Re: Some crazy proposals :-)

[Coda Highland <chighland@...>]

On Thu, Jul 9, 2015 at 10:13 AM, Andrew Starks <andrew.starks@trms.com> wrote:
>
>
> On Thursday, July 9, 2015, Rena <hyperhacker@gmail.com> wrote:
>>
>> On Jul 9, 2015 11:04 AM, "Egor Skriptunoff" <egor.skriptunoff@gmail.com>
>> wrote:
>> >
>> > Hi!
>> >
>> > The following "proposals" are just for fun.
>> >
>> > -----------------------------
>> > 1) A must-have "dont" statement :-)
>> >
>> > dont
>> >    -- code inside dont..end block will be skipped
>> >    -- useful for easy commenting do..end block
>> > end
>> >
>> > "dont" is also applicable to any block: if, while, for, multiline
>> > assignment, function definition, etc.
>> >
>> > dont if ... then -- this condition will not be evaluated
>> >    -- this code will be skipped
>> > else
>> >    -- this code will be skipped too
>> > end
>> >
>> > "dont" statement acts as --[[...]] comment, but only for a single
>> > statement inside
>> > When using "dont" we do not need to search for a place where very long
>> > statement ends, so using "dont" is more easy than --[[...]]
>> > The "dont...end" is a syntactic sugar for "dont do...end"
>> >
>> > -----------------------------
>> > 2) Famous "comefrom" operator as the opposite to "goto"
>> >
>> > ...
>> > ::label1::
>> > ...
>> > comefrom label1, label2, label3
>> > ...
>> > ::label2::
>> > ...
>> > ::label3::
>> > ...
>> >
>> > is equivalent to
>> >
>> > ...
>> > goto label0
>> > ...
>> > ::label0::
>> > ...
>> > goto label0
>> > ...
>> > goto label0
>> > ...
>> >
>> > -----------------------------
>> > 3) Labels are considered to be first-class citizens
>> >
>> > ::Label1::
>> > ...
>> > local my_label = Label1  -- assigning a value of type "label" to a
>> > variable
>> > ...
>> > -- Now "goto" operator gets its real power!
>> > goto my_array_of_labels[where_do_you_want_to_go_today]
>> > ...
>> > -- And of course the same is true for "comefrom" :-)
>> > comefrom get_some_labels()
>> > -- it is equivalent to "comefrom label1, label2,..."
>> > -- where label1, label2,.. are values returned by LAST invocation of
>> > get_some_labels()
>> > -- "comefrom" without labels is valid (it just does nothing useful)
>> > ...
>> >
>> > -----------------------------
>> > 4)  Program can modify its own body using methods of labels
>> > A label is a "bookmark" between statements in a program (or before first
>> > statement or after last statement)
>> > A label may be named (defined at compile time) or unnamed (created at
>> > runtime)
>> >
>> > ...
>> > some_func(some_params)
>> > ...
>> > -- standard library function to create unnamed label just before current
>> > statement
>> > local here = labels.this_label()
>> > -- create label just before some_func invocation
>> > local previous_some_func_invocation = here:search_nearest("backward",
>> > "call", "some_func")
>> > -- replace "some_func()" with "another_func()" in the program body
>> > previous_some_func_invocation:replace_statement("another_func()")
>> > ...
>> > -- go to unnamed label
>> > goto previous_some_func_invocation
>> > ...
>> >
>> > -----------------------------
>> > The source of craziness:
>> > www.modell.com/Magery/SPharmful.html
>> >
>> > -- Egor
>> >
>>
>> Computed goto isn't *that* crazy. It's how things like jump tables and
>> switch statements are implemented. Lua doesn't really *need* them though
>> since it has first class functions.
>
>
> I will not rest until we can use Lua patterns for variable names:
>
> .*_foo = nil
>
> Ruby probably already has this feature.

You already can do it:

_ENV[".*_foo"] = nil

Of course it doesn't do what you were implying (but failing to state)
it ought to do. ;) But that's a different question entirely.

/s/ Adam