Add support for adding custom commands to the engine

README.md

@@ -16,6 +16,7 @@ use embed_nu::{rusty_value::*, CommandGroupConfig, Context, NewEmpty, PipelineDa
 fn main() {
   let mut ctx = Context::builder()
     .with_command_groups(CommandGroupConfig::default().all_groups(true))
+    .unwrap()
     .add_parent_env_vars()
     .build()
     .unwrap();
@@ -73,7 +74,7 @@ fn main() {
     bar: 12
   };
   // convert this struct into a nu value
-  // this is also done implicitely when passing the value to the nu context
+  // this is also done implicitly when passing the value to the nu context
   // as function arguments or variables
   let value = instance.into_value();
   dbg!(value);

src/context/bindings.rs

@@ -1,15 +1,17 @@
 use nu_command::*;
 use nu_protocol::engine::{EngineState, StateWorkingSet};
 
+use crate::error::CrateResult;
+
 macro_rules! bind_commands {
             ($engine_state:expr, $( $command:expr),* $(,)? ) => {
                 bind($engine_state, |working_set| {
                         $( working_set.add_decl(Box::new($command)); )*
-                });
+                })
             };
         }
 
-pub fn bind_core_commands(engine_state: &mut EngineState) {
+pub fn bind_core_commands(engine_state: &mut EngineState) -> CrateResult<()> {
     bind_commands!(
         engine_state,
         Alias,
@@ -45,14 +47,14 @@ pub fn bind_core_commands(engine_state: &mut EngineState) {
         Module,
         Use,
         Version,
-    );
+    )
 }
 
-pub fn bind_chart_commands(engine_state: &mut EngineState) {
+pub fn bind_chart_commands(engine_state: &mut EngineState) -> CrateResult<()> {
-    bind_commands!(engine_state, Histogram);
+    bind_commands!(engine_state, Histogram)
 }
 
-pub fn bind_filter_commands(engine_state: &mut EngineState) {
+pub fn bind_filter_commands(engine_state: &mut EngineState) -> CrateResult<()> {
     bind_commands! {
         engine_state,
         All,
@@ -116,14 +118,14 @@ pub fn bind_filter_commands(engine_state: &mut EngineState) {
         Window,
         Wrap,
         Zip,
-    };
+    }
 }
 
-pub fn bind_misc_commands(engine_state: &mut EngineState) {
+pub fn bind_misc_commands(engine_state: &mut EngineState) -> CrateResult<()> {
-    bind_commands!(engine_state, History, Tutor, HistorySession);
+    bind_commands!(engine_state, History, Tutor, HistorySession)
 }
 
-pub fn bind_path_commands(engine_state: &mut EngineState) {
+pub fn bind_path_commands(engine_state: &mut EngineState) -> CrateResult<()> {
     bind_commands! {
         engine_state,
         Path,
@@ -136,10 +138,10 @@ pub fn bind_path_commands(engine_state: &mut EngineState) {
         PathRelativeTo,
         PathSplit,
         PathType,
-    };
+    }
 }
 
-pub fn bind_system_commands(engine_state: &mut EngineState) {
+pub fn bind_system_commands(engine_state: &mut EngineState) -> CrateResult<()> {
     bind_commands! {
         engine_state,
         Benchmark,
@@ -149,10 +151,10 @@ pub fn bind_system_commands(engine_state: &mut EngineState) {
         NuCheck,
         Sys,
         Ps,
-    };
+    }
 }
 
-pub fn bind_string_commands(engine_state: &mut EngineState) {
+pub fn bind_string_commands(engine_state: &mut EngineState) -> CrateResult<()> {
     bind_commands! {
         engine_state,
         BuildString,
@@ -195,10 +197,10 @@ pub fn bind_string_commands(engine_state: &mut EngineState) {
         StrTrim,
         StrTitleCase,
         StrUpcase
-    };
+    }
 }
 
-pub fn bind_bit_commands(engine_state: &mut EngineState) {
+pub fn bind_bit_commands(engine_state: &mut EngineState) -> CrateResult<()> {
     bind_commands! {
         engine_state,
         Bits,
@@ -213,7 +215,7 @@ pub fn bind_bit_commands(engine_state: &mut EngineState) {
     }
 }
 
-pub fn bind_byte_commands(engine_state: &mut EngineState) {
+pub fn bind_byte_commands(engine_state: &mut EngineState) -> CrateResult<()> {
     bind_commands! {
         engine_state,
         Bytes,
@@ -231,7 +233,7 @@ pub fn bind_byte_commands(engine_state: &mut EngineState) {
     }
 }
 
-pub fn bind_file_system_commands(engine_state: &mut EngineState) {
+pub fn bind_file_system_commands(engine_state: &mut EngineState) -> CrateResult<()> {
     bind_commands! {
         engine_state,
         Cd,
@@ -245,10 +247,10 @@ pub fn bind_file_system_commands(engine_state: &mut EngineState) {
         Touch,
         Glob,
         Watch,
-    };
+    }
 }
 
-pub fn bind_platform_commands(engine_state: &mut EngineState) {
+pub fn bind_platform_commands(engine_state: &mut EngineState) -> CrateResult<()> {
     bind_commands! {
         engine_state,
         Ansi,
@@ -264,10 +266,10 @@ pub fn bind_platform_commands(engine_state: &mut EngineState) {
         KeybindingsList,
         Sleep,
         TermSize,
-    };
+    }
 }
 
-pub fn bind_date_commands(engine_state: &mut EngineState) {
+pub fn bind_date_commands(engine_state: &mut EngineState) -> CrateResult<()> {
     bind_commands! {
         engine_state,
         Date,
@@ -278,10 +280,10 @@ pub fn bind_date_commands(engine_state: &mut EngineState) {
         DateToRecord,
         DateToTable,
         DateToTimezone,
-    };
+    }
 }
 
-pub fn bind_shell_commands(engine_state: &mut EngineState) {
+pub fn bind_shell_commands(engine_state: &mut EngineState) -> CrateResult<()> {
     bind_commands! {
         engine_state,
         Enter,
@@ -290,10 +292,10 @@ pub fn bind_shell_commands(engine_state: &mut EngineState) {
         NextShell,
         PrevShell,
         Shells,
-    };
+    }
 }
 
-pub fn bind_format_commands(engine_state: &mut EngineState) {
+pub fn bind_format_commands(engine_state: &mut EngineState) -> CrateResult<()> {
     bind_commands! {
         engine_state,
         From,
@@ -330,18 +332,18 @@ pub fn bind_format_commands(engine_state: &mut EngineState) {
         ToUrl,
         ToXml,
         ToYaml,
-    };
+    }
 }
 
-pub fn bind_viewer_commands(engine_state: &mut EngineState) {
+pub fn bind_viewer_commands(engine_state: &mut EngineState) -> CrateResult<()> {
     bind_commands! {
         engine_state,
         Griddle,
         Table,
-    };
+    }
 }
 
-pub fn bind_conversion_commands(engine_state: &mut EngineState) {
+pub fn bind_conversion_commands(engine_state: &mut EngineState) -> CrateResult<()> {
     bind_commands! {
         engine_state,
         Fmt,
@@ -354,10 +356,10 @@ pub fn bind_conversion_commands(engine_state: &mut EngineState) {
         IntoFilesize,
         IntoInt,
         IntoString,
-    };
+    }
 }
 
-pub fn bind_environment_commands(engine_state: &mut EngineState) {
+pub fn bind_environment_commands(engine_state: &mut EngineState) -> CrateResult<()> {
     bind_commands! {
         engine_state,
         Env,
@@ -368,10 +370,10 @@ pub fn bind_environment_commands(engine_state: &mut EngineState) {
         WithEnv,
         // nu config commands have been removed as editing isn't possible
         // in this environment
-    };
+    }
 }
 
-pub fn bind_math_commands(engine_state: &mut EngineState) {
+pub fn bind_math_commands(engine_state: &mut EngineState) -> CrateResult<()> {
     bind_commands! {
         engine_state,
         Math,
@@ -390,10 +392,10 @@ pub fn bind_math_commands(engine_state: &mut EngineState) {
         MathStddev,
         MathSum,
         MathVariance,
-    };
+    }
 }
 
-pub fn bind_network_commands(engine_state: &mut EngineState) {
+pub fn bind_network_commands(engine_state: &mut EngineState) -> CrateResult<()> {
     bind_commands! {
         engine_state,
         Fetch,
@@ -407,7 +409,7 @@ pub fn bind_network_commands(engine_state: &mut EngineState) {
     }
 }
 
-pub fn bind_random_commands(engine_state: &mut EngineState) {
+pub fn bind_random_commands(engine_state: &mut EngineState) -> CrateResult<()> {
     bind_commands! {
         engine_state,
         Random,
@@ -417,42 +419,44 @@ pub fn bind_random_commands(engine_state: &mut EngineState) {
         RandomDice,
         RandomInteger,
         RandomUuid,
-    };
+    }
 }
 
-pub fn bind_generator_commands(engine_state: &mut EngineState) {
+pub fn bind_generator_commands(engine_state: &mut EngineState) -> CrateResult<()> {
     bind_commands! {
         engine_state,
         Cal,
         Seq,
         SeqDate,
         SeqChar,
-    };
+    }
 }
 
-pub fn bind_hash_commands(engine_state: &mut EngineState) {
+pub fn bind_hash_commands(engine_state: &mut EngineState) -> CrateResult<()> {
     bind_commands! {
         engine_state,
         Hash,
         HashMd5::default(),
         HashSha256::default(),
-    };
+    }
 }
 
-pub fn bind_experimental_commands(engine_state: &mut EngineState) {
+pub fn bind_experimental_commands(engine_state: &mut EngineState) -> CrateResult<()> {
     bind_commands! {
         engine_state,
         ViewSource,
         IsAdmin,
-    };
+    }
 }
 
 #[inline]
-fn bind<F: Fn(&mut StateWorkingSet)>(engine_state: &mut EngineState, bind_fn: F) {
+fn bind<F: Fn(&mut StateWorkingSet)>(
+    engine_state: &mut EngineState,
+    bind_fn: F,
+) -> CrateResult<()> {
     let mut working_set = StateWorkingSet::new(engine_state);
     bind_fn(&mut working_set);
     let delta = working_set.render();
-    engine_state
+    engine_state.merge_delta(delta)?;
-        .merge_delta(delta)
+    Ok(())
-        .expect("Failed to bind commands");
 }

src/context/builder.rs

@@ -7,7 +7,7 @@ use std::env;
 
 use nu_protocol::{
     ast::Block,
-    engine::{EngineState, Stack, StateWorkingSet},
+    engine::{Command, EngineState, Stack, StateWorkingSet},
     PipelineData, Span,
 };
 
@@ -32,13 +32,13 @@ impl Default for ContextBuilder {
 
 impl ContextBuilder {
     /// Enables certain command groups specified in the Config on the state
-    pub fn with_command_groups(mut self, group_config: CommandGroupConfig) -> Self {
+    pub fn with_command_groups(mut self, group_config: CommandGroupConfig) -> CrateResult<Self> {
         macro_rules! toggle_command_groups {
             ($($group:ident),*) => {
                 paste::item!(
                 $(
                     if group_config.$group {
-                        super::bindings::[<bind_ $group _commands>](&mut self.engine_state);
+                        super::bindings::[<bind_ $group _commands>](&mut self.engine_state)?;
                     }
                 )*
                 )
@@ -70,7 +70,19 @@ impl ContextBuilder {
             hash,
             experimental
         );
-        self
+        Ok(self)
+    }
+
+    /// Adds a custom command to the engine that can be used inside nu expressions
+    /// This method can also be used to pass nu builtin commands to enable single commands
+    /// Instead of whole command groups
+    pub fn add_command<C: Command + 'static>(mut self, command: C) -> CrateResult<Self> {
+        let mut working_set = StateWorkingSet::new(&self.engine_state);
+        working_set.add_decl(Box::new(command));
+        let delta = working_set.render();
+        self.engine_state.merge_delta(delta)?;
+
+        Ok(self)
     }
 
     /// Adds a variable to the state

src/lib.rs

@@ -10,7 +10,7 @@ pub use argument::{Argument, IntoArgument};
 pub use context::{CommandGroupConfig, Context, ContextBuilder};
 pub use into_expression::*;
 pub use into_value::*;
-pub use nu_protocol::{PipelineData, Value};
+pub use nu_protocol::{self, PipelineData, Value};
 pub use rusty_value;
 pub use utils::NewEmpty;
 

tests/test_eval.rs

@@ -1,5 +1,7 @@
-use embed_nu::rusty_value::*;
+use embed_nu::{rusty_value::*, IntoValue};
 use embed_nu::{CommandGroupConfig, Context, NewEmpty, PipelineData};
+use nu_protocol::engine::Command;
+use nu_protocol::{Config, Signature, SyntaxShape};
 
 #[test]
 fn it_evals_strings() {
@@ -45,10 +47,61 @@ fn it_executes_functions() {
     ctx.print_pipeline(pipeline).unwrap();
 }
 
+#[test]
+fn it_executes_custom_commands() {
+    let mut ctx = get_context();
+    let pipeline = ctx
+        .eval_raw(r#"custom_upper "Hello world""#, PipelineData::empty())
+        .unwrap();
+    let string_output = pipeline.collect_string(" ", &Config::default()).unwrap();
+    assert_eq!(string_output, String::from("HELLO WORLD"))
+}
+
 fn get_context() -> Context {
     Context::builder()
         .with_command_groups(CommandGroupConfig::default().all_groups(true))
+        .unwrap()
+        .add_command(CustomCommand)
+        .unwrap()
         .add_parent_env_vars()
         .build()
         .unwrap()
 }
+
+#[derive(Clone)]
+struct CustomCommand;
+
+impl Command for CustomCommand {
+    fn name(&self) -> &str {
+        "custom_upper"
+    }
+
+    fn signature(&self) -> nu_protocol::Signature {
+        Signature::new("custom_upper")
+            .required(
+                "text",
+                SyntaxShape::String,
+                "Text to print in full uppercase.",
+            )
+            .category(nu_protocol::Category::Experimental)
+    }
+
+    fn usage(&self) -> &str {
+        "custom_upper <text>"
+    }
+
+    fn run(
+        &self,
+        _engine_state: &nu_protocol::engine::EngineState,
+        _stack: &mut nu_protocol::engine::Stack,
+        call: &nu_protocol::ast::Call,
+        _input: PipelineData,
+    ) -> Result<PipelineData, nu_protocol::ShellError> {
+        let string_input = call.positional_nth(0).unwrap();
+        let string_input = string_input.as_string().unwrap();
+        let upper = string_input.to_uppercase();
+        println!("{upper}");
+
+        Ok(PipelineData::Value(upper.into_value(), None))
+    }
+}