add graphing calculator

app/src/main/java/net/youapps/calcyou/Destination.kt

@@ -48,6 +48,7 @@ sealed class Destination(open val route: String) {
 
     object Converters : Destination("converters")
     object CharacterInput : Destination("character_input")
+    object Graphing : Destination("graphing")
     sealed class Converter(
         override val route: String,
         @StringRes val resId: Int,

app/src/main/java/net/youapps/calcyou/NavHost.kt

@@ -9,6 +9,7 @@ import net.youapps.calcyou.ui.CalculatorScreen
 import net.youapps.calcyou.ui.screens.CharacterInputScreen
 import net.youapps.calcyou.ui.screens.ConverterGridScreen
 import net.youapps.calcyou.ui.screens.ConverterScreen
+import net.youapps.calcyou.ui.screens.graphing.GraphingScreen
 
 @Composable
 fun AppNavHost(modifier: Modifier = Modifier, navHostController: NavHostController) {
@@ -31,6 +32,10 @@ fun AppNavHost(modifier: Modifier = Modifier, navHostController: NavHostControll
             CharacterInputScreen()
         }
 
+        composable(route = Destination.Graphing.route) {
+            GraphingScreen()
+        }
+
         Destination.Converter.values.forEach { converter ->
             composable(route = converter.route) {
                 ConverterScreen(converter = converter.converter, converterName = converter.resId)

app/src/main/java/net/youapps/calcyou/data/graphing/CompiledExpression.kt

@@ -0,0 +1,41 @@
+/*
+ This code is a modified version of https://github.com/danielgindi/KotlinEval
+ The original source code is licensed under MIT LICENSE
+ */
+
+package net.youapps.calcyou.data.graphing
+
+class CompiledExpression internal constructor(
+    internal var root: Token,
+    var configuration: EvalConfiguration
+) {
+    fun execute(): Double? =
+        Evaluator.execute(expression = this)
+
+    fun execute(constant: Pair<String, Double>): Double? =
+        Evaluator.execute(this, constant)
+
+    fun setConstant(name: String, value: Double) {
+        configuration.setConstant(name = name, value = value)
+    }
+
+    fun removeConstant(name: String) {
+        configuration.removeConstant(name = name)
+    }
+
+    fun setFunction(name: String, func: EvalFunctionBlock) {
+        configuration.setFunction(name = name, func = func)
+    }
+
+    fun removeFunction(name: String) {
+        configuration.removeFunction(name = name)
+    }
+
+    fun clearConstants() {
+        configuration.clearConstants()
+    }
+
+    fun clearFunctions() {
+        configuration.clearConstants()
+    }
+}

app/src/main/java/net/youapps/calcyou/data/graphing/Defaults.kt

@@ -0,0 +1,157 @@
+/*
+ This code is a modified version of https://github.com/danielgindi/KotlinEval
+ The original source code is licensed under MIT LICENSE
+ */
+
+package net.youapps.calcyou.data.graphing
+
+import java.security.InvalidParameterException
+import kotlin.math.abs
+import kotlin.math.acos
+import kotlin.math.asin
+import kotlin.math.atan
+import kotlin.math.atan2
+import kotlin.math.ceil
+import kotlin.math.cos
+import kotlin.math.cosh
+import kotlin.math.exp
+import kotlin.math.floor
+import kotlin.math.ln
+import kotlin.math.log
+import kotlin.math.log10
+import kotlin.math.log2
+import kotlin.math.pow
+import kotlin.math.round
+import kotlin.math.sin
+import kotlin.math.sinh
+import kotlin.math.sqrt
+import kotlin.math.tan
+import kotlin.math.tanh
+import kotlin.math.truncate
+
+object Defaults {
+    val defaultOperatorOrder: List<List<Operator>> = listOf(
+        listOf(Operator.POW),
+        listOf(Operator.DIV, Operator.MUL, Operator.MOD),
+        listOf(Operator.SUB, Operator.ADD),
+    )
+    val defaultRightAssociativeOps: Set<String> = setOf("**")
+    val defaultGenericConstants: Map<String, Double> = mapOf(
+        "PI" to Math.PI,
+        "PI_2" to Math.PI / 2,
+        "LOG2E" to log2(Math.E),
+        "DEG" to Math.PI / 180f,
+        "E" to Math.E
+    )
+    val defaultVarNameChars: Set<Char> =
+        "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789_$".toCharArray().toSet()
+
+    fun getDefaultGenericFunctions(): Map<String, EvalFunctionBlock> {
+        return mapOf(
+            "ABS" to { args ->
+                abs(args.first())
+            },
+            "ACOS" to { args ->
+
+                acos(args.first())
+            },
+            "ASIN" to { args ->
+
+                asin(args.first())
+            },
+            "ATAN" to { args ->
+
+                atan(args.first())
+            },
+            "ATAN2" to { args ->
+                val arg1 = args[0]
+                val arg2 = args[1]
+                if (args.size != 2) {
+                    throw InvalidParameterException()
+                }
+                atan2(arg1, arg2)
+            },
+            "CEILING" to { args ->
+                ceil(args.first())
+            },
+            "COS" to { args ->
+                cos(args.first())
+            },
+            "COSH" to { args ->
+                cosh(args.first())
+            },
+            "EXP" to { args ->
+                exp(args.first())
+            },
+            "FLOOR" to { args ->
+                floor(args.first())
+            },
+            "LOG" to fn@{ args ->
+                if (args.size == 2) {
+                    val arg1 = args[0]
+                    val arg2 = args[1]
+
+                    return@fn log(arg1, arg2)
+                } else if (args.size == 1) {
+                    return@fn ln(args.first())
+                }
+                throw InvalidParameterException()
+            },
+            "LOG2" to { args ->
+                log2(args.first())
+            },
+            "LOG10" to { args ->
+                log10(args.first())
+            },
+            "MAX" to fn@{ args ->
+                var v = args[0]
+                for (arg in args) {
+                    val narg = arg
+                    if (narg > v)
+                        v = narg
+                }
+                v
+            },
+            "MIN" to fn@{ args ->
+                var v = args[0]
+                for (arg in args) {
+                    val narg = arg
+                    if (narg < v)
+                        v = narg
+                }
+                v
+            },
+            "POW" to fn@{ args ->
+                if (args.size == 2) {
+                    val arg1 = args[0]
+                    val arg2 = args[1]
+                    return@fn arg1.pow(arg2)
+                }
+                throw InvalidParameterException()
+            },
+            "ROUND" to { args ->
+                round(args.first())
+            },
+            "SIGN" to { args ->
+                if (args.first() < 0) -1.0 else if (args.first() > 0) 1.0 else 0.0
+            },
+            "SIN" to { args ->
+                sin(args.first())
+            },
+            "SINH" to { args ->
+                sinh(args.first())
+            },
+            "SQRT" to { args ->
+                sqrt(args.first())
+            },
+            "TAN" to { args ->
+                tan(args.first())
+            },
+            "TANH" to { args ->
+                tanh(args.first())
+            },
+            "TRUNCATE" to { args ->
+                truncate(args.first())
+            })
+    }
+}

app/src/main/java/net/youapps/calcyou/data/graphing/EvalConfig.kt

@@ -0,0 +1,87 @@
+/*
+ This code is a modified version of https://github.com/danielgindi/KotlinEval
+ The original source code is licensed under MIT LICENSE
+ */
+
+package net.youapps.calcyou.data.graphing
+
+typealias EvalFunctionBlock = (args: List<Double>) -> Double
+
+class EvalConfiguration(
+    var constants: MutableMap<String, Double>? = null,
+    var functions: MutableMap<String, EvalFunctionBlock>? = null
+) {
+
+    internal var allOperators = listOf<Operator>()
+    private var _operatorOrder = listOf<List<Operator>>()
+    var operatorOrder: List<List<Operator>>
+        get() {
+            return _operatorOrder
+        }
+        set(newValue) {
+            val ops = mutableListOf<Operator>()
+            for (ops2 in newValue)
+                ops.addAll(ops2)
+
+            _operatorOrder = newValue
+            allOperators = ops
+        }
+
+    var rightAssociativeOps = setOf<String>()
+
+    var varNameChars = setOf<Char>()
+
+    var genericConstants = mutableMapOf<String, Double>()
+    var genericFunctions = mutableMapOf<String, EvalFunctionBlock>()
+
+    @Suppress("unused")
+    fun setConstant(name: String, value: Double) {
+        if (constants == null) {
+            constants = mutableMapOf()
+        }
+        constants!![name] = value
+    }
+
+    @Suppress("unused")
+    fun removeConstant(name: String) {
+        if (constants == null) {
+            return
+        }
+        constants?.remove(name)
+    }
+
+    @Suppress("unused")
+    fun setFunction(name: String, func: EvalFunctionBlock) {
+        if (functions == null) {
+            functions = mutableMapOf()
+        }
+        functions!![name] = func
+    }
+
+    @Suppress("unused")
+    fun removeFunction(name: String) {
+        if (functions == null) {
+            return
+        }
+        functions?.remove(name)
+    }
+
+    @Suppress("unused")
+    fun clearConstants() {
+        constants?.clear()
+    }
+
+    @Suppress("unused")
+    fun clearFunctions() {
+        functions?.clear()
+    }
+
+    init {
+        this.operatorOrder = Defaults.defaultOperatorOrder
+        this.rightAssociativeOps = Defaults.defaultRightAssociativeOps
+        this.varNameChars = Defaults.defaultVarNameChars
+        this.genericConstants = Defaults.defaultGenericConstants.toMutableMap()
+        this.genericFunctions = Defaults.getDefaultGenericFunctions().toMutableMap()
+
+    }
+}