[incubator-nlpcraft] branch NLPCRAFT-247 updated: Create NCMacroCompiler.scala

[ar...@apache.org]

This is an automated email from the ASF dual-hosted git repository.

aradzinski pushed a commit to branch NLPCRAFT-247
in repository https://gitbox.apache.org/repos/asf/incubator-nlpcraft.git


The following commit(s) were added to refs/heads/NLPCRAFT-247 by this push:
     new 81a40d4  Create NCMacroCompiler.scala
81a40d4 is described below

commit 81a40d40c6e76e80c9e3bb437803093d9db54153
Author: Aaron Radzinski <ar...@apache.org>
AuthorDate: Sun Feb 21 11:50:31 2021 -0800

    Create NCMacroCompiler.scala
---
 .../nlpcraft/common/makro/NCMacroCompiler.scala    | 108 +++++++++++++++++++++
 1 file changed, 108 insertions(+)

diff --git a/nlpcraft/src/main/scala/org/apache/nlpcraft/common/makro/NCMacroCompiler.scala b/nlpcraft/src/main/scala/org/apache/nlpcraft/common/makro/NCMacroCompiler.scala
new file mode 100644
index 0000000..71a9e13
--- /dev/null
+++ b/nlpcraft/src/main/scala/org/apache/nlpcraft/common/makro/NCMacroCompiler.scala
@@ -0,0 +1,108 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.nlpcraft.common.makro
+
+import com.typesafe.scalalogging.LazyLogging
+import org.antlr.v4.runtime.tree.ParseTreeWalker
+import org.antlr.v4.runtime.{BaseErrorListener, CharStreams, CommonTokenStream, RecognitionException, Recognizer}
+import org.apache.nlpcraft.common.makro.antlr4._
+import org.apache.nlpcraft.common._
+
+/**
+ *
+ */
+object NCMacroCompiler extends LazyLogging {
+    /**
+     *
+     */
+    class FiniteStateMachine extends NCMacroDslBaseListener {
+        /**
+         *
+         * @return
+         */
+        def getExpandedMacro(): Set[String] = ???
+    }
+
+    /**
+     * Custom error handler.
+     */
+    class CompilerErrorListener(in: String) extends BaseErrorListener {
+        /**
+         *
+         * @param len
+         * @param pos
+         * @return
+         */
+        private def makeCharPosPointer(len: Int, pos: Int): String = {
+            val s = (for (_ ← 1 to len) yield '-').mkString("")
+
+            s.substring(0, pos - 1) + '^' + s.substring(pos)
+        }
+
+        /**
+         *
+         * @param recognizer
+         * @param offendingSymbol
+         * @param line
+         * @param charPos
+         * @param msg
+         * @param e
+         */
+        override def syntaxError(
+            recognizer: Recognizer[_, _],
+            offendingSymbol: scala.Any,
+            line: Int,
+            charPos: Int,
+            msg: String,
+            e: RecognitionException): Unit = {
+
+            val errMsg = s"Macro syntax error at line $line:$charPos - $msg\n" +
+                s"  |-- ${c("Macro:")} $in\n" +
+                s"  +-- ${c("Error:")}  ${makeCharPosPointer(in.length, charPos)}"
+
+            throw new NCE(errMsg)
+        }
+    }
+
+    /**
+     *
+     * @param in Macro to expand.
+     * @return Expanded macro as a set of finite strings.
+     */
+    def compile(in: String): Set[String] = {
+        // ANTLR4 armature.
+        val lexer = new NCMacroDslLexer(CharStreams.fromString(in))
+        val tokens = new CommonTokenStream(lexer)
+        val parser = new NCMacroDslParser(tokens)
+
+        // Set custom error handlers.
+        lexer.removeErrorListeners()
+        parser.removeErrorListeners()
+        lexer.addErrorListener(new CompilerErrorListener(in))
+        parser.addErrorListener(new CompilerErrorListener(in))
+
+        // State automata.
+        val fsm = new FiniteStateMachine
+
+        // Parse the input DSL and walk built AST.
+        (new ParseTreeWalker).walk(fsm, parser.line())
+
+        // Return the expanded macro.
+        fsm.getExpandedMacro()
+    }
+}