Custom Games of Life

Question

There's a lot of questions about Conway's Game of Life, but nothing about customization (Related: 2-Player Life). Given an input, determine the result on a 100x100 grid after some iterations. The input is given as a string. For example:

Using the character #, follow the following rules:
If there are 2 or 3 neighboring nothing, turn into #.

Using nothing, follow the following rules:
If there are 3 neighboring #, turn into #.

Output the result after 100 iterations for the cells:
[Lots of cells here]

As you might be able to tell, this is Conway's Game of Life, where a cell is alive if there are three live neighbors, and a live cell with less than two or more than three neighbors dies. You may use any kind of input, but I'll be doing it like this for simplicity.

Input

• For simplicity, a character can also be the phrase "nothing."
• Each rule is separated by two newlines. Each rule starts with, "Using the character X, follow the following rules:" where X represents a character.
• Then, it says "If there are [amount] neighboring X, turn into Y." The amount is some numbers, separated by or, where X and Y represent characters. It may say this multiple times.
• Then it says, "Output the result after N iterations for the cells:" Your job is to return the result after N iterations.
• Then, decode the cells given. The cells are stored with a space for empty cells, and a single character for all the other characters. Newlines separate the rows.

Also, the last rule is always for nothing, and instead starts with "Using nothing, follow the following rules:" A cell will never turn into itself. (So, for #, "If there are 2 $, turn into #." will not happen.)

Simply render "nothing" with a space, and all other characters normally. The other characters are ASCII and not a space.

For the iterating, follow the instructions for each character. When it says "neighboring," it means the cells next to it (including diagonals).

For the borders, "wrap around" the cells. One way to think of wrapping around is to pretend that there are 8 identical grids surrounding the current one, then updating the current ones with the new neighbors. (Sorry if my explanation was weird.)

Test case (replace \n with a newline):

Using the character #, follow the following rules:
If there are 0 or 1 #, turn into $.
If there are 4 or 5 or 6 or 7 or 8 #, turn into nothing.

Using the character $, follow the following rules:
If there are 4 nothing, turn into #.
If there are 4 or 5 or 6 or 7 or 8 $, turn into #.

Using nothing, follow the following rules:
If there are 3 #, turn into #.

Output the result after 25 iterations for the cells:
                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                             $$$$$$$$$$                                             \n                                             $$$$$$$$$$                                             \n                                             #        #                                             \n                                             #        #                                             \n                                             $$$ $$$ $$                                             \n                                              $$$ $$$ $                                             \n                                             $ $$$ $$$                                              \n                                             ####  ####                                             \n                                             ##      ##                                             \n                                             $#$#$#$#$#                                             \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    \n                                                                                                    

Result:

^{(This code golf is inspired by this thingy, and of course, Conway's Game of Life.)}

Answer 1

Python 3.8, 597 bytes

from copy import deepcopy as p
def f(r):
 u,g,b,e={},0,[],' '
 for l in r:
  if g:b+=[list(l)];z=len(l);continue
  j=l[:1]
  if'T'<j:c=[e,l[20]][l[6]>'n'];u[c]=[]
  if'I'==j:
   n=[]
   for s in l[13:].split(' or '):
    n+=[int(s[0])]
    if s[3:]:v=[s[2],e][','<s[3:4]]
   u[c]+=[[v,n,[l[-2],e][l[-3]>e]]]
  if'O'==j:i=int(l.split()[4]);g=1
 for _ in e*i:
  h=p(b)
  for k in range(len(b)*z):
   r,c=k//z,k%z;v={k:0 for k in u}
   for j in range(9):x,y=j//3-1,j%3-1;v[b[(r+y)%len(b)][(c+x)%z]]+=1
   a=b[r][c];v[a]-=1
   for w in u[a]:
    if v[w[0]]in w[1]:h[r][c]=w[2];break
  b=p(h)
 return b

Try it online!

Online custom game of life simulator: Emoji Simulator!

---

Commented code

from copy import deepcopy as p

def f(r):
    """Takes as input a list of lines"""
    
    # dictiornary of rules of the grid
    u = {}
    # flag to extract lines of the grid
    g = 0
    # the grid, as a list of lists of characters
    b = []
    # space used to represent nothing
    e = ' '
    
    
    # PART 1
    # parse the rules
    
    # loop on the input lines
    for l in r:
        
        if g:
            # extract lines of the grid
            b += [list(l)]
            # extract the lenght of the row of the grid
            # used for the loop n the grid
            z = len(l)
            
            # skip other checks
            continue
        
        # extract the first character for each line
        # not [0] since it can be an empty line
        j = l[:1]
        
        if 'T' < j:
            
            # line "Using the character ..."
            
            # extract the character
            # checking if the character is nothing
            c = [e, l[20]][l[6] > 'n']
            
            # initialize an empty list for the rules associated to the character
            u[c] = []
        
        if 'I' == j:
            
            # line "If there are ..."
            
            # initialize list of repetitions
            n = []
            
            # the number of repetitions are split by or
            for s in l[13:].split(' or '):
                
                # extract the number
                # always the first element of the split
                n += [int(s[0])]
                
                # extract the character associated with the repetitions
                # the number is followed by the character
                # this means that the split string is longer
                if s[3:]:
                    
                    # character associated with the repetitons
                    # checking if the character is nothing
                    v = [s[2], e][',' < s[3:4]]
            
            # add the rule
            u[c] += [[
            # character associated with the repetitons
            v,
            # list of number of repetitions
            n,
            # extract the new character to substitute
            # checking if the character is nothing
            [l[-2], e][l[-3] > e]
            ]]
        
        if 'O' == j:
            
            # line "Output the result ..."
            
            # extract the number of steps
            i = int(l.split()[4])
            # set flag to extract the lines of the grid
            g = 1
    
    
    # PART 2
    # evaluate the steps on the grid
    
    # loop for i steps
    # e*i is an auxiliary string of length i to evaluate i steps
    for _ in e * i:
        
        # copy the previous grid state
        h = p(b)
        
        # loop on each cell of the grid
        # loop on height*width
        for k in range(len(b)*z):
            
            # extract the index of row, column from the "total" loop index
            r, c = k//z, k%z
            
            # initialize dictionary of count of neighbouring characters
            v = {k: 0 for k in u}
            
            # loop on the 3x3 square around the actual cell
            for j in range(9):
                
                # scale to range [-1, 0, 1]
                x, y = j//3 - 1, j%3 - 1
                
                # update the count of neighbour
                # extracting the corresponding character in the grid
                v[b[(r+y)%len(b)][(c+x)%z]] += 1
            
            # current character
            a = b[r][c]
            
            # remove the current cell from the count of neighbours
            v[a] -= 1
            
            # check rules
            for w in u[a]:
                
                # if count of neighbour is in list of number of repetitions
                if v[w[0]] in w[1]:
                    
                    # substituite actual character in the grid with the new one
                    h[r][c] = w[2]
                    
                    # rule found, skip others
                    break
        
        # update the actual grid
        b = p(h)
    
    # return the grid after the steps
    return b