deelang/demo/example.dee

## By the end of the book I want to have an interpreter
## for this little language, maybe a compiler too

print(1 + 1) ## 2
print("Hello world!") ## Hello world

name <- read()
print("Hi there $name") ## Hi there <name>

have <- 10
want <- 11
need <- have - want ## This is subtraction
have-want <- 1 ## This is a variable named "have-want"

print(HaVe-WAnt) ## 1 (case doesn't matter)
%%option meaningful-casing
Apples <- 1
print(apples) ## <undef> (or maybe it does)

print("one fish"); print("two fish") ## Two statements on the same line

say-hi <- -> print("Hi from inside a function")
say-hi() ## Hi from inside a function

say-hi-again <- say-hi
say-hi-again() ## "Hi from inside a function" (First class functions!)

duck <- {
	bills <- 1
	talk <- -> print("Quack")
	eats? <- food -> food = "bread"
} ## Objects created on the fly

print duck.eats?("bread") ## true
print duck.eats?("corn") ## false

cow <- {
	talk <- print("Moo")
	eats? <- food -> food oneof "grass", "corn"
}

human <- {
	eats? <- _ -> true
}

print cow.eats?("grass") ## true
print cow.eats?("corn") ## true

talk-or-pass-wind <- character ->
	if character has talk then
		character.talk()
	else
		print("*Fart*")

talk-or-pass-wind(duck) ## "Quack"
talk-or-pass-wind(cow) ## "Moo"
talk-or-pass-wind(human) ## "*Fart*"