JSON Extract, Reformat and Print

Improved slightly over https://news.ycombinator.com/item?id=30916201

     sed 's/.\{4\}//' <<eof|flex -8iCrf
     /* extract, reformat, print json */
    
     int fileno (FILE *);
     #define echo do{if(fwrite(yytext,(size_t)yyleng,1,yyout)){}}while(0)
     #define jmp (yy_start) = 1 + 2 *
     #define pc(x) putchar(x)
    %option nounput noinput noyywrap
    %s x1 x2
    %%
    
    ^\40+ 
     /* quotes
      "key":" 
      "key": " 
     */
    \"[^\":\]\)]*\":\40*\" echo;jmp x1;
    
     /* bracket followed by brace 
      "key":[{ 
      "key": [{ 
     */
    \"[^\":\]\)]*\":\40*\[\40*\{ echo;pc(10);
    
     /* number 
     "key":1
     "key": 1
     */
    \"[^\":\]\)]*\":\40*[0-9\40\12\15]* echo;jmp x2;
    <x2>[,}] pc(10);jmp 0;
    
     /* bracket (unquoted, comma-separated array values)
      "key":[ 
      "key": [ 
     */
    \"[^\":\]\)]*\":\40*\[ echo;jmp x1;
    
     /* brace
      "key":{ 
      "key": { 
     */
    \"[^\":\]\)]*\":\40*\{ echo;pc(10);
    
     /* open brace not closed brace */ 
    <x1>[\]\{\"] echo;pc(10);jmp 0;
    <x1>[^\]\{\"\12]* echo;
    \n|.
    %%
    int main(){ yylex();exit(0);}

   eof

     cc  -std=c89 -Wall -pedantic -pipe lex.yy.c -static -o yy059

   Usage: yy059 < 1.json

yy059 is for extracting JSON from HTML and printing it as a new, left-justified, line-delimited format readable to me.

To use with indented JSON, e.g., json_reformat output (json_reformat from yajl project), first remove the indentation, e.g.,

      sed 's/ *//' 1.json | yy059

NB. This is made for me, primarily for reading YouTube JSON. It is used in a personal YouTube search utility. JSON from non-YouTube sources, e.g., Twitter, may contain escaped quotes, often for including quotes associated with href tags. Remove escaped quotes first, e.g., using yy064, disclosed here: https://news.ycombinator.com/item?id=30916201