1. Trends in Programming
Languages
Anton Moldovan
@AntyaDev

4. • Horse-power of many-core…
• …but how to program those? Concurrent
• Schematized, static, dynamic…
• …so, what’s the sweet spot? Dynamic
• New level of expressiveness…
• …how about the essence? Functional

6. Dynamic
Languages
Simple and succinct
Implicitly typed
Meta-programming
No compilation
Static
Languages
Robust
Performant
Intelligent tools
Better scaling

7. • non-schematized data
•
•
•
• Metaprogramming
•
•

9. Theory of Computation
(Lambda Calculus, Alonzo Church)
LISP Heritage
Reality of Hardware
Fortran Heritage (Memory, John Von Neumann)
ML
SmallTalk
C
Java
C++
C#
Scheme
Haskell

10. var res = xs.Where(C# x => x % 2 == 0);
Visual Basic Dim res = xs.Where(Function(x) x Mod 2 = 0)
F# let res = xs |> Seq.filter (fun x -> x % 2 = 0);
var res = xs.filter(function(x) {
return x % 2 == 0;
});
JavaScript
auto res = find_if(xs.begin(), xs.end(), [] (int i) {
return x % 2 == 0;
});
C++11

11. First class functions
FP
Immutable
data
Referential
transparency
Algebraic data types
Type
inference
Pattern
matching
Essence
Niceties

12. Visual
Studio
.NET
Functional
F#

13. Type Inference

14. “Local” Inference
• Confine your focus to a single
declaration
• Compute the type directly
• Move on to the next one…
• Can't infer parameter types…

22. Pros
• Mostly intuitive behavior
• Very simple to implement
• (the compiler does this work anyway)

31. “Global” Inference
• Look at the literals
• Look at the functions and other values
something interacts with
• Look at any explicit type constraints
• If there are no constraints anywhere,
automatically generalize to generic types

43. function printLabel(labelledObj: {label: string}) {
console.log(labelledObj.label);
}
var myObj = {size: 10, label: "Size 10 Object"};
printLabel(myObj);

46. //start an instance of the firefox browser
start firefox
//go to url
url "http://lefthandedgoat.github.io/canopy/testpages/"
//assert that the element with an id of 'welcome' has
//the text 'Welcome‘
"#welcome" == "Welcome"

47. project "F# DSL Article" starts "01/01/2009"
resource "Dmitri" isa "Writer" with_rate 140
resource "Computer" isa "Dumb Machine" with_rate 0
group "DSL Popularization" done_by "Dmitri"
task "Create basic estimation DSL" takes 1 day
task "Write article" takes 1 day
task "Post article and wait for comments" takes 1 week
group "Infrastructure Support" done_by "Computer"
task "Provide VS2010 and MS Project" takes 1 day
task "Download and deploy TypograFix" takes 1 day
task "Sit idly while owner waits for comments" takes 1 week
prepare my_project