MST expression

kmath-ast/build.gradle.kts

@@ -13,4 +13,9 @@ kotlin.sourceSets {
             implementation("com.github.h0tk3y.betterParse:better-parse-multiplatform:0.4.0-alpha-3")
         }
     }
+    jvmMain{
+        dependencies{
+            implementation("com.github.h0tk3y.betterParse:better-parse-jvm:0.4.0-alpha-3")
+        }
+    }
 }

kmath-ast/src/commonMain/kotlin/scientifik/kmath/ast/MST.kt

@@ -0,0 +1,62 @@
+package scientifik.kmath.ast
+
+import scientifik.kmath.operations.NumericAlgebra
+import scientifik.kmath.operations.RealField
+
+/**
+ * A Mathematical Syntax Tree node for mathematical expressions
+ */
+sealed class MST {
+
+    /**
+     * A node containing unparsed string
+     */
+    data class Singular(val value: String) : MST()
+
+    /**
+     * A node containing a number
+     */
+    data class Numeric(val value: Number) : MST()
+
+    /**
+     * A node containing an unary operation
+     */
+    data class Unary(val operation: String, val value: MST) : MST() {
+        companion object {
+            const val ABS_OPERATION = "abs"
+            //TODO add operations
+        }
+    }
+
+    /**
+     * A node containing binary operation
+     */
+    data class Binary(val operation: String, val left: MST, val right: MST) : MST() {
+        companion object
+    }
+}
+
+//TODO add a function with positional arguments
+
+//TODO add a function with named arguments
+
+fun <T> NumericAlgebra<T>.evaluate(node: MST): T {
+    return when (node) {
+        is MST.Numeric -> number(node.value)
+        is MST.Singular -> raw(node.value)
+        is MST.Unary -> unaryOperation(node.operation, evaluate(node.value))
+        is MST.Binary -> when {
+            node.left is MST.Numeric && node.right is MST.Numeric -> {
+                val number = RealField.binaryOperation(
+                    node.operation,
+                    node.left.value.toDouble(),
+                    node.right.value.toDouble()
+                )
+                number(number)
+            }
+            node.left is MST.Numeric -> leftSideNumberOperation(node.operation, node.left.value, evaluate(node.right))
+            node.right is MST.Numeric -> rightSideNumberOperation(node.operation, evaluate(node.left), node.right.value)
+            else -> binaryOperation(node.operation, evaluate(node.left), evaluate(node.right))
+        }
+    }
+}

kmath-ast/src/commonMain/kotlin/scientifik/kmath/ast/MSTExpression.kt

@@ -0,0 +1,19 @@
+package scientifik.kmath.ast
+
+import scientifik.kmath.expressions.Expression
+import scientifik.kmath.operations.NumericAlgebra
+
+/**
+ * The expression evaluates MST on-flight
+ */
+class MSTExpression<T>(val algebra: NumericAlgebra<T>, val mst: MST) : Expression<T> {
+
+    /**
+     * Substitute algebra raw value
+     */
+    private inner class InnerAlgebra(val arguments: Map<String, T>) : NumericAlgebra<T> by algebra {
+        override fun raw(value: String): T = arguments[value] ?: super.raw(value)
+    }
+
+    override fun invoke(arguments: Map<String, T>): T = InnerAlgebra(arguments).evaluate(mst)
+}

kmath-ast/src/commonMain/kotlin/scientifik/kmath/ast/MathSyntaxTree.kt

@@ -1,61 +0,0 @@
-package scientifik.kmath.ast
-
-import scientifik.kmath.operations.NumericAlgebra
-import scientifik.kmath.operations.RealField
-
-/**
- * A syntax tree node for mathematical expressions
- */
-sealed class MathSyntaxTree
-
-/**
- * A node containing unparsed string
- */
-data class SingularNode(val value: String) : MathSyntaxTree()
-
-/**
- * A node containing a number
- */
-data class NumberNode(val value: Number) : MathSyntaxTree()
-
-/**
- * A node containing an unary operation
- */
-data class UnaryNode(val operation: String, val value: MathSyntaxTree) : MathSyntaxTree() {
-    companion object {
-        const val ABS_OPERATION = "abs"
-        //TODO add operations
-    }
-}
-
-/**
- * A node containing binary operation
- */
-data class BinaryNode(val operation: String, val left: MathSyntaxTree, val right: MathSyntaxTree) : MathSyntaxTree() {
-    companion object
-}
-
-//TODO add a function with positional arguments
-
-//TODO add a function with named arguments
-
-fun <T> NumericAlgebra<T>.compile(node: MathSyntaxTree): T {
-    return when (node) {
-        is NumberNode -> number(node.value)
-        is SingularNode -> raw(node.value)
-        is UnaryNode -> unaryOperation(node.operation, compile(node.value))
-        is BinaryNode -> when {
-            node.left is NumberNode && node.right is NumberNode -> {
-                val number = RealField.binaryOperation(
-                    node.operation,
-                    node.left.value.toDouble(),
-                    node.right.value.toDouble()
-                )
-                number(number)
-            }
-            node.left is NumberNode -> leftSideNumberOperation(node.operation, node.left.value, compile(node.right))
-            node.right is NumberNode -> rightSideNumberOperation(node.operation, compile(node.left), node.right.value)
-            else -> binaryOperation(node.operation, compile(node.left), compile(node.right))
-        }
-    }
-}

kmath-ast/src/jvmMain/kotlin/scientifik/kmath/ast/asm.kt

@@ -20,4 +20,4 @@ inline fun <reified T : Any, A : Algebra<T>> A.asm(
     block: AsmExpressionAlgebra<T, A>.() -> AsmExpression<T>
 ): Expression<T> = TODO()
 
-inline fun <reified T : Any, A : Algebra<T>> A.asm(ast: MathSyntaxTree): Expression<T> = asm { compile(ast) }
+inline fun <reified T : Any, A : Algebra<T>> A.asm(ast: MST): Expression<T> = asm { evaluate(ast) }

kmath-ast/src/jvmMain/kotlin/scientifik/kmath/ast/parser.kt

@@ -0,0 +1,56 @@
+package scientifik.kmath.ast
+
+import com.github.h0tk3y.betterParse.combinators.*
+import com.github.h0tk3y.betterParse.grammar.Grammar
+import com.github.h0tk3y.betterParse.grammar.parseToEnd
+import com.github.h0tk3y.betterParse.grammar.parser
+import com.github.h0tk3y.betterParse.grammar.tryParseToEnd
+import com.github.h0tk3y.betterParse.parser.ParseResult
+import com.github.h0tk3y.betterParse.parser.Parser
+import scientifik.kmath.operations.FieldOperations
+import scientifik.kmath.operations.PowerOperations
+import scientifik.kmath.operations.RingOperations
+import scientifik.kmath.operations.SpaceOperations
+
+private object ArithmeticsEvaluator : Grammar<MST>() {
+    val num by token("-?[\\d.]+(?:[eE]-?\\d+)?")
+    val lpar by token("\\(")
+    val rpar by token("\\)")
+    val mul by token("\\*")
+    val pow by token("\\^")
+    val div by token("/")
+    val minus by token("-")
+    val plus by token("\\+")
+    val ws by token("\\s+", ignore = true)
+
+    val number: Parser<MST> by num use { MST.Numeric(text.toDouble()) }
+
+    val term: Parser<MST> by number or
+            (skip(minus) and parser(this::term) map { MST.Unary(SpaceOperations.MINUS_OPERATION, it) }) or
+            (skip(lpar) and parser(this::rootParser) and skip(rpar))
+
+    val powChain by leftAssociative(term, pow) { a, _, b ->
+        MST.Binary(PowerOperations.POW_OPERATION, a, b)
+    }
+
+    val divMulChain: Parser<MST> by leftAssociative(powChain, div or mul use { type }) { a, op, b ->
+        if (op == div) {
+            MST.Binary(FieldOperations.DIV_OPERATION, a, b)
+        } else {
+            MST.Binary(RingOperations.TIMES_OPERATION, a, b)
+        }
+    }
+
+    val subSumChain: Parser<MST> by leftAssociative(divMulChain, plus or minus use { type }) { a, op, b ->
+        if (op == plus) {
+            MST.Binary(SpaceOperations.PLUS_OPERATION, a, b)
+        } else {
+            MST.Binary(SpaceOperations.MINUS_OPERATION, a, b)
+        }
+    }
+
+    override val rootParser: Parser<MST> by subSumChain
+}
+
+fun String.tryParseMath(): ParseResult<MST> = ArithmeticsEvaluator.tryParseToEnd(this)
+fun String.parseMath(): MST = ArithmeticsEvaluator.parseToEnd(this)

kmath-ast/src/jvmTest/kotlin/scietifik/kmath/ast/ParserTest.kt

@@ -0,0 +1,17 @@
+package scietifik.kmath.ast
+
+import org.junit.jupiter.api.Assertions.assertEquals
+import org.junit.jupiter.api.Test
+import scientifik.kmath.ast.evaluate
+import scientifik.kmath.ast.parseMath
+import scientifik.kmath.operations.Complex
+import scientifik.kmath.operations.ComplexField
+
+internal class ParserTest{
+    @Test
+    fun parsedExpression(){
+        val mst = "2+2*(2+2)".parseMath()
+        val res = ComplexField.evaluate(mst)
+        assertEquals(Complex(10.0,0.0), res)
+    }
+}

kmath-core/src/commonMain/kotlin/scientifik/kmath/expressions/Expression.kt

@@ -7,6 +7,12 @@ import scientifik.kmath.operations.Algebra
  */
 interface Expression<T> {
     operator fun invoke(arguments: Map<String, T>): T
+
+    companion object {
+        operator fun <T> invoke(block: (Map<String, T>) -> T): Expression<T> = object : Expression<T> {
+            override fun invoke(arguments: Map<String, T>): T = block(arguments)
+        }
+    }
 }
 
 operator fun <T> Expression<T>.invoke(vararg pairs: Pair<String, T>): T = invoke(mapOf(*pairs))

kmath-core/src/commonMain/kotlin/scientifik/kmath/expressions/functionalExpressions.kt

@@ -66,8 +66,7 @@ open class FunctionalExpressionField<T>(
     val field: Field<T>
 ) : Field<Expression<T>>, ExpressionAlgebra<T, Expression<T>>, FunctionalExpressionSpace<T>(field) {
 
-    override val one: Expression<T>
-        get() = const(this.field.one)
+    override val one: Expression<T> = ConstantExpression(this.field.one)
 
     fun const(value: Double): Expression<T> = const(field.run { one * value })
 
@@ -80,4 +79,16 @@ open class FunctionalExpressionField<T>(
 
     operator fun T.times(arg: Expression<T>) = arg * this
     operator fun T.div(arg: Expression<T>) = arg / this
-}
+}
+
+/**
+ * Create a functional expression on this [Space]
+ */
+fun <T> Space<T>.buildExpression(block: FunctionalExpressionSpace<T>.() -> Expression<T>): Expression<T> =
+    FunctionalExpressionSpace(this).run(block)
+
+/**
+ * Create a functional expression on this [Field]
+ */
+fun <T> Field<T>.buildExpression(block: FunctionalExpressionField<T>.() -> Expression<T>): Expression<T> =
+    FunctionalExpressionField(this).run(block)

kmath-core/src/commonMain/kotlin/scientifik/kmath/operations/Complex.kt

@@ -50,6 +50,12 @@ object ComplexField : ExtendedField<Complex> {
     operator fun Complex.minus(d: Double) = add(this, -d.toComplex())
 
     operator fun Double.times(c: Complex) = Complex(c.re * this, c.im * this)
+
+    override fun raw(value: String): Complex = if (value == "i") {
+        i
+    } else {
+        super.raw(value)
+    }
 }
 
 /**