def parseUnit(tokens):
tokens = convertToRPN(tokens)
stack = []
for token in tokens:
if token == UC_Common.OPERATOR_ADD:
a = stack.pop()
if not isinstance(a, int):
raise UC_Common.UnitError(f"Expected int; received '{a}'")
b = stack.pop()
if not isinstance(b, int):
raise UC_Common.UnitError(f"Expected int; received '{b}'")
stack.append(b + a)
elif token == UC_Common.OPERATOR_SUB:
a = stack.pop()
if not isinstance(a, int):
raise UC_Common.UnitError(f"Expected int; received '{a}'")
b = stack.pop()
if not isinstance(b, int):
raise UC_Common.UnitError(f"Expected int; received '{b}'")
stack.append(b - a)
elif token == UC_Common.OPERATOR_MUL:
a = stack.pop()
if not isinstance(a, dict): a = {a: 1}
b = stack.pop()
if not isinstance(b, dict): b = {b: 1}
for sym, exp in b.items():
if sym not in a: a[sym] = 0
a[sym] += exp
stack.append(a)
elif token == UC_Common.OPERATOR_DIV:
a = stack.pop()
if not isinstance(a, dict): a = {a: 1}
b = stack.pop()
if not isinstance(b, dict): b = {b: 1}
for sym, exp in a.items():
if sym not in b: b[sym] = 0
b[sym] -= exp
stack.append(b)
elif token == UC_Common.OPERATOR_EXP:
a = stack.pop()
b = stack.pop()
if not isinstance(a, int):
raise UC_Common.UnitError(f"Expected int; received '{a}'")
stack.append({b: a})
else:
if UC_Utils.isInt(token): stack.append(int(token))
else: stack.append(token)
# Aggregate into a single map
units = {}
while stack:
top = stack.pop()
if isinstance(top, dict):
for sym, exp in top.items():
if sym not in units: units[sym] = 0
units[sym] += exp
elif UC_Utils.isValidSymbol(top):
if top not in units: units[top] = 0
units[top] += 1
else:
raise UC_Common.UnitError("Invalid expression")
return units
def aggregateUnits(tokens):
"""
Combine tokens which constitute compound units
@param tokens: a list of tokens
"""
aggregatedTokens = []
unitTokens = []
parsingExp = 0
def appendUnitTokens(aggregatedTokens, unitTokens, token=None):
# Append unit tokens to list of aggregated tokens
if unitTokens:
if unitTokens[-1] == UC_Common.OPERATOR_MUL or unitTokens[
-1] == UC_Common.OPERATOR_DIV:
operator = unitTokens.pop()
aggregatedTokens.append(unitTokens)
aggregatedTokens.append(operator)
else:
aggregatedTokens.append(unitTokens)
if token is not None:
# Inject multiplication if needed
if ((aggregatedTokens)
and (not UC_Utils.isSpecialChar(aggregatedTokens[-1]))
and (token == UC_Common.BRACKET_OPEN)):
aggregatedTokens.append(UC_Common.OPERATOR_MUL)
aggregatedTokens.append(token)
return []
def handleParseExpDecrement(tokens, unitTokens, parsingExp):
# Check if multiplication needs to be injected between adjacent units
if parsingExp != 1: return parsingExp
if tokens:
if tokens[0] == UC_Common.OPERATOR_MUL or tokens[
0] == UC_Common.OPERATOR_DIV:
unitTokens.append(tokens.pop(0))
elif UC_Utils.isValidSymbol(tokens[0]):
unitTokens.append(UC_Common.OPERATOR_MUL)
return 0
def handleAppendUnitSymbol(tokens, unitTokens, parsingExp):
if tokens:
token = tokens[0]
if token == UC_Common.OPERATOR_EXP:
unitTokens.append(tokens.pop(0))
return 1
elif token == UC_Common.OPERATOR_MUL or token == UC_Common.OPERATOR_DIV:
unitTokens.append(tokens.pop(0))
elif UC_Utils.isValidSymbol(token):
unitTokens.append(UC_Common.OPERATOR_MUL)
return parsingExp
while tokens:
token = UC_Utils.getNextToken(tokens)
if token == UC_Common.BRACKET_OPEN:
if parsingExp:
unitTokens.append(token)
parsingExp += 1
else:
unitTokens = appendUnitTokens(aggregatedTokens, unitTokens,
token)
elif token == UC_Common.BRACKET_SHUT:
if parsingExp:
unitTokens.append(token)
parsingExp = handleParseExpDecrement(tokens, unitTokens,
parsingExp - 1)
else:
unitTokens = appendUnitTokens(aggregatedTokens, unitTokens,
token)
elif UC_Utils.isFloat(token):
if parsingExp:
if not UC_Utils.isInt(token):
raise UC_Common.UnitError(
f"Expected int; received '{token}'")
unitTokens.append(token)
parsingExp = handleParseExpDecrement(tokens, unitTokens,
parsingExp)
else:
unitTokens = appendUnitTokens(aggregatedTokens, unitTokens,
token)
elif UC_Utils.isValidSymbol(token):
if parsingExp:
raise UC_Common.UnitError(f"Expected int; received '{token}'")
unitTokens.append(token)
parsingExp = handleAppendUnitSymbol(tokens, unitTokens, parsingExp)
elif UC_Utils.isOperator(token):
if parsingExp:
raise UC_Common.UnitError(f"Expected int; received '{token}'")
else:
unitTokens = appendUnitTokens(aggregatedTokens, unitTokens,
token)
else:
raise UC_Common.UnitError(f"Unknown token; received '{token}'")
appendUnitTokens(aggregatedTokens, unitTokens)
return aggregatedTokens