Implement exclusive and inclusive ranges with ..< and .. (#2541)

* Implement exclusive and inclusive ranges with .. and ..=

This commit adds right-exclusive ranges.

The original a..b inclusive syntax was changed to reflect the Rust notation.
New a..=b syntax was introduced to have the old behavior.

Currently, both a.. and b..= is valid, and it is unclear whether it's valid
to impose restrictions.

The original issue suggests .. for inclusive and ..< for exclusive ranges,
this can be implemented by making simple changes to this commit.

* Fix collect tests by changing ranges to ..=

* Fix clippy lints in exclusive range matching

* Implement exclusive ranges using `..<`

crates/nu-protocol/src/hir.rs

@@ -906,7 +906,7 @@ impl ShellTypeName for Synthetic {
 #[derive(Debug, Ord, PartialOrd, Eq, PartialEq, Clone, Hash, Deserialize, Serialize)]
 pub struct Range {
     pub left: Option<SpannedExpression>,
-    pub dotdot: Span,
+    pub operator: Spanned<RangeOperator>,
     pub right: Option<SpannedExpression>,
 }
 
@@ -919,7 +919,7 @@ impl PrettyDebugWithSource for Range {
             } else {
                 DebugDocBuilder::blank()
             }) + b::space()
-                + b::keyword(self.dotdot.slice(source))
+                + b::keyword(self.operator.span().slice(source))
                 + b::space()
                 + (if let Some(right) = &self.right {
                     right.pretty_debug(source)
@@ -932,6 +932,12 @@ impl PrettyDebugWithSource for Range {
     }
 }
 
+#[derive(Debug, Ord, PartialOrd, Eq, PartialEq, Clone, Hash, Deserialize, Serialize)]
+pub enum RangeOperator {
+    Inclusive,
+    RightExclusive,
+}
+
 #[derive(Debug, Ord, PartialOrd, Eq, PartialEq, Clone, Hash, Deserialize, Serialize)]
 pub enum Literal {
     Number(Number),
@@ -1107,12 +1113,12 @@ impl Expression {
 
     pub fn range(
         left: Option<SpannedExpression>,
-        dotdot: Span,
+        operator: Spanned<RangeOperator>,
         right: Option<SpannedExpression>,
     ) -> Expression {
         Expression::Range(Box::new(Range {
             left,
-            dotdot,
+            operator,
             right,
         }))
     }
@@ -1291,6 +1297,7 @@ pub enum FlatShape {
     Operator,
     Dot,
     DotDot,
+    DotDotLeftAngleBracket,
     InternalCommand,
     ExternalCommand,
     ExternalWord,

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

@@ -1,6 +1,6 @@
 use crate::type_name::ShellTypeName;
 use crate::value::column_path::ColumnPath;
-use crate::value::range::Range;
+use crate::value::range::{Range, RangeInclusion};
 use crate::value::{serde_bigdecimal, serde_bigint};
 use bigdecimal::BigDecimal;
 use chrono::{DateTime, Utc};
@@ -251,8 +251,13 @@ pub fn format_primitive(primitive: &Primitive, field_name: Option<&String>) -> S
         Primitive::Int(i) => i.to_string(),
         Primitive::Decimal(decimal) => format!("{:.4}", decimal),
         Primitive::Range(range) => format!(
-            "{}..{}",
+            "{}..{}{}",
             format_primitive(&range.from.0.item, None),
+            if range.to.1 == RangeInclusion::Exclusive {
+                "<"
+            } else {
+                ""
+            },
             format_primitive(&range.to.0.item, None)
         ),
         Primitive::Pattern(s) => s.to_string(),