3) lambdas are special forms evaluated to a single word - a function's reference added to a dictionary, initially empty - and follow these 3 rules:
3.1) called on a number of words lesser than the number of arguments, a lambda memorizes the given words and returns a new lambda waiting for missing words,
3.2) called on a number of words equal to the number of arguments a lambda returns a word or a sequence of words,
3.3) called on a number of words greater than the number of arguments, the last one gets the exceeding words and the lambda returns a word or a sequence of words.
So:
1) {SWAP Hello}, ie {{lambda {:a :b} :b :a} Hello}, replaces :a by Hello and returns the anonymous unary function {lambda {:b} :b Hello} waiting for the missing one,
2) {SWAP Hello World} replaces :a by Hello and :b by World and returns "World Hello",
3) {SWAP one two three} replaces :a by "one", :b by all following words, here "two three", and returns "two three one"
4 comments
[ 0.21 ms ] story [ 23.6 ms ] threadWhat is {SWAP Hello} ? Or {SWAP one two three} ?
> It's a mistery.
A mystery, even:-)
As explained in this page - http://lambdaway.fr/workshop/?view=coding the lambdatalk evaluator is built so that:
3) lambdas are special forms evaluated to a single word - a function's reference added to a dictionary, initially empty - and follow these 3 rules:
3.1) called on a number of words lesser than the number of arguments, a lambda memorizes the given words and returns a new lambda waiting for missing words,
3.2) called on a number of words equal to the number of arguments a lambda returns a word or a sequence of words,
3.3) called on a number of words greater than the number of arguments, the last one gets the exceeding words and the lambda returns a word or a sequence of words.
So:
1) {SWAP Hello}, ie {{lambda {:a :b} :b :a} Hello}, replaces :a by Hello and returns the anonymous unary function {lambda {:b} :b Hello} waiting for the missing one,
2) {SWAP Hello World} replaces :a by Hello and :b by World and returns "World Hello",
3) {SWAP one two three} replaces :a by "one", :b by all following words, here "two three", and returns "two three one"
The javascript code can be seen in the 100 first lines of this file - http://lambdaway.fr/workshop/meca/JS.js
The lambdaway project is introduced in deep here - http://lambdaway.fr/
with a lot of links to plain explanations on the lambdatalk language.
Thank you for your interest. Alain