Port all? command (#365)

* Implement `From<bool>` for `Value`

* Add `All` command

* Change `IntoPipelineData` and `IntoInterruptiblePipelineData` bounds

* Refactor `PipelineIterator` impls

* Add `PipelineData::into_interruptible_iter`

* Use `into_interruptible_iter` instead of `all` helper

* Merge imports

* Refactor `PipelineData::{filter, map}`

* Change comment pronoun

* Treat `RowCondition` as a block

* Remove unnecessary braces

* Address cluppy warning

crates/nu-command/src/default_context.rs

@@ -20,6 +20,7 @@ pub fn create_default_context() -> EngineState {
         // TODO: sort default context items categorically
         bind_command!(
             Alias,
+            All,
             Append,
             Benchmark,
             BuildString,

crates/nu-command/src/filters/all.rs

@@ -0,0 +1,98 @@
+use nu_engine::eval_block;
+use nu_protocol::{
+    ast::{Call, Expr, Expression},
+    engine::{Command, EngineState, Stack},
+    Category, Example, IntoPipelineData, PipelineData, ShellError, Signature, SyntaxShape,
+};
+
+#[derive(Clone)]
+pub struct All;
+
+impl Command for All {
+    fn name(&self) -> &str {
+        "all?"
+    }
+
+    fn signature(&self) -> Signature {
+        Signature::build(self.name())
+            .required(
+                "predicate",
+                SyntaxShape::RowCondition,
+                "the predicate that must match",
+            )
+            .category(Category::Filters)
+    }
+
+    fn usage(&self) -> &str {
+        "Test if every element of the input matches a predicate."
+    }
+
+    fn examples(&self) -> Vec<Example> {
+        use nu_protocol::Value;
+
+        vec![
+            Example {
+                description: "Find if services are running",
+                example: "echo [[status]; [UP] [UP]] | all? status == UP",
+                result: Some(Value::from(true)),
+            },
+            Example {
+                description: "Check that all values are even",
+                example: "echo [2 4 6 8] | all? ($it mod 2) == 0",
+                result: Some(Value::from(true)),
+            },
+        ]
+    }
+
+    fn run(
+        &self,
+        engine_state: &EngineState,
+        stack: &mut Stack,
+        call: &Call,
+        input: PipelineData,
+    ) -> Result<PipelineData, ShellError> {
+        let predicate = &call.positional[0];
+        let block_id = match predicate {
+            Expression {
+                expr: Expr::RowCondition(block_id),
+                ..
+            } => *block_id,
+            _ => return Err(ShellError::InternalError("Expected row condition".into())),
+        };
+
+        let span = call.head;
+
+        let block = engine_state.get_block(block_id);
+        let var_id = block.signature.get_positional(0).and_then(|arg| arg.var_id);
+        let mut stack = stack.collect_captures(&block.captures);
+
+        let ctrlc = engine_state.ctrlc.clone();
+        let engine_state = engine_state.clone();
+
+        Ok(input
+            .into_interruptible_iter(ctrlc)
+            .all(move |value| {
+                if let Some(var_id) = var_id {
+                    stack.add_var(var_id, value);
+                }
+
+                eval_block(&engine_state, &mut stack, block, PipelineData::new(span))
+                    .map_or(false, |pipeline_data| {
+                        pipeline_data.into_value(span).is_true()
+                    })
+            })
+            .into_pipeline_data())
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_examples() {
+        use crate::test_examples;
+
+        test_examples(All)
+    }
+}

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

@@ -1,3 +1,4 @@
+mod all;
 mod append;
 mod collect;
 mod drop;
@@ -17,6 +18,7 @@ mod where_;
 mod wrap;
 mod zip;
 
+pub use all::All;
 pub use append::Append;
 pub use collect::Collect;
 pub use drop::*;