Function isPlainVariableExpression

packages/graph/src/astToSteps.ts:2567–2578

* Helper to check if an expression is a plain variable reference

(item: import("./AST.js").ReturnItem)

 * Helper to check if an expression is a plain variable reference
 */
function isPlainVariableExpression(item: import("./AST.js").ReturnItem): string | null {
  if (item.variable && !item.property && !item.function && !item.aggregate) {
    return item.variable;
  }
  const expr = item.expression;
  if (expr && typeof expr === "object" && "type" in expr) {
    if (expr.type === "VariableRef") {
      return (expr as import("./AST.js").VariableRef).variable;
    }
  }
  return null;
}

/**
 * Helper to check if an expression is a property access