mod(build): build configuration for examples

build.zig

@@ -4,6 +4,17 @@ pub fn build(b: *std.Build) void {
     const target = b.standardTargetOptions(.{});
     const optimize = b.standardOptimizeOption(.{});
 
+    const Examples = enum {
+        Layout,
+        Scrollable,
+    };
+
+    const example = b.option(Examples, "example", "Example to build and/or run.") orelse .Layout;
+
+    const options = b.addOptions();
+    options.addOption(Examples, "example", example);
+
+    // dependencies
     const zg = b.dependency("zg", .{
         .target = target,
         .optimize = optimize,
@@ -17,27 +28,30 @@ pub fn build(b: *std.Build) void {
     });
     lib.addImport("code_point", zg.module("code_point"));
 
-    // main executable (usually used for testing)
-    const exe = b.addExecutable(.{
-        .name = "zterm",
-        .root_source_file = b.path("src/main.zig"),
+    // Examples.Scrollable
+    const scrollable = b.addExecutable(.{
+        .name = "scrollable",
+        .root_source_file = b.path("examples/scrollable.zig"),
         .target = target,
         .optimize = optimize,
     });
-    exe.root_module.addImport("zterm", lib);
+    scrollable.root_module.addImport("zterm", lib);
 
-    // TODO: add example execution through optional argument to `zig run` to run
-    // an example application instead of the main executable
-
-    // example applications (usually used for documentation and demonstrations)
-    const container = b.addExecutable(.{
-        .name = "container",
-        .root_source_file = b.path("examples/container.zig"),
+    // Examples.Layout
+    const layout = b.addExecutable(.{
+        .name = "layout",
+        .root_source_file = b.path("examples/layout.zig"),
         .target = target,
         .optimize = optimize,
     });
-    container.root_module.addImport("zterm", lib);
-    b.installArtifact(container);
+    layout.root_module.addImport("zterm", lib);
+
+    // mapping of user selected example to compile step
+    const exe = switch (example) {
+        .Layout => layout,
+        .Scrollable => scrollable,
+    };
+    b.installArtifact(exe);
 
     // zig build run
     const run_cmd = b.addRunArtifact(exe);