This is an article that lists most of the idioms frequently used in Funky code. Each idiom is introduced by a name with a link to the place in this tour that describes it, a short description and some schematic code examples.

• Dashes to separate words.

  yield-all right-pad format-table Priority-Queue
  

• Question marks at the end of predicates (functions that return Bool):

  even? odd? whitespace? empty? none? some?
  

• Exclamation marks at the end of partial functions (functions that can crash!):

  first! rest! extract! at!
  

• Special symbols where appropriate:

  + - * / abs^2 let-::
  

Vertical functions

These are the building block of code that reads top to bottom. The example below show some, but not all of the common patterns of types these functions tend to have.

func semicolon-based-1 : V -> V =
    ...

func semicolon-based-2 : A -> V -> V =
    ...

func lambda-based-1 : (B -> V) -> V =
    ...

func lambda-based-2 : C -> (D -> V) -> V =
    ...

func lambda-based-3 : E -> (F -> G -> V) -> V =
    ...

func lambda-based-4 : I -> (J -> V -> V) -> V -> V =
    ...

func usage : V =
    semicolon-based-1;
    semicolon-based-2 a;
    lambda-based-1 \b
    lambda-based-2 c \d
    lambda-based-3 e \f \g
    lambda-based-4 i (
        \j \next
        ...
        next
    );
    ...

If

The if function is used to choose from two alternatives based on a condition.

println (if condition then else);
println (if (x < y) x y);
...

if (n <= 0) 1;
n * factorial (n - 1)

if (invalid? input)
    (println "invalid"; quit);
println "correct!";
...

if (invalid? input) (
    println "your input is wrong!!!";
    println "now you will suffer.";
    ...
);
...

if (op == "+") ...;
if (op == "-") ...;
if (op == "*") ...;
if (op == "/") ...;
if (op == "^") ...;
"invalid operator"

When

The when function is used to conditionally apply/execute a function unlike if which is used to choose between two alternative branches. The imperative analog of when is an if without an else.

when condition function;
...

when (total-price cart < euro 30.0)
    (println "The shipping will not be free.");
...

when (p x) (x ::) (filter xs)

when condition (
    \next
    ...
    next
);
...

Let

Binding values to variables is not a built-in construct in Funky.

let (reverse; range 1 1000000) \numbers
...

let (filter (< pivot) nums)  \left
let (filter (== pivot) nums) \middle
let (filter (> pivot) nums)  \right
...

let-pair (pair "A" 4) \s \x
...

let (
    ...
) \variable
...

Maybe binding

Both of the expressions have type Maybe Int.

let-some (some 7) \x
x + 10

let-some none \x
x + 10

List binding

Both of the expressions have type Maybe something (something is just a placeholder depending on the type of ...).

let-:: [1, 2, 3, 4, 5] \x \xs  # x=1 and xs=[2,3,4,5]
...

let-:: [] \x \xs  # the whole expression is none
...

For

The for function is used to loop over a list of elements. It is functionally equivalent to fold<.

Short for-loop

for list function;
...

for ["A", "B", "C"] println;
quit

for (range 1 10)
    (println . string);
quit

Long for-loop

for list (
    \x \next
    ...
    next
);
...

Looping over pairs

for-pair list-of-pairs (
    \x \y \next
    ...
    next
);
...

for-pair (enumerate names) (
    \i \name \next
    println ("#" ++ string i ++ ": " ++ name);
    next
);
quit