mirror of
https://github.com/titanscouting/tra-analysis.git
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97 lines
2.6 KiB
Python
97 lines
2.6 KiB
Python
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from __future__ import division
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from pyparsing import (Literal, CaselessLiteral, Word, Combine, Group, Optional, ZeroOrMore, Forward, nums, alphas, oneOf)
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from . import py2
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import math
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import operator
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class BNF(object):
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def pushFirst(self, strg, loc, toks):
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self.exprStack.append(toks[0])
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def pushUMinus(self, strg, loc, toks):
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if toks and toks[0] == '-':
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self.exprStack.append('unary -')
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def __init__(self):
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"""
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expop :: '^'
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multop :: '*' | '/'
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addop :: '+' | '-'
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integer :: ['+' | '-'] '0'..'9'+
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atom :: PI | E | real | fn '(' expr ')' | '(' expr ')'
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factor :: atom [ expop factor ]*
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term :: factor [ multop factor ]*
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expr :: term [ addop term ]*
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"""
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point = Literal(".")
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e = CaselessLiteral("E")
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fnumber = Combine(Word("+-" + nums, nums) +
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Optional(point + Optional(Word(nums))) +
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Optional(e + Word("+-" + nums, nums)))
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ident = Word(alphas, alphas + nums + "_$")
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plus = Literal("+")
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minus = Literal("-")
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mult = Literal("*")
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div = Literal("/")
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lpar = Literal("(").suppress()
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rpar = Literal(")").suppress()
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addop = plus | minus
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multop = mult | div
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expop = Literal("^")
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pi = CaselessLiteral("PI")
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expr = Forward()
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atom = ((Optional(oneOf("- +")) +
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(ident + lpar + expr + rpar | pi | e | fnumber).setParseAction(self.pushFirst))
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| Optional(oneOf("- +")) + Group(lpar + expr + rpar)
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).setParseAction(self.pushUMinus)
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factor = Forward()
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factor << atom + \
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ZeroOrMore((expop + factor).setParseAction(self.pushFirst))
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term = factor + \
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ZeroOrMore((multop + factor).setParseAction(self.pushFirst))
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expr << term + \
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ZeroOrMore((addop + term).setParseAction(self.pushFirst))
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self.bnf = expr
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epsilon = 1e-12
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self.opn = {"+": operator.add,
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"-": operator.sub,
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"*": operator.mul,
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"/": operator.truediv,
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"^": operator.pow}
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self.fn = {"sin": math.sin,
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"cos": math.cos,
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"tan": math.tan,
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"exp": math.exp,
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"abs": abs,
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"trunc": lambda a: int(a),
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"round": round,
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"sgn": lambda a: abs(a) > epsilon and py2.cmp(a, 0) or 0}
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def evaluateStack(self, s):
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op = s.pop()
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if op == 'unary -':
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return -self.evaluateStack(s)
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if op in "+-*/^":
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op2 = self.evaluateStack(s)
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op1 = self.evaluateStack(s)
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return self.opn[op](op1, op2)
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elif op == "PI":
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return math.pi
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elif op == "E":
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return math.e
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elif op in self.fn:
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return self.fn[op](self.evaluateStack(s))
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elif op[0].isalpha():
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return 0
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else:
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return float(op)
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def eval(self, num_string, parseAll=True):
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self.exprStack = []
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results = self.bnf.parseString(num_string, parseAll)
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val = self.evaluateStack(self.exprStack[:])
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return val
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