# Dash into Dart

**Forewords**: The core idea here, shall we reflect on the foundation of programming language, before the leap into the Flutter framework. Let's take a look at the primitive programming build blocks from the variables, and operators, to Type. Many credits to [TutorialsPoint](https://www.tutorialspoint.com/dart_programming/dart_programming_environment.htm) for the material, and inspiration from the content.

## Dart Programming Language concepts

the following is based on the **Dark SDK 2.18.6** at the time of writing & (Flutter 3.3.10) in **DartPad** [https://dartpad.dev/](https://dartpad.dev/). Here's a quick summarized code for our studies. Fancy trying it out? Copy and paste to DartPad into a `void main()` function and explore.

```dart
  //Loops & Labels
  currentLoop: 
  for (int i = 0; i < 7; i++) {
    print('hello ${i + 1}');
    if (i==5) break currentLoop; //break means exit the loop
    if(i==4) continue currentLoop; //skip current element
  }
  
  //types
  var abc = 'Smith'; //abc can't be assigned to 1
  //abc = 1; //this has compile error

  dynamic dyn = 'Hello'; //dyn could be assigned to 1
  dyn = 1;

  print(dyn is int); //true, best for checking 'dynamic'
  print(dyn is! String); //false

  //prefer lowerCamelCase for constant names
  /* https://dart.dev/guides/language/effective-dart/style */
  final solidName = 'the rock'; //set once during runtime.
  const heavyName = 'the boulder'; //compile time constant
  
  //operators
  double totalSum = 1 + 2 - 3 * 4 / 5 % 6;
  final integerResult = 5 ~/ 2 ; // expect 2
  final increased5 = ++totalSum;
  final decreased4 = --totalSum;
  
  //Print, Output
  print("$solidName : $abc");
  //=> the rock : Smith
  print("$dyn & $heavyName is $increased5 vs $decreased4");
  //=> 1 & the boulder is 1.6 vs 0.6000000000000001

  //Number, properties, then methods
  totalSum.sign;
  integerResult.isEven;
  print(totalSum.hashCode); //hashcode for numeric value?
  
  print("$totalSum ${totalSum.ceil()}"); //method for ceiling
  print("${(-4).abs()}"); 
  //we do (-4) because the -negate function acts after the function
```

Here's a little break, before we resume with String, Boolean, List & Map, and of Dynamic Type. Personally, I think Dart is a very interesting programming language, much reminded me of the fun learning programming of Java in the older days.

![Target icons created by Freepik - Flaticon](https://cdn.hashnode.com/res/hashnode/image/upload/v1672685160021/ef3aa4f2-75d3-4eb2-9904-4ebb65e52ea6.png align="center")

Photo by [Target icons created by Freepik - Flaticon](https://www.flaticon.com/free-icons/target)

## Look into the String & Boolean

```dart
   // ---------- Strings ----------
  var singleLine = 'hello world';
  var multiLine = '''hello world
    this is a message
    from the far far galaxy ''';
  var jointLine = 'hello in single line '
      'I have a message to write';
  
  print(singleLine); // hello world
  print(multiLine); // print the following include the indent
/*
    hello world
        this is a message
        from the far far galaxy */
  
  print(jointLine); //split message but join as one
    //print: hello in single line I have a message ...

  print('The sum of 100+101 is ${100+101}');
  var newline = singleLine.toUpperCase().toLowerCase().replaceAll('l','n');
  
  //string are immutable, cannot be changed, 
  ////new instance could be made for all the modification
  print(singleLine); 
  print(newline); //prints `henno wornd`
  
  
  // ---------- Boolean ----------
  bool isModified = false;
  bool hadBreakfast = true;
  
  print(isModified || hadBreakfast); // return true
  
  print(singleLine.isEmpty); //property, that return false
  
  //example expect Uniform ID of length 5, 00010
  print('10'.padLeft(5, '0')); //return 00010
```

## Decision-Making with If-else, and Switch Cases

for additional reference, only the linting part, check out this one [**\[Curly\_braces\_in\_flow\_control\_structures\]**](https://dart-lang.github.io/linter/lints/curly_braces_in_flow_control_structures.html)

```dart
  // ---- Decision Making -------
  var fruit = 'apple';
  
  //linter - apply braces for all control statements
  // if -- else
  if(fruit == 'apple'){
    print('red');
  }
  else if(fruit =='banana'){
    print('yellow');
  }
  else{
    print('I don\'t know');
  }
  
  fruit = 'kiwi';
  
  // switch case
  switch(fruit){
    case 'apple': 
      print('red');
      break;
    case 'banana': 
      print('yellow');  
      break;
    default: 
      print('I don\'t know');
  }
```

## List - with null-safety enabled, Map

```dart
  //with null safety enabled
  var fixedList = List<int>.filled(3, 0, growable: false );
  var growableList = List<int>.filled(3, 1, growable: true );
  print(fixedList); // prints [0,0,0]
  print(growableList); //print [1,1,1]

  growableList.add(5);
  
  var keyValuePairs = {'apple':'red', 'banana':'yellow'};
  keyValuePairs['orange']='orange';
  print(keyValuePairs);
  print(keyValuePairs.keys); //apple,banana, orange
  //Dynamic Type - Dart is an optionally typed language
```

the beauty of dart here is that we don't have to loop. The ***print*** would show the primitive content of the list.

## 🎁 Bonus: Fun with the String, Runes

```dart
   //-------- Bonus ----------
  String x = 'ABC aeroplane';
  print(x.codeUnits); //prints the UTF-16 code,
  //Upper and Lower case difference = A 65, a 97 = 32. 
  
  x.runes.forEach((_){
    print(new String.fromCharCode(_));
  });
  
  //Runes access to the character codes
  Runes input = new Runes('\u{1F600}'); //smiley 😀
  print(new String.fromCharCodes(input));
```

## Conclusion

This is merely some handpicked example from Dart, it's not exhaustive. In the future article, we may explore some additional syntax available in the Dart language.