Lazy Hash

lazy_hash.io

#!/usr/bin/env io

# see - http://news.ycombinator.com/item?id=1626018

Hash := Object clone do (
    with := method (
        hash := Map clone
        call message arguments foreach (arg,
            # arg = k(v)  for eg. t(0)
            k := arg name
            v := arg argAt(0) asString
            hash atPut (k, doString (v))
        )
        hash
    )
)


h  := Hash with (t(0), f(1+1), with("hello"), writeln("not writeln!"))
h2 := Hash with (t(100), f("hello" asUppercase), at("my at"), atPut("my atPut"))

# Above lazily goes through the Hash with() building the key/value pairs without ever 
# running methods/functions with, writeln, at, atPut and simply takes the method/func 
# name and evaluates its argument into a key/value pair:


h  at ("writeln") println  # => "not writeln!"
h  at ("f") println        # => 2
h2 at ("f") println        # => "HELLO"