added exercises for 06_Scope_and_Namespaces

exercises/foundations/06_scopes/README.md

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+# Exercise 06 - Scope Station: Reactor Rescue (Scope and Namespaces)
+
+## Description
+Orbital Station Alpha is failing! Engineers rushed the code and left variables in the wrong places: some are trapped inside functions, some are missing the right keyword, and some are hiding Python's own tools.
+
+This is a **debugging game**. `scopes.py` is already written, but it is *almost* working. Your job in each level is to figure out **where each variable must live** (and which keyword, if any, it needs) so the system runs.
+
+Remember the question from the lesson: *"Where does this name live, and who needs to see it?"*
+
+> Do not rename the functions. The tests call them by name. You decide where the variables go.
+
+---
+
+## Levels
+
+### Level 1 - Power Grid (Local vs. Global)
+`show_banner()` crashes with a `NameError`. The station name is created inside `boot_system()`, but two functions need it.
+* **Your job**: make both `boot_system()` and `show_banner()` work.
+* **Expected**: `show_banner()` returns `"=== Orbital Station Alpha ==="`.
+
+> **Next step:** Run `python check.py 06`. Once Level 1 passes, remove the `@pytest.mark.skip` line above `test_level2` in `test_scopes.py`.
+
+### Level 2 - Life Support (Enclosing Scope)
+`build_oxygen_monitor()` returns an inner function `read_level()`, but it can't find the oxygen value.
+* **Your job**: put `oxygen` where `read_level()` can find it by looking outward, and don't use a global.
+* **Expected**: the monitor returns `"Oxygen at 100%"`.
+
+> **Next step:** Unlock `test_level3`.
+
+### Level 3 - Comms Array (Built-in Scope)
+`summarize_signals()` fails with `TypeError: ... object is not callable`. Something is hiding Python's built-in tools.
+* **Your job**: find what is shadowing the built-ins and fix it.
+* **Expected**: `"3 signals, strength 49"`.
+
+> **Next step:** Unlock `test_level4`.
+
+### Level 4 - Reactor Core (`UnboundLocalError`)
+`add_bonus_power()` crashes with `UnboundLocalError`.
+* **Your job**: fix it by sending the value **in** with a parameter and sending the result **out** with `return`. The global `power` must stay `50`, and `global` is not allowed in this level.
+* **Expected**: `add_bonus_power(50)` returns `60`.
+
+> **Next step:** Unlock `test_level5`.
+
+### Level 5 - Cargo Bay (Mutable Objects)
+`load_crate()` adds items to a list that vanishes when the function ends, and `get_manifest()` can't find it.
+* **Your job**: make both functions share the same list. You don't need `global`, because you only change the list's contents.
+* **Expected**: loading `"Titanium"` then `"Ice"` gives a manifest ending in `["Titanium", "Ice"]`.
+
+> **Next step:** Unlock `test_level6`.
+
+### Level 6 - Alarm System (`global`)
+`trigger_alarm()` should count alarms in the global `alarm_count`, but crashes.
+* **Your job**: let the function rebind the global variable.
+* **Expected**: three calls return `1`, `2`, `3` (from a fresh start) and `alarm_count` ends up updated.
+
+> **Next step:** Unlock `test_level7`.
+
+### Level 7 - Drone Memory (`nonlocal`)
+Each drone made by `make_drone_counter()` should remember how many scans it did, but `scan()` crashes.
+* **Your job**: let the inner function update the enclosing variable.
+* **Expected**: one drone counts `1, 2, 3`, and a second drone starts again at `1`.
+
+> **Next step:** Unlock `test_level8`.
+
+### Level 8 - Diagnostics (`globals()` and `locals()`)
+Complete the three helper functions in the `LEVEL 8` section:
+* `list_local_names(a, b)`: return a **sorted list** of the names in the function's local namespace.
+* `is_global(name)`: return `True` if `name` exists in the global namespace.
+* `probe_hidden()`: try to read `secret_code` (it only exists inside `_make_secret()`). Return `True` if Python raises `NameError`.
+
+> **Next step:** Unlock `test_level9`.
+
+### Level 9 - BOSS: Reactor Boot Sequence
+`run_station()` has **three** different scope bugs at once. Use everything you have learned.
+* **Expected**: `"Checks: 3 | Passed: 2 | Peak: 91"`.
+
+> **Next step:** If Level 9 passes, congratulations! You saved the station.
+
+---
+
+## How to Run the Tests
+Run the following command from the repository root:
+```bash
+python check.py 06
+```
+
+Or run directly with pytest:
+```bash
+pytest exercises/foundations/06_scopes/test_scopes.py -v
+```
+
+---
+
+## Resources & Notes
+Review the concepts covered in this exercise in:
+* [The Python Ledger Curriculum: Scope and Namespaces](https://thepythonledger.github.io/Docusaurus-engine/lessons/code-organization/scope-and-namespaces)

exercises/foundations/06_scopes/scopes.py

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+# ORBITAL STATION ALPHA - Reactor Rescue
+# Every system below is almost working. Find WHERE each variable should live.
+# Do not rename the functions - the tests call them by name.
+
+
+# LEVEL 1 - Power Grid
+def boot_system():
+    STATION_NAME = "Orbital Station Alpha"
+    return f"Booting {STATION_NAME}..."
+
+
+def show_banner():
+    return f"=== {STATION_NAME} ==="
+
+
+# LEVEL 2 - Life Support
+def calibrate_sensors():
+    oxygen = 100
+    return "Sensors calibrated"
+
+
+def build_oxygen_monitor():
+    def read_level():
+        return f"Oxygen at {oxygen}%"
+
+    return read_level
+
+
+# LEVEL 3 - Comms Array
+list = [12, 7, 30]  # incoming signal strengths
+sum = 0  # total strength
+
+
+def summarize_signals():
+    return f"{len(list)} signals, strength {sum(list)}"
+
+
+# LEVEL 4 - Reactor Core
+power = 50
+
+
+def add_bonus_power():
+    print("Current power:", power)
+    power = power + 10
+    return power
+
+
+# LEVEL 5 - Cargo Bay
+def load_crate(item):
+    cargo = []
+    cargo.append(item)
+
+
+def get_manifest():
+    return cargo
+
+
+# LEVEL 6 - Alarm System
+alarm_count = 0
+
+
+def trigger_alarm():
+    alarm_count = alarm_count + 1
+    return alarm_count
+
+
+# LEVEL 7 - Drone Memory
+def make_drone_counter():
+    scans = 0
+
+    def scan():
+        scans = scans + 1
+        return scans
+
+    return scan
+
+
+# LEVEL 8 - Diagnostics
+def _make_secret():
+    secret_code = 42
+    return "secret stored"
+
+
+def list_local_names(a, b):
+    c = a + b
+    # Return a sorted list of the names in THIS function's local namespace.
+    pass
+
+
+def is_global(name):
+    # Return True if `name` exists in the global namespace.
+    pass
+
+
+def probe_hidden():
+    _make_secret()
+    # Try to read `secret_code` here. Return True if Python raises NameError
+    # (it is hidden inside _make_secret), otherwise return False.
+    pass
+
+
+# LEVEL 9 - BOSS: Reactor Boot Sequence
+def configure_reactor():
+    REACTOR_TARGET = 80
+    return "Reactor configured"
+
+
+readings = [72, 91, 85]
+max = 0  # highest reading seen so far
+
+
+def run_station():
+    checks = 0
+
+    def run_check(reading):
+        checks = checks + 1
+        return reading >= REACTOR_TARGET
+
+    results = [run_check(r) for r in readings]
+    highest = max(readings)
+    return f"Checks: {checks} | Passed: {results.count(True)} | Peak: {highest}"

exercises/foundations/06_scopes/solution/scopes_solution.py

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+# ORBITAL STATION ALPHA - Reactor Rescue (reference solution)
+
+# LEVEL 1 - Power Grid: shared by two functions -> module level
+STATION_NAME = "Orbital Station Alpha"
+
+
+def boot_system():
+    return f"Booting {STATION_NAME}..."
+
+
+def show_banner():
+    return f"=== {STATION_NAME} ==="
+
+
+# LEVEL 2 - Life Support: lives in the enclosing function
+def calibrate_sensors():
+    return "Sensors calibrated"
+
+
+def build_oxygen_monitor():
+    oxygen = 100
+
+    def read_level():
+        return f"Oxygen at {oxygen}%"
+
+    return read_level
+
+
+# LEVEL 3 - Comms Array: don't shadow built-ins
+signals = [12, 7, 30]
+
+
+def summarize_signals():
+    return f"{len(signals)} signals, strength {sum(signals)}"
+
+
+# LEVEL 4 - Reactor Core: parameter + return instead of global
+power = 50
+
+
+def add_bonus_power(current_power):
+    print("Current power:", current_power)
+    return current_power + 10
+
+
+# LEVEL 5 - Cargo Bay: shared mutable list, no `global` needed
+cargo = []
+
+
+def load_crate(item):
+    cargo.append(item)
+
+
+def get_manifest():
+    return cargo
+
+
+# LEVEL 6 - Alarm System: rebinding a global needs `global`
+alarm_count = 0
+
+
+def trigger_alarm():
+    global alarm_count
+    alarm_count = alarm_count + 1
+    return alarm_count
+
+
+# LEVEL 7 - Drone Memory: rebinding an enclosing variable needs `nonlocal`
+def make_drone_counter():
+    scans = 0
+
+    def scan():
+        nonlocal scans
+        scans = scans + 1
+        return scans
+
+    return scan
+
+
+# LEVEL 8 - Diagnostics
+def _make_secret():
+    secret_code = 42
+    return "secret stored"
+
+
+def list_local_names(a, b):
+    c = a + b
+    return sorted(locals().keys())
+
+
+def is_global(name):
+    return name in globals()
+
+
+def probe_hidden():
+    _make_secret()
+    try:
+        secret_code
+    except NameError:
+        return True
+    return False
+
+
+# LEVEL 9 - BOSS: Reactor Boot Sequence
+REACTOR_TARGET = 80
+readings = [72, 91, 85]
+
+
+def configure_reactor():
+    return "Reactor configured"
+
+
+def run_station():
+    checks = 0
+
+    def run_check(reading):
+        nonlocal checks
+        checks = checks + 1
+        return reading >= REACTOR_TARGET
+
+    results = [run_check(r) for r in readings]
+    highest = max(readings)
+    return f"Checks: {checks} | Passed: {results.count(True)} | Peak: {highest}"