Add do

crates/nu-command/src/default_context.rs

@@ -5,7 +5,7 @@ use nu_protocol::{
     Signature, SyntaxShape,
 };
 
-use crate::{Alias, Benchmark, BuildString, Def, Each, For, If, Length, Let, LetEnv};
+use crate::{Alias, Benchmark, BuildString, Def, Do, Each, For, If, Length, Let, LetEnv};
 
 pub fn create_default_context() -> Rc<RefCell<EngineState>> {
     let engine_state = Rc::new(RefCell::new(EngineState::new()));
@@ -33,6 +33,8 @@ pub fn create_default_context() -> Rc<RefCell<EngineState>> {
 
         working_set.add_decl(Box::new(Each));
 
+        working_set.add_decl(Box::new(Do));
+
         working_set.add_decl(Box::new(Benchmark));
 
         working_set.add_decl(Box::new(Length));

crates/nu-command/src/do_.rs

@@ -0,0 +1,40 @@
+use nu_engine::{eval_block, eval_expression};
+use nu_protocol::ast::Call;
+use nu_protocol::engine::{Command, EvaluationContext};
+use nu_protocol::{Signature, SyntaxShape, Value};
+
+pub struct Do;
+
+impl Command for Do {
+    fn name(&self) -> &str {
+        "do"
+    }
+
+    fn usage(&self) -> &str {
+        "Run a block"
+    }
+
+    fn signature(&self) -> nu_protocol::Signature {
+        Signature::build("do").required("block", SyntaxShape::Block, "the block to run")
+    }
+
+    fn run(
+        &self,
+        context: &EvaluationContext,
+        call: &Call,
+        input: Value,
+    ) -> Result<nu_protocol::Value, nu_protocol::ShellError> {
+        let block = &call.positional[0];
+
+        let out = eval_expression(context, &block)?;
+
+        match out {
+            Value::Block { val: block_id, .. } => {
+                let engine_state = context.engine_state.borrow();
+                let block = engine_state.get_block(block_id);
+                eval_block(context, block, input)
+            }
+            _ => Ok(Value::nothing()),
+        }
+    }
+}

crates/nu-command/src/lib.rs

@@ -3,6 +3,7 @@ mod benchmark;
 mod build_string;
 mod def;
 mod default_context;
+mod do_;
 mod each;
 mod for_;
 mod if_;
@@ -15,6 +16,7 @@ pub use benchmark::Benchmark;
 pub use build_string::BuildString;
 pub use def::Def;
 pub use default_context::create_default_context;
+pub use do_::Do;
 pub use each::Each;
 pub use for_::For;
 pub use if_::If;