Remove MST.Symbolic

Replace it by Symbol
LogicAlgebra

CHANGELOG.md

@@ -30,6 +30,7 @@
 - Rewritten EJML module without ejml-simple
 - Stability of kmath-ast and kmath-kotilngrad promoted to EXPERIMENTAL.
 - ColumnarData returns nullable column
+- Replaced MST.Symbolic by Symbol. Symbol now inherits MST
 
 ### Deprecated
 

benchmarks/src/jvmMain/kotlin/space/kscience/kmath/benchmarks/ExpressionsInterpretersBenchmark.kt

@@ -11,8 +11,6 @@ import kotlinx.benchmark.Scope
 import kotlinx.benchmark.State
 import space.kscience.kmath.asm.compileToExpression
 import space.kscience.kmath.expressions.*
-import space.kscience.kmath.misc.Symbol
-import space.kscience.kmath.misc.symbol
 import space.kscience.kmath.operations.DoubleField
 import space.kscience.kmath.operations.bindSymbol
 import space.kscience.kmath.operations.invoke

examples/src/main/kotlin/space/kscience/kmath/ast/expressions.kt

@@ -6,8 +6,8 @@
 package space.kscience.kmath.ast
 
 import space.kscience.kmath.expressions.MstField
+import space.kscience.kmath.expressions.Symbol.Companion.x
 import space.kscience.kmath.expressions.interpret
-import space.kscience.kmath.misc.Symbol.Companion.x
 import space.kscience.kmath.operations.DoubleField
 import space.kscience.kmath.operations.bindSymbol
 import space.kscience.kmath.operations.invoke

examples/src/main/kotlin/space/kscience/kmath/ast/kotlingradSupport.kt

@@ -8,8 +8,8 @@ package space.kscience.kmath.ast
 import space.kscience.kmath.asm.compileToExpression
 import space.kscience.kmath.expressions.derivative
 import space.kscience.kmath.expressions.invoke
+import space.kscience.kmath.expressions.symbol
 import space.kscience.kmath.kotlingrad.toDiffExpression
-import space.kscience.kmath.misc.symbol
 import space.kscience.kmath.operations.DoubleField
 
 /**

examples/src/main/kotlin/space/kscience/kmath/commons/fit/fitWithAutoDiff.kt

@@ -10,7 +10,7 @@ import kotlinx.html.h3
 import space.kscience.kmath.commons.optimization.chiSquared
 import space.kscience.kmath.commons.optimization.minimize
 import space.kscience.kmath.distributions.NormalDistribution
-import space.kscience.kmath.misc.symbol
+import space.kscience.kmath.expressions.symbol
 import space.kscience.kmath.optimization.FunctionOptimization
 import space.kscience.kmath.optimization.OptimizationResult
 import space.kscience.kmath.real.DoubleVector

kmath-ast/src/commonMain/kotlin/space/kscience/kmath/ast/parser.kt

@@ -17,6 +17,7 @@ import com.github.h0tk3y.betterParse.lexer.regexToken
 import com.github.h0tk3y.betterParse.parser.ParseResult
 import com.github.h0tk3y.betterParse.parser.Parser
 import space.kscience.kmath.expressions.MST
+import space.kscience.kmath.expressions.StringSymbol
 import space.kscience.kmath.operations.FieldOperations
 import space.kscience.kmath.operations.GroupOperations
 import space.kscience.kmath.operations.PowerOperations
@@ -42,7 +43,7 @@ public object ArithmeticsEvaluator : Grammar<MST>() {
     private val ws: Token by regexToken("\\s+".toRegex(), ignore = true)
 
     private val number: Parser<MST> by num use { MST.Numeric(text.toDouble()) }
-    private val singular: Parser<MST> by id use { MST.Symbolic(text) }
+    private val singular: Parser<MST> by id use { StringSymbol(text) }
 
     private val unaryFunction: Parser<MST> by (id and -lpar and parser(ArithmeticsEvaluator::subSumChain) and -rpar)
         .map { (id, term) -> MST.Unary(id.text, term) }

kmath-ast/src/commonMain/kotlin/space/kscience/kmath/ast/rendering/features.kt

@@ -7,6 +7,7 @@ package space.kscience.kmath.ast.rendering
 
 import space.kscience.kmath.ast.rendering.FeaturedMathRenderer.RenderFeature
 import space.kscience.kmath.expressions.MST
+import space.kscience.kmath.expressions.Symbol
 import space.kscience.kmath.misc.UnstableKMathAPI
 import space.kscience.kmath.operations.*
 import kotlin.reflect.KClass
@@ -19,9 +20,8 @@ import kotlin.reflect.KClass
 @UnstableKMathAPI
 public object PrintSymbolic : RenderFeature {
     public override fun render(renderer: FeaturedMathRenderer, node: MST): SymbolSyntax? =
-        if (node !is MST.Symbolic) null
+        if (node !is Symbol) null
-        else
+        else SymbolSyntax(string = node.identity)
-            SymbolSyntax(string = node.value)
 }
 
 /**
@@ -142,7 +142,7 @@ public class PrettyPrintIntegers(public val types: Set<KClass<out Number>>) : Re
 @UnstableKMathAPI
 public class PrettyPrintPi(public val symbols: Set<String>) : RenderFeature {
     public override fun render(renderer: FeaturedMathRenderer, node: MST): SpecialSymbolSyntax? =
-        if (node !is MST.Symbolic || node.value !in symbols)
+        if (node !is Symbol || node.identity !in symbols)
             null
         else
             SpecialSymbolSyntax(kind = SpecialSymbolSyntax.Kind.SMALL_PI)

kmath-ast/src/commonTest/kotlin/space/kscience/kmath/ast/TestCompilerConsistencyWithInterpreter.kt

@@ -7,8 +7,8 @@ package space.kscience.kmath.ast
 
 import space.kscience.kmath.expressions.MstField
 import space.kscience.kmath.expressions.MstRing
+import space.kscience.kmath.expressions.Symbol.Companion.x
 import space.kscience.kmath.expressions.interpret
-import space.kscience.kmath.misc.Symbol.Companion.x
 import space.kscience.kmath.operations.DoubleField
 import space.kscience.kmath.operations.IntRing
 import space.kscience.kmath.operations.bindSymbol

kmath-ast/src/commonTest/kotlin/space/kscience/kmath/ast/TestCompilerOperations.kt

@@ -6,8 +6,8 @@
 package space.kscience.kmath.ast
 
 import space.kscience.kmath.expressions.MstExtendedField
+import space.kscience.kmath.expressions.Symbol.Companion.x
 import space.kscience.kmath.expressions.invoke
-import space.kscience.kmath.misc.Symbol.Companion.x
 import space.kscience.kmath.operations.DoubleField
 import space.kscience.kmath.operations.bindSymbol
 import space.kscience.kmath.operations.invoke
@@ -17,31 +17,31 @@ import kotlin.test.assertEquals
 internal class TestCompilerOperations {
     @Test
     fun testUnaryPlus() = runCompilerTest {
-        val expr = MstExtendedField { +bindSymbol(x) }.compileToExpression(DoubleField)
+        val expr = MstExtendedField { +x }.compileToExpression(DoubleField)
         assertEquals(2.0, expr(x to 2.0))
     }
 
     @Test
     fun testUnaryMinus() = runCompilerTest {
-        val expr = MstExtendedField { -bindSymbol(x) }.compileToExpression(DoubleField)
+        val expr = MstExtendedField { -x }.compileToExpression(DoubleField)
         assertEquals(-2.0, expr(x to 2.0))
     }
 
     @Test
     fun testAdd() = runCompilerTest {
-        val expr = MstExtendedField { bindSymbol(x) + bindSymbol(x) }.compileToExpression(DoubleField)
+        val expr = MstExtendedField { x + x }.compileToExpression(DoubleField)
         assertEquals(4.0, expr(x to 2.0))
     }
 
     @Test
     fun testSine() = runCompilerTest {
-        val expr = MstExtendedField { sin(bindSymbol(x)) }.compileToExpression(DoubleField)
+        val expr = MstExtendedField { sin(x) }.compileToExpression(DoubleField)
         assertEquals(0.0, expr(x to 0.0))
     }
 
     @Test
     fun testCosine() = runCompilerTest {
-        val expr = MstExtendedField { cos(bindSymbol(x)) }.compileToExpression(DoubleField)
+        val expr = MstExtendedField { cos(x) }.compileToExpression(DoubleField)
         assertEquals(1.0, expr(x to 0.0))
     }
 

kmath-ast/src/commonTest/kotlin/space/kscience/kmath/ast/TestCompilerVariables.kt

@@ -6,8 +6,8 @@
 package space.kscience.kmath.ast
 
 import space.kscience.kmath.expressions.MstRing
+import space.kscience.kmath.expressions.Symbol.Companion.x
 import space.kscience.kmath.expressions.invoke
-import space.kscience.kmath.misc.Symbol.Companion.x
 import space.kscience.kmath.operations.IntRing
 import space.kscience.kmath.operations.bindSymbol
 import space.kscience.kmath.operations.invoke

kmath-ast/src/commonTest/kotlin/space/kscience/kmath/ast/utils.kt

@@ -7,7 +7,7 @@ package space.kscience.kmath.ast
 
 import space.kscience.kmath.expressions.Expression
 import space.kscience.kmath.expressions.MST
-import space.kscience.kmath.misc.Symbol
+import space.kscience.kmath.expressions.Symbol
 import space.kscience.kmath.operations.DoubleField
 import space.kscience.kmath.operations.IntRing
 

kmath-ast/src/jsMain/kotlin/space/kscience/kmath/estree/estree.kt

@@ -9,22 +9,23 @@ import space.kscience.kmath.estree.internal.ESTreeBuilder
 import space.kscience.kmath.expressions.Expression
 import space.kscience.kmath.expressions.MST
 import space.kscience.kmath.expressions.MST.*
+import space.kscience.kmath.expressions.Symbol
 import space.kscience.kmath.expressions.invoke
 import space.kscience.kmath.internal.estree.BaseExpression
-import space.kscience.kmath.misc.Symbol
 import space.kscience.kmath.operations.Algebra
 import space.kscience.kmath.operations.NumericAlgebra
+import space.kscience.kmath.operations.bindSymbolOrNull
 
 @PublishedApi
 internal fun <T> MST.compileWith(algebra: Algebra<T>): Expression<T> {
     fun ESTreeBuilder<T>.visit(node: MST): BaseExpression = when (node) {
-        is Symbolic -> {
+        is Symbol -> {
-            val symbol = algebra.bindSymbolOrNull(node.value)
+            val symbol = algebra.bindSymbolOrNull(node)
 
             if (symbol != null)
                 constant(symbol)
             else
-                variable(node.value)
+                variable(node.identity)
         }
 
         is Numeric -> constant(node.value)

kmath-ast/src/jsMain/kotlin/space/kscience/kmath/estree/internal/ESTreeBuilder.kt

@@ -6,14 +6,9 @@
 package space.kscience.kmath.estree.internal
 
 import space.kscience.kmath.expressions.Expression
+import space.kscience.kmath.expressions.Symbol
 import space.kscience.kmath.internal.astring.generate
 import space.kscience.kmath.internal.estree.*
-import space.kscience.kmath.internal.estree.BaseExpression
-import space.kscience.kmath.internal.estree.BlockStatement
-import space.kscience.kmath.internal.estree.Program
-import space.kscience.kmath.internal.estree.VariableDeclaration
-import space.kscience.kmath.internal.estree.VariableDeclarator
-import space.kscience.kmath.misc.Symbol
 
 internal class ESTreeBuilder<T>(val bodyCallback: ESTreeBuilder<T>.() -> BaseExpression) {
     private class GeneratedExpression<T>(val executable: dynamic, val constants: Array<dynamic>) : Expression<T> {

kmath-ast/src/jsMain/kotlin/space/kscience/kmath/wasm/internal/WasmBuilder.kt

@@ -8,9 +8,9 @@ package space.kscience.kmath.wasm.internal
 import space.kscience.kmath.expressions.Expression
 import space.kscience.kmath.expressions.MST
 import space.kscience.kmath.expressions.MST.*
+import space.kscience.kmath.expressions.Symbol
 import space.kscience.kmath.internal.binaryen.*
 import space.kscience.kmath.internal.webassembly.Instance
-import space.kscience.kmath.misc.StringSymbol
 import space.kscience.kmath.operations.*
 import space.kscience.kmath.internal.binaryen.Module as BinaryenModule
 import space.kscience.kmath.internal.webassembly.Module as WasmModule
@@ -23,20 +23,20 @@ internal sealed class WasmBuilder<T>(
     val algebra: Algebra<T>,
     val target: MST,
 ) where T : Number {
-    val keys: MutableList<String> = mutableListOf()
+    val keys: MutableList<Symbol> = mutableListOf()
     lateinit var ctx: BinaryenModule
 
-    open fun visitSymbolic(mst: Symbolic): ExpressionRef {
+    open fun visitSymbolic(mst: Symbol): ExpressionRef {
         try {
-            algebra.bindSymbol(mst.value)
+            algebra.bindSymbol(mst)
         } catch (ignored: Throwable) {
             null
         }?.let { return visitNumeric(Numeric(it)) }
 
-        var idx = keys.indexOf(mst.value)
+        var idx = keys.indexOf(mst)
 
         if (idx == -1) {
-            keys += mst.value
+            keys += mst
             idx = keys.lastIndex
         }
 
@@ -54,7 +54,7 @@ internal sealed class WasmBuilder<T>(
     open fun createModule(): BinaryenModule = js("new \$module\$binaryen.Module()")
 
     fun visit(mst: MST): ExpressionRef = when (mst) {
-        is Symbolic -> visitSymbolic(mst)
+        is Symbol -> visitSymbolic(mst)
         is Numeric -> visitNumeric(mst)
 
         is Unary -> when {
@@ -96,7 +96,7 @@ internal sealed class WasmBuilder<T>(
         })
 
         val i = Instance(c, js("{}") as Any)
-        val symbols = keys.map(::StringSymbol)
+        val symbols = keys
         keys.clear()
 
         Expression<T> { args ->

kmath-ast/src/jsMain/kotlin/space/kscience/kmath/wasm/wasm.kt

@@ -8,8 +8,8 @@ package space.kscience.kmath.wasm
 import space.kscience.kmath.estree.compileWith
 import space.kscience.kmath.expressions.Expression
 import space.kscience.kmath.expressions.MST
+import space.kscience.kmath.expressions.Symbol
 import space.kscience.kmath.expressions.invoke
-import space.kscience.kmath.misc.Symbol
 import space.kscience.kmath.misc.UnstableKMathAPI
 import space.kscience.kmath.operations.DoubleField
 import space.kscience.kmath.operations.IntRing

kmath-ast/src/jsTest/kotlin/space/kscience/kmath/ast/TestExecutionTime.kt

@@ -6,7 +6,6 @@
 package space.kscience.kmath.ast
 
 import space.kscience.kmath.expressions.*
-import space.kscience.kmath.misc.symbol
 import space.kscience.kmath.operations.DoubleField
 import space.kscience.kmath.operations.ExtendedField
 import space.kscience.kmath.operations.bindSymbol

kmath-ast/src/jsTest/kotlin/space/kscience/kmath/ast/utils.kt

@@ -7,7 +7,7 @@ package space.kscience.kmath.ast
 
 import space.kscience.kmath.expressions.Expression
 import space.kscience.kmath.expressions.MST
-import space.kscience.kmath.misc.Symbol
+import space.kscience.kmath.expressions.Symbol
 import space.kscience.kmath.operations.DoubleField
 import space.kscience.kmath.operations.IntRing
 import space.kscience.kmath.estree.compile as estreeCompile

kmath-ast/src/jsTest/kotlin/space/kscience/kmath/wasm/TestWasmSpecific.kt

@@ -8,7 +8,7 @@ package space.kscience.kmath.wasm
 import space.kscience.kmath.expressions.MstExtendedField
 import space.kscience.kmath.expressions.MstRing
 import space.kscience.kmath.expressions.invoke
-import space.kscience.kmath.misc.symbol
+import space.kscience.kmath.expressions.symbol
 import space.kscience.kmath.operations.DoubleField
 import space.kscience.kmath.operations.IntRing
 import space.kscience.kmath.operations.bindSymbol

kmath-ast/src/jvmMain/kotlin/space/kscience/kmath/asm/asm.kt

@@ -10,10 +10,11 @@ import space.kscience.kmath.asm.internal.buildName
 import space.kscience.kmath.expressions.Expression
 import space.kscience.kmath.expressions.MST
 import space.kscience.kmath.expressions.MST.*
+import space.kscience.kmath.expressions.Symbol
 import space.kscience.kmath.expressions.invoke
-import space.kscience.kmath.misc.Symbol
 import space.kscience.kmath.operations.Algebra
 import space.kscience.kmath.operations.NumericAlgebra
+import space.kscience.kmath.operations.bindSymbolOrNull
 
 /**
  * Compiles given MST to an Expression using AST compiler.
@@ -26,13 +27,13 @@ import space.kscience.kmath.operations.NumericAlgebra
 @PublishedApi
 internal fun <T : Any> MST.compileWith(type: Class<T>, algebra: Algebra<T>): Expression<T> {
     fun AsmBuilder<T>.visit(node: MST): Unit = when (node) {
-        is Symbolic -> {
+        is Symbol -> {
-            val symbol = algebra.bindSymbolOrNull(node.value)
+            val symbol = algebra.bindSymbolOrNull(node)
 
             if (symbol != null)
                 loadObjectConstant(symbol as Any)
             else
-                loadVariable(node.value)
+                loadVariable(node.identity)
         }
 
         is Numeric -> loadNumberConstant(node.value)

kmath-ast/src/jvmMain/kotlin/space/kscience/kmath/asm/internal/mapIntrinsics.kt

@@ -7,8 +7,8 @@
 
 package space.kscience.kmath.asm.internal
 
-import space.kscience.kmath.misc.StringSymbol
+import space.kscience.kmath.expressions.StringSymbol
-import space.kscience.kmath.misc.Symbol
+import space.kscience.kmath.expressions.Symbol
 
 /**
  * Gets value with given [key] or throws [NoSuchElementException] whenever it is not present.

kmath-ast/src/jvmTest/kotlin/space/kscience/kmath/ast/utils.kt

@@ -7,7 +7,7 @@ package space.kscience.kmath.ast
 
 import space.kscience.kmath.expressions.Expression
 import space.kscience.kmath.expressions.MST
-import space.kscience.kmath.misc.Symbol
+import space.kscience.kmath.expressions.Symbol
 import space.kscience.kmath.operations.DoubleField
 import space.kscience.kmath.operations.IntRing
 import space.kscience.kmath.asm.compile as asmCompile

kmath-commons/src/main/kotlin/space/kscience/kmath/commons/expressions/DerivativeStructureExpression.kt

@@ -7,7 +7,6 @@ package space.kscience.kmath.commons.expressions
 
 import org.apache.commons.math3.analysis.differentiation.DerivativeStructure
 import space.kscience.kmath.expressions.*
-import space.kscience.kmath.misc.Symbol
 import space.kscience.kmath.misc.UnstableKMathAPI
 import space.kscience.kmath.operations.ExtendedField
 import space.kscience.kmath.operations.NumbersAddOperations

kmath-commons/src/main/kotlin/space/kscience/kmath/commons/optimization/CMOptimization.kt

@@ -14,13 +14,17 @@ import org.apache.commons.math3.optim.nonlinear.scalar.gradient.NonLinearConjuga
 import org.apache.commons.math3.optim.nonlinear.scalar.noderiv.AbstractSimplex
 import org.apache.commons.math3.optim.nonlinear.scalar.noderiv.NelderMeadSimplex
 import org.apache.commons.math3.optim.nonlinear.scalar.noderiv.SimplexOptimizer
-import space.kscience.kmath.expressions.DifferentiableExpression
+import space.kscience.kmath.expressions.*
-import space.kscience.kmath.expressions.Expression
-import space.kscience.kmath.expressions.SymbolIndexer
-import space.kscience.kmath.expressions.derivative
-import space.kscience.kmath.misc.Symbol
 import space.kscience.kmath.misc.UnstableKMathAPI
 import space.kscience.kmath.optimization.*
+import kotlin.collections.HashMap
+import kotlin.collections.List
+import kotlin.collections.Map
+import kotlin.collections.set
+import kotlin.collections.setOf
+import kotlin.collections.toList
+import kotlin.collections.toMap
+import kotlin.collections.toTypedArray
 import kotlin.reflect.KClass
 
 public operator fun PointValuePair.component1(): DoubleArray = point

kmath-commons/src/main/kotlin/space/kscience/kmath/commons/optimization/cmFit.kt

@@ -9,7 +9,7 @@ import org.apache.commons.math3.analysis.differentiation.DerivativeStructure
 import space.kscience.kmath.commons.expressions.DerivativeStructureField
 import space.kscience.kmath.expressions.DifferentiableExpression
 import space.kscience.kmath.expressions.Expression
-import space.kscience.kmath.misc.Symbol
+import space.kscience.kmath.expressions.Symbol
 import space.kscience.kmath.optimization.FunctionOptimization
 import space.kscience.kmath.optimization.OptimizationResult
 import space.kscience.kmath.optimization.noDerivOptimizeWith

kmath-commons/src/test/kotlin/space/kscience/kmath/commons/expressions/DerivativeStructureExpressionTest.kt

@@ -5,11 +5,7 @@
 
 package space.kscience.kmath.commons.expressions
 
-import space.kscience.kmath.expressions.binding
+import space.kscience.kmath.expressions.*
-import space.kscience.kmath.expressions.derivative
-import space.kscience.kmath.expressions.invoke
-import space.kscience.kmath.misc.Symbol
-import space.kscience.kmath.misc.symbol
 import kotlin.contracts.InvocationKind
 import kotlin.contracts.contract
 import kotlin.test.Test

kmath-commons/src/test/kotlin/space/kscience/kmath/commons/optimization/OptimizeTest.kt

@@ -8,7 +8,7 @@ package space.kscience.kmath.commons.optimization
 import kotlinx.coroutines.runBlocking
 import space.kscience.kmath.commons.expressions.DerivativeStructureExpression
 import space.kscience.kmath.distributions.NormalDistribution
-import space.kscience.kmath.misc.symbol
+import space.kscience.kmath.expressions.symbol
 import space.kscience.kmath.optimization.FunctionOptimization
 import space.kscience.kmath.stat.RandomGenerator
 import kotlin.math.pow

kmath-complex/src/commonTest/kotlin/space/kscience/kmath/complex/ExpressionFieldForComplexTest.kt

@@ -7,7 +7,7 @@ package space.kscience.kmath.complex
 
 import space.kscience.kmath.expressions.FunctionalExpressionField
 import space.kscience.kmath.expressions.invoke
-import space.kscience.kmath.misc.symbol
+import space.kscience.kmath.expressions.symbol
 import space.kscience.kmath.operations.bindSymbol
 import kotlin.test.Test
 import kotlin.test.assertEquals

kmath-core/api/kmath-core.api

@@ -21,7 +21,7 @@ public class space/kscience/kmath/expressions/AutoDiffValue {
 
 public final class space/kscience/kmath/expressions/DerivationResult {
 	public fun <init> (Ljava/lang/Object;Ljava/util/Map;Lspace/kscience/kmath/operations/Field;)V
-	public final fun derivative (Lspace/kscience/kmath/misc/Symbol;)Ljava/lang/Object;
+	public final fun derivative (Lspace/kscience/kmath/expressions/Symbol;)Ljava/lang/Object;
 	public final fun div ()Ljava/lang/Object;
 	public final fun getContext ()Lspace/kscience/kmath/operations/Field;
 	public final fun getValue ()Ljava/lang/Object;
@@ -34,7 +34,7 @@ public abstract interface class space/kscience/kmath/expressions/DifferentiableE
 public final class space/kscience/kmath/expressions/DifferentiableExpressionKt {
 	public static final fun derivative (Lspace/kscience/kmath/expressions/DifferentiableExpression;Ljava/lang/String;)Lspace/kscience/kmath/expressions/Expression;
 	public static final fun derivative (Lspace/kscience/kmath/expressions/DifferentiableExpression;Ljava/util/List;)Lspace/kscience/kmath/expressions/Expression;
-	public static final fun derivative (Lspace/kscience/kmath/expressions/DifferentiableExpression;[Lspace/kscience/kmath/misc/Symbol;)Lspace/kscience/kmath/expressions/Expression;
+	public static final fun derivative (Lspace/kscience/kmath/expressions/DifferentiableExpression;[Lspace/kscience/kmath/expressions/Symbol;)Lspace/kscience/kmath/expressions/Expression;
 }
 
 public abstract interface class space/kscience/kmath/expressions/Expression {
@@ -55,7 +55,7 @@ public final class space/kscience/kmath/expressions/ExpressionKt {
 public abstract class space/kscience/kmath/expressions/FirstDerivativeExpression : space/kscience/kmath/expressions/DifferentiableExpression {
 	public fun <init> ()V
 	public final fun derivativeOrNull (Ljava/util/List;)Lspace/kscience/kmath/expressions/Expression;
-	public abstract fun derivativeOrNull (Lspace/kscience/kmath/misc/Symbol;)Lspace/kscience/kmath/expressions/Expression;
+	public abstract fun derivativeOrNull (Lspace/kscience/kmath/expressions/Symbol;)Lspace/kscience/kmath/expressions/Expression;
 }
 
 public abstract class space/kscience/kmath/expressions/FunctionalExpressionAlgebra : space/kscience/kmath/expressions/ExpressionAlgebra {
@@ -146,7 +146,7 @@ public class space/kscience/kmath/expressions/FunctionalExpressionRing : space/k
 	public fun unaryOperationFunction (Ljava/lang/String;)Lkotlin/jvm/functions/Function1;
 }
 
-public abstract class space/kscience/kmath/expressions/MST {
+public abstract interface class space/kscience/kmath/expressions/MST {
 }
 
 public final class space/kscience/kmath/expressions/MST$Binary : space/kscience/kmath/expressions/MST {
@@ -175,17 +175,6 @@ public final class space/kscience/kmath/expressions/MST$Numeric : space/kscience
 	public fun toString ()Ljava/lang/String;
 }
 
-public final class space/kscience/kmath/expressions/MST$Symbolic : space/kscience/kmath/expressions/MST {
-	public fun <init> (Ljava/lang/String;)V
-	public final fun component1 ()Ljava/lang/String;
-	public final fun copy (Ljava/lang/String;)Lspace/kscience/kmath/expressions/MST$Symbolic;
-	public static synthetic fun copy$default (Lspace/kscience/kmath/expressions/MST$Symbolic;Ljava/lang/String;ILjava/lang/Object;)Lspace/kscience/kmath/expressions/MST$Symbolic;
-	public fun equals (Ljava/lang/Object;)Z
-	public final fun getValue ()Ljava/lang/String;
-	public fun hashCode ()I
-	public fun toString ()Ljava/lang/String;
-}
-
 public final class space/kscience/kmath/expressions/MST$Unary : space/kscience/kmath/expressions/MST {
 	public fun <init> (Ljava/lang/String;Lspace/kscience/kmath/expressions/MST;)V
 	public final fun component1 ()Ljava/lang/String;
@@ -206,18 +195,6 @@ public final class space/kscience/kmath/expressions/MSTKt {
 	public static final fun toExpression (Lspace/kscience/kmath/expressions/MST;Lspace/kscience/kmath/operations/Algebra;)Lspace/kscience/kmath/expressions/Expression;
 }
 
-public final class space/kscience/kmath/expressions/MstAlgebra : space/kscience/kmath/operations/NumericAlgebra {
-	public static final field INSTANCE Lspace/kscience/kmath/expressions/MstAlgebra;
-	public fun binaryOperationFunction (Ljava/lang/String;)Lkotlin/jvm/functions/Function2;
-	public synthetic fun bindSymbol (Ljava/lang/String;)Ljava/lang/Object;
-	public fun bindSymbol (Ljava/lang/String;)Lspace/kscience/kmath/expressions/MST$Symbolic;
-	public synthetic fun bindSymbolOrNull (Ljava/lang/String;)Ljava/lang/Object;
-	public fun bindSymbolOrNull (Ljava/lang/String;)Lspace/kscience/kmath/expressions/MST$Symbolic;
-	public synthetic fun number (Ljava/lang/Number;)Ljava/lang/Object;
-	public fun number (Ljava/lang/Number;)Lspace/kscience/kmath/expressions/MST$Numeric;
-	public fun unaryOperationFunction (Ljava/lang/String;)Lkotlin/jvm/functions/Function1;
-}
-
 public final class space/kscience/kmath/expressions/MstExtendedField : space/kscience/kmath/operations/ExtendedField, space/kscience/kmath/operations/NumericAlgebra {
 	public static final field INSTANCE Lspace/kscience/kmath/expressions/MstExtendedField;
 	public synthetic fun acos (Ljava/lang/Object;)Ljava/lang/Object;
@@ -236,7 +213,7 @@ public final class space/kscience/kmath/expressions/MstExtendedField : space/ksc
 	public fun atanh (Lspace/kscience/kmath/expressions/MST;)Lspace/kscience/kmath/expressions/MST$Unary;
 	public fun binaryOperationFunction (Ljava/lang/String;)Lkotlin/jvm/functions/Function2;
 	public synthetic fun bindSymbolOrNull (Ljava/lang/String;)Ljava/lang/Object;
-	public fun bindSymbolOrNull (Ljava/lang/String;)Lspace/kscience/kmath/expressions/MST$Symbolic;
+	public fun bindSymbolOrNull (Ljava/lang/String;)Lspace/kscience/kmath/expressions/Symbol;
 	public synthetic fun cos (Ljava/lang/Object;)Ljava/lang/Object;
 	public fun cos (Lspace/kscience/kmath/expressions/MST;)Lspace/kscience/kmath/expressions/MST$Unary;
 	public synthetic fun cosh (Ljava/lang/Object;)Ljava/lang/Object;
@@ -284,7 +261,7 @@ public final class space/kscience/kmath/expressions/MstField : space/kscience/km
 	public fun add (Lspace/kscience/kmath/expressions/MST;Lspace/kscience/kmath/expressions/MST;)Lspace/kscience/kmath/expressions/MST$Binary;
 	public fun binaryOperationFunction (Ljava/lang/String;)Lkotlin/jvm/functions/Function2;
 	public synthetic fun bindSymbolOrNull (Ljava/lang/String;)Ljava/lang/Object;
-	public fun bindSymbolOrNull (Ljava/lang/String;)Lspace/kscience/kmath/expressions/MST$Symbolic;
+	public fun bindSymbolOrNull (Ljava/lang/String;)Lspace/kscience/kmath/expressions/Symbol;
 	public synthetic fun divide (Ljava/lang/Object;Ljava/lang/Object;)Ljava/lang/Object;
 	public fun divide (Lspace/kscience/kmath/expressions/MST;Lspace/kscience/kmath/expressions/MST;)Lspace/kscience/kmath/expressions/MST$Binary;
 	public synthetic fun getOne ()Ljava/lang/Object;
@@ -312,7 +289,7 @@ public final class space/kscience/kmath/expressions/MstGroup : space/kscience/km
 	public fun add (Lspace/kscience/kmath/expressions/MST;Lspace/kscience/kmath/expressions/MST;)Lspace/kscience/kmath/expressions/MST$Binary;
 	public fun binaryOperationFunction (Ljava/lang/String;)Lkotlin/jvm/functions/Function2;
 	public synthetic fun bindSymbolOrNull (Ljava/lang/String;)Ljava/lang/Object;
-	public fun bindSymbolOrNull (Ljava/lang/String;)Lspace/kscience/kmath/expressions/MST$Symbolic;
+	public fun bindSymbolOrNull (Ljava/lang/String;)Lspace/kscience/kmath/expressions/Symbol;
 	public synthetic fun getZero ()Ljava/lang/Object;
 	public fun getZero ()Lspace/kscience/kmath/expressions/MST$Numeric;
 	public synthetic fun minus (Ljava/lang/Object;Ljava/lang/Object;)Ljava/lang/Object;
@@ -328,13 +305,25 @@ public final class space/kscience/kmath/expressions/MstGroup : space/kscience/km
 	public fun unaryPlus (Lspace/kscience/kmath/expressions/MST;)Lspace/kscience/kmath/expressions/MST$Unary;
 }
 
+public final class space/kscience/kmath/expressions/MstNumericAlgebra : space/kscience/kmath/operations/NumericAlgebra {
+	public static final field INSTANCE Lspace/kscience/kmath/expressions/MstNumericAlgebra;
+	public fun binaryOperationFunction (Ljava/lang/String;)Lkotlin/jvm/functions/Function2;
+	public synthetic fun bindSymbol (Ljava/lang/String;)Ljava/lang/Object;
+	public fun bindSymbol (Ljava/lang/String;)Lspace/kscience/kmath/expressions/Symbol;
+	public synthetic fun bindSymbolOrNull (Ljava/lang/String;)Ljava/lang/Object;
+	public fun bindSymbolOrNull (Ljava/lang/String;)Lspace/kscience/kmath/expressions/Symbol;
+	public synthetic fun number (Ljava/lang/Number;)Ljava/lang/Object;
+	public fun number (Ljava/lang/Number;)Lspace/kscience/kmath/expressions/MST$Numeric;
+	public fun unaryOperationFunction (Ljava/lang/String;)Lkotlin/jvm/functions/Function1;
+}
+
 public final class space/kscience/kmath/expressions/MstRing : space/kscience/kmath/operations/NumbersAddOperations, space/kscience/kmath/operations/Ring, space/kscience/kmath/operations/ScaleOperations {
 	public static final field INSTANCE Lspace/kscience/kmath/expressions/MstRing;
 	public synthetic fun add (Ljava/lang/Object;Ljava/lang/Object;)Ljava/lang/Object;
 	public fun add (Lspace/kscience/kmath/expressions/MST;Lspace/kscience/kmath/expressions/MST;)Lspace/kscience/kmath/expressions/MST$Binary;
 	public fun binaryOperationFunction (Ljava/lang/String;)Lkotlin/jvm/functions/Function2;
 	public synthetic fun bindSymbolOrNull (Ljava/lang/String;)Ljava/lang/Object;
-	public fun bindSymbolOrNull (Ljava/lang/String;)Lspace/kscience/kmath/expressions/MST$Symbolic;
+	public fun bindSymbolOrNull (Ljava/lang/String;)Lspace/kscience/kmath/expressions/Symbol;
 	public synthetic fun getOne ()Ljava/lang/Object;
 	public fun getOne ()Lspace/kscience/kmath/expressions/MST$Numeric;
 	public synthetic fun getZero ()Ljava/lang/Object;
@@ -356,7 +345,7 @@ public final class space/kscience/kmath/expressions/MstRing : space/kscience/kma
 
 public final class space/kscience/kmath/expressions/SimpleAutoDiffExpression : space/kscience/kmath/expressions/FirstDerivativeExpression {
 	public fun <init> (Lspace/kscience/kmath/operations/Field;Lkotlin/jvm/functions/Function1;)V
-	public fun derivativeOrNull (Lspace/kscience/kmath/misc/Symbol;)Lspace/kscience/kmath/expressions/Expression;
+	public fun derivativeOrNull (Lspace/kscience/kmath/expressions/Symbol;)Lspace/kscience/kmath/expressions/Expression;
 	public final fun getField ()Lspace/kscience/kmath/operations/Field;
 	public final fun getFunction ()Lkotlin/jvm/functions/Function1;
 	public fun invoke (Ljava/util/Map;)Ljava/lang/Object;
@@ -445,7 +434,7 @@ public final class space/kscience/kmath/expressions/SimpleAutoDiffKt {
 	public static final fun cos (Lspace/kscience/kmath/expressions/SimpleAutoDiffField;Lspace/kscience/kmath/expressions/AutoDiffValue;)Lspace/kscience/kmath/expressions/AutoDiffValue;
 	public static final fun cosh (Lspace/kscience/kmath/expressions/SimpleAutoDiffField;Lspace/kscience/kmath/expressions/AutoDiffValue;)Lspace/kscience/kmath/expressions/AutoDiffValue;
 	public static final fun exp (Lspace/kscience/kmath/expressions/SimpleAutoDiffField;Lspace/kscience/kmath/expressions/AutoDiffValue;)Lspace/kscience/kmath/expressions/AutoDiffValue;
-	public static final fun grad (Lspace/kscience/kmath/expressions/DerivationResult;[Lspace/kscience/kmath/misc/Symbol;)Lspace/kscience/kmath/structures/Buffer;
+	public static final fun grad (Lspace/kscience/kmath/expressions/DerivationResult;[Lspace/kscience/kmath/expressions/Symbol;)Lspace/kscience/kmath/structures/Buffer;
 	public static final fun ln (Lspace/kscience/kmath/expressions/SimpleAutoDiffField;Lspace/kscience/kmath/expressions/AutoDiffValue;)Lspace/kscience/kmath/expressions/AutoDiffValue;
 	public static final fun pow (Lspace/kscience/kmath/expressions/SimpleAutoDiffField;Lspace/kscience/kmath/expressions/AutoDiffValue;D)Lspace/kscience/kmath/expressions/AutoDiffValue;
 	public static final fun pow (Lspace/kscience/kmath/expressions/SimpleAutoDiffField;Lspace/kscience/kmath/expressions/AutoDiffValue;I)Lspace/kscience/kmath/expressions/AutoDiffValue;
@@ -461,9 +450,42 @@ public final class space/kscience/kmath/expressions/SimpleAutoDiffKt {
 	public static final fun tanh (Lspace/kscience/kmath/expressions/SimpleAutoDiffField;Lspace/kscience/kmath/expressions/AutoDiffValue;)Lspace/kscience/kmath/expressions/AutoDiffValue;
 }
 
+public final class space/kscience/kmath/expressions/StringSymbol : space/kscience/kmath/expressions/Symbol {
+	public static final synthetic fun box-impl (Ljava/lang/String;)Lspace/kscience/kmath/expressions/StringSymbol;
+	public static fun constructor-impl (Ljava/lang/String;)Ljava/lang/String;
+	public fun equals (Ljava/lang/Object;)Z
+	public static fun equals-impl (Ljava/lang/String;Ljava/lang/Object;)Z
+	public static final fun equals-impl0 (Ljava/lang/String;Ljava/lang/String;)Z
+	public fun getIdentity ()Ljava/lang/String;
+	public fun hashCode ()I
+	public static fun hashCode-impl (Ljava/lang/String;)I
+	public fun toString ()Ljava/lang/String;
+	public static fun toString-impl (Ljava/lang/String;)Ljava/lang/String;
+	public final synthetic fun unbox-impl ()Ljava/lang/String;
+}
+
+public abstract interface class space/kscience/kmath/expressions/Symbol : space/kscience/kmath/expressions/MST {
+	public static final field Companion Lspace/kscience/kmath/expressions/Symbol$Companion;
+	public abstract fun getIdentity ()Ljava/lang/String;
+}
+
+public final class space/kscience/kmath/expressions/Symbol$Companion {
+	public final fun getX-uKgCeAI ()Ljava/lang/String;
+	public final fun getY-uKgCeAI ()Ljava/lang/String;
+	public final fun getZ-uKgCeAI ()Ljava/lang/String;
+}
+
 public final class space/kscience/kmath/expressions/SymbolIndexerKt {
 }
 
+public final class space/kscience/kmath/expressions/SymbolKt {
+	public static final fun get (Ljava/util/Map;Ljava/lang/String;)Ljava/lang/Object;
+	public static final fun get (Ljava/util/Map;Lspace/kscience/kmath/expressions/Symbol;)Ljava/lang/Object;
+	public static final fun getSymbol ()Lkotlin/properties/ReadOnlyProperty;
+	public static final fun set (Ljava/util/Map;Ljava/lang/String;Ljava/lang/Object;)V
+	public static final fun set (Ljava/util/Map;Lspace/kscience/kmath/expressions/Symbol;Ljava/lang/Object;)V
+}
+
 public final class space/kscience/kmath/linear/BufferedLinearSpace : space/kscience/kmath/linear/LinearSpace {
 	public fun <init> (Lspace/kscience/kmath/operations/Ring;Lkotlin/jvm/functions/Function2;)V
 	public fun buildMatrix (IILkotlin/jvm/functions/Function3;)Lspace/kscience/kmath/nd/Structure2D;
@@ -677,39 +699,6 @@ public final class space/kscience/kmath/misc/CumulativeKt {
 public abstract interface annotation class space/kscience/kmath/misc/PerformancePitfall : java/lang/annotation/Annotation {
 }
 
-public final class space/kscience/kmath/misc/StringSymbol : space/kscience/kmath/misc/Symbol {
-	public static final synthetic fun box-impl (Ljava/lang/String;)Lspace/kscience/kmath/misc/StringSymbol;
-	public static fun constructor-impl (Ljava/lang/String;)Ljava/lang/String;
-	public fun equals (Ljava/lang/Object;)Z
-	public static fun equals-impl (Ljava/lang/String;Ljava/lang/Object;)Z
-	public static final fun equals-impl0 (Ljava/lang/String;Ljava/lang/String;)Z
-	public fun getIdentity ()Ljava/lang/String;
-	public fun hashCode ()I
-	public static fun hashCode-impl (Ljava/lang/String;)I
-	public fun toString ()Ljava/lang/String;
-	public static fun toString-impl (Ljava/lang/String;)Ljava/lang/String;
-	public final synthetic fun unbox-impl ()Ljava/lang/String;
-}
-
-public abstract interface class space/kscience/kmath/misc/Symbol {
-	public static final field Companion Lspace/kscience/kmath/misc/Symbol$Companion;
-	public abstract fun getIdentity ()Ljava/lang/String;
-}
-
-public final class space/kscience/kmath/misc/Symbol$Companion {
-	public final fun getX-tWtZOCg ()Ljava/lang/String;
-	public final fun getY-tWtZOCg ()Ljava/lang/String;
-	public final fun getZ-tWtZOCg ()Ljava/lang/String;
-}
-
-public final class space/kscience/kmath/misc/SymbolKt {
-	public static final fun get (Ljava/util/Map;Ljava/lang/String;)Ljava/lang/Object;
-	public static final fun get (Ljava/util/Map;Lspace/kscience/kmath/misc/Symbol;)Ljava/lang/Object;
-	public static final fun getSymbol ()Lkotlin/properties/ReadOnlyProperty;
-	public static final fun set (Ljava/util/Map;Ljava/lang/String;Ljava/lang/Object;)V
-	public static final fun set (Ljava/util/Map;Lspace/kscience/kmath/misc/Symbol;Ljava/lang/Object;)V
-}
-
 public abstract interface annotation class space/kscience/kmath/misc/UnstableKMathAPI : java/lang/annotation/Annotation {
 }
 
@@ -1028,8 +1017,8 @@ public final class space/kscience/kmath/operations/AlgebraExtensionsKt {
 }
 
 public final class space/kscience/kmath/operations/AlgebraKt {
-	public static final fun bindSymbol (Lspace/kscience/kmath/operations/Algebra;Lspace/kscience/kmath/misc/Symbol;)Ljava/lang/Object;
+	public static final fun bindSymbol (Lspace/kscience/kmath/operations/Algebra;Lspace/kscience/kmath/expressions/Symbol;)Ljava/lang/Object;
-	public static final fun bindSymbolOrNull (Lspace/kscience/kmath/operations/Algebra;Lspace/kscience/kmath/misc/Symbol;)Ljava/lang/Object;
+	public static final fun bindSymbolOrNull (Lspace/kscience/kmath/operations/Algebra;Lspace/kscience/kmath/expressions/Symbol;)Ljava/lang/Object;
 	public static final fun invoke (Lspace/kscience/kmath/operations/Algebra;Lkotlin/jvm/functions/Function1;)Ljava/lang/Object;
 }
 
@@ -1414,6 +1403,11 @@ public final class space/kscience/kmath/operations/JBigIntegerField : space/ksci
 public abstract interface annotation class space/kscience/kmath/operations/KMathContext : java/lang/annotation/Annotation {
 }
 
+public final class space/kscience/kmath/operations/LogicAlgebra$Companion {
+	public final fun getFALSE ()Lspace/kscience/kmath/expressions/Symbol;
+	public final fun getTRUE ()Lspace/kscience/kmath/expressions/Symbol;
+}
+
 public final class space/kscience/kmath/operations/LongRing : space/kscience/kmath/operations/Norm, space/kscience/kmath/operations/NumericAlgebra, space/kscience/kmath/operations/Ring {
 	public static final field INSTANCE Lspace/kscience/kmath/operations/LongRing;
 	public fun add (JJ)Ljava/lang/Long;

kmath-core/src/commonMain/kotlin/space/kscience/kmath/data/ColumnarData.kt

@@ -5,8 +5,8 @@
 
 package space.kscience.kmath.data
 
+import space.kscience.kmath.expressions.Symbol
 import space.kscience.kmath.misc.PerformancePitfall
-import space.kscience.kmath.misc.Symbol
 import space.kscience.kmath.misc.UnstableKMathAPI
 import space.kscience.kmath.nd.Structure2D
 import space.kscience.kmath.structures.Buffer

kmath-core/src/commonMain/kotlin/space/kscience/kmath/data/XYColumnarData.kt

@@ -5,8 +5,8 @@
 
 package space.kscience.kmath.data
 
+import space.kscience.kmath.expressions.Symbol
 import space.kscience.kmath.misc.PerformancePitfall
-import space.kscience.kmath.misc.Symbol
 import space.kscience.kmath.misc.UnstableKMathAPI
 import space.kscience.kmath.nd.Structure2D
 import space.kscience.kmath.structures.Buffer

kmath-core/src/commonMain/kotlin/space/kscience/kmath/data/XYZColumnarData.kt

@@ -5,7 +5,7 @@
 
 package space.kscience.kmath.data
 
-import space.kscience.kmath.misc.Symbol
+import space.kscience.kmath.expressions.Symbol
 import space.kscience.kmath.misc.UnstableKMathAPI
 import space.kscience.kmath.structures.Buffer
 

kmath-core/src/commonMain/kotlin/space/kscience/kmath/expressions/DifferentiableExpression.kt

@@ -5,9 +5,6 @@
 
 package space.kscience.kmath.expressions
 
-import space.kscience.kmath.misc.StringSymbol
-import space.kscience.kmath.misc.Symbol
-
 /**
  * Represents expression which structure can be differentiated.
  *

kmath-core/src/commonMain/kotlin/space/kscience/kmath/expressions/Expression.kt

@@ -5,8 +5,6 @@
 
 package space.kscience.kmath.expressions
 
-import space.kscience.kmath.misc.StringSymbol
-import space.kscience.kmath.misc.Symbol
 import space.kscience.kmath.operations.Algebra
 import kotlin.jvm.JvmName
 import kotlin.properties.ReadOnlyProperty

kmath-core/src/commonMain/kotlin/space/kscience/kmath/expressions/FunctionalExpressionAlgebra.kt

@@ -5,7 +5,6 @@
 
 package space.kscience.kmath.expressions
 
-import space.kscience.kmath.misc.StringSymbol
 import space.kscience.kmath.operations.*
 
 /**

kmath-core/src/commonMain/kotlin/space/kscience/kmath/expressions/MST.kt

@@ -5,30 +5,23 @@
 
 package space.kscience.kmath.expressions
 
-import space.kscience.kmath.misc.StringSymbol
-import space.kscience.kmath.misc.Symbol
 import space.kscience.kmath.operations.Algebra
 import space.kscience.kmath.operations.NumericAlgebra
+import space.kscience.kmath.operations.bindSymbol
 
 /**
  * A Mathematical Syntax Tree (MST) node for mathematical expressions.
  *
  * @author Alexander Nozik
  */
-public sealed class MST {
+public sealed interface MST {
-    /**
-     * A node containing raw string.
-     *
-     * @property value the value of this node.
-     */
-    public data class Symbolic(val value: String) : MST()
 
     /**
      * A node containing a numeric value or scalar.
      *
      * @property value the value of this number.
      */
-    public data class Numeric(val value: Number) : MST()
+    public data class Numeric(val value: Number) : MST
 
     /**
      * A node containing an unary operation.
@@ -36,7 +29,7 @@ public sealed class MST {
      * @property operation the identifier of operation.
      * @property value the argument of this operation.
      */
-    public data class Unary(val operation: String, val value: MST) : MST()
+    public data class Unary(val operation: String, val value: MST) : MST
 
     /**
      * A node containing binary operation.
@@ -45,7 +38,7 @@ public sealed class MST {
      * @property left the left operand.
      * @property right the right operand.
      */
-    public data class Binary(val operation: String, val left: MST, val right: MST) : MST()
+    public data class Binary(val operation: String, val left: MST, val right: MST) : MST
 }
 
 // TODO add a function with named arguments
@@ -62,7 +55,7 @@ public fun <T> Algebra<T>.evaluate(node: MST): T = when (node) {
     is MST.Numeric -> (this as? NumericAlgebra<T>)?.number(node.value)
         ?: error("Numeric nodes are not supported by $this")
 
-    is MST.Symbolic -> bindSymbol(node.value)
+    is Symbol -> bindSymbol(node)
 
     is MST.Unary -> when {
         this is NumericAlgebra && node.value is MST.Numeric -> unaryOperationFunction(node.operation)(number(node.value.value))

kmath-core/src/commonMain/kotlin/space/kscience/kmath/expressions/MstAlgebra.kt

@@ -11,10 +11,10 @@ import space.kscience.kmath.operations.*
 /**
  * [Algebra] over [MST] nodes.
  */
-public object MstAlgebra : NumericAlgebra<MST> {
+public object MstNumericAlgebra : NumericAlgebra<MST> {
     public override fun number(value: Number): MST.Numeric = MST.Numeric(value)
-    public override fun bindSymbolOrNull(value: String): MST.Symbolic = MST.Symbolic(value)
+    public override fun bindSymbolOrNull(value: String): Symbol = StringSymbol(value)
-    override fun bindSymbol(value: String): MST.Symbolic = bindSymbolOrNull(value)
+    override fun bindSymbol(value: String): Symbol = bindSymbolOrNull(value)
 
     public override fun unaryOperationFunction(operation: String): (arg: MST) -> MST.Unary =
         { arg -> MST.Unary(operation, arg) }
@@ -29,8 +29,8 @@ public object MstAlgebra : NumericAlgebra<MST> {
 public object MstGroup : Group<MST>, NumericAlgebra<MST>, ScaleOperations<MST> {
     public override val zero: MST.Numeric = number(0.0)
 
-    public override fun number(value: Number): MST.Numeric = MstAlgebra.number(value)
+    public override fun number(value: Number): MST.Numeric = MstNumericAlgebra.number(value)
-    public override fun bindSymbolOrNull(value: String): MST.Symbolic = MstAlgebra.bindSymbolOrNull(value)
+    public override fun bindSymbolOrNull(value: String): Symbol = MstNumericAlgebra.bindSymbolOrNull(value)
     public override fun add(a: MST, b: MST): MST.Binary = binaryOperationFunction(GroupOperations.PLUS_OPERATION)(a, b)
     public override operator fun MST.unaryPlus(): MST.Unary =
         unaryOperationFunction(GroupOperations.PLUS_OPERATION)(this)
@@ -45,10 +45,10 @@ public object MstGroup : Group<MST>, NumericAlgebra<MST>, ScaleOperations<MST> {
         binaryOperationFunction(RingOperations.TIMES_OPERATION)(a, number(value))
 
     public override fun binaryOperationFunction(operation: String): (left: MST, right: MST) -> MST.Binary =
-        MstAlgebra.binaryOperationFunction(operation)
+        MstNumericAlgebra.binaryOperationFunction(operation)
 
     public override fun unaryOperationFunction(operation: String): (arg: MST) -> MST.Unary =
-        MstAlgebra.unaryOperationFunction(operation)
+        MstNumericAlgebra.unaryOperationFunction(operation)
 }
 
 /**
@@ -61,7 +61,7 @@ public object MstRing : Ring<MST>, NumbersAddOperations<MST>, ScaleOperations<MS
     public override val one: MST.Numeric = number(1.0)
 
     public override fun number(value: Number): MST.Numeric = MstGroup.number(value)
-    public override fun bindSymbolOrNull(value: String): MST.Symbolic = MstAlgebra.bindSymbolOrNull(value)
+    public override fun bindSymbolOrNull(value: String): Symbol = MstNumericAlgebra.bindSymbolOrNull(value)
     public override fun add(a: MST, b: MST): MST.Binary = MstGroup.add(a, b)
 
     public override fun scale(a: MST, value: Double): MST.Binary =
@@ -78,7 +78,7 @@ public object MstRing : Ring<MST>, NumbersAddOperations<MST>, ScaleOperations<MS
         MstGroup.binaryOperationFunction(operation)
 
     public override fun unaryOperationFunction(operation: String): (arg: MST) -> MST.Unary =
-        MstAlgebra.unaryOperationFunction(operation)
+        MstNumericAlgebra.unaryOperationFunction(operation)
 }
 
 /**
@@ -90,7 +90,7 @@ public object MstField : Field<MST>, NumbersAddOperations<MST>, ScaleOperations<
     public override inline val zero: MST.Numeric get() = MstRing.zero
     public override inline val one: MST.Numeric get() = MstRing.one
 
-    public override fun bindSymbolOrNull(value: String): MST.Symbolic = MstAlgebra.bindSymbolOrNull(value)
+    public override fun bindSymbolOrNull(value: String): Symbol = MstNumericAlgebra.bindSymbolOrNull(value)
     public override fun number(value: Number): MST.Numeric = MstRing.number(value)
     public override fun add(a: MST, b: MST): MST.Binary = MstRing.add(a, b)
 
@@ -120,7 +120,7 @@ public object MstExtendedField : ExtendedField<MST>, NumericAlgebra<MST> {
     public override inline val zero: MST.Numeric get() = MstField.zero
     public override inline val one: MST.Numeric get() = MstField.one
 
-    public override fun bindSymbolOrNull(value: String): MST.Symbolic = MstAlgebra.bindSymbolOrNull(value)
+    public override fun bindSymbolOrNull(value: String): Symbol = MstNumericAlgebra.bindSymbolOrNull(value)
     public override fun number(value: Number): MST.Numeric = MstRing.number(value)
     public override fun sin(arg: MST): MST.Unary = unaryOperationFunction(TrigonometricOperations.SIN_OPERATION)(arg)
     public override fun cos(arg: MST): MST.Unary = unaryOperationFunction(TrigonometricOperations.COS_OPERATION)(arg)
@@ -158,3 +158,23 @@ public object MstExtendedField : ExtendedField<MST>, NumericAlgebra<MST> {
     public override fun unaryOperationFunction(operation: String): (arg: MST) -> MST.Unary =
         MstField.unaryOperationFunction(operation)
 }
+
+/**
+ * Logic algebra for [MST]
+ */
+@UnstableKMathAPI
+public object MstLogicAlgebra : LogicAlgebra<MST> {
+    public override fun bindSymbolOrNull(value: String): MST = super.bindSymbolOrNull(value) ?: StringSymbol(value)
+
+    override fun const(boolean: Boolean): Symbol = if (boolean) {
+        LogicAlgebra.TRUE
+    } else {
+        LogicAlgebra.FALSE
+    }
+
+    override fun MST.not(): MST = MST.Unary(Boolean::not.name, this)
+
+    override fun MST.and(other: MST): MST = MST.Binary(Boolean::and.name, this, other)
+
+    override fun MST.or(other: MST): MST  = MST.Binary(Boolean::or.name, this, other)
+}

kmath-core/src/commonMain/kotlin/space/kscience/kmath/expressions/SimpleAutoDiff.kt

@@ -6,7 +6,6 @@
 package space.kscience.kmath.expressions
 
 import space.kscience.kmath.linear.Point
-import space.kscience.kmath.misc.Symbol
 import space.kscience.kmath.misc.UnstableKMathAPI
 import space.kscience.kmath.operations.*
 import space.kscience.kmath.structures.asBuffer

kmath-core/src/commonMain/kotlin/space/kscience/kmath/expressions/Symbol.kt

@@ -3,15 +3,16 @@
  * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
  */
 
-package space.kscience.kmath.misc
+package space.kscience.kmath.expressions
 
 import kotlin.jvm.JvmInline
 import kotlin.properties.ReadOnlyProperty
 
 /**
- * A marker interface for a symbol. A symbol mus have an identity
+ * A marker interface for a symbol. A symbol must have an identity.
+ * Ic
  */
-public interface Symbol {
+public interface Symbol: MST {
     /**
      * Identity object for the symbol. Two symbols with the same identity are considered to be the same symbol.
      */

kmath-core/src/commonMain/kotlin/space/kscience/kmath/expressions/SymbolIndexer.kt

@@ -6,7 +6,6 @@
 package space.kscience.kmath.expressions
 
 import space.kscience.kmath.linear.Point
-import space.kscience.kmath.misc.Symbol
 import space.kscience.kmath.misc.UnstableKMathAPI
 import space.kscience.kmath.nd.Structure2D
 import space.kscience.kmath.structures.BufferFactory

kmath-core/src/commonMain/kotlin/space/kscience/kmath/operations/Algebra.kt

@@ -5,8 +5,7 @@
 
 package space.kscience.kmath.operations
 
-import space.kscience.kmath.misc.Symbol
+import space.kscience.kmath.expressions.Symbol
-import space.kscience.kmath.misc.UnstableKMathAPI
 
 /**
  * Stub for DSL the [Algebra] is.

kmath-core/src/commonMain/kotlin/space/kscience/kmath/operations/LogicAlgebra.kt

@@ -0,0 +1,71 @@
+/*
+ * Copyright 2018-2021 KMath contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+package space.kscience.kmath.operations
+
+import space.kscience.kmath.expressions.Symbol
+import space.kscience.kmath.expressions.symbol
+import space.kscience.kmath.misc.UnstableKMathAPI
+
+/**
+ * An algebra for generic boolean logic
+ */
+@UnstableKMathAPI
+public interface LogicAlgebra<T : Any> : Algebra<T> {
+
+    /**
+     * Represent constant [Boolean] as [T]
+     */
+    public fun const(boolean: Boolean): T
+
+    override fun bindSymbolOrNull(value: String): T? = value.lowercase().toBooleanStrictOrNull()?.let(::const)
+
+    override fun unaryOperation(operation: String, arg: T): T = when (operation) {
+        Boolean::not.name -> arg.not()
+        else -> super.unaryOperation(operation, arg)
+    }
+
+    override fun binaryOperation(operation: String, left: T, right: T): T = when (operation) {
+        Boolean::and.name -> left.and(right)
+        Boolean::or.name -> left.or(right)
+        else -> super.binaryOperation(operation, left, right)
+    }
+
+    /**
+     * Logic 'not'
+     */
+    public operator fun T.not(): T
+
+    /**
+     * Logic 'and'
+     */
+    public infix fun T.and(other: T): T
+
+    /**
+     * Logic 'or'
+     */
+    public infix fun T.or(other: T): T
+
+    public companion object {
+        public val TRUE: Symbol by symbol
+        public val FALSE: Symbol by symbol
+    }
+}
+
+/**
+ * An implementation of [LogicAlgebra] for primitive booleans
+ */
+@UnstableKMathAPI
+@Suppress("EXTENSION_SHADOWED_BY_MEMBER")
+public object BooleanAlgebra : LogicAlgebra<Boolean> {
+
+    override fun const(boolean: Boolean): Boolean = boolean
+
+    override fun Boolean.not(): Boolean = !this
+
+    override fun Boolean.and(other: Boolean): Boolean = this && other
+
+    override fun Boolean.or(other: Boolean): Boolean = this || other
+}

kmath-core/src/commonTest/kotlin/space/kscience/kmath/expressions/ExpressionFieldTest.kt

@@ -5,7 +5,6 @@
 
 package space.kscience.kmath.expressions
 
-import space.kscience.kmath.misc.symbol
 import space.kscience.kmath.operations.DoubleField
 import space.kscience.kmath.operations.invoke
 import kotlin.test.Test

kmath-core/src/commonTest/kotlin/space/kscience/kmath/expressions/InterpretTest.kt

@@ -5,7 +5,6 @@
 
 package space.kscience.kmath.expressions
 
-import space.kscience.kmath.misc.Symbol
 import space.kscience.kmath.operations.DoubleField
 import space.kscience.kmath.operations.bindSymbol
 import space.kscience.kmath.operations.invoke

kmath-core/src/commonTest/kotlin/space/kscience/kmath/expressions/SimpleAutoDiffTest.kt

@@ -5,8 +5,6 @@
 
 package space.kscience.kmath.expressions
 
-import space.kscience.kmath.misc.Symbol
-import space.kscience.kmath.misc.symbol
 import space.kscience.kmath.operations.DoubleField
 import space.kscience.kmath.operations.bindSymbol
 import space.kscience.kmath.structures.Buffer

kmath-kotlingrad/src/main/kotlin/space/kscience/kmath/kotlingrad/DifferentiableMstExpression.kt

@@ -7,11 +7,7 @@ package space.kscience.kmath.kotlingrad
 
 import edu.umontreal.kotlingrad.api.SFun
 import edu.umontreal.kotlingrad.api.SVar
-import space.kscience.kmath.expressions.DifferentiableExpression
+import space.kscience.kmath.expressions.*
-import space.kscience.kmath.expressions.MST
-import space.kscience.kmath.expressions.MstAlgebra
-import space.kscience.kmath.expressions.interpret
-import space.kscience.kmath.misc.Symbol
 import space.kscience.kmath.operations.NumericAlgebra
 
 /**
@@ -35,8 +31,8 @@ public class DifferentiableMstExpression<T : Number, A : NumericAlgebra<T>>(
         DifferentiableMstExpression(
             algebra,
             symbols.map(Symbol::identity)
-                .map(MstAlgebra::bindSymbol)
+                .map(MstNumericAlgebra::bindSymbol)
-                .map<MST.Symbolic, SVar<KMathNumber<T, A>>>(MST.Symbolic::toSVar)
+                .map<Symbol, SVar<KMathNumber<T, A>>>(Symbol::toSVar)
                 .fold(mst.toSFun(), SFun<KMathNumber<T, A>>::d)
                 .toMst(),
         )

kmath-kotlingrad/src/main/kotlin/space/kscience/kmath/kotlingrad/ScalarsAdapters.kt

@@ -7,9 +7,10 @@ package space.kscience.kmath.kotlingrad
 
 import edu.umontreal.kotlingrad.api.*
 import space.kscience.kmath.expressions.MST
-import space.kscience.kmath.expressions.MstAlgebra
 import space.kscience.kmath.expressions.MstExtendedField
 import space.kscience.kmath.expressions.MstExtendedField.unaryMinus
+import space.kscience.kmath.expressions.MstNumericAlgebra
+import space.kscience.kmath.expressions.Symbol
 import space.kscience.kmath.operations.*
 
 /**
@@ -18,7 +19,7 @@ import space.kscience.kmath.operations.*
  * @receiver The variable.
  * @returnAa node.
  */
-public fun <X : SFun<X>> SVar<X>.toMst(): MST.Symbolic = MstAlgebra.bindSymbol(name)
+public fun <X : SFun<X>> SVar<X>.toMst(): Symbol = MstNumericAlgebra.bindSymbol(name)
 
 /**
  * Maps [SVar] to [MST.Numeric] directly.
@@ -26,7 +27,7 @@ public fun <X : SFun<X>> SVar<X>.toMst(): MST.Symbolic = MstAlgebra.bindSymbol(n
  * @receiver The constant.
  * @return A node.
  */
-public fun <X : SFun<X>> SConst<X>.toMst(): MST.Numeric = MstAlgebra.number(doubleValue)
+public fun <X : SFun<X>> SConst<X>.toMst(): MST.Numeric = MstNumericAlgebra.number(doubleValue)
 
 /**
  * Maps [SFun] objects to [MST]. Some unsupported operations like [Derivative] are bound and converted then.
@@ -85,7 +86,7 @@ public fun <X : SFun<X>> MST.Numeric.toSConst(): SConst<X> = SConst(value)
  * @receiver The node.
  * @return A new variable.
  */
-internal fun <X : SFun<X>> MST.Symbolic.toSVar(): SVar<X> = SVar(value)
+internal fun <X : SFun<X>> Symbol.toSVar(): SVar<X> = SVar(identity)
 
 /**
  * Maps [MST] objects to [SFun]. Unsupported operations throw [IllegalStateException].
@@ -102,7 +103,7 @@ internal fun <X : SFun<X>> MST.Symbolic.toSVar(): SVar<X> = SVar(value)
  */
 public fun <X : SFun<X>> MST.toSFun(): SFun<X> = when (this) {
     is MST.Numeric -> toSConst()
-    is MST.Symbolic -> toSVar()
+    is Symbol -> toSVar()
 
     is MST.Unary -> when (operation) {
         GroupOperations.PLUS_OPERATION -> +value.toSFun<X>()

kmath-kotlingrad/src/test/kotlin/space/kscience/kmath/kotlingrad/AdaptingTests.kt

@@ -8,9 +8,9 @@ package space.kscience.kmath.kotlingrad
 import edu.umontreal.kotlingrad.api.*
 import space.kscience.kmath.asm.compileToExpression
 import space.kscience.kmath.ast.parseMath
-import space.kscience.kmath.expressions.MstAlgebra
+import space.kscience.kmath.expressions.MstNumericAlgebra
+import space.kscience.kmath.expressions.Symbol.Companion.x
 import space.kscience.kmath.expressions.invoke
-import space.kscience.kmath.misc.Symbol.Companion.x
 import space.kscience.kmath.operations.DoubleField
 import kotlin.test.Test
 import kotlin.test.assertEquals
@@ -20,7 +20,7 @@ import kotlin.test.fail
 internal class AdaptingTests {
     @Test
     fun symbol() {
-        val c1 = MstAlgebra.bindSymbol(x.identity)
+        val c1 = MstNumericAlgebra.bindSymbol(x.identity)
         assertEquals(x.identity, c1.toSVar<KMathNumber<Double, DoubleField>>().name)
         val c2 = "kitten".parseMath().toSFun<KMathNumber<Double, DoubleField>>()
         if (c2 is SVar) assertTrue(c2.name == "kitten") else fail()
@@ -28,7 +28,7 @@ internal class AdaptingTests {
 
     @Test
     fun number() {
-        val c1 = MstAlgebra.number(12354324)
+        val c1 = MstNumericAlgebra.number(12354324)
         assertTrue(c1.toSConst<DReal>().doubleValue == 12354324.0)
         val c2 = "0.234".parseMath().toSFun<KMathNumber<Double, DoubleField>>()
         if (c2 is SConst) assertTrue(c2.doubleValue == 0.234) else fail()
@@ -46,7 +46,7 @@ internal class AdaptingTests {
 
     @Test
     fun simpleFunctionDerivative() {
-        val xSVar = MstAlgebra.bindSymbol(x.identity).toSVar<KMathNumber<Double, DoubleField>>()
+        val xSVar = MstNumericAlgebra.bindSymbol(x.identity).toSVar<KMathNumber<Double, DoubleField>>()
         val quadratic = "x^2-4*x-44".parseMath().toSFun<KMathNumber<Double, DoubleField>>()
         val actualDerivative = quadratic.d(xSVar).toMst().compileToExpression(DoubleField)
         val expectedDerivative = "2*x-4".parseMath().compileToExpression(DoubleField)
@@ -55,7 +55,7 @@ internal class AdaptingTests {
 
     @Test
     fun moreComplexDerivative() {
-        val xSVar = MstAlgebra.bindSymbol(x.identity).toSVar<KMathNumber<Double, DoubleField>>()
+        val xSVar = MstNumericAlgebra.bindSymbol(x.identity).toSVar<KMathNumber<Double, DoubleField>>()
         val composition = "-sqrt(sin(x^2)-cos(x)^2-16*x)".parseMath().toSFun<KMathNumber<Double, DoubleField>>()
         val actualDerivative = composition.d(xSVar).toMst().compileToExpression(DoubleField)
 

kmath-stat/src/commonMain/kotlin/space/kscience/kmath/optimization/FunctionOptimization.kt

@@ -5,11 +5,7 @@
 
 package space.kscience.kmath.optimization
 
-import space.kscience.kmath.expressions.AutoDiffProcessor
+import space.kscience.kmath.expressions.*
-import space.kscience.kmath.expressions.DifferentiableExpression
-import space.kscience.kmath.expressions.Expression
-import space.kscience.kmath.expressions.ExpressionAlgebra
-import space.kscience.kmath.misc.Symbol
 import space.kscience.kmath.operations.ExtendedField
 import space.kscience.kmath.structures.Buffer
 import space.kscience.kmath.structures.indices

kmath-stat/src/commonMain/kotlin/space/kscience/kmath/optimization/NoDerivFunctionOptimization.kt

@@ -6,7 +6,7 @@
 package space.kscience.kmath.optimization
 
 import space.kscience.kmath.expressions.Expression
-import space.kscience.kmath.misc.Symbol
+import space.kscience.kmath.expressions.Symbol
 import space.kscience.kmath.structures.Buffer
 import space.kscience.kmath.structures.indices
 import kotlin.math.pow

kmath-stat/src/commonMain/kotlin/space/kscience/kmath/optimization/Optimization.kt

@@ -5,7 +5,7 @@
 
 package space.kscience.kmath.optimization
 
-import space.kscience.kmath.misc.Symbol
+import space.kscience.kmath.expressions.Symbol
 
 public interface OptimizationFeature
 

kmath-stat/src/commonMain/kotlin/space/kscience/kmath/optimization/XYFit.kt

@@ -6,11 +6,7 @@
 package space.kscience.kmath.optimization
 
 import space.kscience.kmath.data.ColumnarData
-import space.kscience.kmath.expressions.AutoDiffProcessor
+import space.kscience.kmath.expressions.*
-import space.kscience.kmath.expressions.DifferentiableExpression
-import space.kscience.kmath.expressions.Expression
-import space.kscience.kmath.expressions.ExpressionAlgebra
-import space.kscience.kmath.misc.Symbol
 import space.kscience.kmath.misc.UnstableKMathAPI
 import space.kscience.kmath.operations.ExtendedField
 import space.kscience.kmath.operations.Field