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CFG grammar parser

Name: Anonymous 2008-04-13 18:52

I know there's gonna be some witty regular expression faggot posting here, but whatever.
Let's see your language do this.


#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <limits.h>

/* CFG grammar */

typedef struct {
    int c;
    const char *str;
} cfg_t;

int eval(const char *buf, const cfg_t *, char *res, size_t sz);

int main(void)
{

    char buf[BUFSIZ];
    char res[BUFSIZ];
    char *p, *s, *tmp;
    int ret;
    size_t n;
    const cfg_t cfg[26] = {
    {'A', "hello"},
    {'B', "world"},
    {'C', "A B"},
    {'D', "A D"}
    };

    while (fgets(buf, sizeof buf, stdin) != NULL) {

    if (*buf && buf[strlen(buf) - 1] == '\n')
        buf[strlen(buf) - 1] = 0;

    p = buf;
    s = res;
    n = 0;

    while ((ret = eval(p, cfg, s, BUFSIZ)) == 1) {
        printf("%lu ==> %s\n", (unsigned long) n, s);
        tmp = p;
        p = s;
        s = tmp;
        n++;
    }

    if (ret == -1)
        printf("'%s': expansion too big to fit in %d buf\n",
           p, BUFSIZ);
    else
        printf("result: '%s'\n", s);

    }

    if (ferror(stdin)) {
    perror("stdin");
    return EXIT_FAILURE;
    }

    return 0;
}

int eval(const char *buf, const cfg_t * cfg, char *res, size_t sz)
{

    size_t i;
    int done = 0;

    while (*buf != 0) {
    if (isupper((unsigned char) *buf)) {
        for (i = 0; i < 26; i++)
        if (*buf == cfg[i].c)
            break;
        if (i != 26) {
        done = 1;
        if (strlen(cfg[i].str) >= sz)
            return -1;
        strcpy(res, cfg[i].str);
        res += strlen(cfg[i].str);
        sz -= strlen(cfg[i].str);
        }
    } else {
        if (sz <= 1)
        return -1;
        *res = *buf;
        res++;
        sz--;
    }
    buf++;
    }
    *res = 0;

    return done;
}

example

$ ./cfg
A
0 ==> hello
result: 'hello'
A B
0 ==> hello world
result: 'hello world'
BB
0 ==> worldworld
result: 'worldworld'
C
0 ==> A B
1 ==> hello world
result: 'hello world'
^D
$

Name: Anonymous 2008-04-13 19:18

{ 'A', "SICP" },
{ 'B', READ A\nB" }

AB

Name: Anonymous 2008-04-13 19:19

$cfg = {'A' => 'hello',
    'B' => 'world',
    'C' => 'A B',
    'D' => 'A D'}

def cfg_eval(str)
    r = ''
    str.split(//).each {|k| r += $cfg.has_key?(k) ? cfg_eval($cfg[k]) : k }
    r
end

$stdin.each_line {|l| puts 'result: ' + cfg_eval(l.rstrip).inspect}

Name: Anonymous 2008-04-13 19:36

>>3
Your solution is recursive, not iterative like OPs.
It would fail in 'D' => 'D'.

Name: Anonymous 2008-04-13 19:53

In "CFG grammar", what does the "G" stand for?

Name: Anonymous 2008-04-13 20:00

>>5
Graph

Name: Anonymous 2008-04-13 20:25

import random, re
cfg = lambda g, r=random, t='%*', d=100: re.sub(r'%(.)', lambda m: cfg(g, r, r.choice(g.get(m.group(1), [m.group(1)])), d-1), t) if d else t

Name: Anonymous 2008-04-13 20:58

>>7
wtf theres no indentation

Name: Anonymous 2008-04-13 21:22

>>8
[spoiler][b][i]THE FORCED UNINDENTATION OF CODE[/i][/b][/spoiler]

Name: Anonymous 2008-04-13 21:30

>>1
I bet you input your PIN number to use an ATM machine so you can obtain money to buy a Network NAS device.

Name: Anonymous 2008-04-13 21:42

I have RAS syndrome

http://en.wikipedia.org/wiki/RAS_syndrome

Name: Anonymous 2008-04-14 0:26

#!/usr/bin/perl

use strict;
use warnings;

my %re=(
    A => "hello",
    B => "world",
    C => "A B",
    D => "A D",
);

sub replace($){
    $_[0]=join "",map{
        while(my($k,$v)=each %re){
            s|$k|$v| and last
        }
       
        $_
    } split //,$_[0];
}
while(my $line=$_=<>){
    my $index=0;
   
    while($line ne replace $_){
        print $index++," => ",$line=$_;
    }
   
    print "result: ",$_;
}

__END__
b:\>perl go.pl
C
0 => A B
1 => hello world
result: hello world
D
0 => A D
1 => hello A D
2 => hello hello A D
3 => hello hello hello A D
4 => hello hello hello hello A D
5 => hello hello hello hello hello A D
6 => hello hello hello hello hello hello A D
7 => hello hello hello hello hello hello hello A D
8 => hello hello hello hello hello hello hello hello A D
9 => hello hello hello hello hello hello hello hello hello A D
10 => hello hello hello hello hello hello hello hello hello hello A D
11 => hello hello hello hello hello hello hello hello hello hello hello A D
12 => hello hello hello hello hello hello hello hello hello hello hello hello A D
13 => hello hello hello hello hello hello hello hello hello hello hello hello hello A D
14 => hello hello hello hello hello hello hello hello hello hello hello hello hello hello A D
15 => hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello A D
16 => hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello hello A D

Name: Anonymous 2008-04-14 0:28

b:\>perl go.pl
wat

Name: Anonymous 2008-04-14 0:57

>>13
Yes, I'm using windows

Name: Anonymous 2008-04-14 1:27

>>11
Hahaha, oh wow, I lol'd (LOL'd Out Loud).

Name: Anonymous 2008-04-14 3:17

>>14
I'm more interested in the b: part.

Are you working off of a 51/4" disk or something?

Name: Anonymous 2008-04-14 3:47

>>16
It's a hard drive. You can rename them now

Name: Anonymous 2008-04-14 4:06

>>17
Ｉ＇ｍ　ｓｏｍｅｗｈａｔ　ｄｉｓａｐｐｏｉｎｔｅｄ　ｎｏｗ　：（

Name: Anonymous 2008-04-14 5:08

>>17
Fuck you :(

Name: Anonymous 2008-04-14 5:13

:-(

Name: Anonymous 2008-04-14 5:36

:(

Name: Anonymous 2008-04-14 5:57

ITT sad

Name: Anonymous 2008-04-14 7:41

:') HAPPY TEARS

Name: Anonymous 2008-04-14 7:52

import Control.Monad (forever)

cfg = [('A', "hello"),
       ('B', "world"),
       ('C', "A B"),
       ('D', "A D")]

fix f x | x' == x   = [x]
        | otherwise = x : fix f x'
    where x' = f x

replace = concatMap (\c -> maybe [c] id $ lookup c cfg)

eval = unlines . enum . fix replace
    where enum = zipWith (\a b -> show a ++ " => " ++ b) [0 ..]

main = forever (getLine >>= putStr . eval)

Name: Anonymous 2008-04-14 8:47

>>4
$cfg = {'A' => 'hello',
    'B' => 'world',
    'C' => 'A B',
    'D' => 'A D'}

def cfg_eval(str)
    c, r = false, str.split(//).inject('') { |m,k|
        m += $cfg.has_key?(k) ? c = true && cfg_eval($cfg[k]).to_s : k }
    c ? cfg_eval(r) : r
end

$stdin.each_line {|l| puts 'result: ' + cfg_eval(l.rstrip).inspect}

Name: Anonymous 2008-04-14 8:48

>>25
Oops, I saved the wrong version.

Name: Anonymous 2008-04-14 8:55

$cfg = {'A' => 'hello',
    'B' => 'world',
    'C' => 'A B',
    'D' => 'A D'}

def cfg_eval(str)
    loop do
        c = false
        str = str.split(//).inject('') { |m,k| m += $cfg.has_key?(k) ? c = true && $cfg[k] : k }
        break if not c
    end
    str
end

$stdin.each_line {|l| puts 'result: ' + cfg_eval(l.rstrip).inspect}

Name: Anonymous 2008-04-14 9:55

No lispus? fale

Name: Anonymous 2008-04-14 10:07

rispu

Name: Anonymous 2008-04-14 10:25

In before flex version.

Name: Anonymous 2008-04-14 10:40

>>28
Shows that nobody on /prog/ has actually read SICP.

Name: Anonymous 2008-04-14 11:54

Not as elegant as the original C code but here's my attempt in Prolog:


a --> "hello".
b --> "world".
c --> a, " ", b.
d --> a, " ", d.

% ?- phrase(a,X), atom_codes(Y,X).
%
% X = [104, 101, 108, 108, 111],
% Y = hello
% ?- phrase((a," ",b),X), atom_codes(Y,X).
%
% X = [104, 101, 108, 108, 111, 32, 119, 111, 114|...],
% Y = 'hello world'
% ?- phrase((b,b),X), atom_codes(Y,X).
%
% X = [119, 111, 114, 108, 100, 119, 111, 114, 108|...],
% Y = worldworld
% ?- phrase(c,X), atom_codes(Y,X).
%
% X = [104, 101, 108, 108, 111, 32, 119, 111, 114|...],
% Y = 'hello world'

Name: Anonymous 2008-04-14 13:37


module CFG where

a = "hello"
b = "world"
c = a ++ " " ++ b
d = a ++ " " ++ d



Prelude> :l CFG
[1 of 1] Compiling CFG              ( CFG.hs, interpreted )
Ok, modules loaded: CFG.
*CFG> a
"hello"
*CFG> b
"world"
*CFG> c
"hello world"
*CFG> d
"hello hello hello hello hello hello hello hello hello hello hello ...

Name: Anonymous 2008-04-14 13:49

>>33
Expert ConFiGuration file programmer.

Name: Anonymous 2008-04-14 15:06

>>33
Ah, but can you compile it and run?

Name: Anonymous 2008-04-14 15:44

>>33
that's fucking fail, read OPs problem, understand why yours is not a solution and come back to us.

Name: Anonymous 2008-04-14 17:09

Here's it in basic:

print"hello world"

Of course it only works if a and b is hello world and the input is a b.

Name: Anonymous 2008-04-14 17:11

>>35,36
YHBT

Name: Anonymous 2008-04-14 17:17

>>10
And he'll use that to send packets through the IP protocol?

Name: Anonymous 2008-04-14 17:37

>>39
Do you have any idea what the IP (or rather, IPv4 or IPv6 -- please be specific) protocol is?
Or what the definition of a packet is?
Was that an attempt at funny internet?

Name: Anonymous 2008-04-14 17:44

>>10
Do you have something against GJS Jay Sussman?

Name: Anonymous 2008-04-14 17:57

>>40
IP protocol.

Internet protocol protocol.

Read >>10 again.

Name: Anonymous 2008-04-14 17:58

>>40
I'm proud to announce that you have been successfully trolled. How do you feel?

Name: 39 2008-04-14 18:08

>>43
I wasn't even trolling, he just completely missed the RAS Syndrome joke I made. Considering I was replying to >>10, who made 3 of those, you can say that this was a severe case of JOKE OVER HEAD.

Which makes him a dumbass, because he's acting like he's an EXPERT NETWORKING PROGRAMMER, yet he didn't realize that IP stands for Internet Protocol.

Name: Anonymous 2008-04-14 18:46

>>44
FUQING BULL
ASK ME ANYTHING ABOUT NETWORQING
OR CAN YOU ONLY MUMBO JUMBO ABOUT 3WAY HANDSHAKE MOTHERFUCKER

Name: Anonymous 2008-04-14 18:48

>>43
ｋｉｎｄ ｏｆ ｂａｄ ：（

Name: Anonymous 2008-04-14 19:02

I hate people who whine about RAS syndrome.

For talking to people who might not know what an acronym means, it can be useful to reduce ambiguity in such a way. Language is around to further communication, not to pedantize about stupid details.

>>1-46 are the same person and IHBTC.

Name: Anonymous 2008-04-14 19:03

>>47
I was trolled as well, but in O(log n)

Name: Anonymous 2008-04-14 19:27

>>47
Don't use the acronym if it will cause confusion.

Name: Anonymous 2008-04-14 19:46

>>49
That's unwieldy.

Name: Anonymous 2008-04-14 20:11

DUTAIIWCC confusion

Name: Anonymous 2008-04-15 1:31

>>40
[b][o][i]DO YOU MOTHERFUCKER?[/b][/o][/i]

Name: Anonymous 2008-04-15 3:23

>>52
Use a stack, not a queue.

Name: Anonymous 2008-04-15 9:00

>>53
I lol'd.

Name: Anonymous 2008-04-15 9:10

>>53
:)

Name: Anonymous 2008-04-15 12:09

+<section
+ title="News: new WineTricks, 1.0 status updates and more"
+ subject="Wine"
+ archive="http://www.xkcd.com"
+ posts="0"
+>
How is the url above related to the title?
It isn't, I had nothing else to put.  I generally leave them blank but
I for some reason decided to throw xkcd in there this time.

Name: Anonymous 2008-04-15 17:34

>>52
BBCODE MAH [b][o][i]

Name: Anonymous 2008-04-15 17:45

>>57
Back to /b/, please

Name: Anonymous 2008-04-15 18:28

>>1
Clever, good job.

Name: Anonymous 2008-04-16 5:19

>>50
PROTIP: When you set the context, you can use the acronym form as there shouldn't be any more abiguity

Name: Anonymous 2008-04-17 11:52

gtfo

Name: Anonymous 2008-04-17 16:44

>>61
No.

Name: Anonymous 2008-04-17 17:31

>>61
saw that reply when I mentioned I'm the OP of this thread.
Obviously >>61,62 is the same person.
You fail, so far I've seen every fucking thing you've tried to do.

Name: Anonymous 2008-04-17 18:09

>>63
Actually no, I am >>61 but not >>62.
Obviously, >>63 and >>62 are the same person since >>63 is the OP.
gtfo

Name: Anonymous 2008-04-17 19:43

Obviously, >>63 and >>62 are the same person since >>63 is the OP.
No that doesn't make sense, but since you sage you are an ally.

Name: Anonymous 2008-04-17 20:27

>>65
That makes sense, and since you sage you are an ally.

Name: Anonymous 2011-02-02 22:58

Name: Sgt.Kabukiman 2012-05-22 3:23

All work and no play makes Jack a dull boy
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 All work and no play makes Jack a dull boy
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