%lex
%%

\r\n|\r|\n            return 'ENDL';
\s+ ;
[0-9]+("."[0-9]+)?\b  return 'DIGIT';
sin                   return 'SIN';
[a-z]                 return 'VAR';
<<EOF>>               return 'EOF';
.                     return yytext;

/lex

%start exp2

%%
exp2: exp EOF {return process($1);}
    ;
exp : v ENDL e  { $$ = { type: 'exp', children: [$1, {type: 'ENDL' }, $3] }; }
    | e  { $$ = { type: 'exp', children: [$1] }; }
    ;
v   : VAR '=' e ';' { $$ = { type: 'v', children: [{type: 'VAR'}, { type: '=' }, $3, {type: ';'}] }; }
    | v ENDL VAR '=' e ';'  { $$ = { type: 'v', children: [$1, { type: 'ENDL' },{type : 'VAR'}, { type: '=' },$5, {type: ';'}]}; }
    ;
e   : e '+' r  { $$ = { type: 'e', children: [$1, { type: '+' }, $3] }; }
    | e '-' r  { $$ = { type: 'e', children: [$1, { type: '-' }, $3] }; }
    | r        { $$ = { type: 'e', children: [$1] }; }
    ;

r   : '(' e ')'   { $$ = { type: 'r', children: [$2] }; }
    | n          { $$ = { type: 'r', children: [$1] }; }
    ;

n   : d { $$ = { type: 'n', children: [$1] }; }
    | SIN '(' e ')' { $$ = { type: 'n', children: [ {type: 'SIN'},{type: '(' }, $3,{type:')'}] }; }
    | u {$$ = {type: 'n', children:[$1]};}
    ;
d   : DIGIT { $$ = { type: 'd', value: $1 }; }
    ;
u   : VAR { $$ = { type: 'u', value: $1 }; }
    ;
%%

var Arr = [];

function indent(ind) {
  var res = "";
  for (var i = 0; i < ind; i++) {
    res += " ";
  }
  return res;
}

function drawtree(node, ind) {
  var ENDL = "\n";
  var res = "";
  if (node.type == 'd' || node.type == 'u' ) {
    res += indent(ind) + node.type + " : " + node.value + ENDL;
  } else if (node.type == '-' || node.type == '+'||node.type == 'VAR'|| node.type == 'ENDL'|| node.type == '='|| node.type == ';' || node.type == 'SIN' || node.type == '(' || node.type == ')') {
    res += indent(ind) + node.type + ENDL;
  } else {
    res += indent(ind) + node.type + ENDL;
    for (var i = 0; i < node.children.length; i++) {
      res += drawtree(node.children[i], ind + 1);
    }
  }
  return res;
}


function process(node) {
  var ENDL = "\n";
  var res = "";
  res += "Grammar Tree:" + ENDL;
  res += ENDL;
  res += drawtree(node, 0);
  res += ENDL;
  return res;
}