Dart Syntax, Statements & Code Organization
Dart code uses C-style block formatting with mandatory statement semicolons (`;`). Code is organized into top-level functions, classes, and libraries. The `dart format` tool enforces opinionated community formatting conventions, ensuring consistent styling across all projects.
"Semicolons in Dart are like periods at the end of written sentences: they mark the precise boundary where one thought ends and the next begins."
Deep Dive: How It Works
Top-Level Scope: Functions, variables, and constants can exist directly at library level without requiring an enclosing class wrapper.
Comments: Single-line (`//`), multi-line (`/* ... */`), and documentation comments (`///`) which generate automated API docs.
Case Conventions: `lowerCamelCase` for variables and functions, `UpperCamelCase` for types and classes, `SCREAMING_CAPS` avoided in modern Dart in favor of `lowerCamelCase` constants.
Syntax Blueprint
/// Documentation comment
void main() {
// Single-line comment
var message = "Structured Code";
print(message);
}Statements terminate with semicolons; documentation uses triple slashes.
Core Rules to Remember
Common Beginner Traps & How to Fix Them
Omitting semicolons when coming from Python or JavaScript/TypeScript.Why it happens: JavaScript has Automatic Semicolon Insertion (ASI); Dart does NOT.
How to fix: Always include terminating semicolons on statements and return expressions.
Live Interactive Example
Hit Run Code to see it liveYour Turn: Micro Challenge
No pressure! Edit the starter code below and test your solution with instant feedback.
Create and Call a Helper Function
- Define a function `int doubleNumber(int n)` that returns `n * 2`.
- Inside `main()`, call `doubleNumber(21)` and print the result.
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