From ad2aea9c70db9801228f8125159b41612cc30a34 Mon Sep 17 00:00:00 2001
From: Pekka Laiho <pekka.i.laiho@gmail.com>
Date: Fri, 19 Jun 2020 19:09:07 +0700
Subject: [PATCH] add database functions

---
 README.md            | 14 +++++++++++
 src/Lib/Database.php | 58 ++++++++++++++++++++++++++++++++++++++++++++
 src/LispFactory.php  |  1 +
 3 files changed, 73 insertions(+)
 create mode 100644 src/Lib/Database.php

diff --git a/README.md b/README.md
index 6c470d2..e9520be 100644
--- a/README.md
+++ b/README.md
@@ -193,6 +193,20 @@ Name    | Example | Example result | Description
 `>`     | `(> 1 2)` | `false` | Return true if first argument is greater than second.
 `>=`    | `(>= 1 2)` | `false` | Return true if first argument is greater or equal to second.
 
+### Database functions
+
+This is just a simple wrapper for [PDO](https://www.php.net/manual/en/book.pdo.php).
+
+Name        | Example | Example result | Description
+----------- | ------- | -------------- | -----------
+db-open     | `(def d (db-open "mysql:host=localhost;dbname=test" "testuser" "testpw"))` | `<object<PDO>>` | Open a database connection.
+db-execute  | `(db-execute d "INSERT INTO test_table (col1, col2) values (?, ?)" [1, 2])` | `1` | Execute a SQL statement and return the number of affected rows.
+db-query    | `(db-query d "SELECT * FROM test_table WHERE col1 = ?" [1])` | | Execute a SELECT statement.
+db-last-id  | `(db-last-id d)` | `"1"` | Return the last id of auto-increment column.
+db-trans    | `(db-trans d)` | `true` | Start a transaction.
+db-commit   | `(db-commit d)` | `true` | Commit a transaction.
+db-rollback | `(db-rollback d)` | `true` | Roll back a transaction.
+
 ### IO functions
 
 Name    | Example | Example result | Description
diff --git a/src/Lib/Database.php b/src/Lib/Database.php
new file mode 100644
index 0000000..c0b9da0
--- /dev/null
+++ b/src/Lib/Database.php
@@ -0,0 +1,58 @@
+<?php
+namespace MadLisp\Lib;
+
+use PDO;
+use PDOStatement;
+
+use MadLisp\Collection;
+use MadLisp\CoreFunc;
+use MadLisp\Env;
+use MadLisp\Hash;
+use MadLisp\Vector;
+
+class Database implements ILib
+{
+    public function register(Env $env): void
+    {
+        $env->set('db-open', new CoreFunc('db-open', 'Open a database connection.', 1, 4,
+            function (string $dsn, ?string $username = null, ?string $password = null, ?Hash $options = null) {
+                return new PDO($dsn, $username, $password, $options ? $options->getData() : []);
+            }
+        ));
+
+        $env->set('db-execute', new CoreFunc('db-execute', 'Execute a database statement.', 2, 3,
+            function (PDO $pdo, string $sql, ?Collection $args = null) {
+                $stmt = $pdo->prepare($sql);
+                $stmt->execute($args ? $args->getData() : []);
+                return $stmt->rowCount();
+            }
+        ));
+
+        $env->set('db-query', new CoreFunc('db-query', 'Execute a database query.', 2, 4,
+            function (PDO $pdo, string $sql, ?Collection $args, bool $rowVectors = false) {
+                $stmt = $pdo->prepare($sql);
+                $stmt->execute($args ? $args->getData() : []);
+                $rows = $stmt->fetchAll($rowVectors ? PDO::FETCH_NUM : PDO::FETCH_ASSOC);
+                return new Vector(
+                    array_map(fn ($row) => $rowVectors ? new Vector($row) : new Hash($row), $rows)
+                );
+            }
+        ));
+
+        $env->set('db-last-id', new CoreFunc('db-last-id', 'Get the last id of auto-increment column.', 1, 1,
+            fn (PDO $pdo) => $pdo->lastInsertId()
+        ));
+
+        $env->set('db-trans', new CoreFunc('db-trans', 'Start a transaction.', 1, 1,
+            fn (PDO $pdo) => $pdo->beginTransaction()
+        ));
+
+        $env->set('db-commit', new CoreFunc('db-commit', 'Commit a transaction.', 1, 1,
+            fn (PDO $pdo) => $pdo->commit()
+        ));
+
+        $env->set('db-rollback', new CoreFunc('db-rollback', 'Roll back a transaction.', 1, 1,
+            fn (PDO $pdo) => $pdo->rollBack()
+        ));
+    }
+}
diff --git a/src/LispFactory.php b/src/LispFactory.php
index 111dd7a..687054d 100644
--- a/src/LispFactory.php
+++ b/src/LispFactory.php
@@ -44,6 +44,7 @@ class LispFactory
         // Register core libraries
         (new Lib\Collections())->register($env);
         (new Lib\Compare())->register($env);
+        (new Lib\Database())->register($env);
         (new Lib\IO())->register($env);
         (new Lib\Json())->register($env);
         (new Lib\Math())->register($env);