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SymbolTable.py
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SymbolTable.py
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from collections import OrderedDict
from MyString import MyString
class SymbolTable:
def __init__(self):
self.symbol_to_value = OrderedDict()
self.value_reached = 1
def search_symbol(self, symbol: str) -> int:
"""
Searches the symbol in the symbol table and returns the numeric value
Returns -1 if the value is not found
Complexity: O(1)
"""
symbol = MyString(symbol)
# Searching for the symbol in a dictionary is an O(1) operation
if symbol in self.symbol_to_value:
# The symbol already exists in the symbol table, we return its previous value
return self.symbol_to_value[symbol]
return -1
def add_symbol(self, symbol: str) -> int:
"""
Adds the symbol in the symbol table and returns the numeric value
Complexity: O(1)
"""
symbol = MyString(symbol)
if self.search_symbol(symbol.value) != -1:
return self.search_symbol(symbol.value)
# The symbol doesn't exist, so we add it to the dict
# and increment the value_reached (for the next symbol to be added)
self.symbol_to_value[symbol] = self.value_reached
self.value_reached += 1
# Return the value reached minus 1 because it was previously incremented
return self.value_reached - 1
def __str__(self):
contents = '\n\t\t'.join(
[f'"{key}": {value}' for key, value in self.symbol_to_value.items()])
return f'SymbolTable{{\n\t\t{contents}\n\t\t}}'
__repr__ = __str__