Automatically install the OOP C++ header

.github/workflows/capi.yaml

@@ -26,6 +26,7 @@ jobs:
           RUSTFLAGS: '-Cinstrument-coverage -Clink-dead-code'
         run: |
           cd pineappl_capi
+          export PINEAPPL_C_INSTALL_PREFIX=/usr/local
           cargo cinstall --verbose --prefix=/usr/local/ --libdir=/usr/local/lib
           ldconfig
 

.github/workflows/release.yml

@@ -36,6 +36,7 @@ jobs:
           curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh -s -- -y --target=${{ matrix.target }}
           cargo install --locked cargo-c
           cd pineappl_capi
+          export PINEAPPL_C_INSTALL_PREFIX=$(pwd)/prefix
           cargo cinstall --destdir=prefix --libdir=lib --library-type=cdylib --locked --prefix=/ --target=${{ matrix.target }} --verbose
           cd prefix
           tar czf ../../pineappl_capi-${{ matrix.target }}.tar.gz .
@@ -105,6 +106,7 @@ jobs:
       - name: Compile library
         run: |
           cd pineappl_capi
+          export PINEAPPL_C_INSTALL_PREFIX=$(pwd)/prefix
           cargo cinstall --destdir=prefix --libdir=lib --library-type=cdylib --locked --prefix=/ --target=${{ matrix.target }} --verbose
           cd prefix
           tar czf ../../pineappl_capi-${{ matrix.target }}.tar.gz .

docs/installation.md

@@ -75,6 +75,7 @@ If you want to build the CAPI from its sources instead, you first need to
 3. Now install `pineappl_capi`, PineAPPL's C API:
 
        cd pineappl_capi
+       export PINEAPPL_C_INSTALL_PREFIX=${prefix} # To copy the OOP C++ header
        cargo cinstall --release --prefix=${prefix} --libdir=${prefix}/lib
        cd ..
 

examples/object-oriented-cpp/dyaa.cpp

@@ -8,8 +8,8 @@
 #include <random>
 #include <vector>
 
-#include "PineAPPL.hpp"
-#include "pineappl_capi.h"
+#include <PineAPPL.hpp>
+#include <pineappl_capi.h>
 
 double int_photo(double s, double t, double u) {
   double alpha0 = 1.0 / 137.03599911;

pineappl_capi/build.rs

@@ -0,0 +1,21 @@
+//! A build script to install the OOP C++ interface to `PineAPPL`.
+
+use std::env;
+use std::fs;
+use std::path::PathBuf;
+
+fn main() {
+    println!("cargo:rerun-if-changed=src/include/PineAPPL.hpp");
+
+    if let Ok(prefix) = env::var("PINEAPPL_C_INSTALL_PREFIX") {
+        let prefix_path = PathBuf::from(prefix);
+        let include_path = prefix_path.join("include").join("pineappl_capi");
+
+        fs::create_dir_all(&include_path).expect("Failed to create include directory.");
+
+        let source_header = PathBuf::from("src/include/PineAPPL.hpp");
+        let dest_header = include_path.join("PineAPPL.hpp");
+
+        fs::copy(&source_header, &dest_header).expect("Failed to copy header file.");
+    }
+}