FRE = 206.835 - 1.015 * (words per sentence) - 84.6 * (syllables per word)

I would not, could not, in the rain.
Not in the dark, not on a train.
Not in a car, not in a tree.
I do not like them, Sam, you see.
Not in a house, not in a box.
Not with a mouse, not with a fox.
I will not eat them here or there.
I do not like them anywhere!

It was a bright cold day in April, and the clocks were striking thirteen.
Winston Smith, his chin nuzzled into his breast in an effort to escape
the vile wind, slipped quickly through the glass doors of Victory Mansions,
though not quickly enough to prevent a swirl of gritty dust from entering
along with him.

When in the Course of human events, it becomes necessary for one people to
dissolve the political bands which have connected them with another, and to
assume among the powers of the earth, the separate and equal station to
which the Laws of Nature and of Nature's God entitle them, a decent respect
to the opinions of mankind requires that they should declare the causes
which impel them to the separation.

#!perl -pa0
s@w+|([.!?])@$s+=$#-,lc($&)=~s![aeiou]+B|([aeiouy]$)!$y+=1-$#-/3!ger@ge}
{$_=206.835-1.015*@F/$s-84.6*$y/@F

$ perl flesch-kincaid.pl < input1.dat
110.730040322581

$ perl flesch-kincaid.pl < input2.dat
65.6097727272728

$ perl flesch-kincaid.pl < input2.dat
1.71366197183096

d,a,v,s,t,w;float R(char*c){for(;*c;++c){s+=*c=='.';if(isalpha(*c)){
w+=!a++;d=(*c&30)>>1;if(*c&1&(d==7|((!(d&1))&(d<6|d>8)))){t+=!v++;}
else v=0;}else v=a=0;}return 206.835-1.*w/s-82.*t/w;}

#include <stdlib.h>
#include <stdio.h>
d,a,/*last character was alphabetic */
  v,/*lastcharacter was a vowel */
  s, /* sentences counted by periods */
  t, /* syllables counted by non-consequtive vowels */
  w; /* words counted by non-letters after letters */
float R/*eadability*/(char*c){
  for(;*c;++c){
    s+=*c=='.';
    if(isalpha(*c)){ /* a letter might mark the start of a word or a
               vowel string */
      w+=!a++; /* It is only the start of a word if the last character
              wasn't a letter */
      /* Extract the four bits of the character that matter in determining
       * vowelness because a vowel might mark a syllable */
      d=(*c&30)>>1;
      if( *c&1  & ( d==7 | ( (!(d&1)) & (d<6|d>8) ) )
      ) { /* These bits 7 or even and not 6, 8 make for a
         vowel */
    printf("Vowel: '%c' (mangled as %d [0x%x]) counts:%dn",*c,d,d,!v);
    t+=!v++;
      } else v=0; /* Not a vowel so set the vowel flag to zero */
    }else v=a=0; /* this input not alphabetic, so set both the
            alphabet and vowel flags to zero... */
  }
  printf("Syllables: %3in",t);
  printf("Words:     %3i       (t/w) = %fn",w,(1.0*t/w));
  printf("Sentences: %3i       (w/s) = %fn",s,(1.0*w/s));
  /* Constants tweaked here due to bad counting behavior ...
   * were:       1.015     84.6 */
  return 206.835-1.   *w/s-82. *t/w;
}
main(c){
  int i=0,n=100;
  char*buf=malloc(n);
  /* Suck in the whole input at once, using a dynamic array for staorage */
  while((c=getc(stdin))!=-1){
    if(i==n-1){ /* Leave room for the termination */
      n*=1.4;
      buf=realloc(buf,n);
      printf("Reallocated to %dn",n);
    }
    buf[i++]=c;
    printf("%c %cn",c,buf[i-1]);
  }
  /* Be sure the string is terminated */
  buf[i]=0;
  printf("'%s'n",buf);
  printf("%fn",R/*eadability*/(buf));
}

$ gcc readability_golf.c
readability_golf.c:1: warning: data definition has no type or storage class
$ ./a.out < readability1.txt
'I would not, could not, in the rain.
Not in the dark, not on a train.
Not in a car, not in a tree.
I do not like them, Sam, you see.
Not in a house, not in a box.
Not with a mouse, not with a fox.
I will not eat them here or there.
I do not like them anywhere!
'
104.074631
$ ./a.out < readability2.txt
'It was a bright cold day in April, and the clocks were striking thirteen.
Winston Smith, his chin nuzzled into his breast in an effort to escape
the vile wind, slipped quickly through the glass doors of Victory Mansions,
though not quickly enough to prevent a swirl of gritty dust from entering
along with him.
'
63.044090
$ ./a.out < readability3.txt
'When in the Course of human events, it becomes necessary for one people to
dissolve the political bands which have connected them with another, and to
assume among the powers of the earth, the separate and equal station to
which the Laws of Nature and of Nature's God entitle them, a decent respect
to the opinions of mankind requires that they should declare the causes
which impel them to the separation.
'
-1.831667

import re
def R(i):r=re.split;w=len(r(r'[ n]',i));s=r('\.',i);y=r('[^aeiou](?i)+',i);return 206.835-1.015*w/(len(s)-s.count('n'))-84.6*(len(y)-y.count(' ')-2)*.98/w

w=len(r(r'[ n]',i))

s=r('\.',i);s=len(s)-s.count('n')

y=r('[^aeiou](?i)+',i);y=len(y)-y.count(' ')-2;

import re
def t(p):
 q=lambda e: e!=''
 w=filter(q,re.split('[ ,nt]',p))
 s=filter(q,re.split('[.?!]',p))
 c=len(w)*1.0
 f=c/len(s)
 return w,f,c
def s(w):
 c= len(re.findall(r'([aeiouyAEIOUY]+)',w))
 v='aeiouAEIOU'
 if len(w)>2 and w[-1]=='e'and w[-2]not in v and w[-3]in v:c-= 1
 return c
def f(p):
 w,f,c=t(p)
 i=0
 for o in w:
  i+=s(o)
 x=i/c
 return 206.835-1.015*f-84.6*x

def test():
 test_cases=[['I would not, could not, in the rain.
        Not in the dark, not on a train.
        Not in a car, not in a tree.
        I do not like them, Sam, you see.
        Not in a house, not in a box.
        Not with a mouse, not with a fox.
        I will not eat them here or there.
        I do not like them anywhere!', 111.38, 103.38, 119.38],
        ['It was a bright cold day in April, and the clocks were striking thirteen.
        Winston Smith, his chin nuzzled into his breast in an effort to escape
        the vile wind, slipped quickly through the glass doors of Victory Mansions,
        though not quickly enough to prevent a swirl of gritty dust from entering
        along with him.', 65.09, 57.09, 73.09],
        ["When in the Course of human events, it becomes necessary for one people to
        dissolve the political bands which have connected them with another, and to
        assume among the powers of the earth, the separate and equal station to
        which the Laws of Nature and of Nature's God entitle them, a decent respect
        to the opinions of mankind requires that they should declare the causes
        which impel them to the separation.", 3.70, -4.70, 11.70]]
 for case in test_cases:
  fre= f(case[0])
  print fre, case[1], (fre>=case[2] and fre<=case[3])

if __name__=='__main__':
 test()

elssar@elssar-laptop:~/code$ python ./golf/readibility.py
108.910685484 111.38 True
63.5588636364 65.09 True
-1.06661971831 3.7 True