slides review

Author: fglock

dev/presentations/German_Perl_Raku_Workshop_2026/slides-part3-integration.md

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+# PerlOnJava — Integration & Future
+
+## Making Perl a First-Class JVM Citizen
+
+German Perl/Raku Workshop 2026 — Flavio Glock
+
+*Part 3: Integration, tooling, and roadmap (10min)*
+
+---
+
+## XSLoader: Java Instead of C
+
+- Loads **Java extensions** instead of C shared libraries
+- **jnr-posix** replaces XS for native POSIX calls
+- No C compiler needed
+
+Note:
+Java equivalents are easier to write and maintain than C/XS. The same API surface is exposed to Perl code.
+
+---
+
+## Module Loading
+
+`require` converts `Module::Name` → `Module/Name.pm`, searches `@INC`, caches in `%INC`.
+
+**300+ modules bundled inside the JAR:**
+```text
+%INC: 'Data/Dumper.pm' =>
+  'file:/path/to/perlonjava.jar!/lib/Data/Dumper.pm'
+```
+
+---
+
+## JSR-223: Embed Perl in Java
+
+JSR-223 is the standard Java scripting API (JDK since Java 6).
+
+```java
+ScriptEngineManager manager = new ScriptEngineManager();
+ScriptEngine perl = manager.getEngineByName("perl");
+
+perl.put("data", myJavaObject);
+Object result = perl.eval("process_data($data)");
+```
+
+**Bidirectional:** Java ↔ Perl seamlessly.
+
+**Use case:** Embed legacy Perl scripts in a modern Java application without rewriting them.
+
+---
+
+## Future Targets
+
+**Current:** Standard JVM (HotSpot)
+
+1. **GraalVM** — native executables, instant startup
+2. **Android DEX** — Perl on mobile devices
+
+The Internal VM is key — custom bytecode is portable to any JVM derivative.
+
+Note:
+Dual backend matters beyond performance. GraalVM gives standalone executables. Android DEX converts JVM to Dalvik bytecode.
+
+---
+
+## Interactive Debugger
+
+**Invoke with `-d` flag:** `./jperl -d script.pl`
+
+```text
+  n        Step over (next line)
+  s        Step into subroutine
+  r        Step out (return)
+  c        Continue to breakpoint
+  b 42     Set breakpoint at line 42
+  l        List source around current line
+  T        Stack trace
+  p $var   Print variable value
+```
+
+Supports `$DB::single`, `@DB::args`, `%DB::sub`, and custom `DB::DB` via `PERL5DB`.
+
+Note:
+Debugger uses Internal VM (forced with -d). DEBUG opcodes inserted at each statement. DebugHooks handles breakpoints, command parsing, and eval in current scope. PERL5DB supported for custom debuggers.
+
+---
+
+## Current Limitations
+
+**JVM-incompatible:**
+- `fork` — not available on JVM
+- `DESTROY` — JVM uses non-deterministic GC
+- Threading — not yet implemented
+
+**Partially implemented:**
+- Some regex features, taint checks
+
+Note:
+Workarounds: jnr-posix for native access, Java threading APIs, file auto-close at exit. XS modules use Java equivalents.
+
+---
+
+## Roadmap
+
+**Stable now:** JVM backend, Perl class features, IPC, sockets, interactive debugger
+
+**In progress:** Internal VM optimization, eval STRING performance
+
+**Next:** More compatible regex engine, additional debugger features
+
+---
+
+# Closing
+
+---
+
+## Perl Was Never Designed to Run on the JVM
+
+We made it work anyway — and made it **fast**.
+
+<span class="metric">~200,000 tests</span> · <span class="metric">400 files</span> · <span class="metric">6,000 commits</span>
+
+No formal spec exists. The tests **are** the specification.
+
+Note:
+This is test-driven development at its most extreme — tests define the language behavior.
+
+---
+
+## Get Involved
+
+**GitHub:** github.com/fglock/PerlOnJava · **License:** Artistic 2.0
+
+- **Test** your scripts and report issues
+- **Port** CPAN modules
+- **Contribute** to core development
+
+---
+
+## Thank You!
+
+**Special thanks to:**
+
+- **Larry Wall** — for creating Perl
+- **Perl test writers** — tests that define Perl's behavior
+- **Perl community** — for decades of innovation
+- **Prior pioneers** — JPL, perljvm, Perlito5
+
+**Questions?** → github.com/fglock/PerlOnJava/issues
+
+---