[Question]
  [
# Description
We consider a slightly simplified version of Tetris where each move consists of:
* rotating the piece clockwise, 0 to 3 times
* positioning the piece at a given column
* fast drop
The goal is to determine the number of completed lines, given a list of such Tetris moves.
Completed rows are removed as pieces are dropped, following standard Tetris rules.
**Playfield**
The playfield is 10-column wide. There's no *Game Over* and it is assumed that there's always enough space and time to perform the above actions, no matter the configuration of the playfield. The height of the playfield doesn't really matter here, but you can use the standard 22 rows as an upper limit.
**Shapes of Tetrominoes**
[![shapes](https://i.stack.imgur.com/4pQum.png)](https://i.stack.imgur.com/4pQum.png)
## Input / Output
**Input**
A comma separated list of Tetris moves encoded with 3 characters. The first two character describe the Tetromino shape to use and the last one describes the position where it's dropped.
1. Tetromino: `I`, `O`, `T`, `L`, `J`, `Z` or `S`, in the same order as above.
2. Number of clockwise rotations: `0` to `3`
3. Column: `0` to `9`. This is the column in which the top-left corner of the piece (marked with an `x` on the above picture) is located after the rotation 1
It is assumed that all moves in the provided list are valid. There's no need to check for invalid entries such as `I07` (horizontal `I` shape put too far on the right).
1 *You are free to either implement a real rotation algorithm or to hardcode all the different shapes, as long as the `x` is located in the column given by the third character of the move.*
**Output**
Number of completed lines.
## Example
[![example](https://i.stack.imgur.com/vDnqP.png)](https://i.stack.imgur.com/vDnqP.png)
`O00,T24` will generate the first position and `O00,T24,S02,T01,L00,Z03,O07,L06,I05` will generate the second position.
Therefore, the following sequence will generate a Tetris and should return `4`:
```
O00,T24,S02,T01,L00,Z03,O07,L06,I05,I19
```
## Test cases
```
1) "O00,T24,S02,T01,L00,Z03,O07,L06,I05,I19" -> 4
2) "S00,J03,L27,Z16,Z18,I10,T22,I01,I05,O01,L27,O05,S13" -> 5
3) "I01,T30,J18,L15,J37,I01,S15,L07,O03,O03,L00,Z00,T38,T01,S06,L18,L14" -> 4
4) "S14,T00,I13,I06,I05,I19,L20,J26,O07,Z14,Z10,Z12,O01,L27,L04,I03,S07,I01,T25,J23,J27,O01,
    I10,I10" -> 8
5) "O00,T24,L32,T16,L04,Z11,O06,L03,I18,J30,L23,Z07,I19,T05,T18,L30,I01,I01,I05,T02" -> 8
```
## Test page
You can use **[this JSFiddle](https://jsfiddle.net/02vkdv99/1/)** to test a move list.
  
[Answer]
# C, ~~401~~ ~~392~~ ~~383~~ ~~378~~ ~~374~~ ~~351~~ ~~335~~ ~~324~~ ~~320~~ ~~318~~ ~~316~~ 305 bytes
```
d[99]={'3Z3Z',983177049,513351321,1016270793,970073931,~0},*L=d+5,V,s;char c;main(x){B:for(c=0;c[++L]|V;V>>=4)c-=(L[c]=*L|(V&15)<<x)>1022;s-=c;if(scanf("%c%1d%d,",&c,&V,&x)>2)for(V=c^79?d[c/4%5]>>24-V*8:27,V=c^73?V/64%4<<8|V/8%8<<4|V%8:V&32?15:4369;;--L)for(c=4;c--;)if(L[c]>>x&V>>c*4&15)goto B;return s;}
```
Takes comma-separated input on stdin, returns the score in the exit status.
Requires `char` to be signed (which is the default for GCC) and requires `'3Z3Z'` to be interpreted as 861549402 (which is the case for GCC on little endian machines, at least).
---
### Usage example:
```
echo "O00,T24,S02,T01,L00,Z03,O07,L06,I05,I19" | ./tetris; echo "$?";
```
---
### High-level explanation:
All shapes except the line can fit in a 3x3 grid with one corner missing:
```
6 7 -
3 4 5
0 1 2
```
That means it's easy to store them in a byte each. For example:
```
- - -         0 0 -
- # -   -->   0 1 0   -->   0b00010111
# # #         1 1 1
```
(we align each piece to the bottom-left of the box to make dropping it easier)
Since we get at least 4 bytes to an int, this means we can store all 4 rotations of each piece in a single integer, with a special case for the line. We can also fit each row of the game grid into an int (only needs 10 bits), and the currently falling piece into a long (4 lines = 40 bits).
---
### Breakdown:
```
d[99]={             // General memory
  '3Z3Z',           //  Shape of "S" piece (multi-char literal, value = 861549402)
  983177049,        //  Shape of "T" piece
  513351321,        //  Shape of "Z" piece
  1016270793,       //  Shape of "J" piece
  970073931,        //  Shape of "L" piece
  ~0                //  Bottom of game grid (solid row)
},                  //  Rest of array stores lines in the game
*L=d+5,             // Working line pointer (start >= base of grid)
V,                  // Current piece after expansion (also stores rotation)
s;                  // Current score (global to initialise as 0)
char c;             // Input shape identifier (also counts deleted lines)
main(x){            // "x" used to store x location
  B:                                // Loop label; jumps here when piece hits floor
  for(c=0;c[++L]|V;V>>=4)           // Paint latest piece & delete completed lines
    c-=(L[c]=*L|(V&15)<<x)>1022;
  s-=c;                             // Increment score
  if(scanf("%c%1d%d,",&c,&V,&x)>2)  // Load next command
    for(V=c^79?                     // Identify piece & rotation
          d[c/4%5]>>24-V*8          //  Not "O": load from data
        :27,                        //  Else "O": always 27
        V=c^73?                     // If not "I" (line):
          V/64%4<<8|V/8%8<<4|V%8    //  expand shape to 16-bits
        :                           // Else we are a line:
          V&32?                     //  "I" coincides with "J"; use this to check
               15:4369;             //  horizontal/vertical
        ;--L)                       // Loop from top-to-bottom of grid
      for(c=4;c--;)                 //  Loop through rows of piece
        if(L[c]>>x&V>>c*4&15)       //   If collides with existing piece:
          goto B;                   //    Exit loops
  return s;                         // Return score in exit status
}
```
---
-4, -1 thanks to @Titus, and -23, -11 with inspiration from their answer
[Answer]
# PHP, ~~405~~ ~~399~~ ~~378~~ ~~372~~ ~~368~~ ~~360~~ ~~354~~ ~~347~~ ~~331~~ ~~330~~ ~~328~~ ~~319~~ ~~309~~ 300 bytes
(with [Dave´s block mapping](https://codegolf.stackexchange.com/questions/90255/given-a-list-of-tetris-moves-return-the-number-of-completed-lines/90357#90357))
```
<?$f=[~0];L:for($y=0;$f[++$d+$y]|$s;$s>>=4)$y-=1022<$f[$d+$y]=$f[$d]|$s%16<<$x;$c-=$y;if(list($p,$r,$x)=$argv[++$z])for($s=I==$p?$r&1?4369:15:hexdec(decoct(O==$p?27:ord(base64_decode('M1ozWjqaF1kemR6ZPJMPyTnSJ0s')[ord($p)/4%5*4+$r])));;$d--)for($y=4;$y--;)if ($f[$d+$y]>>$x&$s>>$y*4&15)goto L;echo$c;
```
program, takes moves as separate arguments, prints result
**breakdown to function:**
takes moves as array, returns result
```
function t($a)
{
    $f=[~$z=0];             // init field $f (no need to init $z in golfed version)
    L:                      // jump label
                            // A: paint previous piece at line $d+1:
#   if($s)paint($f,$s,$d+1,$x);
    for($y=0;               // $y = working line offset and temporary score
        $f[++$d-$y]|$s;$s>>=4)// next field line; while field or piece have pixels ...
        $s>>=4)                 // next piece line
        $y+=1022<               // 3: decrease temp counter if updated line is full
            $f[$d-$y]=$f[$d]    // 2: use $y to copy over dropped lines
                |$s%16<<$x;     // 1: set pixels in working line
    $c+=$y;                         // add temp score to global score
#   paint($f);var_dump($c);
    if(list($p,$r,$x)=$a[$z++])// B: next piece: $p=name; $r=rotation, $x=column
#   {echo"<b>$z:$p$r-$x</b><br>";
        for(                // C: create base 16 value:
            $s=I==$p
                ? $r&1?4369:15  // I shape (rotated:0x1111, not rotated:0xf)
                : hexdec(decoct(    // 5: convert from base 8 to base 16
                    O==$p ? 27  // O shape (rotation irrelevant: 033)
                    : ord(          // 4: cast char to byte
                                    // 0: 4 bytes for each remaining tetromino
                        base64_decode('M1ozWjqaF1kemR6ZPJMPyTnSJ0s')[
                            ord($p)/4%5 // 1: map STZJL to 01234
                            *4      // 2: tetromino offset
                            +$r]    // 3: rotation offset
            )));;$d--
        )
            for($y=4;$y--;) // D: loop $y through piece lines
                if ($f[$d+$y]>>$x & $s>>$y*4 & 15) // if collision ...
                    goto L;         // goto Label: paint piece, tetris, next piece
#   }
    return$c;               // return score
}
```
for reference: the old mapping
```
            hexdec(decoct(          // 3. map from base 8 to base 16
                                    // 0. dword values - from high to low: rotation 3,2,1,0
                [0x991e991e,0xc90f933c,0x4b27d239,0x1b1b1b1b,0,0x5a335a33,0x59179a3a]
                [ord($m[0])/2%9]    // 1. map ZJLO.ST to 0123.56 -> fetch wanted tetromino
                >>8*$m[1]&255       // 2. the $m[1]th byte -> rotated piece
            ))
```
**testing**
see [my other PHP answer](https://codegolf.stackexchange.com/questions/90255/given-a-list-of-tetris-moves-return-the-number-of-completed-lines/90929#90929)
**want to watch?**
remove the `#` from the function source and add this:
```
function paint($f,$s=0,$d=0,$x=0){echo'<pre>';for($y=count($f)+5;$y--;$g=0)if(($t=(($z=$y-$d)==$z&3)*($s>>4*$z&15)<<$x)|$r=$f[$y]|0){$z=$t?" $r|$t=<b".(1022<($z=$t|$r)?' style=color:green':'').">$z":" <b>$r";for($b=1;$b<513;$b*=2)$z=($t&$b?'<b>'.($r&$b?2:1).'</b>':($r&$b?1:'.')).$z;printf("%02d $z</b>\n",$y);}echo'</pre>';}
```
**some golfing steps**
Rev. 5: A big leap (399-**21**=378) came by simply moving the column shift  
from a separate loop to the two existing loops.
Rev. 8: Switching from array to base 16 for the piece ($s) did not give much,  
but made way for some more golfing.
Rev. 17: crunched the values with `base64_encode(pack('V*',<values>))`  
and used byte indexing instead of `unpack` to save **16** bytes
Rev. 25 to 29: inspired by Dave´s code: new hashing (-2), new loop design (-9), goto (-10)  
no pre-shift though; that would cost 17 bytes.
**more potential**
With `/2%9`, I could save 15 bytes (only 14 bytes with `/4%5`)  
by putting binary data into a file `b` and then indexing `file(b)[0]`.  
Do I want that?
UTF-8 characters would cost a lot for the transformation.
**on the hashing**
I used `ZJLO.ST /2%9 -> 0123.56`;
but `T.ZJLOS /3%7 -> 0.23456` is as good.  
one byte longer: `O.STJLZ %13/2 -> 0.23456`  
and three more: `OSTZJ.L %17%12%9 -> 01234.6`
I could not find a short hash (max. 5 bytes) that leaves no gap;  
but Dave found `STZJL /4%5 -> 01234`, dropping the O from the list. wtg!
btw: `TIJSL.ZO (%12%8) -> 01234.67` leaves room for the `I` shape  
(and a fictional `A`, `M` or `Y` shape). `%28%8` and `%84%8`, do the same (but with `E` instead of `A`).
[Answer]
# Ruby, ~~474~~ ~~443~~ ~~428~~ 379 + 48 = 427 bytes
-1 thanks to @Titus
This can definitely be golfed more.
Reads a binary dictionary of pieces (see below) from STDIN or a filename and takes a move list as an argument, e.g. `$ cat pieces | ruby script.rb O00,T24,S02,...`.
```
q=$*.pop
z=$<.read.unpack('S*')
b=c=g=i=0
x=10
u=1023
r=->n{n&2**x-1>0?n:r[n>>x]}
y=->n{n>0?[n&u]+y[n>>x]:[]}
l=->c,n{z.find{|m|m>>x==c<<2|n.to_i}||l[c,n-2]}
q.scan(/(\w)(\d)(\d)/){n=l["IOTLJSZ".index($1),$2.to_i]
v=(n&1|(n&6)<<9|(n&56)<<17|(n&960)<<24)<<$3.to_i
(y[b].size+1).times{t=b<<40
t&v>0&&break
g=t|v
v<<=x}
b=0
a=y[r[g]]
a.grep_v(u){|o|b|=o<<x*i
i+=1}
c+=a.count u}
p c
```
Binary piece data (xxd format)
```
0000000: c003 4b04 d810 d814 b820 9c24 d029 5a2c  ..K...... .$.)Z,
0000010: 7830 9634 e039 ca3c 3841 d444 c849 4e4c  x0.4.9.<8A.D.INL
0000020: 9861 9869 5c64 5c6c f050 f058 9a54 9a5c  .a.i\d\l.P.X.T.\
```
See it on repl.it (with hard-coded arguments, dictionary): <https://repl.it/Cqft/2>
## Ungolfed & explanation
```
# Move list from ARGV
q = $*.pop
# Read piece dictionary; pieces are 16-bit integers: 3 for letter,
# 2 for rotation, 10 for shape (and 1 wasted)
z = $<.read.unpack('S*')
# Empty board and various counters
b = c = g = i = 0
x = 10 # Magic numbers
u = 1023
# A function to remove empty lines
r = ->n{ n & 2**x - 1 > 0 ? n : r[n >> x] }
# A function to split the board into lines
y = ->n{ n > 0 ? [n & u] + y[n >> x] : [] }
# A function to lookup a piece by letter and rotation index
l = ->c,n{ z.find {|m| m >> x == c << 2 | n.to_i } || l[c, n-2] }
# Read the move list
q.scan(/(\w)(\d)(\d)/) {
  # Look up the piece
  n = l["IOTLJSZ".index($1), $2.to_i]
  # Convert the 10-bit piece to a 40-bit piece (4 rows of 10 columns)
  v = (n & 1 |
        (n & 6) << 9 |
        (n & 56) << 17 |
        (n & 960) << 24
      ) << $3.to_i # Shift by the appropriate number of columns
  # Drop the piece onto the board
  (y[b].size + 1).times {
    t = b << 40
    t & v > 0 && break
    g = t | v
    v <<= x
  }
  # Clear completed rows
  b = 0
  a = y[r[g]]
  a.grep_v(u) {|o|
    b |= o << x * i
    i += 1
  }
  c += a.count u # Count cleared rows
}
p c
```
[Answer]
# PHP, ~~454~~ ~~435~~ ~~427~~ ~~420~~ 414 bytes
bit fields for pieces and map; but no special case for the `I` shape as Dave´s golfing.
```
<?$t=[I=>[15,4369],O=>[51],T=>[114,562,39,305],L=>[113,802,71,275],J=>[116,547,23,785],Z=>[54,561],S=>[99,306]];foreach($argv as$z=>$m)if($z){$s=$t[$m[0]][$m[1]%count($t[$m[0]])];for($d=$i=0;$i<4;$i++)for($k=0;$k<4;$k++)if($s>>4*$k&1<<$i){for($y=0;$y++<count($f);)if($f[$y-1]&1<<$m[2]+$i)$d=max($d,$y-$k);$k=3;}for($k=$d;$s;$k++,$s>>=4)if(1022<$f[$k]|=$s%16<<$m[2]){$c++;unset($f[$k]);}$f=array_values($f);}echo$c;
```
takes arguments from command line, prints result
**ungolfed as function**
takes arguments as array, returns result
```
function t($a)
{
    // bitwise description of the stones and rotations
    $t=[I=>[15,4369],O=>[51],T=>[114,562,39,305],L=>[113,802,71,275],J=>[116,547,23,785],Z=>[54,561],S=>[99,306]];
    foreach($a as$m)
    {
        $s=$t[$m[0]][$m[1]%count($t[$m[0]])];   // $s=stone
        // find dropping space
        for($d=$i=0;$i<4;$i++)
            // a) lowest pixel of stone in column i
            for($k=0;$k<4;$k++)
                if($s>>4*$k&1<<$i)
                {
                    // b) top pixel of field in column x+i 
                    for($y=0;$y++<count($f);)
                        if($f[$y-1]&1<<$m[2]+$i)$d=max($d,$y-$k);
                    $k=3; // one byte shorter than `break;`
                }
        // do drop
        for($k=$d;$s;$k++,$s>>=4)
            if(1022<$f[$k]|=$s%16<<$m[2])   // add block pixels to line pixels ... if full,
            {$c++;unset($f[$k]);}           // tetris
        $f=array_values($f);
    }
    return$c;
}
```
**tests** (on function)
```
$data=[
    "O00,T24,S02,T01,L00,Z03,O07,L06,I05,I19"=>4,
    "S00,J03,L27,Z16,Z18,I10,T22,I01,I05,O01,L27,O05,S13" => 5,
    "I01,T30,J18,L15,J37,I01,S15,L07,O03,O03,L00,Z00,T38,T01,S06,L18,L14" => 4,
    "S14,T00,I13,I06,I05,I19,L20,J26,O07,Z14,Z10,Z12,O01,L27,L04,I03,S07,I01,T25,J23,J27,O01,I10,I10" => 8,
    // additional example for the two last tetrominoes:
    'O00,T24,L32,T16,L04,Z11,O06,L03,I18,J30,L23,Z07,I19,T05,T18,L30,I01,I01,I05,T02' => 8,
];
function out($a){if(is_object($a)){foreach($a as$v)$r[]=$v;return'{'.implode(',',$r).'}';}if(!is_array($a))return$a;$r=[];foreach($a as$v)$r[]=out($v);return'['.join(',',$r).']';}
function cmp($a,$b){if(is_numeric($a)&&is_numeric($b))return 1e-2<abs($a-$b);if(is_array($a)&&is_array($b)&&count($a)==count($b)){foreach($a as $v){$w = array_shift($b);if(cmp($v,$w))return true;}return false;}return strcmp($a,$b);}
function test($x,$e,$y){static $h='<table border=1><tr><th>input</th><th>output</th><th>expected</th><th>ok?</th></tr>';echo"$h<tr><td>",out($x),'</td><td>',out($y),'</td><td>',out($e),'</td><td>',cmp($e,$y)?'N':'Y',"</td></tr>";$h='';}
foreach($data as $v=>$e)
{
    $x=explode(',',$v);
    test($x,$e,t($x));
}
```
]