package calculator
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import (
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"errors"
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"math"
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)
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const (
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RadianMode = iota
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AngleMode
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)
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type defS struct {
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argc int
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fun func(expr ...ExprAST) float64
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}
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// enum "RadianMode", "AngleMode"
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var TrigonometricMode = RadianMode
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var defConst = map[string]float64{
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"pi": math.Pi,
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}
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var defFunc map[string]defS
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func init() {
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defFunc = map[string]defS{
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"sin": {1, defSin},
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"cos": {1, defCos},
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"tan": {1, defTan},
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"cot": {1, defCot},
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"sec": {1, defSec},
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"csc": {1, defCsc},
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"abs": {1, defAbs},
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"ceil": {1, defCeil},
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"floor": {1, defFloor},
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"round": {1, defRound},
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"sqrt": {1, defSqrt},
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"cbrt": {1, defCbrt},
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"noerr": {1, defNoerr},
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"max": {-1, defMax},
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"min": {-1, defMin},
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}
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}
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// sin(pi/2) = 1
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func defSin(expr ...ExprAST) float64 {
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return math.Sin(expr2Radian(expr[0]))
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}
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// cos(0) = 1
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func defCos(expr ...ExprAST) float64 {
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return math.Cos(expr2Radian(expr[0]))
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}
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// tan(pi/4) = 1
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func defTan(expr ...ExprAST) float64 {
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return math.Tan(expr2Radian(expr[0]))
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}
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// cot(pi/4) = 1
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func defCot(expr ...ExprAST) float64 {
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return 1 / defTan(expr...)
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}
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// sec(0) = 1
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func defSec(expr ...ExprAST) float64 {
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return 1 / defCos(expr...)
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}
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// csc(pi/2) = 1
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func defCsc(expr ...ExprAST) float64 {
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return 1 / defSin(expr...)
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}
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// abs(-2) = 2
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func defAbs(expr ...ExprAST) float64 {
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return math.Abs(ExprASTResult(expr[0]))
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}
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// ceil(4.2) = ceil(4.8) = 5
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func defCeil(expr ...ExprAST) float64 {
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return math.Ceil(ExprASTResult(expr[0]))
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}
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// floor(4.2) = floor(4.8) = 4
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func defFloor(expr ...ExprAST) float64 {
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return math.Floor(ExprASTResult(expr[0]))
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}
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// round(4.2) = 4
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// round(4.6) = 5
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func defRound(expr ...ExprAST) float64 {
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return math.Round(ExprASTResult(expr[0]))
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}
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// sqrt(4) = 2
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// sqrt(4) = abs(sqrt(4))
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// returns only the absolute value of the result
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func defSqrt(expr ...ExprAST) float64 {
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return math.Sqrt(ExprASTResult(expr[0]))
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}
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// cbrt(27) = 3
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func defCbrt(expr ...ExprAST) float64 {
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return math.Cbrt(ExprASTResult(expr[0]))
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}
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// max(2) = 2
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// max(2, 3) = 3
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// max(2, 3, 1) = 3
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func defMax(expr ...ExprAST) float64 {
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if len(expr) == 0 {
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panic(errors.New("calling function `max` must have at least one parameter."))
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}
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if len(expr) == 1 {
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return ExprASTResult(expr[0])
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}
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maxV := ExprASTResult(expr[0])
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for i := 1; i < len(expr); i++ {
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v := ExprASTResult(expr[i])
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maxV = math.Max(maxV, v)
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}
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return maxV
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}
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// min(2) = 2
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// min(2, 3) = 2
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// min(2, 3, 1) = 1
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func defMin(expr ...ExprAST) float64 {
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if len(expr) == 0 {
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panic(errors.New("calling function `min` must have at least one parameter."))
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}
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if len(expr) == 1 {
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return ExprASTResult(expr[0])
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}
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maxV := ExprASTResult(expr[0])
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for i := 1; i < len(expr); i++ {
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v := ExprASTResult(expr[i])
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maxV = math.Min(maxV, v)
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}
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return maxV
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}
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// noerr(1/0) = 0
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// noerr(2.5/(1-1)) = 0
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func defNoerr(expr ...ExprAST) (r float64) {
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defer func() {
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if e := recover(); e != nil {
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r = 0
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}
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}()
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return ExprASTResult(expr[0])
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}
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