?- catch((writeln('Test1...'),
|    throw(exc('Ups..')),
|    writeln('Unachievable..')), exc(E), writeln(E)).
Test1...
Ups..
E = 'Ups..'.

X> ?- catch((writeln('Test1...'),
X>|    throw(exc('Ups..')),
X>|    writeln('Unachievable..')), exc(E), writeln(E)).
X>Test1...
X>Ups..
X>E = 'Ups..'.
X>

import Control.Monad.State
import Control.Monad.List

type P a = StateT String [] a

pitem :: P Char
pitem = do
    cs <- get
    case cs of
        (c:cs) -> do
            put cs
            return c
        _ -> mzero

psat p = do
    x <- pitem
    if p x then return x else mzero

pchar c = psat (==c)

pmany p = pmany1 p `mplus` return []
pmany1 p = do
    x <- p
    xs <- pmany p
    return $ x:xs

bracketed open close action = do
    open
    x <- action
    close
    return x

braced = bracketed (pchar '(') (pchar ')')

balanced = do {pmany (braced balanced); return ()}

T>import Control.Monad.State
T>import Control.Monad.List

T>type P a = StateT String [] a

T>pitem :: P Char
T>pitem = do
T>    cs <- get
T>    case cs of
T>        (c:cs) -> do
T>            put cs
T>            return c
T>        _ -> mzero

T>psat p = do
T>    x <- pitem
T>    if p x then return x else mzero

T>pchar c = psat (==c)

T>pmany p = pmany1 p `mplus` return []
T>pmany1 p = do
T>    x <- p
T>    xs <- pmany p
T>    return $ x:xs

T>bracketed open close action = do
T>    open
T>    x <- action
T>    close
T>    return x

T>braced = bracketed (pchar '(') (pchar ')')

T>balanced = do {pmany (braced balanced); return ()}
T>

many(What) -->
    What,
    many(What).
many(_) --> [].

bracketed(Open, Close, What) -->
    Open,
    What,
    Close.

braced(What) --> bracketed("(", ")", What).
braced(What) --> bracketed("{", "}", What).
braced(What) --> bracketed("[", "]", What).

balanced -->
    many(braced(balanced)).

test :-
    phrase(balanced, "[](){[{()}]}"),
    phrase(balanced, "[[[()]]]({}{{[]}})[{}]()[]"),
    \+ phrase(balanced, "[[[()]]]({[}{{[]}})[{}]()[]").

?- test.
true .

from System.Diagnostics import Stopwatch

s = Stopwatch()
s.Start()

print sum((float(value.replace(',','.')) for value in open("c:\\numbers_large.txt").read().split(" ") if value))

s.Stop()

print s.ElapsedMilliseconds

T>И какая у этого производительность?

:- set_prolog_flag(float_format,'%.15g').

many1(What, [H | T]) -->
    call(What, H), !,
    many1(What, T).
many1(_, []) --> [].


integer(I) -->
        many1(digit, [D|DD]),
    { number_chars(I, [D|DD])
        }.

digit(D) -->
        [D],
        { code_type(D, digit)
        }.


float(F) -->
    (   "-", {Sign = -1}
    ;   "", {Sign = 1}
    ), !,
    integer(N),
    ",",
    integer(D),
    {F is Sign * (N + D / 10^(ceiling(log10(D))))
    }.

sum(S, Total) -->
    float(F1), !,
    " ",
    { S1 is S + F1},
    sum(S1, Total).
sum(Total, Total) -->
    [].

go1 :-
    phrase_from_file(sum(0, S),'numbers_large.txt', [buffer_size(16384)]),
    writeln(S).

Console.WriteLine((from value in File.ReadAllText(@"c:\numbers_large.txt").Split(' ') where value !=  "" select double.Parse(value)).Sum());

public static class StringHelper
{
    public static IEnumerable<string> AsyncSplit(this string value, char delimiter)
    {
        int start = 0;
        int index = value.IndexOf(delimiter, start);

        while (index != -1)
        {
            yield return value.Substring(start, index - start);
            start = index + 1;
            index = value.IndexOf(delimiter, start);
        }
    }
}