feat(parser): add subscript expressions

gen/python.py

@@ -143,4 +143,9 @@ class ListExpr:
     items: list[Expr]
 
 
+class SubscriptExpr:
+    object: Expr
+    index: Expr
+
+
 ###<

midas/ast/printer.py

@@ -664,7 +664,7 @@ class PythonAstPrinter(
     def visit_literal_expr(self, expr: p.LiteralExpr) -> None:
         self._write_line("LiteralExpr")
         with self._child_level(single=True):
-            self._write_line(f"value: {expr.value}")
+            self._write_line(f"value: {expr.value!r}")
 
     def visit_variable_expr(self, expr: p.VariableExpr) -> None:
         self._write_line("VariableExpr")
@@ -719,3 +719,13 @@ class PythonAstPrinter(
                     if i == len(expr.items) - 1:
                         self._mark_last()
                     item.accept(self)
+
+    def visit_subscript_expr(self, expr: p.SubscriptExpr) -> None:
+        self._write_line("SubscriptExpr")
+        with self._child_level():
+            self._write_line("object")
+            with self._child_level(single=True):
+                expr.object.accept(self)
+            self._write_line("index", last=True)
+            with self._child_level(single=True):
+                expr.index.accept(self)

midas/ast/python.py

@@ -224,6 +224,9 @@ class Expr(ABC):
         @abstractmethod
         def visit_list_expr(self, expr: ListExpr) -> T: ...
 
+        @abstractmethod
+        def visit_subscript_expr(self, expr: SubscriptExpr) -> T: ...
+
 
 @dataclass(frozen=True)
 class BinaryExpr(Expr):
@@ -324,3 +327,12 @@ class ListExpr(Expr):
 
     def accept(self, visitor: Expr.Visitor[T]) -> T:
         return visitor.visit_list_expr(self)
+
+
+@dataclass(frozen=True)
+class SubscriptExpr(Expr):
+    object: Expr
+    index: Expr
+
+    def accept(self, visitor: Expr.Visitor[T]) -> T:
+        return visitor.visit_subscript_expr(self)

midas/cli/highlighter.py

@@ -218,6 +218,10 @@ class PythonHighlighter(
         for item in expr.items:
             item.accept(self)
 
+    def visit_subscript_expr(self, expr: p.SubscriptExpr) -> None:
+        expr.object.accept(self)
+        expr.index.accept(self)
+
 
 class MidasHighlighter(
     Highlighter, m.Stmt.Visitor[None], m.Expr.Visitor[None], m.Type.Visitor[None]

midas/parser/python.py

@@ -23,6 +23,7 @@ from midas.ast.python import (
     MidasType,
     ReturnStmt,
     Stmt,
+    SubscriptExpr,
     TernaryExpr,
     TypeAssign,
     UnaryExpr,
@@ -423,6 +424,13 @@ class PythonParser:
                     items=[self.parse_expr(item) for item in items],
                 )
 
+            case ast.Subscript(value=value, slice=index):
+                return SubscriptExpr(
+                    location=location,
+                    object=self.parse_expr(value),
+                    index=self.parse_expr(index),
+                )
+
             case _:
                 raise UnsupportedSyntaxError(node)
 

tests/serializer/python.py

@@ -22,6 +22,7 @@ from midas.ast.python import (
     MidasType,
     ReturnStmt,
     Stmt,
+    SubscriptExpr,
     TernaryExpr,
     TypeAssign,
     UnaryExpr,
@@ -252,3 +253,10 @@ class PythonAstJsonSerializer(
             "_type": "ListExpr",
             "items": [item.accept(self) for item in expr.items],
         }
+
+    def visit_subscript_expr(self, expr: SubscriptExpr) -> dict:
+        return {
+            "_type": "SubscriptExpr",
+            "object": expr.object.accept(self),
+            "index": expr.index.accept(self),
+        }