4 files changed, 152 insertions, 38 deletions

diff --git a/crates/ra_cli/src/main.rs b/crates/ra_cli/src/main.rs
index 9e6f869c1..a9a9fbddd 100644
--- a/crates/ra_cli/src/main.rs
+++ b/crates/ra_cli/src/main.rs
@@ -21,8 +21,7 @@ fn main() -> Result<()> {
         return Ok(());
     }
     let subcommand = subcommand.unwrap();
-    let mut args: Vec<_> = std::env::args_os().collect();
-    let mut matches = Arguments::from_vec(args.drain(2..).collect());
+    let mut matches = Arguments::from_vec(std::env::args_os().skip(2).collect());
 
     match &*subcommand.to_string_lossy() {
         "parse" => {
diff --git a/crates/ra_tools/Cargo.toml b/crates/ra_tools/Cargo.toml
index b94a0b18d..848ca408d 100644
--- a/crates/ra_tools/Cargo.toml
+++ b/crates/ra_tools/Cargo.toml
@@ -8,7 +8,7 @@ publish = false
 [dependencies]
 walkdir = "2.1.3"
 itertools = "0.8.0"
-clap = { version = "2.32.0", default-features = false }
+pico-args = "0.2.0"
 quote = "1.0.2"
 proc-macro2 = "1.0.1"
 ron = "0.5.1"
diff --git a/crates/ra_tools/src/help.rs b/crates/ra_tools/src/help.rs
new file mode 100644
index 000000000..5bfe65734
--- /dev/null
+++ b/crates/ra_tools/src/help.rs
@@ -0,0 +1,56 @@
+pub fn print_global_help() {

+    println!(

+        "tasks

+

+USAGE:

+    ra_tools <SUBCOMMAND>

+

+FLAGS:

+    -h, --help       Prints help information

+

+SUBCOMMANDS:

+    format

+    format-hook

+    fuzz-tests

+    gen-syntax

+    gen-tests

+    install-ra

+    lint"

+    )

+}

+

+pub fn print_install_ra_help() {

+    println!(

+        "ra_tools-install-ra

+

+USAGE:

+    ra_tools.exe install-ra [FLAGS]

+

+FLAGS:

+        --client-code

+    -h, --help           Prints help information

+        --jemalloc

+        --server"

+    )

+}

+

+pub fn print_no_param_subcommand_help(subcommand: &str) {

+    println!(

+        "ra_tools-{}

+

+USAGE:

+    ra_tools {}

+

+FLAGS:

+    -h, --help       Prints help information",

+        subcommand, subcommand

+    );

+}

+

+pub fn print_install_ra_conflict() {

+    println!(

+        "error: The argument `--server` cannot be used with `--client-code`

+                    

+For more information try --help"

+    )

+}

diff --git a/crates/ra_tools/src/main.rs b/crates/ra_tools/src/main.rs
index 33badf290..5410edea9 100644
--- a/crates/ra_tools/src/main.rs
+++ b/crates/ra_tools/src/main.rs
@@ -1,5 +1,8 @@
-use clap::{App, Arg, SubCommand};
+mod help;
+
+use core::fmt::Write;
 use core::str;
+use pico_args::Arguments;
 use ra_tools::{
     gen_tests, generate_boilerplate, install_format_hook, run, run_clippy, run_fuzzer, run_rustfmt,
     Cmd, Overwrite, Result,
@@ -20,45 +23,101 @@ struct ServerOpt {
 }
 
 fn main() -> Result<()> {
-    let matches = App::new("tasks")
-        .setting(clap::AppSettings::SubcommandRequiredElseHelp)
-        .subcommand(SubCommand::with_name("gen-syntax"))
-        .subcommand(SubCommand::with_name("gen-tests"))
-        .subcommand(
-            SubCommand::with_name("install-ra")
-                .arg(Arg::with_name("server").long("--server"))
-                .arg(Arg::with_name("jemalloc").long("jemalloc"))
-                .arg(Arg::with_name("client-code").long("client-code").conflicts_with("server")),
-        )
-        .alias("install-code")
-        .subcommand(SubCommand::with_name("format"))
-        .subcommand(SubCommand::with_name("format-hook"))
-        .subcommand(SubCommand::with_name("fuzz-tests"))
-        .subcommand(SubCommand::with_name("lint"))
-        .get_matches();
-    match matches.subcommand() {
-        ("install-ra", Some(matches)) => {
-            let opts = InstallOpt {
-                client: if matches.is_present("server") { None } else { Some(ClientOpt::VsCode) },
-                server: if matches.is_present("client-code") {
-                    None
-                } else {
-                    Some(ServerOpt { jemalloc: matches.is_present("jemalloc") })
-                },
-            };
-            install(opts)?
+    let subcommand = std::env::args_os().nth(1);
+    if subcommand.is_none() {
+        help::print_global_help();
+        return Ok(());
+    }
+    let subcommand = subcommand.unwrap();
+    let mut matches = Arguments::from_vec(std::env::args_os().skip(2).collect());
+    let subcommand = &*subcommand.to_string_lossy();
+    match subcommand {
+        "install-ra" | "install-code" => {
+            if matches.contains(["-h", "--help"]) {
+                help::print_install_ra_help();
+                return Ok(());
+            } else {
+                let server = matches.contains("--server");
+                let client_code = matches.contains("--client-code");
+                if server && client_code {
+                    help::print_install_ra_conflict();
+                    return Ok(());
+                }
+                let jemalloc = matches.contains("--jemalloc");
+                matches.finish().or_else(handle_extra_flags)?;
+                let opts = InstallOpt {
+                    client: if server { None } else { Some(ClientOpt::VsCode) },
+                    server: if client_code { None } else { Some(ServerOpt { jemalloc: jemalloc }) },
+                };
+                install(opts)?
+            }
+        }
+        "gen-tests" => {
+            if matches.contains(["-h", "--help"]) {
+                help::print_no_param_subcommand_help(&subcommand);
+                return Ok(());
+            } else {
+                gen_tests(Overwrite)?
+            }
+        }
+        "gen-syntax" => {
+            if matches.contains(["-h", "--help"]) {
+                help::print_no_param_subcommand_help(&subcommand);
+                return Ok(());
+            } else {
+                generate_boilerplate(Overwrite)?
+            }
+        }
+        "format" => {
+            if matches.contains(["-h", "--help"]) {
+                help::print_no_param_subcommand_help(&subcommand);
+                return Ok(());
+            } else {
+                run_rustfmt(Overwrite)?
+            }
+        }
+        "format-hook" => {
+            if matches.contains(["-h", "--help"]) {
+                help::print_no_param_subcommand_help(&subcommand);
+                return Ok(());
+            } else {
+                install_format_hook()?
+            }
+        }
+        "lint" => {
+            if matches.contains(["-h", "--help"]) {
+                help::print_no_param_subcommand_help(&subcommand);
+                return Ok(());
+            } else {
+                run_clippy()?
+            }
         }
-        ("gen-tests", _) => gen_tests(Overwrite)?,
-        ("gen-syntax", _) => generate_boilerplate(Overwrite)?,
-        ("format", _) => run_rustfmt(Overwrite)?,
-        ("format-hook", _) => install_format_hook()?,
-        ("lint", _) => run_clippy()?,
-        ("fuzz-tests", _) => run_fuzzer()?,
-        _ => unreachable!(),
+        "fuzz-tests" => {
+            if matches.contains(["-h", "--help"]) {
+                help::print_no_param_subcommand_help(&subcommand);
+                return Ok(());
+            } else {
+                run_fuzzer()?
+            }
+        }
+        _ => help::print_global_help(),
     }
     Ok(())
 }
 
+fn handle_extra_flags(e: pico_args::Error) -> Result<()> {
+    if let pico_args::Error::UnusedArgsLeft(flags) = e {
+        let mut invalid_flags = String::new();
+        for flag in flags {
+            write!(&mut invalid_flags, "{}, ", flag).expect("Error on write");
+        }
+        let (invalid_flags, _) = invalid_flags.split_at(invalid_flags.len() - 2);
+        Err(format!("Invalid flags: {}", invalid_flags).into())
+    } else {
+        Err(e.to_string().into())
+    }
+}
+
 fn install(opts: InstallOpt) -> Result<()> {
     if cfg!(target_os = "macos") {
         fix_path_for_mac()?