From 5a37fc947d090af244d52b6b5c8f6eb1bf9446ca Mon Sep 17 00:00:00 2001
From: zetashift <rskaraya@gmail.com>
Date: Fri, 10 Mar 2023 18:26:41 +0100
Subject: [PATCH 01/10] Initial example for fs2-data-csv for Scala 3

---
 docs/examples.md | 70 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 70 insertions(+)

diff --git a/docs/examples.md b/docs/examples.md
index 87292f6..f683ceb 100644
--- a/docs/examples.md
+++ b/docs/examples.md
@@ -164,9 +164,79 @@ object Main extends CommandIOApp("mkString", "Concatenates strings from stdin")
 
 @:@
 
+## Parsing and transforming a CSV file
+
+Here, [fs2-data-csv] is used to read and parse a comma separated file. 
+Manual encoders and decoders are defined for our `Passenger`s to showcase `fs2-data` power. 
+
+
+@:select(scala-version)
+
+@:choice(scala-3)
+```scala mdoc:reset:silent
+//> using lib "org.typelevel::toolkit::@VERSION@"
+
+import cats.effect.*
+import fs2.text
+import fs2.data.csv.*
+import fs2.data.csv.generic.semiauto._
+import fs2.io.file.{Path, Flags, Files}
+import cats.data.NonEmptyList
+
+case class Passenger(
+    id: Long,
+    firstName: String,
+    age: Either[String, Int],
+    flightNumber: String,
+    country: String
+)
+
+object Passenger:
+  given csvRowDecoder: CsvRowDecoder[Passenger, String] with
+    def apply(row: CsvRow[String]): DecoderResult[Passenger] =
+      for
+        id <- row.as[Long]("id")
+        firstName <- row.as[String]("First Name")
+        ageOpt <- row.asNonEmpty[Int]("Age")
+        flightNumber <- row.as[String]("flight number")
+        country <- row.as[String]("country")
+      yield
+        val age = ageOpt.toRight[String]("N/A")
+        Passenger(id, firstName, age, flightNumber, country)
+
+    given csvRowEncoder: CsvRowEncoder[Passenger, String] with
+      def apply(p: Passenger): CsvRow[String] =
+        CsvRow.fromNelHeaders(
+          NonEmptyList.of(
+            (p.firstName, "first_name"),
+            (p.age.toString(), "age"),
+            (p.flightNumber, "flight_number"),
+            (p.country, "country")
+          )
+        )
+
+val input = Files[IO]
+  .readAll(Path("./example.csv"), 1024, Flags.Read)
+  .through(text.utf8.decode)
+  .through(decodeUsingHeaders[Passenger]())
+
+object CSVPrinter extends IOApp.Simple:
+  val run =
+    input.evalTap(p => IO.println(p)).compile.drain
+```
+
+
+@:choice(scala-2)
+```scala mdoc:reset:silent
+// TODO
+```
+@:@
+
 
 [fs2]: https://fs2.io/#/
+[fs2-data-csv]: https://fs2-data.gnieh.org/documentation/csv/
 [decline]: https://ben.kirw.in/decline/
 [scala-native]: https://scala-native.org/en/stable/
 [Scala CLI]: https://scala-cli.virtuslab.org/
 [Koroeskohr]: https://github.com/Koroeskohr
+

From 337fd362705a2d092769f368e27930551fc5c71f Mon Sep 17 00:00:00 2001
From: zetashift <rskaraya@gmail.com>
Date: Fri, 10 Mar 2023 18:26:41 +0100
Subject: [PATCH 02/10] Improve doc for the example

---
 docs/examples.md | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/docs/examples.md b/docs/examples.md
index f683ceb..3946b19 100644
--- a/docs/examples.md
+++ b/docs/examples.md
@@ -167,7 +167,16 @@ object Main extends CommandIOApp("mkString", "Concatenates strings from stdin")
 ## Parsing and transforming a CSV file
 
 Here, [fs2-data-csv] is used to read and parse a comma separated file. 
-Manual encoders and decoders are defined for our `Passenger`s to showcase `fs2-data` power. 
+Manual encoders and decoders are defined for our `Passenger`s to show you how to everything from scratch.
+
+Let's start with a CSV file that has records of fictious passengers registered for a flight:
+
+```
+id,First Name,Age,flight number,country
+1,Seyton,44,WX122,Tanzania
+2,Lina,,UX199,Greenland
+3,Grogu,,SW999,Singapore
+```
 
 
 @:select(scala-version)

From 35c1234ccacb7f82419cfff2989028f68a46b561 Mon Sep 17 00:00:00 2001
From: zetashift <rskaraya@gmail.com>
Date: Sat, 11 Mar 2023 17:17:30 +0100
Subject: [PATCH 03/10] Improve fs2-data example and add Scala 2 version

---
 docs/examples.md | 77 +++++++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 69 insertions(+), 8 deletions(-)

diff --git a/docs/examples.md b/docs/examples.md
index 3946b19..675d79e 100644
--- a/docs/examples.md
+++ b/docs/examples.md
@@ -167,12 +167,12 @@ object Main extends CommandIOApp("mkString", "Concatenates strings from stdin")
 ## Parsing and transforming a CSV file
 
 Here, [fs2-data-csv] is used to read and parse a comma separated file. 
-Manual encoders and decoders are defined for our `Passenger`s to show you how to everything from scratch.
+Manual encoders and decoders are defined for our `Passenger`s to show you how to do everything from scratch.
 
 Let's start with a CSV file that has records of fictious passengers registered for a flight:
 
 ```
-id,First Name,Age,flight number,country
+id,First Name,Age,flight number,destination
 1,Seyton,44,WX122,Tanzania
 2,Lina,,UX199,Greenland
 3,Grogu,,SW999,Singapore
@@ -197,10 +197,11 @@ case class Passenger(
     firstName: String,
     age: Either[String, Int],
     flightNumber: String,
-    country: String
+    destination: String
 )
 
 object Passenger:
+  // Here we define a manual decoder for each row in our CSV
   given csvRowDecoder: CsvRowDecoder[Passenger, String] with
     def apply(row: CsvRow[String]): DecoderResult[Passenger] =
       for
@@ -208,11 +209,12 @@ object Passenger:
         firstName <- row.as[String]("First Name")
         ageOpt <- row.asNonEmpty[Int]("Age")
         flightNumber <- row.as[String]("flight number")
-        country <- row.as[String]("country")
+        destination <- row.as[String]("destination")
       yield
         val age = ageOpt.toRight[String]("N/A")
-        Passenger(id, firstName, age, flightNumber, country)
+        Passenger(id, firstName, age, flightNumber, destination)
 
+    // Here we define a manual encoder for encoding Passenger classes to a CSV
     given csvRowEncoder: CsvRowEncoder[Passenger, String] with
       def apply(p: Passenger): CsvRow[String] =
         CsvRow.fromNelHeaders(
@@ -220,7 +222,7 @@ object Passenger:
             (p.firstName, "first_name"),
             (p.age.toString(), "age"),
             (p.flightNumber, "flight_number"),
-            (p.country, "country")
+            (p.destination, "destination")
           )
         )
 
@@ -230,14 +232,73 @@ val input = Files[IO]
   .through(decodeUsingHeaders[Passenger]())
 
 object CSVPrinter extends IOApp.Simple:
-  val run =
+  val run: IO[Unit] =
     input.evalTap(p => IO.println(p)).compile.drain
 ```
 
 
 @:choice(scala-2)
 ```scala mdoc:reset:silent
-// TODO
+
+//> using lib "org.typelevel::toolkit::0.0.2"
+//> using lib "org.gnieh::fs2-data-csv::1.6.1"
+//> using lib "org.gnieh::fs2-data-csv-generic::1.6.1"
+
+import cats.effect.*
+import fs2.text
+import fs2.data.csv.*
+import fs2.data.csv.generic.semiauto._
+import fs2.io.file.{Path, Flags, Files}
+import cats.data.NonEmptyList
+
+case class Passenger(
+    id: Long,
+    firstName: String,
+    age: Either[String, Int],
+    flightNumber: String,
+    destination: String
+)
+
+object Passenger {
+  // Here we define a manual decoder for each row in our CSV
+  implicit val csvRowDecoder: CsvRowDecoder[Passenger, String] =
+    new CsvRowDecoder[Passenger, String] {
+      def apply(row: CsvRow[String]): DecoderResult[Passenger] =
+        for
+          id <- row.as[Long]("id")
+          firstName <- row.as[String]("First Name")
+          ageOpt <- row.asNonEmpty[Int]("Age")
+          flightNumber <- row.as[String]("flight number")
+          destination <- row.as[String]("destination")
+        yield
+          val age = ageOpt.toRight[String]("N/A")
+          Passenger(id, firstName, age, flightNumber, destination)
+    }
+
+  // Here we define a manual encoder for encoding Passenger classes to a CSV
+  implicit val csvRowEncoder: CsvRowEncoder[Passenger, String] =
+    new CsvRowEncoder[Passenger, String] {
+      def apply(p: Passenger): CsvRow[String] =
+        CsvRow.fromNelHeaders(
+          NonEmptyList.of(
+            (p.firstName, "first_name"),
+            (p.age.toString(), "age"),
+            (p.flightNumber, "flight_number"),
+            (p.destination, "destination")
+          )
+        )
+    }
+}
+
+val input = Files[IO]
+  .readAll(Path("./example.csv"), 1024, Flags.Read)
+  .through(text.utf8.decode)
+  .through(decodeUsingHeaders[Passenger]())
+
+object CSVPrinter extends IOApp.Simple {
+  val run: IO[Unit] =
+    input.evalTap(p => IO.println(p)).compile.drain
+}
 ```
 @:@
 

From 42bf21330d238754031119e6f2781e7805805961 Mon Sep 17 00:00:00 2001
From: zetashift <rskaraya@gmail.com>
Date: Sat, 11 Mar 2023 17:23:59 +0100
Subject: [PATCH 04/10] Fix import for Scala 2 fs2-data example

---
 docs/examples.md | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/docs/examples.md b/docs/examples.md
index 675d79e..d3db249 100644
--- a/docs/examples.md
+++ b/docs/examples.md
@@ -239,10 +239,7 @@ object CSVPrinter extends IOApp.Simple:
 
 @:choice(scala-2)
 ```scala mdoc:reset:silent
-
-//> using lib "org.typelevel::toolkit::0.0.2"
-//> using lib "org.gnieh::fs2-data-csv::1.6.1"
-//> using lib "org.gnieh::fs2-data-csv-generic::1.6.1"
+//> using lib "org.typelevel::toolkit::@VERSION@"
 
 import cats.effect.*
 import fs2.text

From 6618846de8f546afc9d6f8e0a8d4af18b318c809 Mon Sep 17 00:00:00 2001
From: zetashift <rskaraya@gmail.com>
Date: Sat, 11 Mar 2023 17:26:47 +0100
Subject: [PATCH 05/10] Remove double fs2-data mention in readme

---
 README.md | 2 --
 1 file changed, 2 deletions(-)

diff --git a/README.md b/README.md
index 5c83260..6c21a37 100644
--- a/README.md
+++ b/README.md
@@ -20,7 +20,6 @@ It currently includes:
 * [Circe] and http4s integration
 * [Decline Effect]
 * [Munit Cats Effect]
-* [fs2-data-csv]
 
 [Scala Toolkit]: https://virtuslab.com/blog/scala-toolkit-makes-scala-powerful-straight-out-of-the-box/
 [Cats]: https://typelevel.org/cats
@@ -32,4 +31,3 @@ It currently includes:
 [Circe]: https://circe.github.io/circe/
 [Decline Effect]: https://ben.kirw.in/decline/effect.html
 [Munit Cats Effect]: https://github.com/typelevel/munit-cats-effect
-[fs2-data-csv]: https://fs2-data.gnieh.org/documentation/csv/

From 92a7ddb587110ecd8ffaeaa8e09560586d7d4866 Mon Sep 17 00:00:00 2001
From: zetashift <rskaraya@gmail.com>
Date: Sat, 11 Mar 2023 18:22:42 +0100
Subject: [PATCH 06/10] Actually make the Scala 2 example decent

---
 docs/examples.md | 30 ++++++++++++++++--------------
 1 file changed, 16 insertions(+), 14 deletions(-)

diff --git a/docs/examples.md b/docs/examples.md
index d3db249..6206396 100644
--- a/docs/examples.md
+++ b/docs/examples.md
@@ -188,7 +188,7 @@ id,First Name,Age,flight number,destination
 import cats.effect.*
 import fs2.text
 import fs2.data.csv.*
-import fs2.data.csv.generic.semiauto._
+import fs2.data.csv.generic.semiauto.*
 import fs2.io.file.{Path, Flags, Files}
 import cats.data.NonEmptyList
 
@@ -241,9 +241,9 @@ object CSVPrinter extends IOApp.Simple:
 ```scala mdoc:reset:silent
 //> using lib "org.typelevel::toolkit::@VERSION@"
 
-import cats.effect.*
+import cats.effect._
 import fs2.text
-import fs2.data.csv.*
+import fs2.data.csv._
 import fs2.data.csv.generic.semiauto._
 import fs2.io.file.{Path, Flags, Files}
 import cats.data.NonEmptyList
@@ -253,7 +253,7 @@ case class Passenger(
     firstName: String,
     age: Either[String, Int],
     flightNumber: String,
-    destination: String
+    country: String
 )
 
 object Passenger {
@@ -261,15 +261,16 @@ object Passenger {
   implicit val csvRowDecoder: CsvRowDecoder[Passenger, String] =
     new CsvRowDecoder[Passenger, String] {
       def apply(row: CsvRow[String]): DecoderResult[Passenger] =
-        for
+        for {
           id <- row.as[Long]("id")
           firstName <- row.as[String]("First Name")
           ageOpt <- row.asNonEmpty[Int]("Age")
           flightNumber <- row.as[String]("flight number")
-          destination <- row.as[String]("destination")
-        yield
+          country <- row.as[String]("country")
+        } yield {
           val age = ageOpt.toRight[String]("N/A")
-          Passenger(id, firstName, age, flightNumber, destination)
+          Passenger(id, firstName, age, flightNumber, country)
+        }
     }
 
   // Here we define a manual encoder for encoding Passenger classes to a CSV
@@ -281,20 +282,21 @@ object Passenger {
             (p.firstName, "first_name"),
             (p.age.toString(), "age"),
             (p.flightNumber, "flight_number"),
-            (p.destination, "destination")
+            (p.country, "country")
           )
         )
     }
 }
 
-val input = Files[IO]
-  .readAll(Path("./example.csv"), 1024, Flags.Read)
-  .through(text.utf8.decode)
-  .through(decodeUsingHeaders[Passenger]())
-
 object CSVPrinter extends IOApp.Simple {
+  val input = Files[IO]
+    .readAll(Path("./example.csv"), 1024, Flags.Read)
+    .through(text.utf8.decode)
+    .through(decodeUsingHeaders[Passenger]())
+
   val run: IO[Unit] =
     input.evalTap(p => IO.println(p)).compile.drain
+
 }
 ```
 @:@

From af2fd1606455c9d4d46dfd001994b8d32f49d43c Mon Sep 17 00:00:00 2001
From: zetashift <rskaraya@gmail.com>
Date: Sat, 11 Mar 2023 18:52:59 +0100
Subject: [PATCH 07/10] Add a bit more fancy console logging to fs2-data
 example

---
 docs/examples.md | 20 +++++++++++++++++---
 1 file changed, 17 insertions(+), 3 deletions(-)

diff --git a/docs/examples.md b/docs/examples.md
index 6206396..0e19263 100644
--- a/docs/examples.md
+++ b/docs/examples.md
@@ -232,8 +232,16 @@ val input = Files[IO]
   .through(decodeUsingHeaders[Passenger]())
 
 object CSVPrinter extends IOApp.Simple:
+
   val run: IO[Unit] =
-    input.evalTap(p => IO.println(p)).compile.drain
+    input
+      .evalTap(p =>
+        IO.println(
+          s"${p.firstName} is taking flight: ${p.flightNumber} to ${p.destination}"
+        )
+      )
+      .compile
+      .drain
 ```
 
 
@@ -295,8 +303,14 @@ object CSVPrinter extends IOApp.Simple {
     .through(decodeUsingHeaders[Passenger]())
 
   val run: IO[Unit] =
-    input.evalTap(p => IO.println(p)).compile.drain
-
+    input
+      .evalTap(p =>
+        IO.println(
+          s"${p.firstName} is taking flight: ${p.flightNumber} to ${p.destination}"
+        )
+      )
+      .compile
+      .drain
 }
 ```
 @:@

From fe7e459df29dd5b52959da5bebb4907f28855136 Mon Sep 17 00:00:00 2001
From: zetashift <rskaraya@gmail.com>
Date: Sat, 11 Mar 2023 19:09:44 +0100
Subject: [PATCH 08/10] Fix destination field for fs2-data example

---
 docs/examples.md | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/docs/examples.md b/docs/examples.md
index 0e19263..0b5d386 100644
--- a/docs/examples.md
+++ b/docs/examples.md
@@ -261,7 +261,7 @@ case class Passenger(
     firstName: String,
     age: Either[String, Int],
     flightNumber: String,
-    country: String
+    destination: String
 )
 
 object Passenger {
@@ -274,10 +274,10 @@ object Passenger {
           firstName <- row.as[String]("First Name")
           ageOpt <- row.asNonEmpty[Int]("Age")
           flightNumber <- row.as[String]("flight number")
-          country <- row.as[String]("country")
+          destination <- row.as[String]("destination")
         } yield {
           val age = ageOpt.toRight[String]("N/A")
-          Passenger(id, firstName, age, flightNumber, country)
+          Passenger(id, firstName, age, flightNumber, destination)
         }
     }
 
@@ -290,7 +290,7 @@ object Passenger {
             (p.firstName, "first_name"),
             (p.age.toString(), "age"),
             (p.flightNumber, "flight_number"),
-            (p.country, "country")
+            (p.destination, "destination")
           )
         )
     }

From 4220fb14e95bfb1a3329cd80ac15ceaf4292425b Mon Sep 17 00:00:00 2001
From: zetashift <rskaraya@gmail.com>
Date: Sat, 11 Mar 2023 20:01:02 +0100
Subject: [PATCH 09/10] Add calculating of mean ages in fs2-data example

---
 docs/examples.md | 28 +++++++++++++++++++++++++---
 1 file changed, 25 insertions(+), 3 deletions(-)

diff --git a/docs/examples.md b/docs/examples.md
index 0b5d386..5001e7a 100644
--- a/docs/examples.md
+++ b/docs/examples.md
@@ -234,6 +234,14 @@ val input = Files[IO]
 object CSVPrinter extends IOApp.Simple:
 
   val run: IO[Unit] =
+    // Let's do an aggregation of all the values in the age column
+    val meanIO =
+      input
+        .foldMap(p => (p.age.getOrElse(0), 1))
+        .compile
+        .lastOrError
+        .map((sum, count) => sum / count)
+
     input
       .evalTap(p =>
         IO.println(
@@ -241,7 +249,9 @@ object CSVPrinter extends IOApp.Simple:
         )
       )
       .compile
-      .drain
+      .drain >> meanIO.flatMap(mean =>
+      IO.println(s"The mean age of the passengers is $mean")
+    )
 ```
 
 
@@ -302,7 +312,16 @@ object CSVPrinter extends IOApp.Simple {
     .through(text.utf8.decode)
     .through(decodeUsingHeaders[Passenger]())
 
-  val run: IO[Unit] =
+
+  val run: IO[Unit] = {
+    // Let's do an aggregation of all the values in the age column
+    val meanIO =
+      input
+        .foldMap(p => (p.age.getOrElse(0), 1))
+        .compile
+        .lastOrError
+        .map((sum, count) => sum / count)
+
     input
       .evalTap(p =>
         IO.println(
@@ -310,7 +329,10 @@ object CSVPrinter extends IOApp.Simple {
         )
       )
       .compile
-      .drain
+      .drain >> meanIO.flatMap(mean =>
+      IO.println(s"The mean age of the passengers is $mean")
+    )
+  }
 }
 ```
 @:@

From 095ec121b8f4e170c0f13338a3f879406245ce88 Mon Sep 17 00:00:00 2001
From: zetashift <rskaraya@gmail.com>
Date: Sat, 11 Mar 2023 20:04:44 +0100
Subject: [PATCH 10/10] Fix scala 2 example for fs2-data

---
 docs/examples.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/docs/examples.md b/docs/examples.md
index 5001e7a..7c52023 100644
--- a/docs/examples.md
+++ b/docs/examples.md
@@ -320,7 +320,7 @@ object CSVPrinter extends IOApp.Simple {
         .foldMap(p => (p.age.getOrElse(0), 1))
         .compile
         .lastOrError
-        .map((sum, count) => sum / count)
+        .map({ case (sum, count) => sum / count})
 
     input
       .evalTap(p =>