dart-use-pattern-matchinglisted

# Implementing Dart Patterns ## Contents - [Pattern Selection Strategy](#pattern-selection-strategy) - [Switch Statements vs. Expressions](#switch-statements-vs-expressions) - [Core Pattern Implementations](#core-pattern-implementations) - [Workflows](#workflows) - [Examples](#examples) ## Pattern Selection Strategy Apply specific pattern types based on the data structure and desired outcome. Follow these conditional guidelines: * **If validating and extracting from deserialized data (e.g., JSON):** Use Map and List patterns to simultaneously check structure and destructure key-value pairs. * **If handling multiple return values:** Use Record patterns to destructure fields directly into local variables. * **If executing type-specific behavior (Algebraic Data Types):** Use Object patterns combined with `sealed` classes to ensure exhaustiveness. * **If matching numeric ranges or conditions:** Use Relational (`>=`, `<=`) and Logical-and (`&&`) patterns. * **If multiple cases share logic:** Use Logical-or (`||`) patterns to share a single case body or guard clause. * **If ignoring specific values:** Use the Wildcard pattern (`_`) or a non-matching Rest element (`...`) in collections. ## Switch Statements vs. Expressions Select the appropriate switch construct based on the execution context: * **If producing a value:** Use a **switch expression**. * Syntax: `switch (value) { pattern => expression, }` * Rule: Each case must be a single expression. N