Start support for commandline args to nu itself (#851)

* cmdline args wip

* WIP

* redirect working

* Add help and examples

* Only show flags in signature of more than help

crates/nu-command/src/filesystem/mod.rs

@@ -14,7 +14,7 @@ pub use cp::Cp;
 pub use ls::Ls;
 pub use mkdir::Mkdir;
 pub use mv::Mv;
-pub use open::Open;
+pub use open::{BufferedReader, Open};
 pub use rm::Rm;
 pub use save::Save;
 pub use touch::Touch;

crates/nu-command/src/filesystem/open.rs

@@ -184,6 +184,12 @@ pub struct BufferedReader<R: Read> {
     input: BufReader<R>,
 }
 
+impl<R: Read> BufferedReader<R> {
+    pub fn new(input: BufReader<R>) -> Self {
+        Self { input }
+    }
+}
+
 impl<R: Read> Iterator for BufferedReader<R> {
     type Item = Result<Vec<u8>, ShellError>;
 

crates/nu-engine/src/documentation.rs

@@ -186,6 +186,10 @@ pub fn get_documentation(
         long_desc.push('\n');
     }
 
+    if !sig.named.is_empty() {
+        long_desc.push_str(&get_flags_section(sig))
+    }
+
     if !sig.required_positional.is_empty()
         || !sig.optional_positional.is_empty()
         || sig.rest_positional.is_some()
@@ -205,13 +209,11 @@ pub fn get_documentation(
             long_desc.push_str(&format!("  ...args: {}\n", rest_positional.desc));
         }
     }
-    if !sig.named.is_empty() {
-        long_desc.push_str(&get_flags_section(sig))
-    }
 
     if !examples.is_empty() {
         long_desc.push_str("\nExamples:");
     }
+
     for example in examples {
         long_desc.push('\n');
         long_desc.push_str("  ");
@@ -222,7 +224,7 @@ pub fn get_documentation(
         } else if let Some(highlighter) = engine_state.find_decl(b"nu-highlight") {
             let decl = engine_state.get_decl(highlighter);
 
-            if let Ok(output) = decl.run(
+            match decl.run(
                 engine_state,
                 stack,
                 &Call::new(),
@@ -232,6 +234,7 @@ pub fn get_documentation(
                 }
                 .into_pipeline_data(),
             ) {
+                Ok(output) => {
                     let result = output.into_value(Span { start: 0, end: 0 });
                     match result.as_string() {
                         Ok(s) => {
@@ -242,6 +245,12 @@ pub fn get_documentation(
                         }
                     }
                 }
+                Err(_) => {
+                    long_desc.push_str(&format!("\n  > {}\n", example.example));
+                }
+            }
+        } else {
+            long_desc.push_str(&format!("\n  > {}\n", example.example));
         }
     }
 

crates/nu-parser/src/lib.rs

@@ -12,9 +12,7 @@ pub use flatten::{
 };
 pub use lex::{lex, Token, TokenContents};
 pub use lite_parse::{lite_parse, LiteBlock};
-pub use parse_keywords::{
-    parse_alias, parse_def, parse_def_predecl, parse_let, parse_module, parse_use,
-};
+
 pub use parser::{find_captures_in_expr, parse, trim_quotes, Import};
 
 #[cfg(feature = "plugin")]

crates/nu-protocol/src/example.rs

@@ -1,5 +1,6 @@
 use crate::Value;
 
+#[derive(Debug)]
 pub struct Example {
     pub example: &'static str,
     pub description: &'static str,

crates/nu-protocol/src/signature.rs

@@ -279,6 +279,14 @@ impl Signature {
         one_liner.push_str(&self.name);
         one_liner.push(' ');
 
+        // Note: the call signature needs flags first because on the nu commandline,
+        // flags will precede the script file name. Flags for internal commands can come
+        // either before or after (or around) positional parameters, so there isn't a strong
+        // preference, so we default to the more constrained example.
+        if self.named.len() > 1 {
+            one_liner.push_str("{flags} ");
+        }
+
         for positional in &self.required_positional {
             one_liner.push_str(&get_positional_short_name(positional, true));
         }
@@ -286,18 +294,14 @@ impl Signature {
             one_liner.push_str(&get_positional_short_name(positional, false));
         }
 
-        if self.rest_positional.is_some() {
-            one_liner.push_str("...args ");
+        if let Some(rest) = &self.rest_positional {
+            one_liner.push_str(&format!("...{}", get_positional_short_name(rest, false)));
         }
 
         // if !self.subcommands.is_empty() {
         //     one_liner.push_str("<subcommand> ");
         // }
 
-        if !self.named.is_empty() {
-            one_liner.push_str("{flags} ");
-        }
-
         one_liner
     }
 

src/eval_file.rs

@@ -13,8 +13,10 @@ use crate::utils::{gather_parent_env_vars, report_error};
 /// Main function used when a file path is found as argument for nu
 pub(crate) fn evaluate(
     path: String,
+    args: &[String],
     init_cwd: PathBuf,
     engine_state: &mut EngineState,
+    input: PipelineData,
 ) -> Result<()> {
     // First, set up env vars as strings only
     gather_parent_env_vars(engine_state);
@@ -82,12 +84,10 @@ pub(crate) fn evaluate(
         std::process::exit(1);
     }
 
-    match eval_block(
-        engine_state,
-        &mut stack,
-        &block,
-        PipelineData::new(Span::new(0, 0)), // Don't try this at home, 0 span is ignored
-    ) {
+    // Next, let's check if there are any flags we want to pass to the main function
+    if args.is_empty() && engine_state.find_decl(b"main").is_none() {
+        // We don't have a main, so evaluate the whole file
+        match eval_block(engine_state, &mut stack, &block, input) {
             Ok(pipeline_data) => {
                 for item in pipeline_data {
                     if let Value::Error { error } = item {
@@ -99,14 +99,16 @@ pub(crate) fn evaluate(
                     }
                     println!("{}", item.into_string("\n", &config));
                 }
-
-            // Next, let's check if there are any flags we want to pass to the main function
-            let args: Vec<String> = std::env::args().skip(2).collect();
-
-            if args.is_empty() && engine_state.find_decl(b"main").is_none() {
-                return Ok(());
             }
+            Err(err) => {
+                let working_set = StateWorkingSet::new(engine_state);
 
+                report_error(&working_set, &err);
+
+                std::process::exit(1);
+            }
+        }
+    } else {
         let args = format!("main {}", args.join(" ")).as_bytes().to_vec();
 
         let (block, delta) = {
@@ -127,12 +129,7 @@ pub(crate) fn evaluate(
             report_error(&working_set, &err);
         }
 
-            match eval_block(
-                engine_state,
-                &mut stack,
-                &block,
-                PipelineData::new(Span::new(0, 0)), // Don't try this at home, 0 span is ignored
-            ) {
+        match eval_block(engine_state, &mut stack, &block, input) {
             Ok(pipeline_data) => {
                 for item in pipeline_data {
                     if let Value::Error { error } = item {
@@ -154,14 +151,6 @@ pub(crate) fn evaluate(
             }
         }
     }
-        Err(err) => {
-            let working_set = StateWorkingSet::new(engine_state);
-
-            report_error(&working_set, &err);
-
-            std::process::exit(1);
-        }
-    }
 
     Ok(())
 }

src/main.rs

@@ -10,11 +10,24 @@ mod utils;
 mod tests;
 
 use miette::Result;
-use nu_command::create_default_context;
-use std::sync::{
+use nu_command::{create_default_context, BufferedReader};
+use nu_engine::get_full_help;
+use nu_parser::parse;
+use nu_protocol::{
+    ast::{Call, Expr, Expression, Pipeline, Statement},
+    engine::{Command, EngineState, Stack, StateWorkingSet},
+    ByteStream, Category, Example, IntoPipelineData, PipelineData, ShellError, Signature, Span,
+    Spanned, SyntaxShape, Value, CONFIG_VARIABLE_ID,
+};
+use std::{
+    io::BufReader,
+    path::Path,
+    sync::{
         atomic::{AtomicBool, Ordering},
         Arc,
+    },
 };
+use utils::report_error;
 
 fn main() -> Result<()> {
     // miette::set_panic_hook();
@@ -51,9 +64,199 @@ fn main() -> Result<()> {
     engine_state.ctrlc = Some(engine_state_ctrlc);
     // End ctrl-c protection section
 
-    if let Some(path) = std::env::args().nth(1) {
-        eval_file::evaluate(path, init_cwd, &mut engine_state)
+    let mut args_to_nushell = vec![];
+    let mut script_name = String::new();
+    let mut args_to_script = vec![];
+
+    // Would be nice if we had a way to parse this. The first flags we see will be going to nushell
+    // then it'll be the script name
+    // then the args to the script
+
+    let mut collect_arg_nushell = false;
+    for arg in std::env::args().skip(1) {
+        if !script_name.is_empty() {
+            args_to_script.push(arg);
+        } else if collect_arg_nushell {
+            args_to_nushell.push(arg);
+            collect_arg_nushell = false;
+        } else if arg.starts_with('-') {
+            // Cool, it's a flag
+            if arg == "-c"
+                || arg == "--commands"
+                || arg == "--develop"
+                || arg == "--debug"
+                || arg == "--loglevel"
+                || arg == "--config-file"
+            {
+                collect_arg_nushell = true;
+            }
+            args_to_nushell.push(arg);
+        } else {
+            // Our script file
+            script_name = arg;
+        }
+    }
+
+    args_to_nushell.insert(0, "nu".into());
+
+    let nushell_commandline_args = args_to_nushell.join(" ");
+
+    let nushell_config =
+        parse_commandline_args(&nushell_commandline_args, &init_cwd, &mut engine_state);
+
+    match nushell_config {
+        Ok(nushell_config) => {
+            if !script_name.is_empty() {
+                let input = if let Some(redirect_stdin) = &nushell_config.redirect_stdin {
+                    let stdin = std::io::stdin();
+                    let buf_reader = BufReader::new(stdin);
+
+                    PipelineData::ByteStream(
+                        ByteStream {
+                            stream: Box::new(BufferedReader::new(buf_reader)),
+                            ctrlc: Some(ctrlc),
+                        },
+                        redirect_stdin.span,
+                        None,
+                    )
+                } else {
+                    PipelineData::new(Span::new(0, 0))
+                };
+
+                eval_file::evaluate(
+                    script_name,
+                    &args_to_script,
+                    init_cwd,
+                    &mut engine_state,
+                    input,
+                )
             } else {
                 repl::evaluate(ctrlc, &mut engine_state)
             }
         }
+        Err(_) => std::process::exit(1),
+    }
+}
+
+fn parse_commandline_args(
+    commandline_args: &str,
+    init_cwd: &Path,
+    engine_state: &mut EngineState,
+) -> Result<NushellConfig, ShellError> {
+    let (block, delta) = {
+        let mut working_set = StateWorkingSet::new(engine_state);
+        working_set.add_decl(Box::new(Nu));
+
+        let (output, err) = parse(&mut working_set, None, commandline_args.as_bytes(), false);
+        if let Some(err) = err {
+            report_error(&working_set, &err);
+
+            std::process::exit(1);
+        }
+
+        working_set.hide_decl(b"nu");
+        (output, working_set.render())
+    };
+
+    let _ = engine_state.merge_delta(delta, None, init_cwd);
+
+    let mut stack = Stack::new();
+    stack.add_var(
+        CONFIG_VARIABLE_ID,
+        Value::Record {
+            cols: vec![],
+            vals: vec![],
+            span: Span::new(0, 0),
+        },
+    );
+
+    // We should have a successful parse now
+    if let Some(Statement::Pipeline(Pipeline { expressions })) = block.stmts.get(0) {
+        if let Some(Expression {
+            expr: Expr::Call(call),
+            ..
+        }) = expressions.get(0)
+        {
+            let redirect_stdin = call.get_named_arg("stdin");
+
+            let help = call.has_flag("help");
+
+            if help {
+                let full_help =
+                    get_full_help(&Nu.signature(), &Nu.examples(), engine_state, &mut stack);
+                print!("{}", full_help);
+                std::process::exit(1);
+            }
+
+            return Ok(NushellConfig { redirect_stdin });
+        }
+    }
+
+    // Just give the help and exit if the above fails
+    let full_help = get_full_help(&Nu.signature(), &Nu.examples(), engine_state, &mut stack);
+    print!("{}", full_help);
+    std::process::exit(1);
+}
+
+struct NushellConfig {
+    redirect_stdin: Option<Spanned<String>>,
+}
+
+#[derive(Clone)]
+struct Nu;
+
+impl Command for Nu {
+    fn name(&self) -> &str {
+        "nu"
+    }
+
+    fn signature(&self) -> Signature {
+        Signature::build("nu")
+            .desc("The nushell language and shell.")
+            .switch("stdin", "redirect the stdin", None)
+            .optional(
+                "script file",
+                SyntaxShape::Filepath,
+                "name of the optional script file to run",
+            )
+            .rest(
+                "script args",
+                SyntaxShape::String,
+                "parameters to the script file",
+            )
+            .category(Category::System)
+    }
+
+    fn usage(&self) -> &str {
+        "The nushell language and shell."
+    }
+
+    fn run(
+        &self,
+        engine_state: &EngineState,
+        stack: &mut Stack,
+        call: &Call,
+        _input: PipelineData,
+    ) -> Result<nu_protocol::PipelineData, nu_protocol::ShellError> {
+        Ok(Value::String {
+            val: get_full_help(&Nu.signature(), &Nu.examples(), engine_state, stack),
+            span: call.head,
+        }
+        .into_pipeline_data())
+    }
+
+    fn examples(&self) -> Vec<nu_protocol::Example> {
+        vec![
+            Example {
+                description: "Run a script",
+                example: "nu myfile.nu",
+                result: None,
+            },
+            Example {
+                description: "Run nushell interactively (as a shell or REPL)",
+                example: "nu",
+                result: None,
+            },
+        ]
+    }
+}

src/utils.rs

@@ -317,7 +317,7 @@ pub(crate) fn eval_source(
         engine_state,
         stack,
         &block,
-        PipelineData::new(Span::new(0, 0)), // Don't try this at home, 0 span is ignored
+        PipelineData::new(Span::new(0, 0)),
     ) {
         Ok(pipeline_data) => {
             if let Err(err) = print_pipeline_data(pipeline_data, engine_state, stack) {