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Rename split-loop-with-lambda to slice-with-lambda

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The refactoring is now published as Slice on sammancoaching.org:
https://sammancoaching.org/refactorings/slice.html

- git mv ideas/split-loop-with-lambda -> ideas/slice-with-lambda
- rename learning-hour file and update frontmatter name
- update paths in tools/rehearse scripts and report title
- update prose: 'Split Loop with Lambda' -> 'Slice with Lambda'
  in learning hour, exercise READMEs, storyboard, solution comments
- link the published Slice refactoring from the pattern draft
This commit is contained in:
Your Name
2026-09-29 15:47:30 +00:00
parent 125bb7ad01
commit 77ae05c28c
114 changed files with 21 additions and 20 deletions
Download Patch File Download Diff File Expand all files Collapse all files
ideas/slice-with-lambda/exercise/rehearsal-runs/C+Q/agents-md.txt
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# Rehearsal workspace — refactoring task
You are refactoring `src/main/java/codingdojo/LongRangeForecasts.java` in this
Maven project. Run `mvn -q test` after each change (mvn is on your PATH). It may
fail — that is expected: the dependency on `Scorer` makes the method untestable —
but the code must still *compile*.
## Goal
In `LongRangeForecasts.longRangeForecast()`, the loop over `interestingDates`
collects weather by calling `scorer` (an unwanted external dependency).
1. Introduce a lambda for the scorer-dependent code and move its definition to
the top of the method, leaving the invocation where it is. (No refactoring
tool supports this — do it as a minimal manual edit.)
2. Extract the weather-collection loop into a new method `collectExpectedWeather`
that takes the lambda as a parameter (suggested type `LongFunction<Boolean>`).
3. Add the lambda as a parameter to `longRangeForecast` itself: the signature
must become `longRangeForecast(LongFunction<Boolean> dayOffsetToWeather)`,
with a public no-arg overload `longRangeForecast()` that delegates and wraps
the `scorer` field in a lambda. Do not keep the `String quarter` parameter.
(`java-refactor change-method-signature` or `java-refactor introduce-param`
may help; fall back to a minimal manual edit if no subcommand can do it.)
4. Stop. Report the final diff.
## Tool rules (variant C)
A semantic Java refactoring CLI, `java-refactor`, is on your PATH
(`java-refactor --help` lists the subcommands). Using it is OPTIONAL — you
may also change code with your normal file-editing tools. Choose per step
whatever you think is most reliable.
Subcommands that may be relevant for this task:
- `extract` — extract selected statements into a new private method
(selection given as start/end line+column; `--dry-run` previews)
- `introduce-param` / `change-method-signature` — alter a method's parameters
- `rename` — rename a symbol project-wide
ideas/slice-with-lambda/exercise/rehearsal-runs/C+Q/diff.patch
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Only in /tmp/rehearsal/runs/C+Q/workspace: AGENTS.md
diff -ru '--exclude=target' /tmp/rehearsal/pristine/src/main/java/codingdojo/LongRangeForecasts.java /tmp/rehearsal/runs/C+Q/workspace/src/main/java/codingdojo/LongRangeForecasts.java
--- /tmp/rehearsal/pristine/src/main/java/codingdojo/LongRangeForecasts.java 2026-09-27 14:58:14.139167804 +0000
+++ /tmp/rehearsal/runs/C+Q/workspace/src/main/java/codingdojo/LongRangeForecasts.java 2026-09-27 15:53:52.292927858 +0000
@@ -3,19 +3,18 @@
import java.time.Instant;
import java.time.temporal.ChronoUnit;
import java.util.*;
+import java.util.function.LongFunction;
public class LongRangeForecasts {
private final Scorer scorer = new Scorer();
- public Map<IceCream, Integer> longRangeForecast(String quarter) {
+ public Map<IceCream, Integer> longRangeForecast() {
+ return longRangeForecast(d -> scorer.lookupWeather(d));
+ }
+ public Map<IceCream, Integer> longRangeForecast(LongFunction<Boolean> dayOffsetToWeather) {
var result = new HashMap<IceCream, Integer>();
- if (Objects.equals(quarter, "Q1") || Objects.equals(quarter, "Q4")) {
- for (IceCream flavour : IceCream.values()) {
- result.put(flavour, 5);
- }
- }
for (IceCream flavour : IceCream.values()) {
result.put(flavour, 0);
}
@@ -25,15 +24,7 @@
Instant.parse("2023-06-05T14:00:00.000-07:00"),
Instant.parse("2023-06-23T14:00:00.000-07:00")
);
- List<Boolean> expectedWeather = new ArrayList<>();
- for (Instant interestingDate : interestingDates) {
- scorer.updateSelection();
- var forecastDate = Instant.parse("2023-04-26T14:00:00.000-07:00");
- long daysForward = ChronoUnit.DAYS.between(forecastDate, interestingDate);
- Boolean lookupWeather = scorer.lookupWeather(daysForward);
- expectedWeather.add(lookupWeather);
- }
-
+ List<Boolean> expectedWeather = collectExpectedWeather(interestingDates, dayOffsetToWeather);
for (IceCream flavour : result.keySet()) {
result.put(flavour, result.get(flavour) + 10);
var sunnyHolidays = expectedWeather.stream().filter(s -> s).count();
@@ -46,4 +37,15 @@
}
return result;
}
+
+ private List<Boolean> collectExpectedWeather(List<Instant> dates, LongFunction<Boolean> dayOffsetToWeather) {
+ List<Boolean> expectedWeather = new ArrayList<>();
+ for (Instant date : dates) {
+ scorer.updateSelection();
+ var forecastDate = Instant.parse("2023-04-26T14:00:00.000-07:00");
+ long daysForward = ChronoUnit.DAYS.between(forecastDate, date);
+ expectedWeather.add(dayOffsetToWeather.apply(daysForward));
+ }
+ return expectedWeather;
+ }
}
ideas/slice-with-lambda/exercise/rehearsal-runs/C+Q/measure.txt
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--- Run C+Q ---
session file: /tmp/rehearsal/runs/C+Q/session/2026-09-27T15-53-02-700Z_01a0e391-ddec-76b3-83b6-8a55d163bf7c.jsonl
model: Qwen/Qwen3.6-35B-A3B
session span: 71.7 s
assistant messages: 16
tool calls: 17 total
bash 7
read 5
edit 5
tokens input: 138747
tokens output: 8337
tokens cacheRead: 0
tokens cacheWrite: 0
tokens reasoning: 2579
tokens TOTAL (sum): 149663
--- /usr/bin/time -v (wall clock + max RSS) ---
Elapsed (wall clock) time (h:mm:ss or m:ss): 1:11.84
Maximum resident set size (kbytes): 226488
Exit status: 0
--- pi stdout (last 15 lines) ---
+ long daysForward = ChronoUnit.DAYS.between(forecastDate, date);
+ expectedWeather.add(dayOffsetToWeather.apply(daysForward));
+ }
+ return expectedWeather;
+ }
}
```
## Summary of changes:
| Step | Change |
|------|--------|
| **1** | Added `import java.util.function.LongFunction`; introduced `dayOffsetToWeather` lambda wrapping `scorer.lookupWeather()` in the original method body, replacing direct scorer calls |
| **2** | Extracted the weather-collection loop into a new `private List<Boolean> collectExpectedWeather(List<Instant>, LongFunction<Boolean>)` method |
| **3** | Removed `String quarter` parameter; added a **no-arg** `longRangeForecast()` that delegates to the parameterized overload wrapping the `scorer`; renamed the main method to accept `LongFunction<Boolean> dayOffsetToWeather` |
ideas/slice-with-lambda/exercise/rehearsal-runs/C+Q/pi-stdout.txt
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The test compilation error is expected — the test still calls the old `longRangeForecast("Q1")` signature which has been replaced by the no-arg overload and the new `LongFunction<Boolean>` parameterized version, per the task requirements. The AGENTS.md notes that test failures are expected.
---
## Refactoring complete. Final diff of `LongRangeForecasts.java`:
```diff
import java.util.*;
+import java.util.function.LongFunction;
public class LongRangeForecasts {
private final Scorer scorer = new Scorer();
- public Map<IceCream, Integer> longRangeForecast(String quarter) {
+ public Map<IceCream, Integer> longRangeForecast() {
+ return longRangeForecast(d -> scorer.lookupWeather(d));
+ }
+ public Map<IceCream, Integer> longRangeForecast(LongFunction<Boolean> dayOffsetToWeather) {
var result = new HashMap<IceCream, Integer>();
- if (Objects.equals(quarter, "Q1") || Objects.equals(quarter, "Q4")) {
- for (IceCream flavour : IceCream.values()) {
- result.put(flavour, 5);
- }
- }
for (IceCream flavour : IceCream.values()) {
result.put(flavour, 0);
}
@@ -25,15 +24,7 @@
Instant.parse("2023-06-05T14:00:00.000-07:00"),
Instant.parse("2023-06-23T14:00:00.000-07:00")
);
- List<Boolean> expectedWeather = new ArrayList<>();
- for (Instant interestingDate : interestingDates) {
- scorer.updateSelection();
- var forecastDate = Instant.parse("2023-04-26T14:00:00.000-07:00");
- long daysForward = ChronoUnit.DAYS.between(forecastDate, interestingDate);
- Boolean lookupWeather = scorer.lookupWeather(daysForward);
- expectedWeather.add(lookupWeather);
- }
-
+ List<Boolean> expectedWeather = collectExpectedWeather(interestingDates, dayOffsetToWeather);
for (IceCream flavour : result.keySet()) {
result.put(flavour, result.get(flavour) + 10);
var sunnyHolidays = expectedWeather.stream().filter(s -> s).count();
@@ -46,4 +37,15 @@
}
return result;
}
+
+ private List<Boolean> collectExpectedWeather(List<Instant> dates, LongFunction<Boolean> dayOffsetToWeather) {
+ List<Boolean> expectedWeather = new ArrayList<>();
+ for (Instant date : dates) {
+ scorer.updateSelection();
+ var forecastDate = Instant.parse("2023-04-26T14:00:00.000-07:00");
+ long daysForward = ChronoUnit.DAYS.between(forecastDate, date);
+ expectedWeather.add(dayOffsetToWeather.apply(daysForward));
+ }
+ return expectedWeather;
+ }
}
```
## Summary of changes:
| Step | Change |
|------|--------|
| **1** | Added `import java.util.function.LongFunction`; introduced `dayOffsetToWeather` lambda wrapping `scorer.lookupWeather()` in the original method body, replacing direct scorer calls |
| **2** | Extracted the weather-collection loop into a new `private List<Boolean> collectExpectedWeather(List<Instant>, LongFunction<Boolean>)` method |
| **3** | Removed `String quarter` parameter; added a **no-arg** `longRangeForecast()` that delegates to the parameterized overload wrapping the `scorer`; renamed the main method to accept `LongFunction<Boolean> dayOffsetToWeather` |
ideas/slice-with-lambda/exercise/rehearsal-runs/C+Q/prompt.txt
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Read AGENTS.md in this directory and execute the refactoring task it describes. Run mvn -q test after each change. When done, stop and report the final diff of LongRangeForecasts.java.
ideas/slice-with-lambda/exercise/rehearsal-runs/C+Q/time.txt
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Command being timed: "timeout -k 15 600 pi -p -a --provider entrim --model Qwen/Qwen3.6-35B-A3B --session-dir /tmp/rehearsal/runs/C+Q/session --name rehearsal-C+Q Read AGENTS.md in this directory and execute the refactoring task it describes. Run mvn -q test after each change. When done, stop and report the final diff of LongRangeForecasts.java."
User time (seconds): 15.34
System time (seconds): 1.11
Percent of CPU this job got: 22%
Elapsed (wall clock) time (h:mm:ss or m:ss): 1:11.84
Average shared text size (kbytes): 0
Average unshared data size (kbytes): 0
Average stack size (kbytes): 0
Average total size (kbytes): 0
Maximum resident set size (kbytes): 226488
Average resident set size (kbytes): 0
Major (requiring I/O) page faults: 0
Minor (reclaiming a frame) page faults: 322002
Voluntary context switches: 32592
Involuntary context switches: 810
Swaps: 0
File system inputs: 0
File system outputs: 920
Socket messages sent: 0
Socket messages received: 0
Signals delivered: 0
Page size (bytes): 4096
Exit status: 0
ideas/slice-with-lambda/exercise/rehearsal-runs/C+Q/verify.txt
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--- Run C+Q ---
final diff vs pristine: 30 changed lines -> /tmp/rehearsal/runs/C+Q/diff.patch
mvn test with solution's test + approved file:
RESULT: PASS (deterministic)
structural checks:
[x] method collectExpectedWeather exists
[x] takes LongFunction<Boolean> parameter
[i] note: 'scorer' still referenced in LongRangeForecasts.java
[x] lambda syntax present
[i] main class differs from reference solution (may still be a valid variant)