build(rechner): exact expression engine, keypad, scientific panel, history, memory; README

Co-Authored-By: Claude Opus 5.5 <[email protected]>

README.md

@@ -8,6 +8,7 @@
 
 | App | Replaces | Status | Install |
 | --- | --- | --- | --- |
+| **Rechner** (`rechner/`) | Google Calculator | alpha | [Obtainium](https://apps.obtainium.imranr.dev/redirect?r=obtainium://app/%7B%22id%22%3A%22app.rechner%22%2C%22url%22%3A%22https%3A%2F%2Fgit.mrblake.cc%2FMrBlake%2FNoGooleApps%22%2C%22author%22%3A%22MrBlake%22%2C%22name%22%3A%22Rechner%22%2C%22overrideSource%22%3A%22Codeberg%22%2C%22preferredApkIndex%22%3A0%2C%22additionalSettings%22%3A%22%7B%5C%22appId%5C%22%3A%5C%22app.rechner%5C%22%2C%5C%22includePrereleases%5C%22%3Atrue%2C%5C%22fallbackToOlderReleases%5C%22%3Atrue%2C%5C%22filterReleaseTitlesByRegEx%5C%22%3A%5C%22%5ERechner%20%5C%22%2C%5C%22apkFilterRegEx%5C%22%3A%5C%22%5Erechner-.%2A%5C%5C%5C%5C.apk%24%5C%22%2C%5C%22autoApkFilterByArch%5C%22%3Afalse%2C%5C%22verifyLatestTag%5C%22%3Afalse%2C%5C%22releaseTitleAsVersion%5C%22%3Afalse%7D%22%7D) · F-Droid: not yet |
 | **Uhr** (`uhr/`) | Google Clock / Pixel Clock | alpha, in daily testing | [Obtainium](https://apps.obtainium.imranr.dev/redirect?r=obtainium://app/%7B%22id%22%3A%22app.uhr%22%2C%22url%22%3A%22https%3A%2F%2Fgit.mrblake.cc%2FMrBlake%2FNoGooleApps%22%2C%22author%22%3A%22MrBlake%22%2C%22name%22%3A%22Uhr%22%2C%22overrideSource%22%3A%22Codeberg%22%2C%22preferredApkIndex%22%3A0%2C%22additionalSettings%22%3A%22%7B%5C%22appId%5C%22%3A%5C%22app.uhr%5C%22%2C%5C%22includePrereleases%5C%22%3Atrue%2C%5C%22fallbackToOlderReleases%5C%22%3Atrue%2C%5C%22filterReleaseTitlesByRegEx%5C%22%3A%5C%22%5EUhr%20%5C%22%2C%5C%22apkFilterRegEx%5C%22%3A%5C%22%5Euhr-.%2A%5C%5C%5C%5C.apk%24%5C%22%2C%5C%22autoApkFilterByArch%5C%22%3Afalse%2C%5C%22verifyLatestTag%5C%22%3Afalse%2C%5C%22releaseTitleAsVersion%5C%22%3Afalse%7D%22%7D) · F-Droid: not yet |
 | **Wetter** (`wetter/`) | Google Weather / Pixel Weather | alpha, in daily testing | [Obtainium](https://apps.obtainium.imranr.dev/redirect?r=obtainium://app/%7B%22id%22%3A%22app.wetter%22%2C%22url%22%3A%22https%3A%2F%2Fgit.mrblake.cc%2FMrBlake%2FNoGooleApps%22%2C%22author%22%3A%22MrBlake%22%2C%22name%22%3A%22Wetter%22%2C%22overrideSource%22%3A%22Codeberg%22%2C%22preferredApkIndex%22%3A0%2C%22additionalSettings%22%3A%22%7B%5C%22appId%5C%22%3A%5C%22app.wetter%5C%22%2C%5C%22includePrereleases%5C%22%3Atrue%2C%5C%22fallbackToOlderReleases%5C%22%3Atrue%2C%5C%22filterReleaseTitlesByRegEx%5C%22%3A%5C%22%5EWetter%20%5C%22%2C%5C%22apkFilterRegEx%5C%22%3A%5C%22%5Ewetter-.%2A%5C%5C%5C%5C.apk%24%5C%22%2C%5C%22autoApkFilterByArch%5C%22%3Afalse%2C%5C%22verifyLatestTag%5C%22%3Afalse%2C%5C%22releaseTitleAsVersion%5C%22%3Afalse%7D%22%7D) · F-Droid: not yet |
 
@@ -43,6 +44,24 @@ A weather app with the look and feel of Pixel Weather: an animated sky that chan
 
 Requires Android 10 (API 29) or newer.
 
+### Rechner
+
+A calculator with the flow of the Pixel calculator: live result while typing, a scientific row that expands into a full panel, and the history in a sheet you pull down from the display.
+
+- **Exact arithmetic.** Numbers are decimal, not floating point: 0,1 + 0,2 is 0,3, 1 ÷ 3 × 3 is 1, 100! is exact. Trigonometry snaps exact angles (sin 30° = 0,5, cos π = −1). The engine is covered by unit tests.
+- **Smart input:** one key for parentheses that opens or closes as needed, operators replace each other, implicit multiplication (2π, 3(4)), percent the way people expect (50 + 10 % = 55), unfinished input still shows a preview.
+- **Scientific:** √ π ^ ! · Deg/Rad · sin cos tan and their inverses (Inv) · e ln log · eˣ 10ˣ x².
+- **History** grouped by day, tap to reuse; copy, paste and a memory (MS/MR) from a long press on the display; wallpaper colours, light and dark.
+- **No permissions** except vibration for key feedback. No network.
+
+<p align="center">
+  <img src="docs/screenshots/rechner/S01-typing-light.png" width="200" alt="Typing with live result">
+  <img src="docs/screenshots/rechner/S02-scientific-dark.png" width="200" alt="Scientific panel">
+  <img src="docs/screenshots/rechner/S03-history-dark.png" width="200" alt="History">
+</p>
+
+Requires Android 10 (API 29) or newer.
+
 ### Uhr
 
 A clock and alarm app with the look and flow of the Pixel clock: alarms in expandable cards, world clock, several timers at once, stopwatch with laps, and a bedtime schedule.
@@ -102,6 +121,16 @@ Same setup as Wetter, with the filters `^Uhr ` (release titles) and `^uhr-.*\.ap
 obtainium://app/%7B%22id%22%3A%22app.uhr%22%2C%22url%22%3A%22https%3A%2F%2Fgit.mrblake.cc%2FMrBlake%2FNoGooleApps%22%2C%22author%22%3A%22MrBlake%22%2C%22name%22%3A%22Uhr%22%2C%22overrideSource%22%3A%22Codeberg%22%2C%22preferredApkIndex%22%3A0%2C%22additionalSettings%22%3A%22%7B%5C%22appId%5C%22%3A%5C%22app.uhr%5C%22%2C%5C%22includePrereleases%5C%22%3Atrue%2C%5C%22fallbackToOlderReleases%5C%22%3Atrue%2C%5C%22filterReleaseTitlesByRegEx%5C%22%3A%5C%22%5EUhr%20%5C%22%2C%5C%22apkFilterRegEx%5C%22%3A%5C%22%5Euhr-.%2A%5C%5C%5C%5C.apk%24%5C%22%2C%5C%22autoApkFilterByArch%5C%22%3Afalse%2C%5C%22verifyLatestTag%5C%22%3Afalse%2C%5C%22releaseTitleAsVersion%5C%22%3Afalse%7D%22%7D
 ```
 
+### Rechner
+
+[<img src="https://raw.githubusercontent.com/ImranR98/Obtainium/main/assets/graphics/badge_obtainium.png" alt="Get it on Obtainium" height="54">](https://apps.obtainium.imranr.dev/redirect?r=obtainium://app/%7B%22id%22%3A%22app.rechner%22%2C%22url%22%3A%22https%3A%2F%2Fgit.mrblake.cc%2FMrBlake%2FNoGooleApps%22%2C%22author%22%3A%22MrBlake%22%2C%22name%22%3A%22Rechner%22%2C%22overrideSource%22%3A%22Codeberg%22%2C%22preferredApkIndex%22%3A0%2C%22additionalSettings%22%3A%22%7B%5C%22appId%5C%22%3A%5C%22app.rechner%5C%22%2C%5C%22includePrereleases%5C%22%3Atrue%2C%5C%22fallbackToOlderReleases%5C%22%3Atrue%2C%5C%22filterReleaseTitlesByRegEx%5C%22%3A%5C%22%5ERechner%20%5C%22%2C%5C%22apkFilterRegEx%5C%22%3A%5C%22%5Erechner-.%2A%5C%5C%5C%5C.apk%24%5C%22%2C%5C%22autoApkFilterByArch%5C%22%3Afalse%2C%5C%22verifyLatestTag%5C%22%3Afalse%2C%5C%22releaseTitleAsVersion%5C%22%3Afalse%7D%22%7D)
+
+Filters: `^Rechner ` (release titles) and `^rechner-.*\.apk$` (APKs). Raw link:
+
+```
+obtainium://app/%7B%22id%22%3A%22app.rechner%22%2C%22url%22%3A%22https%3A%2F%2Fgit.mrblake.cc%2FMrBlake%2FNoGooleApps%22%2C%22author%22%3A%22MrBlake%22%2C%22name%22%3A%22Rechner%22%2C%22overrideSource%22%3A%22Codeberg%22%2C%22preferredApkIndex%22%3A0%2C%22additionalSettings%22%3A%22%7B%5C%22appId%5C%22%3A%5C%22app.rechner%5C%22%2C%5C%22includePrereleases%5C%22%3Atrue%2C%5C%22fallbackToOlderReleases%5C%22%3Atrue%2C%5C%22filterReleaseTitlesByRegEx%5C%22%3A%5C%22%5ERechner%20%5C%22%2C%5C%22apkFilterRegEx%5C%22%3A%5C%22%5Erechner-.%2A%5C%5C%5C%5C.apk%24%5C%22%2C%5C%22autoApkFilterByArch%5C%22%3Afalse%2C%5C%22verifyLatestTag%5C%22%3Afalse%2C%5C%22releaseTitleAsVersion%5C%22%3Afalse%7D%22%7D
+```
+
 **Releases.** Every app is published as a release titled `<App> <version>` (for example `Wetter 0.1.0`, tag `wetter-v0.1.0`) with one asset named `<app>-<version>.apk`. Obtainium shows *"no matching version"* until the first release of an app exists.
 
 **F-Droid:** not available yet. The apps contain no proprietary libraries, so an F-Droid build is planned (either the main repository or a self-hosted F-Droid repo).
@@ -120,6 +149,8 @@ Every app is rebuilt with **[Replica](https://github.com/Jakeschincariol/replica
 | 4 | `replica-build` | The app itself, screen by screen, with a [build log](replica/wetter/build-log.md) and [screenshots](replica/wetter/clone-screens/) rendered from a real API response |
 | next | `replica-test`, `replica-diff`, `replica-entrepreneur`, `replica-brand`, `replica-launch`, `replica-deploy`, `replica-backend` | QA, parity scoring against the original, reading real user reviews for improvements, naming and branding, store listing, release |
 
+**Rechner** too: [recon](replica/rechner/recon.md), [architecture](replica/rechner/architecture.md), [tokens](replica/rechner/design/tokens.json) (24 pairs AA), [build log](replica/rechner/build-log.md), [screenshots](replica/rechner/clone-screens/).
+
 **Uhr** went through the same steps from scratch: [recon](replica/uhr/recon.md) (17 screens, 9 flows), [architecture](replica/uhr/architecture.md), [design tokens](replica/uhr/design/tokens.json) (39 pairs AA), [build log](replica/uhr/build-log.md) and [screenshots](replica/uhr/clone-screens/).
 
 The rules Replica enforces, and that this project follows:
@@ -143,7 +174,7 @@ Each commit says what changed and carries a `Co-Authored-By` line for the AI.
 Requirements: JDK 17 or newer and the Android SDK (platform 36).
 
 ```bash
-cd wetter        # or: cd uhr
+cd wetter        # or: cd uhr, cd rechner
 ./gradlew :app:assembleRelease            # APK in app/build/outputs/apk/release/
 ./gradlew :app:testDebugUnitTest          # unit + screenshot tests
 ./gradlew :app:recordRoborazziDebug       # re-render replica/wetter/clone-screens/
@@ -156,6 +187,7 @@ Release builds are signed with the project key from `~/.android/nogoogleapps-rel
 ```
 replica/<app>/    recon, architecture, design system, build log, screenshots (one folder per app)
 wetter/           the weather app (Kotlin, Jetpack Compose, Glance widgets, Room, WorkManager)
+rechner/          the calculator (Kotlin, Jetpack Compose, own exact expression engine)
 uhr/              the clock and alarm app (Kotlin, Jetpack Compose, AlarmManager, Glance, Room)
 ```