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Quick Tour of the Jogo Programming Language

mfichman edited this page Jan 6, 2013 · 13 revisions

This page is a brief summary of the Jogo syntax, for folks who want to get a feel for the language. Check out the full tutorial for more depth.

Expressions

Io::println('hello world')
# Local type inference
x = 1 + 2
# Explicit type declaration
y Int = 9

Control structures

# Conditionals
if x == 9 {
    Io::println('x is 9')
} else {
    Io::println('x is not 9')
}
# Conditional match
match variable {
with 8: 
    Io::println('matched 8')
with 7: 
    Io::println('matched 7')
default:
    Io::println('default')
}
# Type match 
match any {
with String: 
    Io::println('matched String')
with Int:
    Io::println('matched Int')
}
# While loop
while condition {
    Io::println('loop')
}
# For-each loop
for leaf in tree {
    Io::println(leaf)
}

Collections

# Array
array = ['one', 'two', 'three', 'four']
array = Array[String](10)
array[0] = 'five'
# Hash
hash = {one: 'two', three: 'four'}
hash = Hash[String, String]()
hash['one'] = 'five'

Functions

# Free function
add(first Int, second Int) Int {
    ret first + second
}
# Closure
message = 'hello world'
greet = func() { Io::println(message) }
greet()

Data Structures

# Objects (reference types)
Truck < Object {
    passengers = 0

    @init(passengers Int) {
        self.passengers = passengers
    }

    drive() {
        Io::println("rollin' out")
    }
}
  
truck = Truck(2)
truck.drive()
truck.passengers = 1
# Objects (value types) 
Vector3 < Value {
    x Int
    y Int
    z Int
}

vec1 = Vector3()
vec1.x = 10
vec2 = vec1 
# Copy by value
# Enums
Fruit = APPLE | BANANA | PEAR | ORANGE
# Tagged unions
Choice = String | Int | Truck

Modules

import Io, File

println('opening a file')
file = open('file.txt', 'r')

Interfaces

# Structural typing
Vehicle < Interface {
    drive()
}

drive(vehicle Vehicle) {
    vechicle.drive()
}  

drive(new Truck())

Generics

Box[:a] < Object {
    object :a
}

box = Box[String]()
box.object = 'abc'

Coroutines

i = 100
task = Coroutine() func() {
    while i > 0 {
        Io::println(i.str)
        yield
    }
}
task()
task()
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