Add minimum working tinyopt example

Author: julien-michot

CMakeLists.txt

@@ -0,0 +1,32 @@
+cmake_minimum_required (VERSION 3.5)
+
+project(tinyopt-example VERSION 0.0.1
+                        DESCRIPTION "A Tinyopt Example Project"
+                        LANGUAGES CXX)
+
+# Compiler flags
+set(CMAKE_CXX_STANDARD 20)
+
+# Import Eigen (Mandatory)
+find_package(Eigen3 REQUIRED NO_MODULE)
+
+# Find Tinyopt, fetch it if not found
+find_package(Tinyopt)
+
+if (NOT Tinyopt_FOUND)
+  message("Tinyopt not found locally, fetching it")
+  include(FetchContent)
+  FetchContent_Declare(
+      tinyopt
+      GIT_REPOSITORY  https://github.com/julien-michot/tinyopt.git
+      GIT_TAG         main
+      GIT_SHALLOW     TRUE
+      GIT_PROGRESS    TRUE
+  )
+  set(BUILD_TINYOPT_TESTS OFF)
+  FetchContent_MakeAvailable(tinyopt)
+endif()
+
+# Header-only library
+add_executable(example src/example.cpp)
+target_link_libraries(example PUBLIC Eigen3::Eigen tinyopt)

README.md

@@ -1,2 +1,48 @@
+
+![Tinyopt-example Builds](https://github.com/julien-michot/tinyopt-example/actions/workflows/build.yml/badge.svg)
+
 # tinyopt-example
 Minimal Tinyopt project
+
+## CMakeLists.txt
+
+```cmake
+set(CMAKE_CXX_STANDARD 20)
+
+find_package(Eigen3 REQUIRED NO_MODULE)
+find_package(Tinyopt)
+
+add_executable(example src/example.cpp)
+target_link_libraries(example PUBLIC Eigen3::Eigen tinyopt)
+```
+
+
+## Example.cpp
+
+Here is an example of usage of 'tinyopt' where we compute the square root of 2.
+
+```cpp
+#include <tinyopt/tinyopt.h>
+
+int main(int, char **argv) {
+  double x = 1;
+  tinyopt::Optimize(x, [](const auto &x) { return x * x - 2.0; });
+  std::cout << "What's √2 already?\n" << x << "\n";
+  return 0;
+}
+```
+
+### Building
+
+```shell
+git clone https://github.com/julien-michot/tinyopt-example
+cd tinyopt-example && mkdir build && cd build
+cmake ..
+make -j
+```
+
+### Running
+
+```shell
+./example
+```

src/example.cpp

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+/// This is free and unencumbered software released into the public domain.
+/// Example of usage of 'tinyopt' and compute the square root of 2.
+
+#include <tinyopt/tinyopt.h>
+
+int main(int, char **argv) {
+
+  double x = 1;
+  auto loss = [](const auto &x) { return x * x - 2.0; };
+
+  tinyopt::Options options;
+  const auto &out = tinyopt::Optimize(x, loss, options);
+
+  std::cout << "What's √2 already?\n" << x << "\n";
+  return 0;
+}