/prog/ - Functional Programming in C/C++

Name: Anonymous 2012-10-01 20:15

I present you with a simple BASH script which adds lambdas to C/C++.

Now you can finally run your:



qsort(array, nelts, sizeof(int), lambda (int) (int *x, int *y) () return *x<*y; endLambda)

It expands code like



#include <stdio.h>



int main(int argc, char **argv) {

  int a = 1;

  int b = 2;

  printf("%d\n",

   (lambda (int) (int x) (int a, int b) return x+a+b; endLambda)(4));

  return 0;

}

into:



static int *_la_1337_a;

static int *_la_1337_b;

static int _lf_1337(int x);

#include <stdio.h>



int main(int argc, char **argv) {

  int a = 1;

  int b = 2;

  printf("%d\n",

   ((_la_1337_a=&a,_la_1337_b=&b,_lf_1337))(4));

  return 0;

}





int _lf_1337(int x) {

#define a (*_la_1337_a)

#define b (*_la_1337_b)

 return x+a+b; 

#undef a

#undef b

}

So you worst!



#!/bin/bash



File=$(cat "$1" | tr '\n' '$')

Out="$2"

CODE=1337

Lambs=$(echo "$File" | grep -o "lambda.*endLambda")

trim() { sed 's/^ *\(.*\) *$/\1/'; }

part() { sed "s/lambda.*(\(.*\)).*(\(.*\)).*(\(.*\))\(.*\)endLambda/\\$1/"; }

RetType="$(echo "$Lambs" | part 1)"

Args="$(echo "$Lambs" | part 2)"

Vars="$(echo "$Lambs" | part 3)"

Body="$(echo "$Lambs" | part 4)"





Result="$(echo "$Vars" | tr ',' '\n' | trim | sed "s/^\(.*\) \([^ ]*\)\$/_la_${CODE}_\2=\\\\\&\2/" | tr '\n' ',')"

Result="(${Result}_lf_${CODE})"



echo "$Result"

echo "$Vars" | tr ',' '\n' | trim | sed "s/^\(.*\) \([^ ]*\)\$/static \1 *_la_${

CODE}_\2;/" > "$Out"

echo "static ${RetType} _lf_${CODE}($Args);" >> "$Out"



echo "$File" | sed "s/lambda.*endLambda/$Result/" | tr '$' '\n' >> "$Out"



echo "${RetType} _lf_${CODE}($Args) {" >> "$Out"

echo "$Vars" | tr ',' '\n' | trim | sed "s/^\(.*\) \([^ ]*\)\$/#define \2 (*_la_${CODE}_\2)/" >> "$Out"

echo "$Body" >> "$Out"

echo "$Vars" | tr ',' '\n' | trim | sed "s/^\(.*\) \([^ ]*\)\$/#undef \2/" >> "$Out"

echo "}" >> "$Out"

Name: Anonymous 2012-10-01 21:11

cool

Name: Anonymous 2012-10-01 21:30

You're still a bad programmer.

Name: Poop 2012-10-01 21:53

I love 1337 stuff.

Name: Anonymous 2012-10-01 22:20

7/10 would consider using

Name: Anonymous 2012-10-01 22:28

A somewhat fixed version, which provides shorter syntax:



#include <stdio.h>



int main(int argc, char **argv) {

  int a=1;

  int b=2;

  printf("%d\n", <:int; int x; int a, int b => return a+b+x:>(4));

  return 0;

}



#!/bin/bash



File=$(cat "$1" | tr '\n' '$')

Out="$2"

CODE=1337

Lambs=$(echo "$File" | grep -o "<:.*:>")

trim() { sed 's/ *$//' | sed 's/^ *//'; }

part() { sed "s/<:.*\(.*\);\(.*\);\(.*\)=>\(.*\):>/\\$1/"; }

RetType="$(echo "$Lambs" | part 1)"

Args="$(echo "$Lambs" | part 2 | trim)"

Vars="$(echo "$Lambs" | part 3 | tr ',' '\n' | trim)"

Body="$(echo "$Lambs" | part 4)"



Result="$(echo "$Vars" | sed "s/^\(.*\) \([^ ]*\)\$/_la_${CODE}_\2=\\\\\&\2/" | tr '\n' ',')"

if [ "$Result" == "," ]; then Result=""; fi

Result="(0,${Result}_lf_${CODE})"



echo "$Vars" | tr ',' '\n' | trim | sed "s/^\(.*\) \([^ ]*\)\$/static \1 *_la_${CODE}_\2;/" > "$Out"

echo "static ${RetType} _lf_${CODE}($Args);" >> "$Out"

echo "$File" | sed "s/<:.*:>/$Result/" | tr '$' '\n' >> "$Out"

echo "${RetType} _lf_${CODE}($Args) {" >> "$Out"

echo "$Vars" | sed "s/^\(.*\) \([^ ]*\)\$/#define \2 (*_la_${CODE}_\2)/" >> "$Out"

echo "$Body;" | tr '$' '\n' >> "$Out"echo "$Vars" | sed "s/^\(.*\) \([^ ]*\)\$/#undef \2/" >> "$Out"

echo "}" >> "$Out"

Name: Anonymous 2012-10-01 22:40

GCC supports this out of box:



#include <stdio.h>



#define lambda(l_ret_type, l_arguments, l_body)         \

  ({                                                    \

    l_ret_type l_anonymous_functions_name l_arguments   \

      l_body                                            \

    &l_anonymous_functions_name;                        \

  })



int main(int argc, char **argv) {

  int a=1;

  int b=2;

  printf("%d\n", lambda(int, (int x), {return a+b+x;})(4));

  return 0;

}

Name: Anonymous 2012-10-01 22:59

Scheme supports this out of box:



(lambda (w)

  (lambda (f)

    (f ((w w) f))))

Name: Anonymous 2012-10-01 23:02

Sure, Alonzo Church invented this out of the box, but did he Abelson invent it out of the box?

Name: Anonymous 2012-10-01 23:06

>>8
C/C++ is faster and they even pay you for using it.

Name: Anonymous 2012-10-01 23:20

>>8
Okay, what the fuck does that do?

Name: Anonymous 2012-10-01 23:41

>>11
it carries out and is Y

Name: Anonymous 2012-10-01 23:50

C/C++.
C++ already has lambdas.

Name: Anonymous 2012-10-01 23:54

>>13
And has had it for years with Boost.Lambda.

Name: Anonymous 2012-10-02 0:25

>>14
How are they different from C++0x lambdas?

Name: Anonymous 2012-10-02 0:33

>>15
Boost is already implemented, Sepplesox isn't.

Name: Anonymous 2012-10-02 0:44

>>16
what is the point implementing something that is already present?

Name: Anonymous 2012-10-02 1:20

>>17
Boost is anti-standard.

Name: Anonymous 2012-10-02 7:22

There are no jews. Please continue with this programming-related discussion.

Functional Programming in C/C++

1 Name: Anonymous 2012-10-01 20:15

2 Name: Anonymous 2012-10-01 21:11

3 Name: Anonymous 2012-10-01 21:30

4 Name: Poop 2012-10-01 21:53

5 Name: Anonymous 2012-10-01 22:20

6 Name: Anonymous 2012-10-01 22:28

7 Name: Anonymous 2012-10-01 22:40

8 Name: Anonymous 2012-10-01 22:59

9 Name: Anonymous 2012-10-01 23:02

10 Name: Anonymous 2012-10-01 23:06

11 Name: Anonymous 2012-10-01 23:20

12 Name: Anonymous 2012-10-01 23:41

13 Name: Anonymous 2012-10-01 23:50

14 Name: Anonymous 2012-10-01 23:54

15 Name: Anonymous 2012-10-02 0:25

16 Name: Anonymous 2012-10-02 0:33

17 Name: Anonymous 2012-10-02 0:44

18 Name: Anonymous 2012-10-02 1:20

19 Name: Anonymous 2012-10-02 7:22