Move Abacus core into Kotlin.

core/src/main/kotlin/org/nwapw/abacus/Abacus.kt

@@ -0,0 +1,85 @@
+package org.nwapw.abacus
+
+import org.nwapw.abacus.config.Configuration
+import org.nwapw.abacus.number.NumberInterface
+import org.nwapw.abacus.number.PromotionManager
+import org.nwapw.abacus.parsing.LexerTokenizer
+import org.nwapw.abacus.parsing.ShuntingYardParser
+import org.nwapw.abacus.parsing.TreeBuilder
+import org.nwapw.abacus.plugin.NumberImplementation
+import org.nwapw.abacus.plugin.PluginManager
+import org.nwapw.abacus.plugin.StandardPlugin
+import org.nwapw.abacus.tree.NumberReducer
+import org.nwapw.abacus.tree.TreeNode
+import org.nwapw.abacus.variables.VariableDatabase
+
+/**
+ * Core class to handle all mathematics.
+ *
+ * The main calculator class. This is responsible
+ * for piecing together all of the components, allowing
+ * their interaction with each other.
+ *
+ * @property configuration the configuration to use.
+ */
+class Abacus(val configuration: Configuration) {
+
+    /**
+     * The tokenizer used to convert strings into tokens.
+     */
+    private val tokenizer = LexerTokenizer()
+    /**
+     * Parser the parser used to convert tokens into trees.
+     */
+    private val parser = ShuntingYardParser()
+    /**
+     * The plugin manager used to handle loading and unloading plugins.
+     */
+    val pluginManager = PluginManager(this)
+    /**
+     * The reducer used to turn trees into a single number.
+     */
+    val numberReducer = NumberReducer(this)
+    /**
+     * The tree builder that handles the conversion of strings into trees.
+     */
+    val treeBuilder = TreeBuilder(tokenizer, parser)
+    /**
+     * The promotion manager used to convert between number implementations.
+     */
+    val promotionManager = PromotionManager(this)
+    /**
+     * The number implementation used by default.
+     */
+    val numberImplementation: NumberImplementation
+        get() {
+            val selectedImplementation =
+                    pluginManager.numberImplementationFor(configuration.numberImplementation)
+            if (selectedImplementation != null) return selectedImplementation
+            return StandardPlugin.IMPLEMENTATION_NAIVE
+        }
+
+    init {
+        pluginManager.addListener(tokenizer)
+        pluginManager.addListener(parser)
+        pluginManager.addListener(promotionManager)
+    }
+
+    /**
+     * Parses a string into a tree structure using the main
+     * tree builder.
+     *
+     * @param input the input string to parse
+     * @return the resulting tree, null if the tree builder or the produced tree are null.
+     */
+    fun parseString(input: String): TreeNode? = treeBuilder.fromString(input)
+    /**
+     * Evaluates the given tree using the main
+     * number reducer.
+     *
+     * @param tree the tree to reduce, must not be null.
+     * @return the resulting number, or null of the reduction failed.
+     */
+    fun evaluateTree(tree: TreeNode): NumberInterface? = tree.reduce(numberReducer)
+
+}