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Fixed -.33 bug in calculator from gjs

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This commit is contained in:
Piotr Mitros
2012-01-16 12:33:29 -05:00
parent d65d268045
commit 56c81a07fd
1 changed files with 21 additions and 10 deletions
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31
courseware/capa/calc.py
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@@ -19,6 +19,9 @@ def evaluator(variables, functions, string):
"+" : operator.add,
"-" : operator.sub,
}
# We eliminated extreme ones, since they're rarely used, and potentially
# confusing. They may also conflict with variables if we ever allow e.g.
# 5R instead of 5*R
suffixes={'%':0.01,'k':1e3,'M':1e6,'G':1e9,
'T':1e12,#'P':1e15,'E':1e18,'Z':1e21,'Y':1e24,
'c':1e-2,'m':1e-3,'u':1e-6,
@@ -66,16 +69,18 @@ def evaluator(variables, functions, string):
def func_parse_action(x):
return [functions[x[0]](x[1])]
number_suffix=reduce(lambda a,b:a|b, map(Literal,suffixes.keys()), NoMatch())
number_suffix=reduce(lambda a,b:a|b, map(Literal,suffixes.keys()), NoMatch()) # SI suffixes and percent
(dot,minus,plus,times,div,lpar,rpar,exp)=map(Literal,".-+*/()^")
number_part=Word(nums)
number=Optional(minus | plus)+number_part+Optional("."+number_part)+ \
inner_number = ( number_part+Optional("."+number_part) ) | ("."+number_part) # 0.33 or 7 or .34
number=Optional(minus | plus)+ inner_number + \
Optional(CaselessLiteral("E")+Optional("-")+number_part)+ \
Optional(number_suffix)
number=number.setParseAction( number_parse_action )
Optional(number_suffix) # 0.33k or -17
number=number.setParseAction( number_parse_action ) # Convert to number
expr = Forward()
# Predefine recursive variables
expr = Forward()
factor = Forward()
def sreduce(f, l):
@@ -86,24 +91,28 @@ def evaluator(variables, functions, string):
return l[0]
return reduce(f, l)
# Handle variables passed in. E.g. if we have {'R':0.5}, we make the substitution.
# Special case for no variables because of how we understand PyParsing is put together
if len(variables)>0:
varnames = sreduce(lambda x,y:x|y, map(lambda x: CaselessLiteral(x), variables.keys()))
varnames.setParseAction(lambda x:map(lambda y:variables[y], x))
else:
varnames=NoMatch()
if len(variables)>0:
# Same thing for functions.
if len(functions)>0:
funcnames = sreduce(lambda x,y:x|y, map(lambda x: CaselessLiteral(x), functions.keys()))
function = funcnames+lpar.suppress()+expr+rpar.suppress()
function.setParseAction(func_parse_action)
else:
function = NoMatch()
atom = number | varnames | lpar+expr+rpar | function
factor << (atom + ZeroOrMore(exp+atom)).setParseAction(exp_parse_action)
paritem = factor + ZeroOrMore(Literal('||')+factor)
factor << (atom + ZeroOrMore(exp+atom)).setParseAction(exp_parse_action) # 7^6
paritem = factor + ZeroOrMore(Literal('||')+factor) # 5k || 4k
paritem=paritem.setParseAction(parallel)
term = paritem + ZeroOrMore((times|div)+paritem)
term = paritem + ZeroOrMore((times|div)+paritem) # 7 * 5 / 4 - 3
term = term.setParseAction(prod_parse_action)
expr << Optional((plus|minus)) + term + ZeroOrMore((plus|minus)+term)
expr << Optional((plus|minus)) + term + ZeroOrMore((plus|minus)+term) # -5 + 4 - 3
expr=expr.setParseAction(sum_parse_action)
return (expr+stringEnd).parseString(string)[0]
@@ -117,4 +126,6 @@ if __name__=='__main__':
print evaluator({'a': 2.2997471478310274, 'k': 9, 'm': 8, 'x': 0.66009498411213041}, {}, "5")
print evaluator({},{}, "-1")
print evaluator({},{}, "-(7+5)")
print evaluator({},{}, "-0.33")
print evaluator({},{}, "-.33")
print evaluator({},{}, "5+7 QWSEKO")