Adds more efficient internal pretty-printing (#1403)

CHANGELOG.md

@@ -34,8 +34,10 @@ Thank you to all who have contributed!
 - Change `StaticType.AnyOfType`'s `.toString` to not perform `.flatten()`
 
 ### Deprecated
+- The current SqlBlock, SqlDialect, and SqlLayout are marked as deprecated and will be slightly changed in the next release. 
 
 ### Fixed
+- Updates the default `.sql()` method to use a more efficient (internal) printer implementation.
 
 ### Removed
 
@@ -44,6 +46,7 @@ Thank you to all who have contributed!
 ### Contributors
 Thank you to all who have contributed!
 - @<your-username>
+- @rchowell
 
 ## [0.14.4]
 

partiql-ast/src/main/kotlin/org/partiql/ast/sql/Sql.kt

@@ -1,15 +1,41 @@
 package org.partiql.ast.sql
 
 import org.partiql.ast.AstNode
+import org.partiql.ast.sql.internal.InternalSqlDialect
+import org.partiql.ast.sql.internal.InternalSqlLayout
+
+/**
+ * No argument uses optimized internal. Leaving older ones for backwards-compatibility.
+ */
+public fun AstNode.sql(): String {
+    val head = InternalSqlDialect.PARTIQL.apply(this)
+    return InternalSqlLayout.format(head)
+}
 
 /**
  * Pretty-print this [AstNode] as SQL text with the given [SqlLayout]
  */
-@JvmOverloads
+@Deprecated("To be removed in the next major version")
 public fun AstNode.sql(
     layout: SqlLayout = SqlLayout.DEFAULT,
+): String = SqlDialect.PARTIQL.apply(this).sql(layout)
+
+/**
+ * Pretty-print this [AstNode] as SQL text with the given [SqlDialect]
+ */
+@Deprecated("To be removed in the next major version")
+public fun AstNode.sql(
     dialect: SqlDialect = SqlDialect.PARTIQL,
-): String = accept(dialect, SqlBlock.Nil).sql(layout)
+): String = dialect.apply(this).sql(SqlLayout.DEFAULT)
+
+/**
+ * Pretty-print this [AstNode] as SQL text with the given [SqlLayout] and [SqlDialect]
+ */
+@Deprecated("To be removed in the next major version")
+public fun AstNode.sql(
+    layout: SqlLayout,
+    dialect: SqlDialect,
+): String = dialect.apply(this).sql(layout)
 
 // a <> b  <-> a concat b
 

partiql-ast/src/main/kotlin/org/partiql/ast/sql/SqlBlock.kt

@@ -6,11 +6,13 @@ package org.partiql.ast.sql
  * @param layout    SQL formatting ruleset
  * @return SQL text
  */
+@Deprecated("To be removed in the next major version")
 public fun SqlBlock.sql(layout: SqlLayout = SqlLayout.DEFAULT): String = layout.format(this)
 
 /**
  * Representation of some textual corpus; akin to Wadler's "A prettier printer" Document type.
  */
+@Deprecated("This will be changed in the next major version")
 sealed interface SqlBlock {
 
     public override fun toString(): String
@@ -54,6 +56,7 @@ sealed interface SqlBlock {
     }
 }
 
+@Deprecated("This will be changed in the next major version")
 public interface BlockVisitor<R, C> {
 
     public fun visit(block: SqlBlock, ctx: C): R
@@ -69,6 +72,7 @@ public interface BlockVisitor<R, C> {
     public fun visitLink(block: SqlBlock.Link, ctx: C): R
 }
 
+@Deprecated("This will be changed in the next major version")
 public abstract class BlockBaseVisitor<R, C> : BlockVisitor<R, C> {
 
     public abstract fun defaultReturn(block: SqlBlock, ctx: C): R

partiql-ast/src/main/kotlin/org/partiql/ast/sql/SqlDialect.kt

@@ -26,6 +26,7 @@ import java.io.PrintStream
 /**
  * SqlDialect represents the base behavior for transforming an [AstNode] tree into a [SqlBlock] tree.
  */
+@Deprecated("This will be changed in the next major version")
 @Suppress("PARAMETER_NAME_CHANGED_ON_OVERRIDE")
 public abstract class SqlDialect : AstBaseVisitor<SqlBlock, SqlBlock>() {
 

partiql-ast/src/main/kotlin/org/partiql/ast/sql/SqlLayout.kt

@@ -3,6 +3,7 @@ package org.partiql.ast.sql
 /**
  * [SqlLayout] determines how an [SqlBlock] tree is transformed in SQL text.
  */
+@Deprecated("This will be changed in the next major version")
 public abstract class SqlLayout {
 
     abstract val indent: Indent

partiql-ast/src/main/kotlin/org/partiql/ast/sql/internal/InternalSqlBlock.kt

@@ -0,0 +1,58 @@
+/*
+ * Copyright Amazon.com, Inc. or its affiliates.  All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License").
+ *  You may not use this file except in compliance with the License.
+ * A copy of the License is located at:
+ *
+ *      http://aws.amazon.com/apache2.0/
+ *
+ *  or in the "license" file accompanying this file. This file 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.partiql.ast.sql.internal
+
+/**
+ * Representation of some textual elements as a token (singly-linked) list.
+ */
+internal sealed class InternalSqlBlock {
+
+    /**
+     * Next token (if any) in the list.
+     */
+    internal var next: InternalSqlBlock? = null
+
+    /**
+     * A newline / link break token.
+     */
+    internal class NL : InternalSqlBlock()
+
+    /**
+     * A raw text token. Cannot be broken.
+     */
+    internal class Text(val text: String) : InternalSqlBlock()
+
+    /**
+     * A nest token representing a (possible indented) token sublist.
+     *
+     * @property prefix     A prefix character such as '{', '(', or '['.
+     * @property postfix    A postfix character such as  '}', ')', or ']].
+     * @property child
+     */
+    internal class Nest(
+        val prefix: String?,
+        val postfix: String?,
+        val child: InternalSqlBlock,
+    ) : InternalSqlBlock()
+
+    companion object {
+
+        /**
+         * Helper function to create root node (empty).
+         */
+        @JvmStatic
+        internal fun root(): InternalSqlBlock = Text("")
+    }
+}