SmallJS

SmallJS syntax

Here’s an example SmallJS class declaration
containing

Explanation of syntax used:

• CLASS : Is followed by the class name.

• EXTENDS : Indicates the base class. Object is the root class.
• MODULE : The JS module this class should be put in.
• CLASSVARS : Variables of the class itself (not its instances). Like JS static class vars.
• VARS : Instance variables of objects created from the class, e.g.: MyTest new.
• "This is a comment ..." : Comments are put in double quotes.
• CLASSMETHODS : Following methods will be added to the (meta)class, like JS static class methods.
• METHODS : Following methods will be added to class instances, like JS regular class methods.
  (Is the default method type if neither CLASSMETHODS nor METHODS is specified.)
• Message sending types, ordered from highest to lowest evaluation precedence:
  • method1 : Unary method, has no arguments.
  • ++ var : Binary (operator) method, has one argument.
  • method2Arg1: aVar1 arg2: aVar2 : Keyword method, has one or more arguments.
• | locVar lv2 lv3 | : Local variables declaration.
• ! : End of method
• Constants
  • 'aaa': String, uses single quotes
  • 1 : Integer
  • 3.14 : Float
  • true, false: Boolean
  • nil : Nil singelton, like JS null.
  • $c : Character
• var1 := 3 : variable assignment
  • var1 = 3 tests for equality.
• ^ 42 : Return a value.
• #( 1 3.14 'aaa' ) : array with 3 values.
• [ 1 + 2 ] : block, like JS lambda functions.
  • [ :a | :b | ^ a + b ] : block with 2 arguments returning sum from method (not block).
• INLINE : Inline JS code, not transpiled.
  ST variables can be accessed in it using the same name
• Control flow statements in ST use messages and blocks from above.
  • 1 + 2 = 3 ifTrue: [ 'Checks out' ]
    Like JS: if( 1 + 2 == 3 ) { … }
  • a > 0 ifTrue: [ 'Positive' ] ifFalse: [ 'Zero or negative' ]
    Like JS: if( a > 0 ) { … } else { … }
  • 1 to: 10 do: [ :n | self log: n ]
    Like JS: for( n = 1; n <= 10; ++n ) { … }
  • [ a > 0 ] whileTrue: [ self log: a. a decrement ]
    Like JS: while( a > 0 ) { … }
  • [ self log: a. a decrement ] doWhile: [ a > 0 ]
    Like JS: do { … } while( a > 0 )

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