RosettaCodeData/Task/Arithmetic-evaluation/Wren/arithmetic-evaluation.wren

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import "./pattern" for Pattern
/* if string is empty, returns zero */
var toDoubleOrZero = Fn.new { |s|
var n = Num.fromString(s)
return n ? n : 0
}
var multiply = Fn.new { |s|
var b = s.split("*").map { |t| toDoubleOrZero.call(t) }.toList
return (b[0] * b[1]).toString
}
var divide = Fn.new { |s|
var b = s.split("/").map { |t| toDoubleOrZero.call(t) }.toList
return (b[0] / b[1]).toString
}
var add = Fn.new { |s|
var p1 = Pattern.new("/+", Pattern.start)
var p2 = Pattern.new("+1/+")
var t = p1.replaceAll(s, "")
t = p2.replaceAll(t, "+")
var b = t.split("+").map { |u| toDoubleOrZero.call(u) }.toList
return (b[0] + b[1]).toString
}
var subtract = Fn.new { |s|
var p = Pattern.new("[/+-|-/+]")
var t = p.replaceAll(s, "-")
if (t.contains("--")) return add.call(t.replace("--", "+"))
var b = t.split("-").map { |u| toDoubleOrZero.call(u) }.toList
return ((b.count == 3) ? -b[1] - b[2] : b[0] - b[1]).toString
}
var evalExp = Fn.new { |s|
var p = Pattern.new("[(|)|/s]")
var t = p.replaceAll(s, "")
var i = "*/"
var pMD = Pattern.new("+1/f/i~/n+1/f", Pattern.within, i)
var pM = Pattern.new("*")
var pAS = Pattern.new("~-+1/f+1/n+1/f")
var pA = Pattern.new("/d/+")
while (true) {
var match = pMD.find(t)
if (!match) break
var exp = match.text
var match2 = pM.find(exp)
t = match2 ? t.replace(exp, multiply.call(exp)) : t.replace(exp, divide.call(exp))
}
while (true) {
var match = pAS.find(t)
if (!match) break
var exp = match.text
var match2 = pA.find(exp)
t = match2 ? t.replace(exp, add.call(exp)) : t.replace(exp, subtract.call(exp))
}
return t
}
var evalArithmeticExp = Fn.new { |s|
var p1 = Pattern.new("/s")
var p2 = Pattern.new("/+", Pattern.start)
var t = p1.replaceAll(s, "")
t = p2.replaceAll(t, "")
var i = "()"
var pPara = Pattern.new("(+0/I)", Pattern.within, i)
while (true) {
var match = pPara.find(t)
if (!match) break
var exp = match.text
t = t.replace(exp, evalExp.call(exp))
}
return toDoubleOrZero.call(evalExp.call(t))
}
[
"2+3",
"2+3/4",
"2*3-4",
"2*(3+4)+5/6",
"2 * (3 + (4 * 5 + (6 * 7) * 8) - 9) * 10",
"2*-3--4+-0.25",
"-4 - 3",
"((((2))))+ 3 * 5",
"1 + 2 * (3 + (4 * 5 + 6 * 7 * 8) - 9) / 10",
"1 + 2*(3 - 2*(3 - 2)*((2 - 4)*5 - 22/(7 + 2*(3 - 1)) - 1)) + 1"
].each { |s| System.print("%(s) = %(evalArithmeticExp.call(s))") }