Anonymous user
Category:Lambdatalk: Difference between revisions
no edit summary
No edit summary |
No edit summary |
||
Line 11:
2) {lambda talk}, a purely functional language unifying authoring, styling and scripting in a single and coherent s-expression based syntax.
=={lambda talk} in a few words==
1) Expressions are written in a prefix notation using curly braces.
Line 20:
-> 2+3 is equal to 5
{def foo
Line 31:
==more about {lambda talk}==
{lambda talk} is freely inspired by the '''λ-calculus''. At the lowest level a {lambda talk} expression is exclusively made of words, abstractions and applications:
===structure & evaluation===
Line 53:
{def word expression}
allowing to create constants added to the dictionary and to give names to anonymous functions.
What can be done with so little?
Line 101:
{def CDR {lambda {:z} {:z {lambda {:x :y} :y}}}} -> CDR
{CAR {CONS Hello World}} -> Hello
{
===about the implementation===
Line 116:
};
'''1) eval_forms()''': Using a single '''regular expression''' the eval_forms() function loops over the code string, skips the words out of curly braces, matches nested forms {first rest} from inside out, and replaces them by words. The repeated substitutions inside the code string overcomes limitations of regular language. It's a kind of Turing machine.
- lambdas are '''first class functions''', they can be called as functions' arguments and returned from functions,
Line 125:
- lambdas accept de facto '''partial function application''': called with a number of values lesser than its arity, a lambda memorizes the given values and returns a new lambda waiting for the rest.
'''Note:''': This is what Ward Cunningham wrote about that: ''« I was surprised that the technique worked so well in so many cases. I knew that regex are highly optimized and the cpus themselves optimize sequential access to memory which the regex must have at its core. [..] Yes, this has at its heart the repeated application of a text transformation. The fact that it is repeated application of the same transformation makes it exceptional. [..] Repeated application of Regular Expressions can perform Touring Complete computations. This works because the needed "state" is in the partially evaluated text itself. »'' All is said!
===and?===
| |||