An ambiguous language called Nano
nano it's a simple (trust me) language that proposes a new way to create extensibility through what I call "permisive operators". A permisive operator can be built using arbitrary characters and can be applied without leaving whitespace.
Building Matematical Notation
nano has few built-in operations based on lambda-calculus. All these use normal
prefix notation. The following declarations declare the
- operators with
let infixr 1 x + y = add x y let infixr 2 x - y = sub x y
By default operators are use prefix notations. There aren't negative lexicals in nano. Nano is powerful enough, that we can just define a "-" unary operator for writing negative lexicals.
let 10 - x = sub 0 x
Nano is so simplistic that it doesn't even define expressions or grouping. You can define them yourself by using closed operators.
let closed ( x ) = x
All you need is recursion :)
let rec suffix n ! = if (n==0) 1 (n * (n-1)!)
There's no even list sugar syntax, but you can create it!
let infixr 2 x : y = cons x y let  = empty let rec infixr l [ idx = if (idx == 0) (hd l) ((rest l)[(idx -1)) let suffix x ] = x let 10 [ x = x let infixr x , y = x : y let suffix x ] = x : empty let rec infixr x ... y = if (x > y) empty (cons x ((x+1)...y)) let infixl 4 x ? y = if x (cons y empty) (empty) let infixl 4 x : y = if (isNull x) y (hd x)
Since application doesn't require whitespace, is possible to have real hungarian notation.
let infixl x default y = if (isNull (fst x)) y (hd (fst x)) let s x = if x "true" "false" let i x = if x 1 0
And closing operators can be used to have a mini-xml language
let infixr x ; y = buildPair x y let closed <html> x </html> = buildPair "html" x let closed <head> x </head> = buildPair "body" x let closed <body> x </body> = buildPair "body" x let closed <div> x </div> = buildPair "div" x