Require block params (#4505)

* Require block params

* Improve errors

crates/nu-command/src/core_commands/tutor.rs

@@ -303,7 +303,7 @@ The `each` command gives us a way of working with each individual row or
 element of a list one at a time. It reads these in from the pipeline and
 runs a block on each element. A block is a group of pipelines.
 ```
-echo 1 2 3 | each { $it + 10}
+echo 1 2 3 | each { |it| $it + 10}
 ```
 This example iterates over each element sent by `echo`, giving us three new
 values that are the original value + 10. Here, the `$it` is a variable that

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

@@ -46,7 +46,7 @@ impl Command for Each {
         ];
 
         vec![Example {
-            example: "[1 2 3] | each { 2 * $it }",
+            example: "[1 2 3] | each { |it| 2 * $it }",
             description: "Multiplies elements in list",
             result: Some(Value::List {
                 vals: stream_test_1,

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

@@ -42,7 +42,7 @@ impl Command for EachGroup {
         ];
 
         vec![Example {
-            example: "echo [1 2 3 4] | each group 2 { $it.0 + $it.1 }",
+            example: "echo [1 2 3 4] | each group 2 { |it| $it.0 + $it.1 }",
             description: "Echo the sum of each pair",
             result: Some(Value::List {
                 vals: stream_test_1,

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

@@ -68,7 +68,7 @@ impl Command for EachWindow {
 
         vec![
             Example {
-                example: "echo [1 2 3 4] | each window 2 { $it.0 + $it.1 }",
+                example: "echo [1 2 3 4] | each window 2 { |it| $it.0 + $it.1 }",
                 description: "A sliding window of two elements",
                 result: Some(Value::List {
                     vals: stream_test_1,

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

@@ -72,7 +72,7 @@ impl Command for Empty {
             },
             Example {
                 description: "use a block if setting the empty cell contents is wanted",
-                example: "[[2020/04/16 2020/07/10 2020/11/16]; ['' [27] [37]]] | empty? 2020/04/16 -b { [33 37] }",
+                example: "[[2020/04/16 2020/07/10 2020/11/16]; ['' [27] [37]]] | empty? 2020/04/16 -b { |_| [33 37] }",
                 result: Some(
                     Value::List {
                         vals: vec![

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

@@ -60,7 +60,7 @@ impl Command for Find {
             },
             Example {
                 description: "Find the first odd value",
-                example: "echo [2 4 3 6 5 8] | find --predicate { ($it mod 2) == 1 }",
+                example: "echo [2 4 3 6 5 8] | find --predicate { |it| ($it mod 2) == 1 }",
                 result: Some(Value::List {
                     vals: vec![Value::test_int(3), Value::test_int(5)],
                     span: Span::test_data()
@@ -68,7 +68,7 @@ impl Command for Find {
             },
             Example {
                 description: "Find if a service is not running",
-                example: "echo [[version patch]; [0.1.0 $false] [0.1.1 $true] [0.2.0 $false]] | find -p { $it.patch }",
+                example: "echo [[version patch]; [0.1.0 $false] [0.1.1 $true] [0.2.0 $false]] | find -p { |it| $it.patch }",
                 result: Some(Value::List {
                     vals: vec![Value::test_record(
                             vec!["version", "patch"],

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

@@ -32,7 +32,7 @@ impl Command for ParEach {
 
     fn examples(&self) -> Vec<Example> {
         vec![Example {
-            example: "[1 2 3] | par-each { 2 * $it }",
+            example: "[1 2 3] | par-each { |it| 2 * $it }",
             description: "Multiplies elements in list",
             result: None,
         }]

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

@@ -24,7 +24,7 @@ impl Command for Reduce {
             )
             .required(
                 "block",
-                SyntaxShape::Block(Some(vec![SyntaxShape::Any])),
+                SyntaxShape::Block(Some(vec![SyntaxShape::Any, SyntaxShape::Any])),
                 "reducing function",
             )
             .switch("numbered", "iterate with an index", Some('n'))
@@ -37,7 +37,7 @@ impl Command for Reduce {
     fn examples(&self) -> Vec<Example> {
         vec![
             Example {
-                example: "[ 1 2 3 4 ] | reduce { $it.acc + $it.item }",
+                example: "[ 1 2 3 4 ] | reduce {|it, acc| $it + $acc }",
                 description: "Sum values of a list (same as 'math sum')",
                 result: Some(Value::Int {
                     val: 10,
@@ -45,7 +45,7 @@ impl Command for Reduce {
                 }),
             },
             Example {
-                example: "[ 1 2 3 4 ] | reduce -f 10 { $it.acc + $it.item }",
+                example: "[ 1 2 3 4 ] | reduce -f 10 {|it, acc| $acc + $it }",
                 description: "Sum values with a starting value (fold)",
                 result: Some(Value::Int {
                     val: 20,
@@ -53,7 +53,7 @@ impl Command for Reduce {
                 }),
             },
             Example {
-                example: r#"[ i o t ] | reduce -f "Arthur, King of the Britons" { $it.acc | str find-replace -a $it.item "X" }"#,
+                example: r#"[ i o t ] | reduce -f "Arthur, King of the Britons" {|it, acc| $acc | str find-replace -a $it "X" }"#,
                 description: "Replace selected characters in a string with 'X'",
                 result: Some(Value::String {
                     val: "ArXhur, KXng Xf Xhe BrXXXns".to_string(),
@@ -61,11 +61,11 @@ impl Command for Reduce {
                 }),
             },
             Example {
-                example: r#"[ one longest three bar ] | reduce -n {
+                example: r#"[ one longest three bar ] | reduce -n { |it, acc|
-        if ($it.item | str length) > ($it.acc | str length) {
+        if ($it.item | str length) > ($acc | str length) {
             $it.item
         } else {
-            $it.acc
+            $acc
         }
     }"#,
                 description: "Find the longest string and its index",
@@ -147,32 +147,28 @@ impl Command for Reduce {
                     if let Some(var_id) = &var.var_id {
                         let it = if numbered {
                             Value::Record {
-                                cols: vec![
+                                cols: vec!["index".to_string(), "item".to_string()],
-                                    "index".to_string(),
-                                    "acc".to_string(),
-                                    "item".to_string(),
-                                ],
                                 vals: vec![
                                     Value::Int {
                                         val: idx as i64 + off,
                                         span,
                                     },
-                                    acc,
                                     x,
                                 ],
                                 span,
                             }
                         } else {
-                            Value::Record {
+                            x
-                                cols: vec!["acc".to_string(), "item".to_string()],
-                                vals: vec![acc, x],
-                                span,
-                            }
                         };
 
                         stack.add_var(*var_id, it);
                     }
                 }
+                if let Some(var) = block.signature.get_positional(1) {
+                    if let Some(var_id) = &var.var_id {
+                        stack.add_var(*var_id, acc);
+                    }
+                }
 
                 let v = match eval_block(engine_state, &mut stack, block, PipelineData::new(span)) {
                     Ok(v) => v.into_value(span),

crates/nu-command/tests/commands/each.rs

@@ -5,7 +5,7 @@ fn each_works_separately() {
     let actual = nu!(
         cwd: "tests/fixtures/formats", pipeline(
         r#"
-        echo [1 2 3] | each { echo $it 10 | math sum } | to json -r
+        echo [1 2 3] | each { |it| echo $it 10 | math sum } | to json -r
         "#
     ));
 
@@ -17,7 +17,7 @@ fn each_group_works() {
     let actual = nu!(
         cwd: "tests/fixtures/formats", pipeline(
         r#"
-        echo [1 2 3 4 5 6] | each group 3 { $it } | to json --raw
+        echo [1 2 3 4 5 6] | each group 3 { |it| $it } | to json --raw
         "#
     ));
 
@@ -29,7 +29,7 @@ fn each_window() {
     let actual = nu!(
         cwd: "tests/fixtures/formats", pipeline(
         r#"
-        echo [1 2 3 4] | each window 3 { $it } | to json --raw
+        echo [1 2 3 4] | each window 3 { |it| $it } | to json --raw
         "#
     ));
 
@@ -41,7 +41,7 @@ fn each_window_stride() {
     let actual = nu!(
         cwd: "tests/fixtures/formats", pipeline(
         r#"
-        echo [1 2 3 4 5 6] | each window 3 -s 2 { echo $it } | to json --raw
+        echo [1 2 3 4 5 6] | each window 3 -s 2 { |it| echo $it } | to json --raw
         "#
     ));
 
@@ -65,7 +65,7 @@ fn each_implicit_it_in_block() {
     let actual = nu!(
         cwd: "tests/fixtures/formats", pipeline(
         r#"
-        echo [[foo bar]; [a b] [c d] [e f]] | each { nu --testbin cococo $it.foo } | str collect
+        echo [[foo bar]; [a b] [c d] [e f]] | each { |it| nu --testbin cococo $it.foo } | str collect
         "#
     ));
 

crates/nu-command/tests/commands/echo.rs

@@ -17,7 +17,7 @@ fn echo_range_handles_inclusive() {
     let actual = nu!(
         cwd: "tests/fixtures/formats", pipeline(
         r#"
-        echo 1..3 | each { $it } | to json --raw
+        echo 1..3 | each { |x| $x } | to json --raw
         "#
     ));
 
@@ -29,7 +29,7 @@ fn echo_range_handles_exclusive() {
     let actual = nu!(
         cwd: "tests/fixtures/formats", pipeline(
         r#"
-        echo 1..<3 | each { $it } | to json --raw
+        echo 1..<3 | each { |x| $x } | to json --raw
         "#
     ));
 
@@ -41,7 +41,7 @@ fn echo_range_handles_inclusive_down() {
     let actual = nu!(
         cwd: "tests/fixtures/formats", pipeline(
         r#"
-        echo 3..1 | each { $it } | to json --raw
+        echo 3..1 | each { |it| $it } | to json --raw
         "#
     ));
 
@@ -53,7 +53,7 @@ fn echo_range_handles_exclusive_down() {
     let actual = nu!(
         cwd: "tests/fixtures/formats", pipeline(
         r#"
-        echo 3..<1 | each { $it } | to json --raw
+        echo 3..<1 | each { |it| $it } | to json --raw
         "#
     ));
 

crates/nu-command/tests/commands/into_int.rs

@@ -5,7 +5,7 @@ fn into_int_filesize() {
     let actual = nu!(
         cwd: ".", pipeline(
         r#"
-        echo 1kb | into int | each { $it / 1000 }
+        echo 1kb | into int | each { |it| $it / 1000 }
         "#
     ));
 
@@ -17,7 +17,7 @@ fn into_int_filesize2() {
     let actual = nu!(
         cwd: ".", pipeline(
         r#"
-        echo 1kib | into int | each { $it / 1024 }
+        echo 1kib | into int | each { |it| $it / 1024 }
         "#
     ));
 
@@ -29,7 +29,7 @@ fn into_int_int() {
     let actual = nu!(
         cwd: ".", pipeline(
         r#"
-        echo 1024 | into int | each { $it / 1024 }
+        echo 1024 | into int | each { |it| $it / 1024 }
         "#
     ));
 

crates/nu-command/tests/commands/ls.rs

@@ -87,7 +87,7 @@ fn lists_all_files_in_directories_from_stream() {
             cwd: dirs.test(), pipeline(
             r#"
                 echo dir_a dir_b
-                | each { ls $it }
+                | each { |it| ls $it }
                 | flatten | length
             "#
         ));

crates/nu-command/tests/commands/parse.rs

@@ -22,7 +22,7 @@ mod simple {
                 r#"
                     open key_value_separated_arepa_ingredients.txt
                     | lines
-                    | each { echo $it | parse "{Name}={Value}" }
+                    | each { |it| echo $it | parse "{Name}={Value}" }
                     | flatten
                     | get 1
                     | get Value

crates/nu-command/tests/commands/reduce.rs

@@ -8,7 +8,7 @@ fn reduce_table_column() {
         echo "[{month:2,total:30}, {month:3,total:10}, {month:4,total:3}, {month:5,total:60}]"
         | from json
         | get total
-        | reduce -f 20 { $it.item + (math eval $"($it.acc)^1.05")}
+        | reduce -f 20 { |it, acc| $it + (math eval $"($acc)^1.05")}
         | into string -d 1
         "#
         )
@@ -23,7 +23,7 @@ fn reduce_table_column_with_path() {
         cwd: ".", pipeline(
         r#"
         [{month:2,total:30}, {month:3,total:10}, {month:4,total:3}, {month:5,total:60}]
-        | reduce -f 20 { $it.item.total + (math eval $"($it.acc)^1.05")}
+        | reduce -f 20 { |it, acc| $it.total + (math eval $"($acc)^1.05")}
         | into string -d 1
         "#
         )
@@ -38,7 +38,7 @@ fn reduce_rows_example() {
         cwd: ".", pipeline(
         r#"
         [[a,b]; [1,2] [3,4]]
-        | reduce -f 1.6 { $it.acc * ($it.item.a | into int) + ($it.item.b | into int) }
+        | reduce -f 1.6 { |it, acc| $acc * ($it.a | into int) + ($it.b | into int) }
         "#
         )
     );
@@ -54,7 +54,7 @@ fn reduce_numbered_example() {
         cwd: ".", pipeline(
         r#"
         echo one longest three bar
-        reduce -n { if ($it.item | str length) > ($acc.item | str length) {echo $it} {echo $acc}}
+        reduce -n { |it, acc| if ($it | str length) > ($acc | str length) {echo $it} else {echo $acc}}
         | get index
         "#
         )
@@ -69,7 +69,7 @@ fn reduce_numbered_integer_addition_example() {
         cwd: ".", pipeline(
         r#"
         echo [1 2 3 4]
-        | reduce -n { $it.acc + $it.item }
+        | reduce -n { |it, acc| $acc + $it.item }
         | get item
         "#
         )
@@ -84,9 +84,9 @@ fn folding_with_tables() {
         cwd: ".", pipeline(
         r#"
         echo [10 20 30 40]
-        | reduce -f [] {
+        | reduce -f [] { |it, acc|
-            with-env [value $it.item] {
+            with-env [value $it] {
-              echo $it.acc | append (10 * ($env.value | into int))
+              echo $acc | append (10 * ($env.value | into int))
             }
           }
         | math sum
@@ -102,7 +102,7 @@ fn error_reduce_fold_type_mismatch() {
     let actual = nu!(
         cwd: ".", pipeline(
         r#"
-        echo a b c | reduce -f 0 { $it.acc + $it.item }
+        echo a b c | reduce -f 0 { |it, acc| $acc + $it }
         "#
         )
     );
@@ -115,7 +115,7 @@ fn error_reduce_empty() {
     let actual = nu!(
         cwd: ".", pipeline(
         r#"
-        reduce { $it.$acc + $it.item }
+        reduce { |it, acc| $acc + $it }
         "#
         )
     );

crates/nu-command/tests/commands/roll.rs

@@ -135,7 +135,7 @@ mod columns {
             transpose bit --ignore-titles
             | get bit
             | reverse
-            | each --numbered {
+            | each --numbered { |it|
                 $it.item * (2 ** $it.index)
             }
             | math sum
@@ -155,7 +155,7 @@ mod columns {
             pipeline(
                 r#"
             split chars
-            | each { $it | into int }
+            | each { |it| $it | into int }
             | rotate --ccw
             | rename bit1 bit2 bit3 bit4 bit5 bit6 bit7 bit8
         "#

crates/nu-command/tests/commands/str_/collect.rs

@@ -44,7 +44,7 @@ fn sum_one_to_four() {
     let actual = nu!(
         cwd: ".", pipeline(
         r#"
-        1..4 | each { $it } | into string | str collect "+" | math eval
+        1..4 | each { |it| $it } | into string | str collect "+" | math eval
         "#
         )
     );

crates/nu-parser/src/errors.rs

@@ -175,6 +175,15 @@ pub enum ParseError {
     #[diagnostic(code(nu::parser::rest_needs_name), url(docsrs))]
     RestNeedsName(#[label = "needs a parameter name"] Span),
 
+    #[error("Parameter not correct type.")]
+    #[diagnostic(code(nu::parser::parameter_mismatch_type), url(docsrs))]
+    ParameterMismatchType(
+        String,
+        String,
+        String,
+        #[label = "parameter {0} needs to be '{1}' instead of '{2}'"] Span,
+    ),
+
     #[error("Extra columns.")]
     #[diagnostic(code(nu::parser::extra_columns), url(docsrs))]
     ExtraColumns(

crates/nu-parser/src/parser.rs

@@ -2894,7 +2894,7 @@ pub fn parse_block_expression(
     working_set.enter_scope();
 
     // Check to see if we have parameters
-    let (mut signature, amt_to_skip): (Option<Box<Signature>>, usize) = match output.first() {
+    let (signature, amt_to_skip): (Option<(Box<Signature>, Span)>, usize) = match output.first() {
         Some(Token {
             contents: TokenContents::Pipe,
             span,
@@ -2923,16 +2923,14 @@ pub fn parse_block_expression(
                 end
             };
 
-            let (signature, err) = parse_signature_helper(
+            let signature_span = Span {
-                working_set,
+                start: start_point,
-                Span {
+                end: end_point,
-                    start: start_point,
+            };
-                    end: end_point,
+            let (signature, err) = parse_signature_helper(working_set, signature_span);
-                },
-            );
             error = error.or(err);
 
-            (Some(signature), amt_to_skip)
+            (Some((signature, signature_span)), amt_to_skip)
         }
         _ => (None, 0),
     };
@@ -2942,19 +2940,48 @@ pub fn parse_block_expression(
 
     // TODO: Finish this
     if let SyntaxShape::Block(Some(v)) = shape {
-        if signature.is_none() && v.len() == 1 {
+        if let Some((sig, sig_span)) = &signature {
-            // We'll assume there's an `$it` present
+            if sig.num_positionals() != v.len() {
-            let var_id = working_set.add_variable(b"$it".to_vec(), Type::Unknown);
+                error = error.or_else(|| {
+                    Some(ParseError::Expected(
+                        format!(
+                            "{} block parameter{}",
+                            v.len(),
+                            if v.len() > 1 { "s" } else { "" }
+                        ),
+                        *sig_span,
+                    ))
+                });
+            }
 
-            let mut new_sigature = Signature::new("");
+            for (expected, PositionalArg { name, shape, .. }) in
-            new_sigature.required_positional.push(PositionalArg {
+                v.iter().zip(sig.required_positional.iter())
-                var_id: Some(var_id),
+            {
-                name: "$it".into(),
+                if expected != shape && *shape != SyntaxShape::Any {
-                desc: String::new(),
+                    error = error.or_else(|| {
-                shape: SyntaxShape::Any,
+                        Some(ParseError::ParameterMismatchType(
+                            name.to_owned(),
+                            expected.to_string(),
+                            shape.to_string(),
+                            *sig_span,
+                        ))
+                    });
+                }
+            }
+        } else if !v.is_empty() {
+            error = error.or_else(|| {
+                Some(ParseError::Expected(
+                    format!(
+                        "{} block parameter{}",
+                        v.len(),
+                        if v.len() > 1 { "s" } else { "" }
+                    ),
+                    Span {
+                        start: span.start + 1,
+                        end: span.start + 1,
+                    },
+                ))
             });
-
-            signature = Some(Box::new(new_sigature));
         }
     }
 
@@ -2962,7 +2989,7 @@ pub fn parse_block_expression(
     error = error.or(err);
 
     if let Some(signature) = signature {
-        output.signature = signature;
+        output.signature = signature.0;
     } else if let Some(last) = working_set.delta.scope.last() {
         // FIXME: this only supports the top $it. Is this sufficient?
 

docs/commands/each.md

@@ -19,6 +19,6 @@ Run a block on each element of input
 
 Multiplies elements in list
 ```shell
-> [1 2 3] | each { 2 * $it }
+> [1 2 3] | each { |it| 2 * $it }
 ```
 

docs/commands/par-each.md

@@ -19,6 +19,6 @@ Run a block on each element of input in parallel
 
 Multiplies elements in list
 ```shell
-> [1 2 3] | par-each { 2 * $it }
+> [1 2 3] | par-each { |it| 2 * $it }
 ```
 

src/tests/test_engine.rs

@@ -86,7 +86,7 @@ fn scope_variable() -> TestResult {
 #[test]
 fn earlier_errors() -> TestResult {
     fail_test(
-        r#"[1, "bob"] | each { $it + 3 } | each { $it / $it } | table"#,
+        r#"[1, "bob"] | each { |it| $it + 3 } | each { |it| $it / $it } | table"#,
         "int",
     )
 }

src/tests/test_iteration.rs

@@ -3,7 +3,7 @@ use crate::tests::{run_test, TestResult};
 #[test]
 fn better_block_types() -> TestResult {
     run_test(
-        r#"([1, 2, 3] | each -n { $"($it.index) is ($it.item)" }).1"#,
+        r#"([1, 2, 3] | each -n { |it| $"($it.index) is ($it.item)" }).1"#,
         "1 is 2",
     )
 }
@@ -11,14 +11,14 @@ fn better_block_types() -> TestResult {
 #[test]
 fn row_iteration() -> TestResult {
     run_test(
-        "[[name, size]; [tj, 100], [rl, 200]] | each { $it.size * 8 } | get 1",
+        "[[name, size]; [tj, 100], [rl, 200]] | each { |it| $it.size * 8 } | get 1",
         "1600",
     )
 }
 
 #[test]
 fn record_iteration() -> TestResult {
-    run_test("([[name, level]; [aa, 100], [bb, 200]] | each { $it | each { |x| if $x.column == \"level\" { $x.value + 100 } else { $x.value } } }).level | get 1", "300")
+    run_test("([[name, level]; [aa, 100], [bb, 200]] | each { |it| $it | each { |x| if $x.column == \"level\" { $x.value + 100 } else { $x.value } } }).level | get 1", "300")
 }
 
 #[test]
@@ -45,7 +45,7 @@ fn for_loops() -> TestResult {
 #[test]
 fn par_each() -> TestResult {
     run_test(
-        r#"1..10 | par-each --numbered { ([[index, item]; [$it.index, ($it.item > 5)]]).0 } | where index == 4 | get item.0"#,
+        r#"1..10 | par-each --numbered { |it| ([[index, item]; [$it.index, ($it.item > 5)]]).0 } | where index == 4 | get item.0"#,
         "false",
     )
 }

src/tests/test_parser.rs

@@ -40,7 +40,7 @@ fn alias_recursion() -> TestResult {
 
 #[test]
 fn block_param1() -> TestResult {
-    run_test("[3] | each { $it + 10 } | get 0", "13")
+    run_test("[3] | each { |it| $it + 10 } | get 0", "13")
 }
 
 #[test]
@@ -50,7 +50,7 @@ fn block_param2() -> TestResult {
 
 #[test]
 fn block_param3_list_iteration() -> TestResult {
-    run_test("[1,2,3] | each { $it + 10 } | get 1", "12")
+    run_test("[1,2,3] | each { |it| $it + 10 } | get 1", "12")
 }
 
 #[test]
@@ -70,7 +70,7 @@ fn range_iteration2() -> TestResult {
 
 #[test]
 fn simple_value_iteration() -> TestResult {
-    run_test("4 | each { $it + 10 }", "14")
+    run_test("4 | each { |it| $it + 10 }", "14")
 }
 
 #[test]
@@ -116,7 +116,7 @@ fn bad_var_name() -> TestResult {
 #[test]
 fn long_flag() -> TestResult {
     run_test(
-        r#"([a, b, c] | each --numbered { if $it.index == 1 { 100 } else { 0 } }).1"#,
+        r#"([a, b, c] | each --numbered { |it| if $it.index == 1 { 100 } else { 0 } }).1"#,
         "100",
     )
 }
@@ -314,3 +314,18 @@ fn capture_row_condition() -> TestResult {
 fn proper_missing_param() -> TestResult {
     fail_test(r#"def foo [x y z w] { }; foo a b c"#, "missing w")
 }
+
+#[test]
+fn block_arity_check1() -> TestResult {
+    fail_test(r#"ls | each { 1 }"#, "expected 1 block parameter")
+}
+
+#[test]
+fn block_arity_check2() -> TestResult {
+    fail_test(r#"ls | reduce { 1 }"#, "expected 2 block parameters")
+}
+
+#[test]
+fn block_arity_check3() -> TestResult {
+    fail_test(r#"ls | each { |x, y| 1}"#, "expected 1 block parameter")
+}

src/tests/test_strings.rs

@@ -7,13 +7,13 @@ fn build_string1() -> TestResult {
 
 #[test]
 fn build_string2() -> TestResult {
-    run_test("'nu' | each {build-string $it 'shell'}", "nushell")
+    run_test("'nu' | each { |it| build-string $it 'shell'}", "nushell")
 }
 
 #[test]
 fn build_string3() -> TestResult {
     run_test(
-        "build-string 'nu' 'shell' | each {build-string $it ' rocks'}",
+        "build-string 'nu' 'shell' | each { |it| build-string $it ' rocks'}",
         "nushell rocks",
     )
 }
@@ -21,7 +21,7 @@ fn build_string3() -> TestResult {
 #[test]
 fn build_string4() -> TestResult {
     run_test(
-        "['sam','rick','pete'] | each { build-string $it ' is studying'} | get 2",
+        "['sam','rick','pete'] | each { |it| build-string $it ' is studying'} | get 2",
         "pete is studying",
     )
 }

tests/shell/mod.rs

@@ -23,7 +23,7 @@ fn plugins_are_declared_with_wix() {
                 | where Directory.attributes.Id == "$(var.PlatformProgramFilesFolder)"
                 | get Directory.children.Directory.children.0 | last
                 | get Directory.children.Component.children
-                | each { echo $it | first }
+                | each { |it| echo $it | first }
                 | skip
                 | where File.attributes.Name =~ "nu_plugin"
                 | str substring [_, -4] File.attributes.Name
@@ -32,7 +32,7 @@ fn plugins_are_declared_with_wix() {
                 | wrap wix
             }
             | default wix _
-            | each { if $it.wix != $it.cargo { 1 } { 0 } }
+            | each { |it| if $it.wix != $it.cargo { 1 } { 0 } }
             | math sum
             "#
     ));

tests/shell/pipeline/commands/external.rs

@@ -111,7 +111,7 @@ mod it_evaluation {
                 ls
                 | sort-by name
                 | get name
-                | each { nu --testbin cococo $it }
+                | each { |it| nu --testbin cococo $it }
                 | get 1
                 "#
             ));
@@ -136,7 +136,7 @@ mod it_evaluation {
             r#"
                 open nu_candies.txt
                 | lines
-                | each { nu --testbin chop $it}
+                | each { |it| nu --testbin chop $it}
                 | get 1
                 "#
             ));

tests/shell/pipeline/commands/internal.rs

@@ -22,7 +22,7 @@ fn takes_rows_of_nu_value_strings_and_pipes_it_to_stdin_of_external() {
         r#"
             open nu_times.csv
             | get origin
-            | each { ^echo $it | nu --testbin chop }
+            | each { |it| ^echo $it | nu --testbin chop }
             | get 2
             "#
         ));
@@ -76,7 +76,7 @@ fn argument_subexpression() {
     let actual = nu!(
         cwd: ".",
         r#"
-            echo "foo" | each { echo (echo $it) }
+            echo "foo" | each { |it| echo (echo $it) }
         "#
     );
 
@@ -102,7 +102,7 @@ fn subexpression_handles_dot() {
         r#"
             echo (open nu_times.csv)
             | get name
-            | each { nu --testbin chop $it }
+            | each { |it| nu --testbin chop $it }
             | get 3
             "#
         ));
@@ -116,7 +116,7 @@ fn string_interpolation_with_it() {
     let actual = nu!(
         cwd: ".",
         r#"
-                    echo "foo" | each { echo $"($it)" }
+                    echo "foo" | each { |it| echo $"($it)" }
             "#
     );
 
@@ -128,7 +128,7 @@ fn string_interpolation_with_it_column_path() {
     let actual = nu!(
         cwd: ".",
         r#"
-                    echo [[name]; [sammie]] | each { echo $"($it.name)" } | get 0
+                    echo [[name]; [sammie]] | each { |it| echo $"($it.name)" } | get 0
         "#
     );
 
@@ -1048,7 +1048,7 @@ fn duration_overflow() {
     let actual = nu!(
         cwd: ".", pipeline(
         r#"
-        ls | get modified | each { $it + 10000000000000000day }
+        ls | get modified | each { |it| $it + 10000000000000000day }
         "#)
     );
 
@@ -1060,7 +1060,7 @@ fn date_and_duration_overflow() {
     let actual = nu!(
         cwd: ".", pipeline(
         r#"
-        ls | get modified | each { $it + 1000000000day }
+        ls | get modified | each { |it| $it + 1000000000day }
         "#)
     );
 
@@ -1336,17 +1336,17 @@ mod variable_scoping {
                 == "ZZZ"
         );
         test_variable_scope_list!(
-            r#" def test [input] { echo [0 1 2] | each { echo $input } }
+            r#" def test [input] { echo [0 1 2] | each { |_| echo $input } }
                 test ZZZ "#
                 == ["ZZZ", "ZZZ", "ZZZ"]
         );
         test_variable_scope_list!(
-            r#" def test [input] { echo [0 1 2] | each { if $it > 0 {echo $input} else {echo $input}} }
+            r#" def test [input] { echo [0 1 2] | each { |it| if $it > 0 {echo $input} else {echo $input}} }
                 test ZZZ "#
                 == ["ZZZ", "ZZZ", "ZZZ"]
         );
         test_variable_scope_list!(
-            r#" def test [input] { echo [0 1 2] | each { if $input == $input {echo $input} else {echo $input}} }
+            r#" def test [input] { echo [0 1 2] | each { |_| if $input == $input {echo $input} else {echo $input}} }
                 test ZZZ "#
                 == ["ZZZ", "ZZZ", "ZZZ"]
         );