Pipeline blocks (#1579)

* Making Commands match what UntaggedValue needs

* WIP

* WIP

* WIP

* Moved to expressions for conditions

* Add 'each' command to use command blocks

* More cleanup

* Add test for 'each'

* Instead use an expression block

crates/nu-protocol/src/lib.rs

@@ -2,6 +2,7 @@
 mod macros;
 
 mod call_info;
+pub mod hir;
 mod maybe_owned;
 mod return_value;
 mod signature;
@@ -19,7 +20,7 @@ pub use crate::type_name::{PrettyType, ShellTypeName, SpannedTypeName};
 pub use crate::type_shape::{Row as RowType, Type};
 pub use crate::value::column_path::{did_you_mean, ColumnPath, PathMember, UnspannedPathMember};
 pub use crate::value::dict::{Dictionary, TaggedDictBuilder};
-pub use crate::value::evaluate::{Evaluate, EvaluateTrait, Scope};
+pub use crate::value::evaluate::Scope;
 pub use crate::value::primitive::Primitive;
 pub use crate::value::primitive::{format_date, format_duration, format_primitive};
 pub use crate::value::range::{Range, RangeInclusion};

crates/nu-protocol/src/syntax_shape.rs

@@ -30,6 +30,8 @@ pub enum SyntaxShape {
     Unit,
     /// An operator
     Operator,
+    /// A condition, eg `foo > 1`
+    Condition,
 }
 
 impl PrettyDebug for SyntaxShape {
@@ -49,6 +51,7 @@ impl PrettyDebug for SyntaxShape {
             SyntaxShape::Table => "table",
             SyntaxShape::Unit => "unit",
             SyntaxShape::Operator => "operator",
+            SyntaxShape::Condition => "condition",
         })
     }
 }

crates/nu-protocol/src/value.rs

@@ -8,9 +8,9 @@ pub mod range;
 mod serde_bigdecimal;
 mod serde_bigint;
 
+use crate::hir;
 use crate::type_name::{ShellTypeName, SpannedTypeName};
 use crate::value::dict::Dictionary;
-use crate::value::evaluate::Evaluate;
 use crate::value::primitive::Primitive;
 use crate::value::range::{Range, RangeInclusion};
 use crate::{ColumnPath, PathMember};
@@ -38,7 +38,7 @@ pub enum UntaggedValue {
     Error(ShellError),
 
     /// A block of Nu code, eg `{ ls | get name }`
-    Block(Evaluate),
+    Block(hir::Commands),
 }
 
 impl UntaggedValue {

crates/nu-protocol/src/value/evaluate.rs

@@ -1,9 +1,5 @@
 use crate::value::{Primitive, UntaggedValue, Value};
 use indexmap::IndexMap;
-use nu_errors::ShellError;
-use query_interface::{interfaces, vtable_for, Object, ObjectHash};
-use serde::{Deserialize, Serialize};
-use std::cmp::{Ord, Ordering, PartialOrd};
 use std::fmt::Debug;
 
 /// An evaluation scope. Scopes map variable names to Values and aid in evaluating blocks and expressions.
@@ -42,67 +38,3 @@ impl Scope {
         }
     }
 }
-
-#[typetag::serde(tag = "type")]
-pub trait EvaluateTrait: Debug + Send + Sync + Object + ObjectHash + 'static {
-    fn invoke(&self, scope: &Scope) -> Result<Value, ShellError>;
-    fn clone_box(&self) -> Evaluate;
-}
-
-interfaces!(Evaluate: dyn ObjectHash);
-
-#[typetag::serde]
-impl EvaluateTrait for Evaluate {
-    fn invoke(&self, scope: &Scope) -> Result<Value, ShellError> {
-        self.expr.invoke(scope)
-    }
-
-    fn clone_box(&self) -> Evaluate {
-        self.expr.clone_box()
-    }
-}
-
-#[derive(Debug, Serialize, Deserialize)]
-pub struct Evaluate {
-    expr: Box<dyn EvaluateTrait>,
-}
-
-impl Evaluate {
-    pub fn new(evaluate: impl EvaluateTrait) -> Evaluate {
-        Evaluate {
-            expr: Box::new(evaluate),
-        }
-    }
-}
-
-impl std::hash::Hash for Evaluate {
-    fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
-        self.expr.obj_hash(state)
-    }
-}
-
-impl Clone for Evaluate {
-    fn clone(&self) -> Evaluate {
-        self.expr.clone_box()
-    }
-}
-
-impl Ord for Evaluate {
-    fn cmp(&self, _: &Self) -> Ordering {
-        Ordering::Equal
-    }
-}
-
-impl PartialOrd for Evaluate {
-    fn partial_cmp(&self, _: &Evaluate) -> Option<Ordering> {
-        Some(Ordering::Equal)
-    }
-}
-
-impl PartialEq for Evaluate {
-    fn eq(&self, _: &Evaluate) -> bool {
-        true
-    }
-}
-
-impl Eq for Evaluate {}