String generator based on a wildcard

Question

Your task, if you accept it, is to make a string generator that generates strings based on a wildcard.

You can make a function or a full program that receives 1 argument and sends to the standard output/console a string that matches.

Wildcard characters and sequences:

• * produces 0 or more random characters
• ? produces exactly 1 random character
• [] detonates a group and produces any one of the characters from the group, exactly once.
• []* produces at least 0 of the characters from that group
• []? produces any one of the characters from that group, at most once
• []{n} produces n characters in that group
• Anything else is a literal string

The supported characters to return are a-z, A-Z and 0-9.
Casing doesn't matter.

You can do whatever you want with invalid input.

Examples:

f('a[d-f]{3}') //return 'addd', 'adde', 'addf' ...

f('a*') //returns 'a' or anything starting with 'a'

f('[bt]est') //returns 'best', 'test'

Scoring:

• Shortest code in bytes wins.
• -10% bonus if you support symbols
• -10% bonus if you implement multiple matches, inside each group (e.g.: [ae,c-d,0-5])
• -20% bonus if you implement negated group (e.g.: [^a-f] returns anything that doesn't start with a-f)
• -10% if you support at least 3 regex character classes (e.g.: \d,\s,\D)
• Standard loopholes are not allowed!

Any doubts, feel free to ask in a comment.

Answer 1

Python 3, 511 bytes - 10% = 459.9

It's early morning over here so golfing mode hasn't quite kicked into my system yet, but it was a really fun-looking problem so I thought I'd try it anyway.

from random import*
C=0
r=input()
i=0
S=""
Q=""
while i<len(r):
 c=r[i]
 if i<len(r)-1:d=r[i+1]
 if"]"==c:
  C=0
  if d not in"*?{":S+=choice(Q)
 elif"["==c:C=1;Q=""
 elif"*"==c:
  while random()>.2:S+=choice(Q)
 elif"?"==c:S+=choice(Q)*randint(0,1)
 elif"{"==c:
  a=""
  while r[i+1]!="}":a+=r[i+1];i+=1
  S+="".join(choice(Q)for _ in range(int(a)))
 elif"}"!=c:
  if"-"==d:Q+="".join(chr(x)for x in range(ord(c),ord(r[i+2])+1));i+=2
  else:
   Q=C*Q+c
   if not C and d not in"*?{":S+=choice(Q)
 i+=1
print(S)

I'm claiming the "multiple matches, inside each group" bonus. You can try it out like so:

[abA-C0]*