code.kerkeslager.com Git - fur/blob - interpreter.py

   1 import sys
   2
   3 import crossplatform_ir_generation
   4
   5 class Environment(object):
   6     def __init__(self, parent):
   7         self.symbols = {}
   8         self.parent = parent
   9
  10     def __getitem__(self, symbol):
  11         if symbol in self.symbols:
  12             return self.symbols[symbol]
  13
  14         if self.parent is None:
  15             raise Exception('Symbol "{}" not found'.format(symbol))
  16
  17         return self.parent[symbol]
  18
  19     def __setitem__(self, symbol, value):
  20         self.symbols[symbol] = value
  21
  22 def builtin_print(*outputs):
  23     outputs = list(outputs)
  24
  25     for i in range(len(outputs)):
  26         output = outputs[i]
  27
  28         if isinstance(output, bool):
  29             outputs[i] = str(output).lower()
  30
  31     print(*outputs, end='')
  32
  33 BUILTIN_ENVIRONMENT = Environment(None)
  34 BUILTIN_ENVIRONMENT.symbols = {
  35     'false': False,
  36     'pow': lambda base, exponent: pow(base, exponent),
  37     'print': builtin_print,
  38     'true': True,
  39 }
  40
  41 def interpret(program):
  42     environment = Environment(BUILTIN_ENVIRONMENT)
  43
  44     label_indices = {}
  45
  46     for i in range(len(program.entry_list)):
  47         if isinstance(program.entry_list[i], crossplatform_ir_generation.CIRLabel):
  48             if program.entry_list[i].label in label_indices:
  49                 raise Exception('Label already in labels')
  50
  51             label_indices[program.entry_list[i].label] = i
  52
  53     program_counter = label_indices['__main__'] + 1
  54     stack = []
  55
  56     while True:
  57         while isinstance(program.entry_list[program_counter], crossplatform_ir_generation.CIRLabel):
  58             program_counter += 1
  59
  60         instruction = program.entry_list[program_counter].instruction
  61         argument = program.entry_list[program_counter].argument
  62
  63         if instruction in ('add', 'idiv', 'mod', 'mul', 'sub'):
  64             assert argument == 2
  65             right = stack.pop()
  66             left = stack.pop()
  67             assert isinstance(left, int)
  68             assert isinstance(right, int)
  69
  70             if instruction == 'add':
  71                 result = left + right
  72             elif instruction == 'idiv':
  73                 result = left // right
  74             elif instruction == 'mod':
  75                 result = left % right
  76             elif instruction == 'mul':
  77                 result = left * right
  78             elif instruction == 'sub':
  79                 result = left - right
  80
  81             stack.append(result)
  82
  83         elif instruction in ('gt', 'gte', 'lt', 'lte'):
  84             assert argument == 2
  85             right = stack.pop()
  86             left = stack.pop()
  87             assert isinstance(left, int)
  88             assert isinstance(right, int)
  89
  90             if instruction == 'gt':
  91                 result = left > right
  92             elif instruction == 'gte':
  93                 result = left >= right
  94             elif instruction == 'lt':
  95                 result = left < right
  96             elif instruction == 'lte':
  97                 result = left <= right
  98
  99             stack.append(result)
 100
 101         elif instruction in ('eq', 'neq'):
 102             assert argument == 2
 103             right = stack.pop()
 104             left = stack.pop()
 105
 106             if instruction == 'eq':
 107                 result = left == right
 108             elif instruction == 'neq':
 109                 result = left != right
 110
 111             stack.append(result)
 112
 113         elif instruction == 'call':
 114             assert isinstance(argument, int)
 115             args = []
 116
 117             f = stack.pop()
 118
 119             for i in range(argument):
 120                 args.append(stack.pop())
 121
 122             args = list(reversed(args))
 123
 124             stack.append(f(*args))
 125
 126         elif instruction == 'concat':
 127             assert argument == 2
 128             right = stack.pop()
 129             left = stack.pop()
 130             assert isinstance(left, str)
 131             assert isinstance(right, str)
 132
 133             stack.append(left + right)
 134
 135         elif instruction == 'drop':
 136             assert argument is None
 137             stack.pop()
 138
 139         elif instruction == 'end':
 140             assert argument is None
 141             sys.exit(0)
 142
 143         elif instruction == 'get':
 144             index = stack.pop()
 145             assert isinstance(argument, int)
 146             xs = stack.pop()
 147             assert isinstance(xs, list)
 148             stack.append(xs[index])
 149
 150         elif instruction == 'jump_if_false':
 151             program_counter = label_indices[argument]
 152
 153         elif instruction == 'list':
 154             assert isinstance(argument, int)
 155
 156             result = []
 157
 158             for i in range(argument):
 159                 result.append(stack.pop())
 160
 161             stack.append(list(reversed(result)))
 162
 163         elif instruction == 'neg':
 164             stack.append(-stack.pop())
 165
 166         elif instruction == 'pop':
 167             assert argument.startswith('sym(')
 168             assert argument.endswith(')')
 169             environment[argument[4:-1]] = stack.pop()
 170
 171         elif instruction == 'push':
 172             assert argument.startswith('sym(')
 173             assert argument.endswith(')')
 174             stack.append(environment[argument[4:-1]])
 175
 176         elif instruction == 'push_integer':
 177             assert isinstance(argument, int)
 178             stack.append(argument)
 179
 180         elif instruction == 'push_string':
 181             assert argument.startswith('"')
 182             assert argument.endswith('"')
 183             stack.append(argument[1:-1].encode('utf-8').decode('unicode_escape'))
 184
 185         else:
 186             raise Exception('Instruction "{}" not supported (argument {}).'.format(
 187                 instruction,
 188                 argument,
 189             ))
 190
 191         program_counter += 1