AssignmentStatement represents an assignment, e.g., `x = 5`.

BinaryExpression represents binary operations, e.g., `x + y`.

CaseStatement represents each case in a switch.

Expression represents different types of expressions, with a Kind field to specify the type.

ExpressionStatement represents a standalone expression, like a function call.

ForStatement represents a for-loop.

FunctionCall represents a function call, e.g., `foo(x, y)`.

IfStatement represents an if statement with an optional else block.

Literal represents basic values like integers, strings, etc.

ReturnStatement represents a return statement, e.g., `return x`.

Statement represents different types of statements, with a Kind field to specify the type.

SwitchStatement represents a switch-case structure.

VarDeclaration represents a variable declaration, e.g., `var x int = 5`.

Variable represents a variable, e.g., `x`.

ExpressionKind is an enum-like type representing the kind of expression.

StatementKind is an enum-like type representing the kind of statement.