token::Tok::As,
         "assert" => token::Tok::Assert,

crates/ruff_python_parser/src/token.rs

@@ -157,6 +157,10 @@ pub enum Tok {
     VbarEqual,
     /// Token value for caret equal `^=`.
     CircumflexEqual,
+    /// Token value for `++`.
+    Increment,
+    /// Token value for `--`.
+    Decrement,
     /// Token value for left shift equal `<<=`.
     LeftShiftEqual,
     /// Token value for right shift equal `>>=`.
@@ -343,6 +347,8 @@ impl fmt::Display for Tok {
             With => f.write_str("'with'"),
             Yield => f.write_str("'yield'"),
             ColonEqual => f.write_str("':='"),
+            Increment => f.write_str("++"),
+            Decrement => f.write_str("--"),
         }
     }
 }
@@ -526,6 +532,8 @@ pub enum TokenKind {
     StartModule,
     StartInteractive,
     StartExpression,
+    Increment,
+    Decrement,
 }
 
 impl TokenKind {
@@ -620,6 +628,8 @@ impl TokenKind {
                 | TokenKind::AmperEqual
                 | TokenKind::VbarEqual
                 | TokenKind::CircumflexEqual
+                | TokenKind::Increment
+                | TokenKind::Decrement
                 | TokenKind::LeftShiftEqual
                 | TokenKind::RightShiftEqual
                 | TokenKind::DoubleStarEqual
@@ -799,6 +809,8 @@ impl TokenKind {
             Tok::Yield => TokenKind::Yield,
             Tok::StartModule => TokenKind::StartModule,
             Tok::StartExpression => TokenKind::StartExpression,
+            Tok::Increment => TokenKind::Increment,
+            Tok::Decrement => TokenKind::Decrement,
         }
     }
 }