Create draft UI for roc init

crates/cli/src/lib.rs

@@ -53,6 +53,7 @@ pub const CMD_CHECK: &str = "check";
 pub const CMD_VERSION: &str = "version";
 pub const CMD_FORMAT: &str = "format";
 pub const CMD_TEST: &str = "test";
+pub const CMD_INIT: &str = "init";
 pub const CMD_GLUE: &str = "glue";
 pub const CMD_GEN_STUB_LIB: &str = "gen-stub-lib";
 pub const CMD_PREPROCESS_HOST: &str = "preprocess-host";
@@ -84,6 +85,8 @@ pub const ROC_FILE: &str = "ROC_FILE";
 pub const ROC_DIR: &str = "ROC_DIR";
 pub const GLUE_DIR: &str = "GLUE_DIR";
 pub const GLUE_SPEC: &str = "GLUE_SPEC";
+pub const ROC_PLATFORM: &str = "ROC_PLATFORM";
+pub const INIT_DIR: &str = "INIT_DIR";
 pub const DIRECTORY_OR_FILES: &str = "DIRECTORY_OR_FILES";
 pub const ARGS_FOR_APP: &str = "ARGS_FOR_APP";
 pub const FLAG_PP_HOST: &str = "host";
@@ -381,6 +384,21 @@ pub fn build_app() -> Command {
                     .default_value(DEFAULT_ROC_FILENAME),
                 )
         )
+        .subcommand(Command::new(CMD_INIT)
+            .about("Generate a project based on a platform init.roc file")
+            .arg(
+                Arg::new(ROC_PLATFORM)
+                    .help("The target platform that provides the init.roc file.")
+                    .value_parser(value_parser!(PathBuf))
+                    .required(true)
+            )
+            .arg(
+                Arg::new(INIT_DIR)
+                    .help("The directory for the generated init code.\nNote: The implementation can write to any file in this directory.")
+                    .value_parser(value_parser!(PathBuf))
+                    .required(true)
+            )
+        )
         .subcommand(Command::new(CMD_GLUE)
             .about("Generate glue code between a platform's Roc API and its host language")
             .arg(&flag_dev)

crates/cli/src/main.rs

@@ -4,11 +4,11 @@ use roc_build::link::LinkType;
 use roc_build::program::{check_file, CodeGenBackend};
 use roc_cli::{
     build_app, format_files, format_src, test, BuildConfig, FormatMode, CMD_BUILD, CMD_CHECK,
-    CMD_DEV, CMD_DOCS, CMD_FORMAT, CMD_GEN_STUB_LIB, CMD_GLUE, CMD_PREPROCESS_HOST, CMD_REPL,
-    CMD_RUN, CMD_TEST, CMD_VERSION, DIRECTORY_OR_FILES, FLAG_CHECK, FLAG_DEV, FLAG_LIB, FLAG_MAIN,
-    FLAG_NO_COLOR, FLAG_NO_HEADER, FLAG_NO_LINK, FLAG_OUTPUT, FLAG_PP_DYLIB, FLAG_PP_HOST,
-    FLAG_PP_PLATFORM, FLAG_STDIN, FLAG_STDOUT, FLAG_TARGET, FLAG_TIME, GLUE_DIR, GLUE_SPEC,
-    ROC_FILE, VERSION,
+    CMD_DEV, CMD_DOCS, CMD_FORMAT, CMD_GEN_STUB_LIB, CMD_GLUE, CMD_INIT, CMD_PREPROCESS_HOST,
+    CMD_REPL, CMD_RUN, CMD_TEST, CMD_VERSION, DIRECTORY_OR_FILES, FLAG_CHECK, FLAG_DEV, FLAG_LIB,
+    FLAG_MAIN, FLAG_NO_COLOR, FLAG_NO_HEADER, FLAG_NO_LINK, FLAG_OUTPUT, FLAG_PP_DYLIB,
+    FLAG_PP_HOST, FLAG_PP_PLATFORM, FLAG_STDIN, FLAG_STDOUT, FLAG_TARGET, FLAG_TIME, GLUE_DIR,
+    GLUE_SPEC, INIT_DIR, ROC_FILE, ROC_PLATFORM, VERSION,
 };
 use roc_docs::generate_docs_html;
 use roc_error_macros::user_error;
@@ -101,6 +101,20 @@ fn main() -> io::Result<()> {
                 Ok(1)
             }
         }
+        Some((CMD_INIT, matches)) => {
+            let _platform_path = matches.get_one::<PathBuf>(ROC_PLATFORM).unwrap();
+            let output_path = matches.get_one::<PathBuf>(INIT_DIR).unwrap();
+
+            if !output_path.exists() || output_path.is_dir() {
+                // TODO: implement
+                eprintln!("This feature is currently being implemented");
+                Ok(0)
+            } else {
+                eprintln!("`roc init` must be given a directory to output into, because the init might generate multiple files.");
+
+                Ok(1)
+            }
+        }
         Some((CMD_GLUE, matches)) => {
             let input_path = matches.get_one::<PathBuf>(ROC_FILE).unwrap();
             let output_path = matches.get_one::<PathBuf>(GLUE_DIR).unwrap();