#663 add unit examples, add get value functions to meta cursor

examples/c/reflection/units/.gitignore

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+.bake_cache
+.DS_Store
+.vscode
+gcov
+bin

examples/c/reflection/units/include/units.h

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+#ifndef UNITS_H
+#define UNITS_H
+
+/* This generated file contains includes for project dependencies */
+#include "units/bake_config.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
+

examples/c/reflection/units/include/units/bake_config.h

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+/*
+                                   )
+                                  (.)
+                                  .|.
+                                  | |
+                              _.--| |--._
+                           .-';  ;`-'& ; `&.
+                          \   &  ;    &   &_/
+                           |"""---...---"""|
+                           \ | | | | | | | /
+                            `---.|.|.|.---'
+
+ * This file is generated by bake.lang.c for your convenience. Headers of
+ * dependencies will automatically show up in this file. Include bake_config.h
+ * in your main project file. Do not edit! */
+
+#ifndef UNITS_BAKE_CONFIG_H
+#define UNITS_BAKE_CONFIG_H
+
+/* Headers of public dependencies */
+#include <flecs.h>
+
+#endif
+

examples/c/reflection/units/project.json

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+{
+    "id": "units",
+    "type": "application",
+    "value": {
+        "use": [
+            "flecs"
+        ]
+    }
+}

examples/c/reflection/units/src/main.c

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+#include <units.h>
+#include <stdio.h>
+
+typedef struct {
+    double temperature;
+    double pressure;
+    double precipitation;
+} WeatherStation;
+
+void print_value(ecs_world_t *world, const ecs_meta_cursor_t *cur) {
+    // Get unit entity and component
+    ecs_entity_t u = ecs_meta_get_unit(cur);
+    const EcsUnit *u_data = ecs_get(world, u, EcsUnit);
+
+    // Print value with unit symbol
+    printf("%s: %.1f %s\n", ecs_meta_get_member(cur), ecs_meta_get_float(cur),
+        u_data->symbol);
+}
+
+int main(int argc, char *argv[]) {
+    ecs_world_t *ecs = ecs_init_w_args(argc, argv);
+
+    // Import units module.
+    ECS_IMPORT(ecs, FlecsUnits);
+
+    ECS_COMPONENT(ecs, WeatherStation);
+
+    // Register reflection data with units. This can improve the way information
+    // is visualized in tools, such as the explorer.
+    ecs_struct_init(ecs, &(ecs_struct_desc_t) {
+        .entity.entity = ecs_id(WeatherStation),
+        .members = {
+            {
+                .name = "temperature", 
+                .type = ecs_id(ecs_f64_t), 
+                .unit = EcsCelsius 
+            },
+            { 
+                .name = "pressure", 
+                .type = ecs_id(ecs_f64_t), 
+                .unit = EcsBar 
+            },
+            {
+                .name = "precipitation", 
+                .type = ecs_id(ecs_f64_t), 
+                .unit = EcsMilliMeters 
+            },
+        }
+    });
+
+    ecs_entity_t e = ecs_set(ecs, 0, WeatherStation, {24, 1.2, 0.5});
+
+    // Use cursor API to print values with units
+    WeatherStation *ptr = ecs_get_mut(ecs, e, WeatherStation, 0);
+    ecs_meta_cursor_t cur = ecs_meta_cursor(ecs, ecs_id(WeatherStation), ptr);
+
+    ecs_meta_push(&cur);
+    print_value(ecs, &cur);
+    ecs_meta_next(&cur);
+    print_value(ecs, &cur);
+    ecs_meta_next(&cur);
+    print_value(ecs, &cur);
+    ecs_meta_pop(&cur);
+
+    return ecs_fini(ecs);
+
+    // Output:
+    //  temperature: 24.0 °C
+    //  pressure: 1.2 bar
+    //  precipitation: 0.5 mm
+}

examples/cpp/reflection/units/include/units.h

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+#ifndef UNITS_H
+#define UNITS_H
+
+/* This generated file contains includes for project dependencies */
+#include "units/bake_config.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
+

examples/cpp/reflection/units/include/units/bake_config.h

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+/*
+                                   )
+                                  (.)
+                                  .|.
+                                  | |
+                              _.--| |--._
+                           .-';  ;`-'& ; `&.
+                          \   &  ;    &   &_/
+                           |"""---...---"""|
+                           \ | | | | | | | /
+                            `---.|.|.|.---'
+
+ * This file is generated by bake.lang.c for your convenience. Headers of
+ * dependencies will automatically show up in this file. Include bake_config.h
+ * in your main project file. Do not edit! */
+
+#ifndef UNITS_BAKE_CONFIG_H
+#define UNITS_BAKE_CONFIG_H
+
+/* Headers of public dependencies */
+#include <flecs.h>
+
+#endif
+

examples/cpp/reflection/units/project.json

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+{
+    "id": "units",
+    "type": "application",
+    "value": {
+        "use": [
+            "flecs"
+        ],
+        "language": "c++",
+        "public": false
+    }
+}

examples/cpp/reflection/units/src/main.cpp

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+#include <units.h>
+#include <iostream>
+
+struct WeatherStation {
+    double temperature;
+    double pressure;
+    double precipitation;
+};
+
+void print_value(const flecs::meta::cursor& cur) {
+    // Get unit entity and component
+    flecs::entity u = cur.get_unit();
+    const flecs::Unit *u_data = u.get<flecs::Unit>();
+
+    // Print value with unit symbol
+    std::cout << cur.get_member() << ": " << cur.get_float() 
+        << " " << u_data->symbol << "\n";
+}
+
+int main(int, char *[]) {
+    flecs::world ecs;
+
+    // Import units module.
+    ecs.import<flecs::units>();
+
+    // Register reflection data with units. This can improve the way information
+    // is visualized in tools, such as the explorer.
+    ecs.component<WeatherStation>()
+        .member<double, flecs::units::temperature::Celsius>("temperature")
+        .member<double, flecs::units::pressure::Bar>("pressure")
+        .member<double, flecs::units::length::MilliMeters>("precipitation");
+
+    auto e = ecs.entity().set<WeatherStation>({24, 1.2, 0.5});
+
+    // Use cursor API to print values with units
+    WeatherStation *ptr = e.get_mut<WeatherStation>();
+    auto cur = ecs.cursor<WeatherStation>(ptr);
+    cur.push();
+    print_value(cur);
+    cur.next();
+    print_value(cur);
+    cur.next();
+    print_value(cur);
+    cur.pop();
+
+    // Output:
+    //  temperature: 24 °C
+    //  pressure: 1.2 bar
+    //  precipitation: 0.5 mm
+}