From b6e8ae5c706c60fe4ed8e5e02b6c14373ff1b4ea Mon Sep 17 00:00:00 2001
From: Nenad <xinef.it@gmail.com>
Date: Tue, 5 Aug 2025 19:00:13 +0200
Subject: [PATCH 01/15] implement tests and stub

---
 .../concept/rpn-calculator/.meta/config.json  |   4 +-
 exercises/concept/rpn-calculator/Scarb.toml   |   7 +
 .../concept/rpn-calculator/src/lib.cairo      |  14 ++
 .../rpn-calculator/tests/rpn_calculator.cairo | 171 ++++++++++++++++++
 4 files changed, 194 insertions(+), 2 deletions(-)

diff --git a/exercises/concept/rpn-calculator/.meta/config.json b/exercises/concept/rpn-calculator/.meta/config.json
index b8399302..b26a480c 100644
--- a/exercises/concept/rpn-calculator/.meta/config.json
+++ b/exercises/concept/rpn-calculator/.meta/config.json
@@ -1,6 +1,6 @@
 {
   "authors": [
-    "<your_gh_username>"
+    "0xNeshi"
   ],
   "files": {
     "solution": [
@@ -19,5 +19,5 @@
   "forked_from": [
     "rust/rpn-calculator"
   ],
-  "blurb": "Use some of `Array`'s methods to evaluate Reverse Polish notation"
+  "blurb": "Use some of `Span`'s methods to evaluate Reverse Polish notation"
 }
diff --git a/exercises/concept/rpn-calculator/Scarb.toml b/exercises/concept/rpn-calculator/Scarb.toml
index e69de29b..08bc8d35 100644
--- a/exercises/concept/rpn-calculator/Scarb.toml
+++ b/exercises/concept/rpn-calculator/Scarb.toml
@@ -0,0 +1,7 @@
+[package]
+name = "rpn_calculator"
+version = "0.1.0"
+edition = "2024_07"
+
+[dev-dependencies]
+cairo_test = "2.9.2"
diff --git a/exercises/concept/rpn-calculator/src/lib.cairo b/exercises/concept/rpn-calculator/src/lib.cairo
index e69de29b..6fef9108 100644
--- a/exercises/concept/rpn-calculator/src/lib.cairo
+++ b/exercises/concept/rpn-calculator/src/lib.cairo
@@ -0,0 +1,14 @@
+#[derive(Debug, Drop)]
+pub enum CalculatorInput {
+    Add,
+    Subtract,
+    Multiply,
+    Divide,
+    Value: i32,
+}
+
+pub fn evaluate(inputs: Span<CalculatorInput>) -> Option<i32> {
+    panic!(
+        "Given the inputs: {inputs:?}, evaluate them as though they were a Reverse Polish notation expression",
+    )
+}
diff --git a/exercises/concept/rpn-calculator/tests/rpn_calculator.cairo b/exercises/concept/rpn-calculator/tests/rpn_calculator.cairo
index e69de29b..6cfda6ec 100644
--- a/exercises/concept/rpn-calculator/tests/rpn_calculator.cairo
+++ b/exercises/concept/rpn-calculator/tests/rpn_calculator.cairo
@@ -0,0 +1,171 @@
+use rpn_calculator::*;
+
+fn calculator_input(s: ByteArray) -> Span<CalculatorInput> {
+    let mut calc_input = ArrayTrait::new();
+
+    let components = split_input_into_components(s);
+    for c in components {
+        let ci = if c == @"+" {
+            CalculatorInput::Add
+        } else if c == @"-" {
+            CalculatorInput::Subtract
+        } else if c == @"*" {
+            CalculatorInput::Multiply
+        } else if c == @"/" {
+            CalculatorInput::Divide
+        } else {
+            CalculatorInput::Value(parse_int(c).unwrap())
+        };
+        calc_input.append(ci)
+    };
+
+    calc_input.span()
+}
+
+
+fn parse_int(num: @ByteArray) -> Option<i32> {
+    let mut result: Option<i32> = Option::Some(0);
+    let mut size = num.len();
+    let mut i = 0;
+
+    let mut is_signed = false;
+    if num.at(i).unwrap() == '-' {
+        is_signed = true;
+        i += 1;
+    }
+
+    for i in i..size {
+        match char_to_digit(num[i]) {
+            Option::Some(v) => {
+                if let Option::Some(num) = result {
+                    result = Option::Some(num * 10 + v.into());
+                }
+            },
+            Option::None => {
+                result = Option::None;
+                break;
+            },
+        }
+    };
+
+    if let Option::Some(val) = result {
+        if (is_signed) {
+            result = Option::Some(val * -1)
+        }
+    }
+    result
+}
+
+
+// Utility function to convert a char representing a digit into its numerical value (u32 equivalent)
+fn char_to_digit(c: u8) -> Option<u8> {
+    let zero_ascii = '0';
+    let nine_ascii = '9';
+
+    if c >= zero_ascii && c <= nine_ascii {
+        Option::Some(c - zero_ascii)
+    } else {
+        Option::None // Return None for invalid characters
+    }
+}
+
+fn split_input_into_components(input: ByteArray) -> Span<ByteArray> {
+    let mut components: Array<ByteArray> = ArrayTrait::new();
+    let mut current_component = "";
+
+    let mut i = 0;
+    while i < input.len() {
+        let char = input[i];
+
+        if char == ' ' {
+            components.append(current_component.clone());
+            current_component = "";
+        } else {
+            current_component.append_byte(char);
+        }
+
+        i += 1;
+    };
+
+    if current_component.len() > 0 {
+        components.append(current_component);
+    }
+
+    components.span()
+}
+
+#[test]
+fn empty_input_returns_none() {
+    let input = calculator_input("");
+    assert_eq!(evaluate(input), Option::None);
+}
+
+#[test]
+#[ignore]
+fn simple_value() {
+    let input = calculator_input("10");
+    assert_eq!(evaluate(input), Option::Some(10));
+}
+
+#[test]
+#[ignore]
+fn simple_addition() {
+    let input = calculator_input("2 2 +");
+    assert_eq!(evaluate(input), Option::Some(4));
+}
+
+#[test]
+#[ignore]
+fn simple_subtraction() {
+    let input = calculator_input("7 11 -");
+    assert_eq!(evaluate(input), Option::Some(-4));
+}
+
+#[test]
+#[ignore]
+fn simple_multiplication() {
+    let input = calculator_input("6 9 *");
+    assert_eq!(evaluate(input), Option::Some(54));
+}
+
+#[test]
+#[ignore]
+fn simple_division() {
+    let input = calculator_input("57 19 /");
+    assert_eq!(evaluate(input), Option::Some(3));
+}
+
+#[test]
+#[ignore]
+fn complex_operation() {
+    let input = calculator_input("4 8 + 7 5 - /");
+    assert_eq!(evaluate(input), Option::Some(6));
+}
+
+#[test]
+#[ignore]
+fn too_few_operands_returns_none() {
+    let input = calculator_input("2 +");
+    assert_eq!(evaluate(input), Option::None);
+}
+
+#[test]
+#[ignore]
+fn too_many_operands_returns_none() {
+    let input = calculator_input("2 2");
+    assert_eq!(evaluate(input), Option::None);
+}
+
+#[test]
+#[ignore]
+fn zero_operands_returns_none() {
+    let input = calculator_input("+");
+    assert_eq!(evaluate(input), Option::None);
+}
+
+#[test]
+#[ignore]
+fn intermediate_error_returns_none() {
+    let input = calculator_input("+ 2 2 *");
+    assert_eq!(evaluate(input), Option::None);
+}

From 564c2fa5ea1f5b2b2951f23e64e3a271860d2a4d Mon Sep 17 00:00:00 2001
From: Nenad <xinef.it@gmail.com>
Date: Tue, 5 Aug 2025 21:45:26 +0200
Subject: [PATCH 02/15] impl exemplar

---
 .../rpn-calculator/.meta/exemplar.cairo       | 113 ++++++++++++++++++
 .../concept/rpn-calculator/src/lib.cairo      |   2 +-
 2 files changed, 114 insertions(+), 1 deletion(-)

diff --git a/exercises/concept/rpn-calculator/.meta/exemplar.cairo b/exercises/concept/rpn-calculator/.meta/exemplar.cairo
index e69de29b..e3329a96 100644
--- a/exercises/concept/rpn-calculator/.meta/exemplar.cairo
+++ b/exercises/concept/rpn-calculator/.meta/exemplar.cairo
@@ -0,0 +1,113 @@
+#[derive(Drop, Debug)]
+pub enum CalculatorInput {
+    Add,
+    Subtract,
+    Multiply,
+    Divide,
+    Value: i32,
+}
+
+pub fn evaluate(inputs: Span<CalculatorInput>) -> Option<i32> {
+    let mut stack: Array<i32> = ArrayTrait::new();
+
+    let mut cancelled = false;
+
+    for input in inputs {
+        match input {
+            CalculatorInput::Add => {
+                let mut stack_span = stack.span();
+                let rhs = match stack_span.pop_back() {
+                    Option::Some(value) => *value,
+                    Option::None => {
+                        cancelled = true;
+                        break;
+                    },
+                };
+                let lhs = match stack_span.pop_back() {
+                    Option::Some(value) => *value,
+                    Option::None => {
+                        cancelled = true;
+                        break;
+                    },
+                };
+                stack = array![];
+                stack.append_span(stack_span);
+                stack.append(lhs + rhs);
+            },
+            CalculatorInput::Subtract => {
+                let mut stack_span = stack.span();
+                let rhs = match stack_span.pop_back() {
+                    Option::Some(value) => *value,
+                    Option::None => {
+                        cancelled = true;
+                        break;
+                    },
+                };
+                let lhs = match stack_span.pop_back() {
+                    Option::Some(value) => *value,
+                    Option::None => {
+                        cancelled = true;
+                        break;
+                    },
+                };
+
+                stack = array![];
+                stack.append_span(stack_span);
+                stack.append(lhs - rhs);
+            },
+            CalculatorInput::Multiply => {
+                let mut stack_span = stack.span();
+                let rhs = match stack_span.pop_back() {
+                    Option::Some(value) => *value,
+                    Option::None => {
+                        cancelled = true;
+                        break;
+                    },
+                };
+                let lhs = match stack_span.pop_back() {
+                    Option::Some(value) => *value,
+                    Option::None => {
+                        cancelled = true;
+                        break;
+                    },
+                };
+
+                stack = array![];
+                stack.append_span(stack_span);
+                stack.append(lhs * rhs);
+            },
+            CalculatorInput::Divide => {
+                let mut stack_span = stack.span();
+                let rhs = match stack_span.pop_back() {
+                    Option::Some(value) => *value,
+                    Option::None => {
+                        cancelled = true;
+                        break;
+                    },
+                };
+                let lhs = match stack_span.pop_back() {
+                    Option::Some(value) => *value,
+                    Option::None => {
+                        cancelled = true;
+                        break;
+                    },
+                };
+                stack = array![];
+                stack.append_span(stack_span);
+                stack.append(lhs / rhs);
+            },
+            CalculatorInput::Value(value) => stack.append(*value),
+        }
+    };
+
+    if cancelled {
+        return Option::None;
+    }
+
+    let output = stack.pop_front();
+    if stack.is_empty() {
+        output
+    } else {
+        Option::None
+    }
+}
diff --git a/exercises/concept/rpn-calculator/src/lib.cairo b/exercises/concept/rpn-calculator/src/lib.cairo
index 6fef9108..291502f4 100644
--- a/exercises/concept/rpn-calculator/src/lib.cairo
+++ b/exercises/concept/rpn-calculator/src/lib.cairo
@@ -1,4 +1,4 @@
-#[derive(Debug, Drop)]
+#[derive(Drop, Debug)]
 pub enum CalculatorInput {
     Add,
     Subtract,

From ef05a51fa0e8ecaff82817fa0127dda8b15ce3d5 Mon Sep 17 00:00:00 2001
From: Nenad <xinef.it@gmail.com>
Date: Tue, 5 Aug 2025 22:52:19 +0200
Subject: [PATCH 03/15] ref to use panics (broken)

---
 .../concept/rpn-calculator/.meta/design.md    | 22 +++++++++++++++++++
 .../concept/rpn-calculator/src/lib.cairo      |  6 ++---
 .../rpn-calculator/tests/rpn_calculator.cairo | 12 +++++-----
 3 files changed, 30 insertions(+), 10 deletions(-)

diff --git a/exercises/concept/rpn-calculator/.meta/design.md b/exercises/concept/rpn-calculator/.meta/design.md
index e69de29b..290fb652 100644
--- a/exercises/concept/rpn-calculator/.meta/design.md
+++ b/exercises/concept/rpn-calculator/.meta/design.md
@@ -0,0 +1,22 @@
+# Design
+
+## Learning objectives
+
+- Know how to use control flow constructs.
+- Know how to use enums.
+- Know how to use pattern matching.
+
+## Out of scope
+
+- Generic enums.
+- `if let` and `while let` statements.
+- The `Option` and `Result` enums.
+
+## Concepts
+
+- Control flow
+- Enums
+
+## Prerequisites
+
+- Arrays
diff --git a/exercises/concept/rpn-calculator/src/lib.cairo b/exercises/concept/rpn-calculator/src/lib.cairo
index 291502f4..627c265d 100644
--- a/exercises/concept/rpn-calculator/src/lib.cairo
+++ b/exercises/concept/rpn-calculator/src/lib.cairo
@@ -7,8 +7,6 @@ pub enum CalculatorInput {
     Value: i32,
 }
 
-pub fn evaluate(inputs: Span<CalculatorInput>) -> Option<i32> {
-    panic!(
-        "Given the inputs: {inputs:?}, evaluate them as though they were a Reverse Polish notation expression",
-    )
+pub fn evaluate(inputs: Span<CalculatorInput>) -> i32 {
+    panic!("implement `evaluate`")
 }
diff --git a/exercises/concept/rpn-calculator/tests/rpn_calculator.cairo b/exercises/concept/rpn-calculator/tests/rpn_calculator.cairo
index 6cfda6ec..66fca248 100644
--- a/exercises/concept/rpn-calculator/tests/rpn_calculator.cairo
+++ b/exercises/concept/rpn-calculator/tests/rpn_calculator.cairo
@@ -104,42 +104,42 @@ fn empty_input_returns_none() {
 #[ignore]
 fn simple_value() {
     let input = calculator_input("10");
-    assert_eq!(evaluate(input), Option::Some(10));
+    assert_eq!(evaluate(input), 10);
 }
 
 #[test]
 #[ignore]
 fn simple_addition() {
     let input = calculator_input("2 2 +");
-    assert_eq!(evaluate(input), Option::Some(4));
+    assert_eq!(evaluate(input), 4);
 }
 
 #[test]
 #[ignore]
 fn simple_subtraction() {
     let input = calculator_input("7 11 -");
-    assert_eq!(evaluate(input), Option::Some(-4));
+    assert_eq!(evaluate(input), -4);
 }
 
 #[test]
 #[ignore]
 fn simple_multiplication() {
     let input = calculator_input("6 9 *");
-    assert_eq!(evaluate(input), Option::Some(54));
+    assert_eq!(evaluate(input), 54);
 }
 
 #[test]
 #[ignore]
 fn simple_division() {
     let input = calculator_input("57 19 /");
-    assert_eq!(evaluate(input), Option::Some(3));
+    assert_eq!(evaluate(input), 3);
 }
 
 #[test]
 #[ignore]
 fn complex_operation() {
     let input = calculator_input("4 8 + 7 5 - /");
-    assert_eq!(evaluate(input), Option::Some(6));
+    assert_eq!(evaluate(input), 6);
 }
 
 #[test]

From cc151073074fe490aba184ad2eed110c0ad4da3b Mon Sep 17 00:00:00 2001
From: Nenad <xinef.it@gmail.com>
Date: Sat, 9 Aug 2025 14:33:10 +0200
Subject: [PATCH 04/15] implement a new exercise weather-report

---
 config.json                                   |  10 +-
 .../concept/rpn-calculator/.docs/hints.md     |   0
 .../rpn-calculator/.docs/instructions.md      |   0
 .../rpn-calculator/.docs/introduction.md      |   0
 .../rpn-calculator/.meta/exemplar.cairo       | 113 ------------
 .../concept/rpn-calculator/src/lib.cairo      |  12 --
 .../rpn-calculator/tests/rpn_calculator.cairo | 171 ------------------
 .../concept/weather-report/.docs/hints.md     |  15 ++
 .../weather-report/.docs/instructions.md      |  34 ++++
 .../weather-report/.docs/introduction.md      |  66 +++++++
 .../.meta/config.json                         |   5 +-
 .../.meta/design.md                           |   5 +-
 .../weather-report/.meta/exemplar.cairo       |  25 +++
 .../Scarb.toml                                |   2 +-
 .../concept/weather-report/src/lib.cairo      |  15 ++
 .../weather-report/tests/weather_report.cairo |  63 +++++++
 16 files changed, 227 insertions(+), 309 deletions(-)
 delete mode 100644 exercises/concept/rpn-calculator/.docs/hints.md
 delete mode 100644 exercises/concept/rpn-calculator/.docs/instructions.md
 delete mode 100644 exercises/concept/rpn-calculator/.docs/introduction.md
 delete mode 100644 exercises/concept/rpn-calculator/.meta/exemplar.cairo
 delete mode 100644 exercises/concept/rpn-calculator/src/lib.cairo
 delete mode 100644 exercises/concept/rpn-calculator/tests/rpn_calculator.cairo
 create mode 100644 exercises/concept/weather-report/.docs/hints.md
 create mode 100644 exercises/concept/weather-report/.docs/instructions.md
 create mode 100644 exercises/concept/weather-report/.docs/introduction.md
 rename exercises/concept/{rpn-calculator => weather-report}/.meta/config.json (66%)
 rename exercises/concept/{rpn-calculator => weather-report}/.meta/design.md (78%)
 create mode 100644 exercises/concept/weather-report/.meta/exemplar.cairo
 rename exercises/concept/{rpn-calculator => weather-report}/Scarb.toml (78%)
 create mode 100644 exercises/concept/weather-report/src/lib.cairo
 create mode 100644 exercises/concept/weather-report/tests/weather_report.cairo

diff --git a/config.json b/config.json
index e9cd57ec..382928b6 100644
--- a/config.json
+++ b/config.json
@@ -88,15 +88,15 @@
         "status": "wip"
       },
       {
-        "slug": "rpn-calculator",
-        "name": "RPN Calculator",
+        "slug": "weather-report",
+        "name": "Weather Report",
         "uuid": "536d9f09-5910-4a26-93fd-2242667b0b87",
         "concepts": [
-          "control-flow",
-          "enums"
+          "enums",
+          "match-basics"
         ],
         "prerequisites": [
-          "arrays"
+          "felts"
         ],
         "status": "wip"
       },
diff --git a/exercises/concept/rpn-calculator/.docs/hints.md b/exercises/concept/rpn-calculator/.docs/hints.md
deleted file mode 100644
index e69de29b..00000000
diff --git a/exercises/concept/rpn-calculator/.docs/instructions.md b/exercises/concept/rpn-calculator/.docs/instructions.md
deleted file mode 100644
index e69de29b..00000000
diff --git a/exercises/concept/rpn-calculator/.docs/introduction.md b/exercises/concept/rpn-calculator/.docs/introduction.md
deleted file mode 100644
index e69de29b..00000000
diff --git a/exercises/concept/rpn-calculator/.meta/exemplar.cairo b/exercises/concept/rpn-calculator/.meta/exemplar.cairo
deleted file mode 100644
index e3329a96..00000000
--- a/exercises/concept/rpn-calculator/.meta/exemplar.cairo
+++ /dev/null
@@ -1,113 +0,0 @@
-#[derive(Drop, Debug)]
-pub enum CalculatorInput {
-    Add,
-    Subtract,
-    Multiply,
-    Divide,
-    Value: i32,
-}
-
-pub fn evaluate(inputs: Span<CalculatorInput>) -> Option<i32> {
-    let mut stack: Array<i32> = ArrayTrait::new();
-
-    let mut cancelled = false;
-
-    for input in inputs {
-        match input {
-            CalculatorInput::Add => {
-                let mut stack_span = stack.span();
-                let rhs = match stack_span.pop_back() {
-                    Option::Some(value) => *value,
-                    Option::None => {
-                        cancelled = true;
-                        break;
-                    },
-                };
-                let lhs = match stack_span.pop_back() {
-                    Option::Some(value) => *value,
-                    Option::None => {
-                        cancelled = true;
-                        break;
-                    },
-                };
-                stack = array![];
-                stack.append_span(stack_span);
-                stack.append(lhs + rhs);
-            },
-            CalculatorInput::Subtract => {
-                let mut stack_span = stack.span();
-                let rhs = match stack_span.pop_back() {
-                    Option::Some(value) => *value,
-                    Option::None => {
-                        cancelled = true;
-                        break;
-                    },
-                };
-                let lhs = match stack_span.pop_back() {
-                    Option::Some(value) => *value,
-                    Option::None => {
-                        cancelled = true;
-                        break;
-                    },
-                };
-
-                stack = array![];
-                stack.append_span(stack_span);
-                stack.append(lhs - rhs);
-            },
-            CalculatorInput::Multiply => {
-                let mut stack_span = stack.span();
-                let rhs = match stack_span.pop_back() {
-                    Option::Some(value) => *value,
-                    Option::None => {
-                        cancelled = true;
-                        break;
-                    },
-                };
-                let lhs = match stack_span.pop_back() {
-                    Option::Some(value) => *value,
-                    Option::None => {
-                        cancelled = true;
-                        break;
-                    },
-                };
-
-                stack = array![];
-                stack.append_span(stack_span);
-                stack.append(lhs * rhs);
-            },
-            CalculatorInput::Divide => {
-                let mut stack_span = stack.span();
-                let rhs = match stack_span.pop_back() {
-                    Option::Some(value) => *value,
-                    Option::None => {
-                        cancelled = true;
-                        break;
-                    },
-                };
-                let lhs = match stack_span.pop_back() {
-                    Option::Some(value) => *value,
-                    Option::None => {
-                        cancelled = true;
-                        break;
-                    },
-                };
-                stack = array![];
-                stack.append_span(stack_span);
-                stack.append(lhs / rhs);
-            },
-            CalculatorInput::Value(value) => stack.append(*value),
-        }
-    };
-
-    if cancelled {
-        return Option::None;
-    }
-
-    let output = stack.pop_front();
-    if stack.is_empty() {
-        output
-    } else {
-        Option::None
-    }
-}
diff --git a/exercises/concept/rpn-calculator/src/lib.cairo b/exercises/concept/rpn-calculator/src/lib.cairo
deleted file mode 100644
index 627c265d..00000000
--- a/exercises/concept/rpn-calculator/src/lib.cairo
+++ /dev/null
@@ -1,12 +0,0 @@
-#[derive(Drop, Debug)]
-pub enum CalculatorInput {
-    Add,
-    Subtract,
-    Multiply,
-    Divide,
-    Value: i32,
-}
-
-pub fn evaluate(inputs: Span<CalculatorInput>) -> i32 {
-    panic!("implement `evaluate`")
-}
diff --git a/exercises/concept/rpn-calculator/tests/rpn_calculator.cairo b/exercises/concept/rpn-calculator/tests/rpn_calculator.cairo
deleted file mode 100644
index 66fca248..00000000
--- a/exercises/concept/rpn-calculator/tests/rpn_calculator.cairo
+++ /dev/null
@@ -1,171 +0,0 @@
-use rpn_calculator::*;
-
-fn calculator_input(s: ByteArray) -> Span<CalculatorInput> {
-    let mut calc_input = ArrayTrait::new();
-
-    let components = split_input_into_components(s);
-    for c in components {
-        let ci = if c == @"+" {
-            CalculatorInput::Add
-        } else if c == @"-" {
-            CalculatorInput::Subtract
-        } else if c == @"*" {
-            CalculatorInput::Multiply
-        } else if c == @"/" {
-            CalculatorInput::Divide
-        } else {
-            CalculatorInput::Value(parse_int(c).unwrap())
-        };
-        calc_input.append(ci)
-    };
-
-    calc_input.span()
-}
-
-
-fn parse_int(num: @ByteArray) -> Option<i32> {
-    let mut result: Option<i32> = Option::Some(0);
-    let mut size = num.len();
-    let mut i = 0;
-
-    let mut is_signed = false;
-    if num.at(i).unwrap() == '-' {
-        is_signed = true;
-        i += 1;
-    }
-
-    for i in i..size {
-        match char_to_digit(num[i]) {
-            Option::Some(v) => {
-                if let Option::Some(num) = result {
-                    result = Option::Some(num * 10 + v.into());
-                }
-            },
-            Option::None => {
-                result = Option::None;
-                break;
-            },
-        }
-    };
-
-    if let Option::Some(val) = result {
-        if (is_signed) {
-            result = Option::Some(val * -1)
-        }
-    }
-    result
-}
-
-
-// Utility function to convert a char representing a digit into its numerical value (u32 equivalent)
-fn char_to_digit(c: u8) -> Option<u8> {
-    let zero_ascii = '0';
-    let nine_ascii = '9';
-
-    if c >= zero_ascii && c <= nine_ascii {
-        Option::Some(c - zero_ascii)
-    } else {
-        Option::None // Return None for invalid characters
-    }
-}
-
-fn split_input_into_components(input: ByteArray) -> Span<ByteArray> {
-    let mut components: Array<ByteArray> = ArrayTrait::new();
-    let mut current_component = "";
-
-    let mut i = 0;
-    while i < input.len() {
-        let char = input[i];
-
-        if char == ' ' {
-            components.append(current_component.clone());
-            current_component = "";
-        } else {
-            current_component.append_byte(char);
-        }
-
-        i += 1;
-    };
-
-    if current_component.len() > 0 {
-        components.append(current_component);
-    }
-
-    components.span()
-}
-
-#[test]
-fn empty_input_returns_none() {
-    let input = calculator_input("");
-    assert_eq!(evaluate(input), Option::None);
-}
-
-#[test]
-#[ignore]
-fn simple_value() {
-    let input = calculator_input("10");
-    assert_eq!(evaluate(input), 10);
-}
-
-#[test]
-#[ignore]
-fn simple_addition() {
-    let input = calculator_input("2 2 +");
-    assert_eq!(evaluate(input), 4);
-}
-
-#[test]
-#[ignore]
-fn simple_subtraction() {
-    let input = calculator_input("7 11 -");
-    assert_eq!(evaluate(input), -4);
-}
-
-#[test]
-#[ignore]
-fn simple_multiplication() {
-    let input = calculator_input("6 9 *");
-    assert_eq!(evaluate(input), 54);
-}
-
-#[test]
-#[ignore]
-fn simple_division() {
-    let input = calculator_input("57 19 /");
-    assert_eq!(evaluate(input), 3);
-}
-
-#[test]
-#[ignore]
-fn complex_operation() {
-    let input = calculator_input("4 8 + 7 5 - /");
-    assert_eq!(evaluate(input), 6);
-}
-
-#[test]
-#[ignore]
-fn too_few_operands_returns_none() {
-    let input = calculator_input("2 +");
-    assert_eq!(evaluate(input), Option::None);
-}
-
-#[test]
-#[ignore]
-fn too_many_operands_returns_none() {
-    let input = calculator_input("2 2");
-    assert_eq!(evaluate(input), Option::None);
-}
-
-#[test]
-#[ignore]
-fn zero_operands_returns_none() {
-    let input = calculator_input("+");
-    assert_eq!(evaluate(input), Option::None);
-}
-
-#[test]
-#[ignore]
-fn intermediate_error_returns_none() {
-    let input = calculator_input("+ 2 2 *");
-    assert_eq!(evaluate(input), Option::None);
-}
diff --git a/exercises/concept/weather-report/.docs/hints.md b/exercises/concept/weather-report/.docs/hints.md
new file mode 100644
index 00000000..b5f97f98
--- /dev/null
+++ b/exercises/concept/weather-report/.docs/hints.md
@@ -0,0 +1,15 @@
+# Hints
+
+## General
+
+- [The Cairo Book - Enums][tcb-enums]
+- [The Cairo Book - Match][tcb-match]
+
+## 1. Generate weather reports
+
+- `match` comes in handy when working with enums.
+  In this case, see how you might use it when figuring out what kind of weather report to generate.
+- Remember to convert the enum variants to uppercase strings in your reports.
+
+[tcb-enums]: https://www.starknet.io/cairo-book/ch06-01-enums.html
+[tcb-match]: https://www.starknet.io/cairo-book/ch06-02-the-match-control-flow-construct.html
diff --git a/exercises/concept/weather-report/.docs/instructions.md b/exercises/concept/weather-report/.docs/instructions.md
new file mode 100644
index 00000000..0abd8487
--- /dev/null
+++ b/exercises/concept/weather-report/.docs/instructions.md
@@ -0,0 +1,34 @@
+# Instructions
+
+In this exercise you'll be generating weather reports for a local news station.
+
+## Generate weather reports
+
+You'll start with some stubbed functions and the following enum:
+
+```rust
+#[derive(Drop, Clone, PartialEq, Debug)]
+pub enum WeatherCondition {
+    Sunny,
+    Rainy,
+    Cloudy,
+    Stormy
+}
+```
+
+Your goal is to emit a weather report as follows: `"Today is <CONDITION> with a temperature of <TEMPERATURE> degrees Celsius."`.
+You'll need to implement functions that correspond with weather conditions.
+
+For example, the below snippet demonstrates an expected output for the `get_weather_report` function.
+
+```rust
+get_weather_report(WeatherCondition::Rainy, "25")
+// Returns: "Today is RAINY with a temperature of 25 degrees Celsius."
+```
+
+And for `sunny_day`:
+
+```rust
+get_weather_report(WeatherCondition::Sunny, "30")
+// Returns: "Today is SUNNY with a temperature of 30 degrees Celsius."
+```
diff --git a/exercises/concept/weather-report/.docs/introduction.md b/exercises/concept/weather-report/.docs/introduction.md
new file mode 100644
index 00000000..a326e963
--- /dev/null
+++ b/exercises/concept/weather-report/.docs/introduction.md
@@ -0,0 +1,66 @@
+# Introduction
+
+Enums in Cairo allow you to define a type that can be one of several named variants.
+
+## Basics
+
+Enums, short for enumerations, limit all possible values of some data to a predefined set. The possible values of an `enum` are called variants:
+
+```rust
+#[derive(Drop)]
+enum Direction {
+    North,
+    South,
+    East,
+    West,
+}
+```
+
+Create enum values by specifying the variant:
+
+```rust
+let my_direction = Direction::North;
+let another_direction = Direction::West;
+```
+
+## Pattern Matching
+
+Use match to handle different enum variants:
+
+```rust
+match my_direction {
+    Direction::North => println!("Going north!"),
+    Direction::South => println!("Going south!"),
+    Direction::East => println!("Going east!"),
+    Direction::West => println!("Going west!"),
+}
+```
+
+Each arm of the match handles one variant of the enum.
+
+## Enums with Data
+
+Enum variants can hold additional data:
+
+```rust
+struct Location {
+    x: u32,
+    y: u32,
+}
+
+enum Message {
+    Text: ByteArray,
+    Number: u32,
+    Location: Location,
+}
+```
+
+Pattern match to extract the data:
+
+```rust
+match msg {
+    Message::Text(content) => println!("Text: {}", content),
+    Message::Number(val) => println!("Number: {}", val),
+    Message::Location(Location { x, y }) => println!("Position: ({}, {})", x, y),
+}
+```
diff --git a/exercises/concept/rpn-calculator/.meta/config.json b/exercises/concept/weather-report/.meta/config.json
similarity index 66%
rename from exercises/concept/rpn-calculator/.meta/config.json
rename to exercises/concept/weather-report/.meta/config.json
index b26a480c..3f0e8845 100644
--- a/exercises/concept/rpn-calculator/.meta/config.json
+++ b/exercises/concept/weather-report/.meta/config.json
@@ -16,8 +16,5 @@
       "Scarb.toml"
     ]
   },
-  "forked_from": [
-    "rust/rpn-calculator"
-  ],
-  "blurb": "Use some of `Span`'s methods to evaluate Reverse Polish notation"
+  "blurb": "Learn enums while building a weather reporting system."
 }
diff --git a/exercises/concept/rpn-calculator/.meta/design.md b/exercises/concept/weather-report/.meta/design.md
similarity index 78%
rename from exercises/concept/rpn-calculator/.meta/design.md
rename to exercises/concept/weather-report/.meta/design.md
index 290fb652..9a3ad6e4 100644
--- a/exercises/concept/rpn-calculator/.meta/design.md
+++ b/exercises/concept/weather-report/.meta/design.md
@@ -2,7 +2,6 @@
 
 ## Learning objectives
 
-- Know how to use control flow constructs.
 - Know how to use enums.
 - Know how to use pattern matching.
 
@@ -14,9 +13,9 @@
 
 ## Concepts
 
-- Control flow
 - Enums
+- Pattern matching basics
 
 ## Prerequisites
 
-- Arrays
+- Felts
diff --git a/exercises/concept/weather-report/.meta/exemplar.cairo b/exercises/concept/weather-report/.meta/exemplar.cairo
new file mode 100644
index 00000000..7027b49c
--- /dev/null
+++ b/exercises/concept/weather-report/.meta/exemplar.cairo
@@ -0,0 +1,25 @@
+#[derive(Drop)]
+pub enum WeatherCondition {
+    Sunny,
+    Rainy,
+    Cloudy,
+    Stormy,
+}
+
+pub fn get_weather_report(condition: WeatherCondition, temperature: ByteArray) -> ByteArray {
+    match condition {
+        WeatherCondition::Sunny => format!(
+            "Today is SUNNY with a temperature of {temperature} degrees Celsius.",
+        ),
+        WeatherCondition::Rainy => format!(
+            "Today is RAINY with a temperature of {temperature} degrees Celsius.",
+        ),
+        WeatherCondition::Cloudy => format!(
+            "Today is CLOUDY with a temperature of {temperature} degrees Celsius.",
+        ),
+        WeatherCondition::Stormy => format!(
+            "Today is STORMY with a temperature of {temperature} degrees Celsius.",
+        ),
+    }
+}
+
diff --git a/exercises/concept/rpn-calculator/Scarb.toml b/exercises/concept/weather-report/Scarb.toml
similarity index 78%
rename from exercises/concept/rpn-calculator/Scarb.toml
rename to exercises/concept/weather-report/Scarb.toml
index 08bc8d35..1ff0d4ce 100644
--- a/exercises/concept/rpn-calculator/Scarb.toml
+++ b/exercises/concept/weather-report/Scarb.toml
@@ -1,5 +1,5 @@
 [package]
-name = "rpn_calculator"
+name = "weather_report"
 version = "0.1.0"
 edition = "2024_07"
 
diff --git a/exercises/concept/weather-report/src/lib.cairo b/exercises/concept/weather-report/src/lib.cairo
new file mode 100644
index 00000000..63f11c7b
--- /dev/null
+++ b/exercises/concept/weather-report/src/lib.cairo
@@ -0,0 +1,15 @@
+/// various weather conditions
+#[derive(Drop)]
+pub enum WeatherCondition {
+    Sunny,
+    Rainy,
+    Cloudy,
+    Stormy,
+}
+
+/// primary function for generating weather reports
+pub fn get_weather_report(condition: WeatherCondition, temperature: ByteArray) -> ByteArray {
+    // return a weather report for the given condition
+    panic!("implement `get_weather_report`")
+}
+
diff --git a/exercises/concept/weather-report/tests/weather_report.cairo b/exercises/concept/weather-report/tests/weather_report.cairo
new file mode 100644
index 00000000..bec1976b
--- /dev/null
+++ b/exercises/concept/weather-report/tests/weather_report.cairo
@@ -0,0 +1,63 @@
+use weather_report::{get_weather_report, WeatherCondition};
+
+#[test]
+fn reports_sunny_weather() {
+    assert_eq!(
+        get_weather_report(WeatherCondition::Sunny, "30"),
+        "Today is SUNNY with a temperature of 30 degrees Celsius.",
+    );
+}
+
+#[test]
+#[ignore]
+fn reports_rainy_weather() {
+    assert_eq!(
+        get_weather_report(WeatherCondition::Rainy, "25"),
+        "Today is RAINY with a temperature of 25 degrees Celsius.",
+    );
+}
+
+#[test]
+#[ignore]
+fn reports_cloudy_weather() {
+    assert_eq!(
+        get_weather_report(WeatherCondition::Cloudy, "27"),
+        "Today is CLOUDY with a temperature of 27 degrees Celsius.",
+    );
+}
+
+#[test]
+#[ignore]
+fn get_weather_report_sunny() {
+    assert_eq!(
+        get_weather_report(WeatherCondition::Sunny, "35"),
+        "Today is SUNNY with a temperature of 35 degrees Celsius.",
+    );
+}
+
+#[test]
+#[ignore]
+fn get_weather_report_rainy() {
+    assert_eq!(
+        get_weather_report(WeatherCondition::Rainy, "20"),
+        "Today is RAINY with a temperature of 20 degrees Celsius.",
+    );
+}
+
+#[test]
+#[ignore]
+fn get_weather_report_cloudy() {
+    assert_eq!(
+        get_weather_report(WeatherCondition::Cloudy, "22"),
+        "Today is CLOUDY with a temperature of 22 degrees Celsius.",
+    );
+}
+
+#[test]
+#[ignore]
+fn add_stormy_variant() {
+    assert_eq!(
+        get_weather_report(WeatherCondition::Stormy, "15"),
+        "Today is STORMY with a temperature of 15 degrees Celsius.",
+    );
+}

From ef405410c598cf0f3628822594ca1c1b8c203fda Mon Sep 17 00:00:00 2001
From: Nenad <xinef.it@gmail.com>
Date: Sat, 9 Aug 2025 14:37:41 +0200
Subject: [PATCH 05/15] fix config name

---
 exercises/concept/weather-report/.docs/introduction.md | 3 ++-
 exercises/concept/weather-report/.meta/config.json     | 2 +-
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/exercises/concept/weather-report/.docs/introduction.md b/exercises/concept/weather-report/.docs/introduction.md
index a326e963..68041012 100644
--- a/exercises/concept/weather-report/.docs/introduction.md
+++ b/exercises/concept/weather-report/.docs/introduction.md
@@ -4,7 +4,8 @@ Enums in Cairo allow you to define a type that can be one of several named varia
 
 ## Basics
 
-Enums, short for enumerations, limit all possible values of some data to a predefined set. The possible values of an `enum` are called variants:
+Enums, short for enumerations, limit all possible values of some data to a predefined set.
+The possible values of an `enum` are called variants:
 
 ```rust
 #[derive(Drop)]
diff --git a/exercises/concept/weather-report/.meta/config.json b/exercises/concept/weather-report/.meta/config.json
index 3f0e8845..b50232ca 100644
--- a/exercises/concept/weather-report/.meta/config.json
+++ b/exercises/concept/weather-report/.meta/config.json
@@ -7,7 +7,7 @@
       "src/lib.cairo"
     ],
     "test": [
-      "tests/rpn_calculator.cairo"
+      "tests/weather_report.cairo"
     ],
     "exemplar": [
       ".meta/exemplar.cairo"

From 73cf4345e148d94707219d392a046a4ea4f85b43 Mon Sep 17 00:00:00 2001
From: Nenad <xinef.it@gmail.com>
Date: Sun, 10 Aug 2025 10:32:05 +0200
Subject: [PATCH 06/15] change prerequisite to functions

---
 config.json | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/config.json b/config.json
index 382928b6..5523da8b 100644
--- a/config.json
+++ b/config.json
@@ -96,7 +96,7 @@
           "match-basics"
         ],
         "prerequisites": [
-          "felts"
+          "functions"
         ],
         "status": "wip"
       },

From 418cc80ff63b45d1f5b951d6597b8d561e0224fc Mon Sep 17 00:00:00 2001
From: Nenad <xinef.it@gmail.com>
Date: Sun, 10 Aug 2025 10:33:59 +0200
Subject: [PATCH 07/15] wip -> beta

---
 config.json | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/config.json b/config.json
index 5523da8b..ce0f718d 100644
--- a/config.json
+++ b/config.json
@@ -98,7 +98,7 @@
         "prerequisites": [
           "functions"
         ],
-        "status": "wip"
+        "status": "beta"
       },
       {
         "slug": "welcome-to-tech-palace",

From ab57e880db6e1ad0687c7446e80ead01a9248e55 Mon Sep 17 00:00:00 2001
From: Nenad <xinef.it@gmail.com>
Date: Sun, 17 Aug 2025 09:47:47 +0200
Subject: [PATCH 08/15] Update
 exercises/concept/weather-report/.docs/instructions.md
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Co-authored-by: András B Nagy <20251272+BNAndras@users.noreply.github.com>
---
 exercises/concept/weather-report/.docs/instructions.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/exercises/concept/weather-report/.docs/instructions.md b/exercises/concept/weather-report/.docs/instructions.md
index 0abd8487..60b2ff1b 100644
--- a/exercises/concept/weather-report/.docs/instructions.md
+++ b/exercises/concept/weather-report/.docs/instructions.md
@@ -16,7 +16,7 @@ pub enum WeatherCondition {
 }
 ```
 
-Your goal is to emit a weather report as follows: `"Today is <CONDITION> with a temperature of <TEMPERATURE> degrees Celsius."`.
+You will need to format a weather report like `"Today is <CONDITION> with a temperature of <TEMPERATURE> degrees Celsius."`.
 You'll need to implement functions that correspond with weather conditions.
 
 For example, the below snippet demonstrates an expected output for the `get_weather_report` function.

From c83612ea1fd7dc2da789e192571b80ea757a0c68 Mon Sep 17 00:00:00 2001
From: 0xNeshi <xinef.it@gmail.com>
Date: Sun, 17 Aug 2025 10:04:14 +0200
Subject: [PATCH 09/15] apply review suggestions

---
 .../concept/weather-report/.docs/instructions.md   |  6 +++---
 .../concept/weather-report/.meta/exemplar.cairo    |  2 +-
 exercises/concept/weather-report/src/lib.cairo     |  2 +-
 .../weather-report/tests/weather_report.cairo      | 14 +++++++-------
 4 files changed, 12 insertions(+), 12 deletions(-)

diff --git a/exercises/concept/weather-report/.docs/instructions.md b/exercises/concept/weather-report/.docs/instructions.md
index 60b2ff1b..251333f9 100644
--- a/exercises/concept/weather-report/.docs/instructions.md
+++ b/exercises/concept/weather-report/.docs/instructions.md
@@ -17,16 +17,16 @@ pub enum WeatherCondition {
 ```
 
 You will need to format a weather report like `"Today is <CONDITION> with a temperature of <TEMPERATURE> degrees Celsius."`.
-You'll need to implement functions that correspond with weather conditions.
+You'll need to implement the function that outputs the correct weather conditions.
 
-For example, the below snippet demonstrates an expected output for the `get_weather_report` function.
+For example, the below snippet demonstrates an expected output for the `get_weather_report` function for a "rainy" day.
 
 ```rust
 get_weather_report(WeatherCondition::Rainy, "25")
 // Returns: "Today is RAINY with a temperature of 25 degrees Celsius."
 ```
 
-And for `sunny_day`:
+And for a "sunny" day:
 
 ```rust
 get_weather_report(WeatherCondition::Sunny, "30")
diff --git a/exercises/concept/weather-report/.meta/exemplar.cairo b/exercises/concept/weather-report/.meta/exemplar.cairo
index 7027b49c..de3deca8 100644
--- a/exercises/concept/weather-report/.meta/exemplar.cairo
+++ b/exercises/concept/weather-report/.meta/exemplar.cairo
@@ -6,7 +6,7 @@ pub enum WeatherCondition {
     Stormy,
 }
 
-pub fn get_weather_report(condition: WeatherCondition, temperature: ByteArray) -> ByteArray {
+pub fn get_weather_report(condition: WeatherCondition, temperature: u32) -> ByteArray {
     match condition {
         WeatherCondition::Sunny => format!(
             "Today is SUNNY with a temperature of {temperature} degrees Celsius.",
diff --git a/exercises/concept/weather-report/src/lib.cairo b/exercises/concept/weather-report/src/lib.cairo
index 63f11c7b..0ec921c7 100644
--- a/exercises/concept/weather-report/src/lib.cairo
+++ b/exercises/concept/weather-report/src/lib.cairo
@@ -8,7 +8,7 @@ pub enum WeatherCondition {
 }
 
 /// primary function for generating weather reports
-pub fn get_weather_report(condition: WeatherCondition, temperature: ByteArray) -> ByteArray {
+pub fn get_weather_report(condition: WeatherCondition, temperature: u32) -> ByteArray {
     // return a weather report for the given condition
     panic!("implement `get_weather_report`")
 }
diff --git a/exercises/concept/weather-report/tests/weather_report.cairo b/exercises/concept/weather-report/tests/weather_report.cairo
index bec1976b..3eb123a5 100644
--- a/exercises/concept/weather-report/tests/weather_report.cairo
+++ b/exercises/concept/weather-report/tests/weather_report.cairo
@@ -3,7 +3,7 @@ use weather_report::{get_weather_report, WeatherCondition};
 #[test]
 fn reports_sunny_weather() {
     assert_eq!(
-        get_weather_report(WeatherCondition::Sunny, "30"),
+        get_weather_report(WeatherCondition::Sunny, 30),
         "Today is SUNNY with a temperature of 30 degrees Celsius.",
     );
 }
@@ -12,7 +12,7 @@ fn reports_sunny_weather() {
 #[ignore]
 fn reports_rainy_weather() {
     assert_eq!(
-        get_weather_report(WeatherCondition::Rainy, "25"),
+        get_weather_report(WeatherCondition::Rainy, 25),
         "Today is RAINY with a temperature of 25 degrees Celsius.",
     );
 }
@@ -21,7 +21,7 @@ fn reports_rainy_weather() {
 #[ignore]
 fn reports_cloudy_weather() {
     assert_eq!(
-        get_weather_report(WeatherCondition::Cloudy, "27"),
+        get_weather_report(WeatherCondition::Cloudy, 27),
         "Today is CLOUDY with a temperature of 27 degrees Celsius.",
     );
 }
@@ -30,7 +30,7 @@ fn reports_cloudy_weather() {
 #[ignore]
 fn get_weather_report_sunny() {
     assert_eq!(
-        get_weather_report(WeatherCondition::Sunny, "35"),
+        get_weather_report(WeatherCondition::Sunny, 35),
         "Today is SUNNY with a temperature of 35 degrees Celsius.",
     );
 }
@@ -39,7 +39,7 @@ fn get_weather_report_sunny() {
 #[ignore]
 fn get_weather_report_rainy() {
     assert_eq!(
-        get_weather_report(WeatherCondition::Rainy, "20"),
+        get_weather_report(WeatherCondition::Rainy, 20),
         "Today is RAINY with a temperature of 20 degrees Celsius.",
     );
 }
@@ -48,7 +48,7 @@ fn get_weather_report_rainy() {
 #[ignore]
 fn get_weather_report_cloudy() {
     assert_eq!(
-        get_weather_report(WeatherCondition::Cloudy, "22"),
+        get_weather_report(WeatherCondition::Cloudy, 22),
         "Today is CLOUDY with a temperature of 22 degrees Celsius.",
     );
 }
@@ -57,7 +57,7 @@ fn get_weather_report_cloudy() {
 #[ignore]
 fn add_stormy_variant() {
     assert_eq!(
-        get_weather_report(WeatherCondition::Stormy, "15"),
+        get_weather_report(WeatherCondition::Stormy, 15),
         "Today is STORMY with a temperature of 15 degrees Celsius.",
     );
 }

From 0a0fa58d370865a19b255d426cadb3b393f26f4e Mon Sep 17 00:00:00 2001
From: 0xNeshi <xinef.it@gmail.com>
Date: Sun, 17 Aug 2025 10:12:34 +0200
Subject: [PATCH 10/15] add back rpn-calculator (deprecated) + create new uuid
 for weather-report

---
 config.json                                   | 28 ++++++++++++-------
 .../concept/rpn-calculator/.docs/hints.md     |  0
 .../rpn-calculator/.docs/instructions.md      |  0
 .../rpn-calculator/.docs/introduction.md      |  0
 .../concept/rpn-calculator/.meta/config.json  | 23 +++++++++++++++
 .../concept/rpn-calculator/.meta/design.md    |  0
 .../rpn-calculator/.meta/exemplar.cairo       |  0
 exercises/concept/rpn-calculator/Scarb.toml   |  0
 .../concept/rpn-calculator/src/lib.cairo      |  0
 .../tests/the_realm_of_echoes.cairo           |  0
 10 files changed, 41 insertions(+), 10 deletions(-)
 create mode 100644 exercises/concept/rpn-calculator/.docs/hints.md
 create mode 100644 exercises/concept/rpn-calculator/.docs/instructions.md
 create mode 100644 exercises/concept/rpn-calculator/.docs/introduction.md
 create mode 100644 exercises/concept/rpn-calculator/.meta/config.json
 create mode 100644 exercises/concept/rpn-calculator/.meta/design.md
 create mode 100644 exercises/concept/rpn-calculator/.meta/exemplar.cairo
 create mode 100644 exercises/concept/rpn-calculator/Scarb.toml
 create mode 100644 exercises/concept/rpn-calculator/src/lib.cairo
 create mode 100644 exercises/concept/rpn-calculator/tests/the_realm_of_echoes.cairo

diff --git a/config.json b/config.json
index 8b3de8e9..9d16d231 100644
--- a/config.json
+++ b/config.json
@@ -94,17 +94,12 @@
         "status": "beta"
       },
       {
-        "slug": "weather-report",
-        "name": "Weather Report",
+        "slug": "rpn-calculator",
+        "name": "RPN Calculator",
         "uuid": "536d9f09-5910-4a26-93fd-2242667b0b87",
-        "concepts": [
-          "enums",
-          "match-basics"
-        ],
-        "prerequisites": [
-          "functions"
-        ],
-        "status": "beta"
+        "concepts": [],
+        "prerequisites": [],
+        "status": "deprecated"
       },
       {
         "slug": "welcome-to-tech-palace",
@@ -264,6 +259,19 @@
           "error-handling"
         ],
         "status": "beta"
+      },
+      {
+        "slug": "weather-report",
+        "name": "weather-report",
+        "uuid": "b91da5c2-f639-40cb-8a28-607228e6b48b",
+        "concepts": [
+          "enums",
+          "match-basics"
+        ],
+        "prerequisites": [
+          "functions"
+        ],
+        "status": "beta"
       }
     ],
     "practice": [
diff --git a/exercises/concept/rpn-calculator/.docs/hints.md b/exercises/concept/rpn-calculator/.docs/hints.md
new file mode 100644
index 00000000..e69de29b
diff --git a/exercises/concept/rpn-calculator/.docs/instructions.md b/exercises/concept/rpn-calculator/.docs/instructions.md
new file mode 100644
index 00000000..e69de29b
diff --git a/exercises/concept/rpn-calculator/.docs/introduction.md b/exercises/concept/rpn-calculator/.docs/introduction.md
new file mode 100644
index 00000000..e69de29b
diff --git a/exercises/concept/rpn-calculator/.meta/config.json b/exercises/concept/rpn-calculator/.meta/config.json
new file mode 100644
index 00000000..b8399302
--- /dev/null
+++ b/exercises/concept/rpn-calculator/.meta/config.json
@@ -0,0 +1,23 @@
+{
+  "authors": [
+    "<your_gh_username>"
+  ],
+  "files": {
+    "solution": [
+      "src/lib.cairo"
+    ],
+    "test": [
+      "tests/rpn_calculator.cairo"
+    ],
+    "exemplar": [
+      ".meta/exemplar.cairo"
+    ],
+    "invalidator": [
+      "Scarb.toml"
+    ]
+  },
+  "forked_from": [
+    "rust/rpn-calculator"
+  ],
+  "blurb": "Use some of `Array`'s methods to evaluate Reverse Polish notation"
+}
diff --git a/exercises/concept/rpn-calculator/.meta/design.md b/exercises/concept/rpn-calculator/.meta/design.md
new file mode 100644
index 00000000..e69de29b
diff --git a/exercises/concept/rpn-calculator/.meta/exemplar.cairo b/exercises/concept/rpn-calculator/.meta/exemplar.cairo
new file mode 100644
index 00000000..e69de29b
diff --git a/exercises/concept/rpn-calculator/Scarb.toml b/exercises/concept/rpn-calculator/Scarb.toml
new file mode 100644
index 00000000..e69de29b
diff --git a/exercises/concept/rpn-calculator/src/lib.cairo b/exercises/concept/rpn-calculator/src/lib.cairo
new file mode 100644
index 00000000..e69de29b
diff --git a/exercises/concept/rpn-calculator/tests/the_realm_of_echoes.cairo b/exercises/concept/rpn-calculator/tests/the_realm_of_echoes.cairo
new file mode 100644
index 00000000..e69de29b

From 1b6123f311f27d88185851e89b26b384d1195648 Mon Sep 17 00:00:00 2001
From: 0xNeshi <xinef.it@gmail.com>
Date: Sun, 17 Aug 2025 10:12:53 +0200
Subject: [PATCH 11/15] fix test name

---
 .../tests/{the_realm_of_echoes.cairo => rpn_calculator.cairo}     | 0
 1 file changed, 0 insertions(+), 0 deletions(-)
 rename exercises/concept/rpn-calculator/tests/{the_realm_of_echoes.cairo => rpn_calculator.cairo} (100%)

diff --git a/exercises/concept/rpn-calculator/tests/the_realm_of_echoes.cairo b/exercises/concept/rpn-calculator/tests/rpn_calculator.cairo
similarity index 100%
rename from exercises/concept/rpn-calculator/tests/the_realm_of_echoes.cairo
rename to exercises/concept/rpn-calculator/tests/rpn_calculator.cairo

From c45e3334298fc00cc6a57ecb17c21034ac265b87 Mon Sep 17 00:00:00 2001
From: 0xNeshi <nenad.misic@openzeppelin.com>
Date: Sun, 17 Aug 2025 15:32:04 +0200
Subject: [PATCH 12/15] add bakery-order-system scaffold

---
 config.json                                   | 12 +++
 .../bakery-order-system/.docs/hints.md        |  0
 .../bakery-order-system/.docs/instructions.md |  0
 .../bakery-order-system/.docs/introduction.md |  0
 .../bakery-order-system/.meta/config.json     | 20 +++++
 .../bakery-order-system/.meta/design.md       |  0
 .../bakery-order-system/.meta/exemplar.cairo  |  0
 .../concept/bakery-order-system/Scarb.toml    |  1 +
 .../concept/bakery-order-system/src/lib.cairo |  0
 .../tests/bakery_order_system.cairo           | 84 +++++++++++++++++++
 10 files changed, 117 insertions(+)
 create mode 100644 exercises/concept/bakery-order-system/.docs/hints.md
 create mode 100644 exercises/concept/bakery-order-system/.docs/instructions.md
 create mode 100644 exercises/concept/bakery-order-system/.docs/introduction.md
 create mode 100644 exercises/concept/bakery-order-system/.meta/config.json
 create mode 100644 exercises/concept/bakery-order-system/.meta/design.md
 create mode 100644 exercises/concept/bakery-order-system/.meta/exemplar.cairo
 create mode 100644 exercises/concept/bakery-order-system/Scarb.toml
 create mode 100644 exercises/concept/bakery-order-system/src/lib.cairo
 create mode 100644 exercises/concept/bakery-order-system/tests/bakery_order_system.cairo

diff --git a/config.json b/config.json
index 9d16d231..2f32fe4c 100644
--- a/config.json
+++ b/config.json
@@ -101,6 +101,18 @@
         "prerequisites": [],
         "status": "deprecated"
       },
+      {
+        "slug": "bakery-order-system",
+        "name": "Bakery Order System",
+        "uuid": "a979b9a0-7fd9-46f7-bacf-f0044c3c9bb0",
+        "concepts": [
+          "control-flow"
+        ],
+        "prerequisites": [
+          "match-basics"
+        ],
+        "status": "wip"
+      },
       {
         "slug": "welcome-to-tech-palace",
         "name": "Welcome To Tech Palace!",
diff --git a/exercises/concept/bakery-order-system/.docs/hints.md b/exercises/concept/bakery-order-system/.docs/hints.md
new file mode 100644
index 00000000..e69de29b
diff --git a/exercises/concept/bakery-order-system/.docs/instructions.md b/exercises/concept/bakery-order-system/.docs/instructions.md
new file mode 100644
index 00000000..e69de29b
diff --git a/exercises/concept/bakery-order-system/.docs/introduction.md b/exercises/concept/bakery-order-system/.docs/introduction.md
new file mode 100644
index 00000000..e69de29b
diff --git a/exercises/concept/bakery-order-system/.meta/config.json b/exercises/concept/bakery-order-system/.meta/config.json
new file mode 100644
index 00000000..1e086ed8
--- /dev/null
+++ b/exercises/concept/bakery-order-system/.meta/config.json
@@ -0,0 +1,20 @@
+{
+  "authors": [
+    "<author>"
+  ],
+  "files": {
+    "solution": [
+      "src/lib.cairo"
+    ],
+    "test": [
+      "tests/bakery_order_system.cairo"
+    ],
+    "exemplar": [
+      ".meta/exemplar.cairo"
+    ],
+    "invalidator": [
+      "Scarb.toml"
+    ]
+  },
+  "blurb": "<blurb>"
+}
diff --git a/exercises/concept/bakery-order-system/.meta/design.md b/exercises/concept/bakery-order-system/.meta/design.md
new file mode 100644
index 00000000..e69de29b
diff --git a/exercises/concept/bakery-order-system/.meta/exemplar.cairo b/exercises/concept/bakery-order-system/.meta/exemplar.cairo
new file mode 100644
index 00000000..e69de29b
diff --git a/exercises/concept/bakery-order-system/Scarb.toml b/exercises/concept/bakery-order-system/Scarb.toml
new file mode 100644
index 00000000..8b137891
--- /dev/null
+++ b/exercises/concept/bakery-order-system/Scarb.toml
@@ -0,0 +1 @@
+
diff --git a/exercises/concept/bakery-order-system/src/lib.cairo b/exercises/concept/bakery-order-system/src/lib.cairo
new file mode 100644
index 00000000..e69de29b
diff --git a/exercises/concept/bakery-order-system/tests/bakery_order_system.cairo b/exercises/concept/bakery-order-system/tests/bakery_order_system.cairo
new file mode 100644
index 00000000..13b7f095
--- /dev/null
+++ b/exercises/concept/bakery-order-system/tests/bakery_order_system.cairo
@@ -0,0 +1,84 @@
+use welcome_to_tech_palace::*;
+
+#[test]
+fn welcome_message_for_customer_with_first_letter_capitalized() {
+    let customer = 'Judy';
+    let actual = welcome_message(customer);
+    let expected = "Welcome to the Tech Palace, JUDY";
+    assert_eq!(expected, actual);
+}
+
+#[test]
+#[ignore]
+fn welcome_message_for_customer_with_only_lowercase_letters() {
+    let customer = 'lars';
+    let actual = welcome_message(customer);
+    let expected = "Welcome to the Tech Palace, LARS";
+    assert_eq!(expected, actual);
+}
+
+#[test]
+#[ignore]
+fn welcome_message_for_customer_with_dash_in_name() {
+    let customer = 'Peter-James';
+    let actual = welcome_message(customer);
+    let expected = "Welcome to the Tech Palace, PETER-JAMES";
+    assert_eq!(expected, actual);
+}
+
+#[test]
+#[ignore]
+fn welcome_message_for_customer_with_only_uppercase_letters() {
+    let customer = 'MJ';
+    let actual = welcome_message(customer);
+    let expected = "Welcome to the Tech Palace, MJ";
+    assert_eq!(expected, actual);
+}
+
+#[test]
+#[ignore]
+fn add_border_with_10_stars_per_line() {
+    let welcome_msg = "Welcome!";
+    let num_stars_per_line = 10;
+    let actual = add_border(welcome_msg, num_stars_per_line);
+    let expected = "**********\nWelcome!\n**********";
+    assert_eq!(expected, actual);
+}
+
+#[test]
+#[ignore]
+fn add_border_with_2_stars_per_line() {
+    let welcome_msg = "Hi";
+    let num_stars_per_line = 2;
+    let actual = add_border(welcome_msg, num_stars_per_line);
+    let expected = "**\nHi\n**";
+    assert_eq!(expected, actual);
+}
+
+#[test]
+#[ignore]
+fn clean_up_message_with_many_stars_and_leading_and_trailing_whitespace() {
+    let old_msg =
+        "**************************\n*    BUY NOW, SAVE 10%   *\n**************************";
+    let actual = clean_up_message(old_msg);
+    let expected = "BUY NOW, SAVE 10%";
+    assert_eq!(expected, actual);
+}
+
+#[test]
+#[ignore]
+fn clean_up_message_without_leading_or_trailing_whitespace() {
+    let old_msg = "**********\n*DISCOUNT*\n**********";
+    let actual = clean_up_message(old_msg);
+    let expected = "DISCOUNT";
+    assert_eq!(expected, actual);
+}
+
+#[test]
+#[ignore]
+fn clean_up_message_without_leading_whitespace() {
+    let old_msg = "*****\n SALE\n*****";
+    let actual = clean_up_message(old_msg);
+    let expected = "SALE";
+    assert_eq!(expected, actual);
+}

From f75763926f54ba278d3643382b3775ae0ed4d4d5 Mon Sep 17 00:00:00 2001
From: 0xNeshi <nenad.misic@openzeppelin.com>
Date: Sun, 17 Aug 2025 15:36:04 +0200
Subject: [PATCH 13/15] remove scarb.toml in bos

---
 exercises/concept/bakery-order-system/Scarb.toml | 1 -
 1 file changed, 1 deletion(-)
 delete mode 100644 exercises/concept/bakery-order-system/Scarb.toml

diff --git a/exercises/concept/bakery-order-system/Scarb.toml b/exercises/concept/bakery-order-system/Scarb.toml
deleted file mode 100644
index 8b137891..00000000
--- a/exercises/concept/bakery-order-system/Scarb.toml
+++ /dev/null
@@ -1 +0,0 @@
-

From 162d0950f47b7f08fdd3219f7dd1e0f2023ba93d Mon Sep 17 00:00:00 2001
From: 0xNeshi <nenad.misic@openzeppelin.com>
Date: Sun, 17 Aug 2025 15:48:51 +0200
Subject: [PATCH 14/15] Revert "remove scarb.toml in bos"

This reverts commit f75763926f54ba278d3643382b3775ae0ed4d4d5.
---
 exercises/concept/bakery-order-system/Scarb.toml | 1 +
 1 file changed, 1 insertion(+)
 create mode 100644 exercises/concept/bakery-order-system/Scarb.toml

diff --git a/exercises/concept/bakery-order-system/Scarb.toml b/exercises/concept/bakery-order-system/Scarb.toml
new file mode 100644
index 00000000..8b137891
--- /dev/null
+++ b/exercises/concept/bakery-order-system/Scarb.toml
@@ -0,0 +1 @@
+

From 9644a9d92c5c838733d8683d08d70c8bd6201add Mon Sep 17 00:00:00 2001
From: 0xNeshi <nenad.misic@openzeppelin.com>
Date: Sun, 17 Aug 2025 15:48:51 +0200
Subject: [PATCH 15/15] Revert "add bakery-order-system scaffold"

This reverts commit c45e3334298fc00cc6a57ecb17c21034ac265b87.
---
 config.json                                   | 12 ---
 .../bakery-order-system/.docs/hints.md        |  0
 .../bakery-order-system/.docs/instructions.md |  0
 .../bakery-order-system/.docs/introduction.md |  0
 .../bakery-order-system/.meta/config.json     | 20 -----
 .../bakery-order-system/.meta/design.md       |  0
 .../bakery-order-system/.meta/exemplar.cairo  |  0
 .../concept/bakery-order-system/Scarb.toml    |  1 -
 .../concept/bakery-order-system/src/lib.cairo |  0
 .../tests/bakery_order_system.cairo           | 84 -------------------
 10 files changed, 117 deletions(-)
 delete mode 100644 exercises/concept/bakery-order-system/.docs/hints.md
 delete mode 100644 exercises/concept/bakery-order-system/.docs/instructions.md
 delete mode 100644 exercises/concept/bakery-order-system/.docs/introduction.md
 delete mode 100644 exercises/concept/bakery-order-system/.meta/config.json
 delete mode 100644 exercises/concept/bakery-order-system/.meta/design.md
 delete mode 100644 exercises/concept/bakery-order-system/.meta/exemplar.cairo
 delete mode 100644 exercises/concept/bakery-order-system/Scarb.toml
 delete mode 100644 exercises/concept/bakery-order-system/src/lib.cairo
 delete mode 100644 exercises/concept/bakery-order-system/tests/bakery_order_system.cairo

diff --git a/config.json b/config.json
index 2f32fe4c..9d16d231 100644
--- a/config.json
+++ b/config.json
@@ -101,18 +101,6 @@
         "prerequisites": [],
         "status": "deprecated"
       },
-      {
-        "slug": "bakery-order-system",
-        "name": "Bakery Order System",
-        "uuid": "a979b9a0-7fd9-46f7-bacf-f0044c3c9bb0",
-        "concepts": [
-          "control-flow"
-        ],
-        "prerequisites": [
-          "match-basics"
-        ],
-        "status": "wip"
-      },
       {
         "slug": "welcome-to-tech-palace",
         "name": "Welcome To Tech Palace!",
diff --git a/exercises/concept/bakery-order-system/.docs/hints.md b/exercises/concept/bakery-order-system/.docs/hints.md
deleted file mode 100644
index e69de29b..00000000
diff --git a/exercises/concept/bakery-order-system/.docs/instructions.md b/exercises/concept/bakery-order-system/.docs/instructions.md
deleted file mode 100644
index e69de29b..00000000
diff --git a/exercises/concept/bakery-order-system/.docs/introduction.md b/exercises/concept/bakery-order-system/.docs/introduction.md
deleted file mode 100644
index e69de29b..00000000
diff --git a/exercises/concept/bakery-order-system/.meta/config.json b/exercises/concept/bakery-order-system/.meta/config.json
deleted file mode 100644
index 1e086ed8..00000000
--- a/exercises/concept/bakery-order-system/.meta/config.json
+++ /dev/null
@@ -1,20 +0,0 @@
-{
-  "authors": [
-    "<author>"
-  ],
-  "files": {
-    "solution": [
-      "src/lib.cairo"
-    ],
-    "test": [
-      "tests/bakery_order_system.cairo"
-    ],
-    "exemplar": [
-      ".meta/exemplar.cairo"
-    ],
-    "invalidator": [
-      "Scarb.toml"
-    ]
-  },
-  "blurb": "<blurb>"
-}
diff --git a/exercises/concept/bakery-order-system/.meta/design.md b/exercises/concept/bakery-order-system/.meta/design.md
deleted file mode 100644
index e69de29b..00000000
diff --git a/exercises/concept/bakery-order-system/.meta/exemplar.cairo b/exercises/concept/bakery-order-system/.meta/exemplar.cairo
deleted file mode 100644
index e69de29b..00000000
diff --git a/exercises/concept/bakery-order-system/Scarb.toml b/exercises/concept/bakery-order-system/Scarb.toml
deleted file mode 100644
index 8b137891..00000000
--- a/exercises/concept/bakery-order-system/Scarb.toml
+++ /dev/null
@@ -1 +0,0 @@
-
diff --git a/exercises/concept/bakery-order-system/src/lib.cairo b/exercises/concept/bakery-order-system/src/lib.cairo
deleted file mode 100644
index e69de29b..00000000
diff --git a/exercises/concept/bakery-order-system/tests/bakery_order_system.cairo b/exercises/concept/bakery-order-system/tests/bakery_order_system.cairo
deleted file mode 100644
index 13b7f095..00000000
--- a/exercises/concept/bakery-order-system/tests/bakery_order_system.cairo
+++ /dev/null
@@ -1,84 +0,0 @@
-use welcome_to_tech_palace::*;
-
-#[test]
-fn welcome_message_for_customer_with_first_letter_capitalized() {
-    let customer = 'Judy';
-    let actual = welcome_message(customer);
-    let expected = "Welcome to the Tech Palace, JUDY";
-    assert_eq!(expected, actual);
-}
-
-#[test]
-#[ignore]
-fn welcome_message_for_customer_with_only_lowercase_letters() {
-    let customer = 'lars';
-    let actual = welcome_message(customer);
-    let expected = "Welcome to the Tech Palace, LARS";
-    assert_eq!(expected, actual);
-}
-
-#[test]
-#[ignore]
-fn welcome_message_for_customer_with_dash_in_name() {
-    let customer = 'Peter-James';
-    let actual = welcome_message(customer);
-    let expected = "Welcome to the Tech Palace, PETER-JAMES";
-    assert_eq!(expected, actual);
-}
-
-#[test]
-#[ignore]
-fn welcome_message_for_customer_with_only_uppercase_letters() {
-    let customer = 'MJ';
-    let actual = welcome_message(customer);
-    let expected = "Welcome to the Tech Palace, MJ";
-    assert_eq!(expected, actual);
-}
-
-#[test]
-#[ignore]
-fn add_border_with_10_stars_per_line() {
-    let welcome_msg = "Welcome!";
-    let num_stars_per_line = 10;
-    let actual = add_border(welcome_msg, num_stars_per_line);
-    let expected = "**********\nWelcome!\n**********";
-    assert_eq!(expected, actual);
-}
-
-#[test]
-#[ignore]
-fn add_border_with_2_stars_per_line() {
-    let welcome_msg = "Hi";
-    let num_stars_per_line = 2;
-    let actual = add_border(welcome_msg, num_stars_per_line);
-    let expected = "**\nHi\n**";
-    assert_eq!(expected, actual);
-}
-
-#[test]
-#[ignore]
-fn clean_up_message_with_many_stars_and_leading_and_trailing_whitespace() {
-    let old_msg =
-        "**************************\n*    BUY NOW, SAVE 10%   *\n**************************";
-    let actual = clean_up_message(old_msg);
-    let expected = "BUY NOW, SAVE 10%";
-    assert_eq!(expected, actual);
-}
-
-#[test]
-#[ignore]
-fn clean_up_message_without_leading_or_trailing_whitespace() {
-    let old_msg = "**********\n*DISCOUNT*\n**********";
-    let actual = clean_up_message(old_msg);
-    let expected = "DISCOUNT";
-    assert_eq!(expected, actual);
-}
-
-#[test]
-#[ignore]
-fn clean_up_message_without_leading_whitespace() {
-    let old_msg = "*****\n SALE\n*****";
-    let actual = clean_up_message(old_msg);
-    let expected = "SALE";
-    assert_eq!(expected, actual);
-}