From a60bb4c075244aeb114c657b31ddd0ad38d0f5b4 Mon Sep 17 00:00:00 2001
From: Magnus Madsen <magnusm@cs.au.dk>
Date: Tue, 10 Mar 2026 12:42:20 +0100
Subject: [PATCH 1/2] fix: update Console references to use Sys.Console and new
 effect API

- Add `use Sys.Console` import to all code blocks using the Console effect
- Replace `Console.readLine()` with `Console.readln()` to match new API
- Update printing-to-stdout.md to show the effect declaration instead of old module

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
---
 src/monadic-for-yield.md  | 12 +++++++-----
 src/next-steps.md         | 10 ++++++----
 src/printing-to-stdout.md | 18 +++++++++++-------
 3 files changed, 24 insertions(+), 16 deletions(-)

diff --git a/src/monadic-for-yield.md b/src/monadic-for-yield.md
index 3fd22246..a9a3212f 100644
--- a/src/monadic-for-yield.md
+++ b/src/monadic-for-yield.md
@@ -61,12 +61,14 @@ Similarly, we can use `forM` to work with the `Result[e, t]` data type. For
 example:
 
 ```flix
-def main(): Result[String, Unit] \ IO = 
+use Sys.Console
+
+def main(): Result[String, Unit] \ IO =
     println("Please enter your first name, last name, and age:");
     forM (
-        fstName <- Console.readLine();
-        lstName <- Console.readLine();
-        ageLine <- Console.readLine();
+        fstName <- Console.readln();
+        lstName <- Console.readln();
+        ageLine <- Console.readln();
         ageNum  <- Int32.parse(10, ageLine)
     ) yield {
         println("Hello ${lstName}, ${fstName}.");
@@ -75,7 +77,7 @@ def main(): Result[String, Unit] \ IO =
 ```
 
 Here `main` prompts the user to enter their first name, last name, and age. Each
-call to `Console.readLine` returns a `Result[String, String]` value which is
+call to `Console.readln` returns a `Result[String, String]` value which is
 either an error or the input string. Thus the local variables `fstName`,
 `lstName`, and `ageLine` are `String`s. We parse `ageLine` into an `Int32` using
 `Int32.parse`, which returns a `Result[String, Int32]` value. If every operation
diff --git a/src/next-steps.md b/src/next-steps.md
index 1a012bbb..4f56eb88 100644
--- a/src/next-steps.md
+++ b/src/next-steps.md
@@ -8,21 +8,23 @@ UNIX.
 We will use the opportunity to illustrate how to use algebraic effects in Flix.
 
 ```flix
+use Sys.Console
+
 def wc(file: String): Unit \ {Console, FileReadWithResult} = {
        match FileReadWithResult.readLines(file) {
-            case Ok(lines) => 
+            case Ok(lines) =>
                 let totalLines = List.length(lines);
                 let totalWords = List.sumWith(numberOfWords, lines);
                 Console.println("Lines: ${totalLines}, Words: ${totalWords}")
-            case Err(_) => 
+            case Err(_) =>
                 Console.println("Unable to read file: ${file}")
         }
 }
 
-def numberOfWords(s: String): Int32 = 
+def numberOfWords(s: String): Int32 =
      s |> String.words |> List.length
 
-def main(): Unit \ IO = 
+def main(): Unit \ IO =
     run {
         wc("Main.flix")
     } with Console.runWithIO
diff --git a/src/printing-to-stdout.md b/src/printing-to-stdout.md
index 20e82fbe..78ed68e4 100644
--- a/src/printing-to-stdout.md
+++ b/src/printing-to-stdout.md
@@ -21,15 +21,19 @@ The `println` function is rightfully effectful, hence it cannot be called from a
 pure function. To debug a pure function, use the builtin [debugging
 facilities](./debugging.md).
 
-## The Console Module
+## The Console Effect
 
-The `Console` module defines additional functions for reading from or writing to
-the terminal: 
+The `Console` effect defines operations for reading from and writing to the
+terminal:
 
 ```flix
-mod Console {
-    def print(x: a): Unit \ IO with ToString[a]
-    def println(x: a): Unit \ IO with ToString[a]
-    def readLine(): Result[String, String] \ IO Impure
+use Sys.Console
+
+eff Console {
+    def readln(): String
+    def print(s: String): Unit
+    def eprint(s: String): Unit
+    def println(s: String): Unit
+    def eprintln(s: String): Unit
 }
 ```

From cb153ddf70ab42b8bcc34f2b94992621911eb0da Mon Sep 17 00:00:00 2001
From: Magnus Madsen <magnus-madsen@users.noreply.github.com>
Date: Tue, 10 Mar 2026 12:43:14 +0100
Subject: [PATCH 2/2] Remove Sys.Console import from documentation

Removed unnecessary import of Sys.Console from the Console effect documentation.
---
 src/printing-to-stdout.md | 2 --
 1 file changed, 2 deletions(-)

diff --git a/src/printing-to-stdout.md b/src/printing-to-stdout.md
index 78ed68e4..bac41fe4 100644
--- a/src/printing-to-stdout.md
+++ b/src/printing-to-stdout.md
@@ -27,8 +27,6 @@ The `Console` effect defines operations for reading from and writing to the
 terminal:
 
 ```flix
-use Sys.Console
-
 eff Console {
     def readln(): String
     def print(s: String): Unit