Make arg eval lazy, remove old arg evaluation code (#3603)

* Remove old argument eval

* Merge main

* fmt

* clippy

* clippy

* clippy

crates/nu-ansi-term/src/style.rs

@@ -603,7 +603,7 @@ mod serde_json_tests {
             Color::Fixed(255),
         ];
 
-        for color in colors.into_iter() {
+        for color in colors.iter() {
             let serialized = serde_json::to_string(&color).unwrap();
             let deserialized: Color = serde_json::from_str(&serialized).unwrap();
 

crates/nu-command/src/commands.rs

@@ -1,6 +1,3 @@
-#[macro_use]
-pub(crate) mod macros;
-
 mod from_delimited_data;
 mod to_delimited_data;
 

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

@@ -54,7 +54,6 @@ impl WholeStreamCommand for Command {
 fn all(args: CommandArgs) -> Result<OutputStream, ShellError> {
     let ctx = EvaluationContext::from_args(&args);
     let tag = args.call_info.name_tag.clone();
-    let args = args.evaluate_once()?;
     let all_args = AllArgs {
         predicate: args.req(0)?,
     };
@@ -83,7 +82,7 @@ fn all(args: CommandArgs) -> Result<OutputStream, ShellError> {
         }
     };
 
-    let scope = args.scope();
+    let scope = args.scope().clone();
 
     let init = Ok(InputStream::one(
         UntaggedValue::boolean(true).into_value(&tag),

crates/nu-command/src/commands/ansi/command.rs

@@ -113,8 +113,6 @@ Format: #
     }
 
     fn run(&self, args: CommandArgs) -> Result<OutputStream, ShellError> {
-        let args = args.evaluate_once()?;
-
         let code: Option<Tagged<String>> = args.opt(0)?;
         let escape: Option<Tagged<String>> = args.get_flag("escape")?;
         let osc: Option<Tagged<String>> = args.get_flag("osc")?;
@@ -170,7 +168,7 @@ Format: #
             Err(ShellError::labeled_error(
                 "Expected ansi code",
                 "expect ansi code",
-                args.call_info.name_tag.clone(),
+                &args.call_info.name_tag,
             ))
         }
     }

crates/nu-command/src/commands/ansi/gradient.rs

@@ -84,7 +84,6 @@ impl WholeStreamCommand for SubCommand {
 }
 
 fn operate(args: CommandArgs) -> Result<OutputStream, ShellError> {
-    let args = args.evaluate_once()?;
     let fgstart: Option<Value> = args.get_flag("fgstart")?;
     let fgend: Option<Value> = args.get_flag("fgend")?;
     let bgstart: Option<Value> = args.get_flag("bgstart")?;

crates/nu-command/src/commands/ansi/strip.rs

@@ -38,8 +38,6 @@ impl WholeStreamCommand for SubCommand {
 }
 
 fn operate(args: CommandArgs) -> Result<OutputStream, ShellError> {
-    let args = args.evaluate_once()?;
-
     let column_paths: Vec<_> = args.rest(0)?;
 
     let result: Vec<Value> = args

crates/nu-command/src/commands/any.rs

@@ -54,7 +54,6 @@ impl WholeStreamCommand for Command {
 fn any(args: CommandArgs) -> Result<OutputStream, ShellError> {
     let ctx = EvaluationContext::from_args(&args);
     let tag = args.call_info.name_tag.clone();
-    let args = args.evaluate_once()?;
     let any_args = AnyArgs {
         predicate: args.req(0)?,
     };
@@ -83,7 +82,7 @@ fn any(args: CommandArgs) -> Result<OutputStream, ShellError> {
         }
     };
 
-    let scope = args.scope();
+    let scope = args.scope().clone();
 
     let init = Ok(InputStream::one(
         UntaggedValue::boolean(false).into_value(&tag),

crates/nu-command/src/commands/append.rs

@@ -22,8 +22,7 @@ impl WholeStreamCommand for Command {
         "Append a row to the table."
     }
 
-    fn run(&self, args: CommandArgs) -> Result<OutputStream, ShellError> {
+    fn run(&self, mut args: CommandArgs) -> Result<OutputStream, ShellError> {
-        let mut args = args.evaluate_once()?;
         let mut value: Value = args.req(0)?;
 
         let mut prepend = vec![];

crates/nu-command/src/commands/benchmark.rs

@@ -74,7 +74,6 @@ fn benchmark(args: CommandArgs) -> Result<OutputStream, ShellError> {
     let mut context = EvaluationContext::from_args(&args);
     let scope = args.scope().clone();
 
-    let args = args.evaluate_once()?;
     let cmd_args = BenchmarkArgs {
         block: args.req(0)?,
         passthrough: args.get_flag("passthrough")?,

crates/nu-command/src/commands/build_string.rs

@@ -23,7 +23,6 @@ impl WholeStreamCommand for BuildString {
 
     fn run(&self, args: CommandArgs) -> Result<OutputStream, ShellError> {
         let tag = args.call_info.name_tag.clone();
-        let args = args.evaluate_once()?;
         let rest: Vec<Value> = args.rest(0)?;
 
         let mut output_string = String::new();

crates/nu-command/src/commands/cal.rs

@@ -1,9 +1,10 @@
 use crate::prelude::*;
 use chrono::{Datelike, Local, NaiveDate};
 use indexmap::IndexMap;
-use nu_engine::{EvaluatedCommandArgs, WholeStreamCommand};
+use nu_engine::WholeStreamCommand;
 use nu_errors::ShellError;
 use nu_protocol::{Dictionary, Signature, SyntaxShape, UntaggedValue, Value};
+use nu_source::Tagged;
 
 pub struct Cal;
 
@@ -66,7 +67,6 @@ impl WholeStreamCommand for Cal {
 }
 
 pub fn cal(args: CommandArgs) -> Result<ActionStream, ShellError> {
-    let args = args.evaluate_once()?;
     let mut calendar_vec_deque = VecDeque::new();
     let tag = args.call_info.name_tag.clone();
 
@@ -75,15 +75,12 @@ pub fn cal(args: CommandArgs) -> Result<ActionStream, ShellError> {
     let mut selected_year: i32 = current_year;
     let mut current_day_option: Option<u32> = Some(current_day);
 
-    let month_range = if let Some(full_year_value) = args.call_info.args.get("full-year") {
+    let full_year_value: Option<u64> = args.get_flag("full-year")?;
-        if let Ok(year_u64) = full_year_value.as_u64() {
+    let month_range = if let Some(full_year_value) = full_year_value {
-            selected_year = year_u64 as i32;
+        selected_year = full_year_value as i32;
 
-            if selected_year != current_year {
+        if selected_year != current_year {
-                current_day_option = None
+            current_day_option = None
-            }
-        } else {
-            return Err(get_invalid_year_shell_error(&full_year_value.tag()));
         }
 
         (1, 12)
@@ -165,7 +162,7 @@ fn get_current_date() -> (i32, u32, u32) {
 }
 
 fn add_months_of_year_to_table(
-    args: &EvaluatedCommandArgs,
+    args: &CommandArgs,
     mut calendar_vec_deque: &mut VecDeque<Value>,
     tag: &Tag,
     selected_year: i32,
@@ -198,7 +195,7 @@ fn add_months_of_year_to_table(
 }
 
 fn add_month_to_table(
-    args: &EvaluatedCommandArgs,
+    args: &CommandArgs,
     calendar_vec_deque: &mut VecDeque<Value>,
     tag: &Tag,
     selected_year: i32,
@@ -207,9 +204,11 @@ fn add_month_to_table(
 ) -> Result<(), ShellError> {
     let month_helper_result = MonthHelper::new(selected_year, current_month);
 
+    let full_year_value: Option<Tagged<u64>> = args.get_flag("full-year")?;
+
     let month_helper = match month_helper_result {
         Ok(month_helper) => month_helper,
-        Err(()) => match args.call_info.args.get("full-year") {
+        Err(()) => match full_year_value {
             Some(full_year_value) => {
                 return Err(get_invalid_year_shell_error(&full_year_value.tag()))
             }
@@ -235,17 +234,15 @@ fn add_month_to_table(
 
     let mut week_start_day = days_of_the_week[0].to_string();
 
-    if let Some(week_start_value) = args.call_info.args.get("week-start") {
+    if let Some(day) = args.get_flag::<Tagged<String>>("week-start")? {
-        if let Ok(day) = week_start_value.as_string() {
+        if days_of_the_week.contains(&day.item.as_str()) {
-            if days_of_the_week.contains(&day.as_str()) {
+            week_start_day = day.item;
-                week_start_day = day;
+        } else {
-            } else {
+            return Err(ShellError::labeled_error(
-                return Err(ShellError::labeled_error(
+                "The specified week start day is invalid",
-                    "The specified week start day is invalid",
+                "invalid week start day",
-                    "invalid week start day",
+                day.tag(),
-                    week_start_value.tag(),
+            ));
-                ));
-            }
         }
     }
 

crates/nu-command/src/commands/cd.rs

@@ -27,7 +27,6 @@ impl WholeStreamCommand for Cd {
     fn run_with_actions(&self, args: CommandArgs) -> Result<ActionStream, ShellError> {
         let name = args.call_info.name_tag.clone();
         let shell_manager = args.shell_manager();
-        let args = args.evaluate_once()?;
         let args = CdArgs { path: args.opt(0)? };
 
         shell_manager.cd(args, name)

crates/nu-command/src/commands/char_.rs

@@ -168,7 +168,6 @@ impl WholeStreamCommand for Char {
 
     fn run(&self, args: CommandArgs) -> Result<OutputStream, ShellError> {
         let args_tag = args.call_info.name_tag.clone();
-        let args = args.evaluate_once()?;
         let args = CharArgs {
             name: args.opt(0)?,
             rest: args.rest(1)?,

crates/nu-command/src/commands/compact.rs

@@ -38,11 +38,12 @@ impl WholeStreamCommand for Compact {
 }
 
 pub fn compact(args: CommandArgs) -> Result<OutputStream, ShellError> {
-    let (args, input) = args.extract(|params| {
+    let (args, input) = (
-        Ok(CompactArgs {
+        CompactArgs {
-            columns: params.rest(0)?,
+            columns: args.rest(0)?,
-        })
+        },
-    })?;
+        args.input,
+    );
 
     Ok(input
         .filter(move |item| {

crates/nu-command/src/commands/config/get.rs

@@ -38,7 +38,6 @@ impl WholeStreamCommand for SubCommand {
 pub fn get(args: CommandArgs) -> Result<OutputStream, ShellError> {
     let name = args.call_info.name_tag.clone();
     let ctx = EvaluationContext::from_args(&args);
-    let args = args.evaluate_once()?;
 
     let column_path = args.req(0)?;
 

crates/nu-command/src/commands/config/remove.rs

@@ -39,7 +39,6 @@ impl WholeStreamCommand for SubCommand {
 pub fn remove(args: CommandArgs) -> Result<OutputStream, ShellError> {
     let name = args.call_info.name_tag.clone();
     let ctx = EvaluationContext::from_args(&args);
-    let args = args.evaluate_once()?;
     let remove: Tagged<String> = args.req(0)?;
 
     let key = remove.to_string();

crates/nu-command/src/commands/config/set.rs

@@ -53,7 +53,6 @@ impl WholeStreamCommand for SubCommand {
 pub fn set(args: CommandArgs) -> Result<OutputStream, ShellError> {
     let name = args.call_info.name_tag.clone();
     let ctx = EvaluationContext::from_args(&args);
-    let args = args.evaluate_once()?;
 
     let column_path = args.req(0)?;
     let mut value: Value = args.req(1)?;

crates/nu-command/src/commands/config/set_into.rs

@@ -39,7 +39,6 @@ impl WholeStreamCommand for SubCommand {
 pub fn set_into(args: CommandArgs) -> Result<OutputStream, ShellError> {
     let name = args.call_info.name_tag.clone();
     let ctx = EvaluationContext::from_args(&args);
-    let args = args.evaluate_once()?;
 
     let set_into: Tagged<String> = args.req(0)?;
 

crates/nu-command/src/commands/cp.rs

@@ -28,7 +28,6 @@ impl WholeStreamCommand for Cpy {
     fn run_with_actions(&self, args: CommandArgs) -> Result<ActionStream, ShellError> {
         let shell_manager = args.shell_manager();
         let name = args.call_info.name_tag.clone();
-        let args = args.evaluate_once()?;
 
         let args = CopyArgs {
             src: args.req(0)?,

crates/nu-command/src/commands/dataframe/aggregate.rs

@@ -121,9 +121,8 @@ impl WholeStreamCommand for DataFrame {
     }
 }
 
-fn command(args: CommandArgs) -> Result<OutputStream, ShellError> {
+fn command(mut args: CommandArgs) -> Result<OutputStream, ShellError> {
     let tag = args.call_info.name_tag.clone();
-    let mut args = args.evaluate_once()?;
 
     let quantile: Option<Tagged<f64>> = args.get_flag("quantile")?;
     let operation: Tagged<String> = args.req(0)?;
@@ -139,11 +138,9 @@ fn command(args: CommandArgs) -> Result<OutputStream, ShellError> {
         None => (None, Span::unknown()),
     };
 
-    let value = args.input.next().ok_or(ShellError::labeled_error(
+    let value = args.input.next().ok_or_else(|| {
-        "Empty stream",
+        ShellError::labeled_error("Empty stream", "No value found in the stream", &tag)
-        "No value found in the stream",
+    })?;
-        &tag,
-    ))?;
 
     let res = match value.value {
         UntaggedValue::DataFrame(PolarsData::GroupBy(nu_groupby)) => {

crates/nu-command/src/commands/dataframe/column.rs

@@ -37,9 +37,8 @@ impl WholeStreamCommand for DataFrame {
     }
 }
 
-fn command(args: CommandArgs) -> Result<OutputStream, ShellError> {
+fn command(mut args: CommandArgs) -> Result<OutputStream, ShellError> {
     let tag = args.call_info.name_tag.clone();
-    let mut args = args.evaluate_once()?;
     let column: Tagged<String> = args.req(0)?;
 
     let df = NuDataFrame::try_from_stream(&mut args.input, &tag.span)?;

crates/nu-command/src/commands/dataframe/drop.rs

@@ -37,16 +37,15 @@ impl WholeStreamCommand for DataFrame {
     }
 }
 
-fn command(args: CommandArgs) -> Result<OutputStream, ShellError> {
+fn command(mut args: CommandArgs) -> Result<OutputStream, ShellError> {
     let tag = args.call_info.name_tag.clone();
-    let mut args = args.evaluate_once()?;
 
     let columns: Vec<Value> = args.req(0)?;
     let (col_string, col_span) = convert_columns(&columns, &tag)?;
 
     let df = NuDataFrame::try_from_stream(&mut args.input, &tag.span)?;
 
-    let new_df = match col_string.iter().next() {
+    let new_df = match col_string.get(0) {
         Some(col) => df
             .as_ref()
             .drop(col)

crates/nu-command/src/commands/dataframe/drop_duplicates.rs

@@ -39,9 +39,8 @@ impl WholeStreamCommand for DataFrame {
     }
 }
 
-fn command(args: CommandArgs) -> Result<OutputStream, ShellError> {
+fn command(mut args: CommandArgs) -> Result<OutputStream, ShellError> {
     let tag = args.call_info.name_tag.clone();
-    let mut args = args.evaluate_once()?;
 
     // Extracting the selection columns of the columns to perform the aggregation
     let columns: Option<Vec<Value>> = args.opt(0)?;

crates/nu-command/src/commands/dataframe/drop_nulls.rs

@@ -37,9 +37,8 @@ impl WholeStreamCommand for DataFrame {
     }
 }
 
-fn command(args: CommandArgs) -> Result<OutputStream, ShellError> {
+fn command(mut args: CommandArgs) -> Result<OutputStream, ShellError> {
     let tag = args.call_info.name_tag.clone();
-    let mut args = args.evaluate_once()?;
 
     // Extracting the selection columns of the columns to perform the aggregation
     let columns: Option<Vec<Value>> = args.opt(0)?;

crates/nu-command/src/commands/dataframe/dtypes.rs

@@ -31,9 +31,8 @@ impl WholeStreamCommand for DataFrame {
     }
 }
 
-fn command(args: CommandArgs) -> Result<OutputStream, ShellError> {
+fn command(mut args: CommandArgs) -> Result<OutputStream, ShellError> {
     let tag = args.call_info.name_tag.clone();
-    let mut args = args.evaluate_once()?;
 
     let df = NuDataFrame::try_from_stream(&mut args.input, &tag.span)?;
     let col_names = df

crates/nu-command/src/commands/dataframe/dummies.rs

@@ -33,9 +33,8 @@ impl WholeStreamCommand for DataFrame {
     }
 }
 
-fn command(args: CommandArgs) -> Result<OutputStream, ShellError> {
+fn command(mut args: CommandArgs) -> Result<OutputStream, ShellError> {
     let tag = args.call_info.name_tag.clone();
-    let mut args = args.evaluate_once()?;
 
     let df = NuDataFrame::try_from_stream(&mut args.input, &tag.span)?;
     let res = df.as_ref().to_dummies().map_err(|e| {

crates/nu-command/src/commands/dataframe/get.rs

@@ -36,9 +36,8 @@ impl WholeStreamCommand for DataFrame {
     }
 }
 
-fn command(args: CommandArgs) -> Result<OutputStream, ShellError> {
+fn command(mut args: CommandArgs) -> Result<OutputStream, ShellError> {
     let tag = args.call_info.name_tag.clone();
-    let mut args = args.evaluate_once()?;
     let columns: Vec<Value> = args.req(0)?;
 
     let (col_string, col_span) = convert_columns(&columns, &tag)?;

crates/nu-command/src/commands/dataframe/groupby.rs

@@ -40,9 +40,8 @@ impl WholeStreamCommand for DataFrame {
     }
 }
 
-fn command(args: CommandArgs) -> Result<OutputStream, ShellError> {
+fn command(mut args: CommandArgs) -> Result<OutputStream, ShellError> {
     let tag = args.call_info.name_tag.clone();
-    let mut args = args.evaluate_once()?;
 
     // Extracting the names of the columns to perform the groupby
     let by_columns: Vec<Value> = args.req(0)?;

crates/nu-command/src/commands/dataframe/head.rs

@@ -37,9 +37,8 @@ impl WholeStreamCommand for DataFrame {
     }
 }
 
-fn command(args: CommandArgs) -> Result<OutputStream, ShellError> {
+fn command(mut args: CommandArgs) -> Result<OutputStream, ShellError> {
     let tag = args.call_info.name_tag.clone();
-    let mut args = args.evaluate_once()?;
     let rows: Option<Tagged<usize>> = args.opt(0)?;
 
     let rows = match rows {

crates/nu-command/src/commands/dataframe/join.rs

@@ -65,9 +65,8 @@ impl WholeStreamCommand for DataFrame {
     }
 }
 
-fn command(args: CommandArgs) -> Result<OutputStream, ShellError> {
+fn command(mut args: CommandArgs) -> Result<OutputStream, ShellError> {
     let tag = args.call_info.name_tag.clone();
-    let mut args = args.evaluate_once()?;
 
     let r_df: Value = args.req(0)?;
     let l_col: Vec<Value> = args.req(1)?;

crates/nu-command/src/commands/dataframe/list.rs

@@ -19,8 +19,6 @@ impl WholeStreamCommand for DataFrame {
     }
 
     fn run(&self, args: CommandArgs) -> Result<OutputStream, ShellError> {
-        let args = args.evaluate_once()?;
-
         let values = args
             .context
             .scope

crates/nu-command/src/commands/dataframe/load.rs

@@ -1,7 +1,7 @@
 use std::path::PathBuf;
 
 use crate::{commands::dataframe::utils::parse_polars_error, prelude::*};
-use nu_engine::{EvaluatedCommandArgs, WholeStreamCommand};
+use nu_engine::WholeStreamCommand;
 use nu_errors::ShellError;
 use nu_protocol::{
     dataframe::NuDataFrame, Primitive, Signature, SyntaxShape, UntaggedValue, Value,
@@ -75,7 +75,6 @@ impl WholeStreamCommand for DataFrame {
 
 fn command(args: CommandArgs) -> Result<OutputStream, ShellError> {
     let tag = args.call_info.name_tag.clone();
-    let args = args.evaluate_once()?;
     let file: Tagged<PathBuf> = args.req(0)?;
 
     let df = match file.item().extension() {
@@ -108,7 +107,7 @@ fn command(args: CommandArgs) -> Result<OutputStream, ShellError> {
     };
 
     let df_tag = Tag {
-        anchor: Some(AnchorLocation::File(file_name.to_string())),
+        anchor: Some(AnchorLocation::File(file_name)),
         span: tag.span,
     };
 
@@ -117,7 +116,7 @@ fn command(args: CommandArgs) -> Result<OutputStream, ShellError> {
     )))
 }
 
-fn from_parquet(args: EvaluatedCommandArgs) -> Result<polars::prelude::DataFrame, ShellError> {
+fn from_parquet(args: CommandArgs) -> Result<polars::prelude::DataFrame, ShellError> {
     let file: Tagged<PathBuf> = args.req(0)?;
 
     let r = File::open(&file.item)
@@ -130,7 +129,7 @@ fn from_parquet(args: EvaluatedCommandArgs) -> Result<polars::prelude::DataFrame
         .map_err(|e| parse_polars_error::<&str>(&e, &file.tag.span, None))
 }
 
-fn from_json(args: EvaluatedCommandArgs) -> Result<polars::prelude::DataFrame, ShellError> {
+fn from_json(args: CommandArgs) -> Result<polars::prelude::DataFrame, ShellError> {
     let file: Tagged<PathBuf> = args.req(0)?;
 
     let r = File::open(&file.item)
@@ -143,7 +142,7 @@ fn from_json(args: EvaluatedCommandArgs) -> Result<polars::prelude::DataFrame, S
         .map_err(|e| parse_polars_error::<&str>(&e, &file.tag.span, None))
 }
 
-fn from_csv(args: EvaluatedCommandArgs) -> Result<polars::prelude::DataFrame, ShellError> {
+fn from_csv(args: CommandArgs) -> Result<polars::prelude::DataFrame, ShellError> {
     let file: Tagged<PathBuf> = args.req(0)?;
     let delimiter: Option<Tagged<String>> = args.get_flag("delimiter")?;
     let no_header: bool = args.has_flag("no_header");
@@ -164,7 +163,7 @@ fn from_csv(args: EvaluatedCommandArgs) -> Result<polars::prelude::DataFrame, Sh
                     &d.tag,
                 ));
             } else {
-                let delimiter = match d.item.chars().nth(0) {
+                let delimiter = match d.item.chars().next() {
                     Some(d) => d as u8,
                     None => unreachable!(),
                 };

crates/nu-command/src/commands/dataframe/melt.rs

@@ -39,9 +39,8 @@ impl WholeStreamCommand for DataFrame {
     }
 }
 
-fn command(args: CommandArgs) -> Result<OutputStream, ShellError> {
+fn command(mut args: CommandArgs) -> Result<OutputStream, ShellError> {
     let tag = args.call_info.name_tag.clone();
-    let mut args = args.evaluate_once()?;
 
     let id_col: Vec<Value> = args.req(0)?;
     let val_col: Vec<Value> = args.req(1)?;
@@ -67,7 +66,7 @@ fn check_column_datatypes<T: AsRef<str>>(
     cols: &[T],
     col_span: &Span,
 ) -> Result<(), ShellError> {
-    if cols.len() == 0 {
+    if cols.is_empty() {
         return Err(ShellError::labeled_error(
             "Merge error",
             "empty column list",

crates/nu-command/src/commands/dataframe/pivot.rs

@@ -78,9 +78,8 @@ impl WholeStreamCommand for DataFrame {
     }
 }
 
-fn command(args: CommandArgs) -> Result<OutputStream, ShellError> {
+fn command(mut args: CommandArgs) -> Result<OutputStream, ShellError> {
     let tag = args.call_info.name_tag.clone();
-    let mut args = args.evaluate_once()?;
 
     // Extracting the pivot col from arguments
     let pivot_col: Tagged<String> = args.req(0)?;

crates/nu-command/src/commands/dataframe/sample.rs

@@ -53,9 +53,8 @@ impl WholeStreamCommand for DataFrame {
     }
 }
 
-fn command(args: CommandArgs) -> Result<OutputStream, ShellError> {
+fn command(mut args: CommandArgs) -> Result<OutputStream, ShellError> {
     let tag = args.call_info.name_tag.clone();
-    let mut args = args.evaluate_once()?;
 
     let rows: Option<Tagged<usize>> = args.get_flag("n_rows")?;
     let fraction: Option<Tagged<f64>> = args.get_flag("fraction")?;

crates/nu-command/src/commands/dataframe/select.rs

@@ -37,9 +37,8 @@ impl WholeStreamCommand for DataFrame {
     }
 }
 
-fn command(args: CommandArgs) -> Result<OutputStream, ShellError> {
+fn command(mut args: CommandArgs) -> Result<OutputStream, ShellError> {
     let tag = args.call_info.name_tag.clone();
-    let mut args = args.evaluate_once()?;
 
     let columns: Vec<Value> = args.req(0)?;
 

crates/nu-command/src/commands/dataframe/show.rs

@@ -47,9 +47,8 @@ impl WholeStreamCommand for DataFrame {
     }
 }
 
-fn command(args: CommandArgs) -> Result<OutputStream, ShellError> {
+fn command(mut args: CommandArgs) -> Result<OutputStream, ShellError> {
     let tag = args.call_info.name_tag.clone();
-    let mut args = args.evaluate_once()?;
 
     let rows: Option<Tagged<usize>> = args.get_flag("n_rows")?;
     let tail: bool = args.has_flag("tail");

crates/nu-command/src/commands/dataframe/slice.rs

@@ -34,9 +34,8 @@ impl WholeStreamCommand for DataFrame {
     }
 }
 
-fn command(args: CommandArgs) -> Result<OutputStream, ShellError> {
+fn command(mut args: CommandArgs) -> Result<OutputStream, ShellError> {
     let tag = args.call_info.name_tag.clone();
-    let mut args = args.evaluate_once()?;
 
     let offset: Tagged<usize> = args.req(0)?;
     let size: Tagged<usize> = args.req(1)?;

crates/nu-command/src/commands/dataframe/sort.rs

@@ -38,9 +38,8 @@ impl WholeStreamCommand for DataFrame {
     }
 }
 
-fn command(args: CommandArgs) -> Result<OutputStream, ShellError> {
+fn command(mut args: CommandArgs) -> Result<OutputStream, ShellError> {
     let tag = args.call_info.name_tag.clone();
-    let mut args = args.evaluate_once()?;
     let columns: Vec<Value> = args.req(0)?;
     let reverse = args.has_flag("reverse");
 

crates/nu-command/src/commands/dataframe/tail.rs

@@ -36,9 +36,8 @@ impl WholeStreamCommand for DataFrame {
     }
 }
 
-fn command(args: CommandArgs) -> Result<OutputStream, ShellError> {
+fn command(mut args: CommandArgs) -> Result<OutputStream, ShellError> {
     let tag = args.call_info.name_tag.clone();
-    let mut args = args.evaluate_once()?;
     let rows: Option<Tagged<usize>> = args.opt(0)?;
 
     let rows = match rows {

crates/nu-command/src/commands/dataframe/to_csv.rs

@@ -57,9 +57,8 @@ impl WholeStreamCommand for DataFrame {
     }
 }
 
-fn command(args: CommandArgs) -> Result<OutputStream, ShellError> {
+fn command(mut args: CommandArgs) -> Result<OutputStream, ShellError> {
     let tag = args.call_info.name_tag.clone();
-    let mut args = args.evaluate_once()?;
     let file_name: Tagged<PathBuf> = args.req(0)?;
     let delimiter: Option<Tagged<String>> = args.get_flag("delimiter")?;
     let no_header: bool = args.has_flag("no_header");
@@ -92,7 +91,7 @@ fn command(args: CommandArgs) -> Result<OutputStream, ShellError> {
                     &d.tag,
                 ));
             } else {
-                let delimiter = match d.item.chars().nth(0) {
+                let delimiter = match d.item.chars().next() {
                     Some(d) => d as u8,
                     None => unreachable!(),
                 };

crates/nu-command/src/commands/dataframe/to_df.rs

@@ -20,7 +20,6 @@ impl WholeStreamCommand for DataFrame {
 
     fn run(&self, args: CommandArgs) -> Result<OutputStream, ShellError> {
         let tag = args.call_info.name_tag.clone();
-        let args = args.evaluate_once()?;
 
         let df = NuDataFrame::try_from_iter(args.input, &tag)?;
 

crates/nu-command/src/commands/dataframe/to_parquet.rs

@@ -44,9 +44,8 @@ impl WholeStreamCommand for DataFrame {
     }
 }
 
-fn command(args: CommandArgs) -> Result<OutputStream, ShellError> {
+fn command(mut args: CommandArgs) -> Result<OutputStream, ShellError> {
     let tag = args.call_info.name_tag.clone();
-    let mut args = args.evaluate_once()?;
     let file_name: Tagged<PathBuf> = args.req(0)?;
 
     let mut df = NuDataFrame::try_from_stream(&mut args.input, &tag.span)?;

crates/nu-command/src/commands/dataframe/to_series.rs

@@ -25,7 +25,6 @@ impl WholeStreamCommand for DataFrame {
 
     fn run(&self, args: CommandArgs) -> Result<OutputStream, ShellError> {
         let tag = args.call_info.name_tag.clone();
-        let args = args.evaluate_once()?;
 
         let name: Option<Tagged<String>> = args.opt(0)?;
         let name = name.map(|v| v.item);

crates/nu-command/src/commands/dataframe/utils.rs

@@ -5,13 +5,12 @@ use polars::prelude::PolarsError;
 
 // Converts a Vec<Value> to a Vec<String> with a Span marking the whole
 // location of the columns for error referencing
-pub(crate) fn convert_columns<'columns>(
+pub(crate) fn convert_columns(
-    columns: &'columns [Value],
+    columns: &[Value],
     tag: &Tag,
 ) -> Result<(Vec<String>, Span), ShellError> {
     let mut col_span = match columns
-        .iter()
+        .get(0)
-        .nth(0)
         .map(|v| Span::new(v.tag.span.start(), v.tag.span.end()))
     {
         Some(span) => span,

crates/nu-command/src/commands/dataframe/where_.rs

@@ -1,5 +1,5 @@
 use crate::prelude::*;
-use nu_engine::{evaluate_baseline_expr, EvaluatedCommandArgs, WholeStreamCommand};
+use nu_engine::{evaluate_baseline_expr, WholeStreamCommand};
 use nu_errors::ShellError;
 use nu_protocol::{
     dataframe::NuDataFrame,
@@ -44,7 +44,6 @@ impl WholeStreamCommand for DataFrame {
 
 fn command(args: CommandArgs) -> Result<OutputStream, ShellError> {
     let tag = args.call_info.name_tag.clone();
-    let args = args.evaluate_once()?;
 
     let block: CapturedBlock = args.req(0)?;
 
@@ -65,21 +64,21 @@ fn command(args: CommandArgs) -> Result<OutputStream, ShellError> {
                     _ => None,
                 })
         })
-        .ok_or(ShellError::labeled_error(
+        .ok_or_else(|| {
-            "Expected a condition",
+            ShellError::labeled_error("Expected a condition", "expected a condition", &tag.span)
-            "expected a condition",
+        })?;
-            &tag.span,
-        ))?;
 
     let lhs = match &expression.left.expr {
         Expression::FullColumnPath(p) => p.as_ref().tail.get(0),
         _ => None,
     }
-    .ok_or(ShellError::labeled_error(
+    .ok_or_else(|| {
-        "No column name",
+        ShellError::labeled_error(
-        "Not a column name found in left hand side of comparison",
+            "No column name",
-        &expression.left.span,
+            "Not a column name found in left hand side of comparison",
-    ))?;
+            &expression.left.span,
+        )
+    })?;
 
     let (col_name, col_name_span) = match &lhs.unspanned {
         UnspannedPathMember::String(name) => Ok((name, &lhs.span)),
@@ -90,7 +89,7 @@ fn command(args: CommandArgs) -> Result<OutputStream, ShellError> {
         )),
     }?;
 
-    let rhs = evaluate_baseline_expr(&expression.right, &args.args.context)?;
+    let rhs = evaluate_baseline_expr(&expression.right, &args.context)?;
 
     filter_dataframe(args, &col_name, &col_name_span, &rhs, &expression.op)
 }
@@ -128,7 +127,7 @@ macro_rules! comparison_arm {
 // With the information extracted from the block we can filter the dataframe using
 // polars operations
 fn filter_dataframe(
-    mut args: EvaluatedCommandArgs,
+    mut args: CommandArgs,
     col_name: &str,
     col_name_span: &Span,
     rhs: &Value,
@@ -212,6 +211,6 @@ fn filter_dataframe(
 
     Ok(OutputStream::one(NuDataFrame::dataframe_to_value(
         res,
-        args.call_info.name_tag.clone(),
+        args.call_info.name_tag,
     )))
 }

crates/nu-command/src/commands/dataframe/with_column.rs

@@ -40,9 +40,8 @@ impl WholeStreamCommand for DataFrame {
     }
 }
 
-fn command(args: CommandArgs) -> Result<OutputStream, ShellError> {
+fn command(mut args: CommandArgs) -> Result<OutputStream, ShellError> {
     let tag = args.call_info.name_tag.clone();
-    let mut args = args.evaluate_once()?;
     let value: Value = args.req(0)?;
     let name: Tagged<String> = args.req(2)?;
 

crates/nu-command/src/commands/date/format.rs

@@ -44,7 +44,6 @@ impl WholeStreamCommand for Date {
 
 pub fn format(args: CommandArgs) -> Result<OutputStream, ShellError> {
     let tag = args.call_info.name_tag.clone();
-    let args = args.evaluate_once()?;
 
     let format: Tagged<String> = args.req(0)?;
     let table: Option<bool> = args.get_flag("table")?;

crates/nu-command/src/commands/date/list_timezone.rs

@@ -41,8 +41,7 @@ impl WholeStreamCommand for Date {
 }
 
 fn list_timezone(args: CommandArgs) -> Result<OutputStream, ShellError> {
-    let args = args.evaluate_once()?;
+    let tag = args.call_info.name_tag;
-    let tag = args.call_info.name_tag.clone();
 
     let list = TZ_VARIANTS.iter().map(move |tz| {
         let mut entries = IndexMap::new();

crates/nu-command/src/commands/date/now.rs

@@ -31,8 +31,6 @@ pub fn date_now(tag: &Tag) -> Value {
 }
 
 pub fn now(args: CommandArgs) -> Result<OutputStream, ShellError> {
-    let args = args.evaluate_once()?;
-
     let value = date_now(&args.call_info.name_tag);
 
     Ok(OutputStream::one(value))

crates/nu-command/src/commands/date/to_table.rs

@@ -34,7 +34,6 @@ impl WholeStreamCommand for Date {
 }
 
 fn to_table(args: CommandArgs) -> Result<OutputStream, ShellError> {
-    let args = args.evaluate_once()?;
     let tag = args.call_info.name_tag.clone();
     let input = if args.input.is_empty() {
         InputStream::one(crate::commands::date::now::date_now(&tag))

crates/nu-command/src/commands/date/to_timezone.rs

@@ -55,7 +55,6 @@ impl WholeStreamCommand for Date {
 
 fn to_timezone(args: CommandArgs) -> Result<OutputStream, ShellError> {
     let tag = args.call_info.name_tag.clone();
-    let args = args.evaluate_once()?;
 
     let timezone: Tagged<String> = args.req(0)?;
 

crates/nu-command/src/commands/debug.rs

@@ -24,7 +24,6 @@ impl WholeStreamCommand for Debug {
 }
 
 fn debug_value(args: CommandArgs) -> Result<ActionStream, ShellError> {
-    let args = args.evaluate_once()?;
     let raw = args.has_flag("raw");
     let input = args.input;
 

crates/nu-command/src/commands/default.rs

@@ -40,7 +40,6 @@ impl WholeStreamCommand for Default {
 }
 
 fn default(args: CommandArgs) -> Result<ActionStream, ShellError> {
-    let args = args.evaluate_once()?;
     let column: Tagged<String> = args.req(0)?;
     let value: Value = args.req(1)?;
 

crates/nu-command/src/commands/do_.rs

@@ -59,11 +59,10 @@ impl WholeStreamCommand for Do {
     }
 }
 
-fn do_(raw_args: CommandArgs) -> Result<OutputStream, ShellError> {
+fn do_(args: CommandArgs) -> Result<OutputStream, ShellError> {
-    let external_redirection = raw_args.call_info.args.external_redirection;
+    let external_redirection = args.call_info.args.external_redirection;
 
-    let context = EvaluationContext::from_args(&raw_args);
+    let context = args.context().clone();
-    let args = raw_args.evaluate_once()?;
     let do_args = DoArgs {
         block: args.req(0)?,
         ignore_errors: args.has_flag("ignore-errors"),

crates/nu-command/src/commands/drop/column.rs

@@ -43,7 +43,6 @@ impl WholeStreamCommand for SubCommand {
 }
 
 fn drop(args: CommandArgs) -> Result<OutputStream, ShellError> {
-    let args = args.evaluate_once()?;
     let columns: Option<Tagged<u64>> = args.opt(0)?;
 
     let to_drop = if let Some(quantity) = columns {

crates/nu-command/src/commands/drop/command.rs

@@ -47,7 +47,6 @@ impl WholeStreamCommand for Command {
 }
 
 fn drop(args: CommandArgs) -> Result<OutputStream, ShellError> {
-    let args = args.evaluate_once()?;
     let rows: Option<Tagged<u64>> = args.opt(0)?;
     let v: Vec<_> = args.input.into_vec();
 

crates/nu-command/src/commands/du.rs

@@ -88,8 +88,6 @@ fn du(args: CommandArgs) -> Result<ActionStream, ShellError> {
     let ctrl_c = args.ctrl_c();
     let ctrl_c_copy = ctrl_c.clone();
 
-    let args = args.evaluate_once()?;
-
     let args = DuArgs {
         path: args.opt(0)?,
         all: args.has_flag("all"),

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

@@ -114,10 +114,9 @@ pub(crate) fn make_indexed_item(index: usize, item: Value) -> Value {
     dict.into_value()
 }
 
-fn each(raw_args: CommandArgs) -> Result<OutputStream, ShellError> {
+fn each(args: CommandArgs) -> Result<OutputStream, ShellError> {
-    let context = Arc::new(EvaluationContext::from_args(&raw_args));
+    let context = Arc::new(args.context.clone());
-    let external_redirection = raw_args.call_info.args.external_redirection;
+    let external_redirection = args.call_info.args.external_redirection;
-    let args = raw_args.evaluate_once()?;
 
     let block: CapturedBlock = args.req(0)?;
     let numbered: bool = args.has_flag("numbered");

crates/nu-command/src/commands/each/group.rs

@@ -37,10 +37,9 @@ impl WholeStreamCommand for EachGroup {
         }]
     }
 
-    fn run(&self, raw_args: CommandArgs) -> Result<OutputStream, ShellError> {
+    fn run(&self, args: CommandArgs) -> Result<OutputStream, ShellError> {
-        let context = Arc::new(EvaluationContext::from_args(&raw_args));
+        let context = Arc::new(args.context.clone());
-        let external_redirection = raw_args.call_info.args.external_redirection;
+        let external_redirection = args.call_info.args.external_redirection;
-        let args = raw_args.evaluate_once()?;
 
         let group_size: Tagged<usize> = args.req(0)?;
         let block: CapturedBlock = args.req(1)?;

crates/nu-command/src/commands/each/window.rs

@@ -41,11 +41,10 @@ impl WholeStreamCommand for EachWindow {
         }]
     }
 
-    fn run(&self, raw_args: CommandArgs) -> Result<OutputStream, ShellError> {
+    fn run(&self, mut args: CommandArgs) -> Result<OutputStream, ShellError> {
-        let context = Arc::new(EvaluationContext::from_args(&raw_args));
+        let context = Arc::new(EvaluationContext::from_args(&args));
-        let external_redirection = raw_args.call_info.args.external_redirection;
+        let external_redirection = args.call_info.args.external_redirection;
 
-        let mut args = raw_args.evaluate_once()?;
         let window_size: Tagged<usize> = args.req(0)?;
         let block: CapturedBlock = args.req(1)?;
         let stride: Option<Tagged<usize>> = args.get_flag("stride")?;

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

@@ -54,7 +54,6 @@ pub fn expand_value_to_stream(v: Value) -> InputStream {
 }
 
 fn echo(args: CommandArgs) -> Result<InputStream, ShellError> {
-    let args = args.evaluate_once()?;
     let rest: Vec<Value> = args.rest(0)?;
 
     let stream = rest.into_iter().map(|i| match i.as_string() {

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

@@ -84,7 +84,6 @@ fn is_empty(args: CommandArgs) -> Result<ActionStream, ShellError> {
     let tag = args.call_info.name_tag.clone();
     let name_tag = Arc::new(args.call_info.name_tag.clone());
     let context = Arc::new(EvaluationContext::from_args(&args));
-    let args = args.evaluate_once()?;
     let block: Option<CapturedBlock> = args.get_flag("block")?;
     let columns: Vec<ColumnPath> = args.rest(0)?;
 

crates/nu-command/src/commands/enter.rs

@@ -74,7 +74,6 @@ fn enter(args: CommandArgs) -> Result<ActionStream, ShellError> {
     let context = args.context.clone();
     let scope = args.scope().clone();
     let path = args.context.shell_manager.path();
-    let args = args.evaluate_once()?;
 
     let location: Tagged<PathBuf> = args.req(0)?;
     let encoding: Option<Tagged<String>> = args.get_flag("encoding")?;

crates/nu-command/src/commands/every.rs

@@ -56,8 +56,6 @@ impl WholeStreamCommand for Every {
 }
 
 fn every(args: CommandArgs) -> Result<ActionStream, ShellError> {
-    let args = args.evaluate_once()?;
-
     let stride: u64 = args.req(0)?;
     let skip: bool = args.has_flag("skip");
     let input = args.input;

crates/nu-command/src/commands/exec.rs

@@ -64,7 +64,6 @@ fn exec(args: CommandArgs) -> Result<OutputStream, ShellError> {
     use std::process::Command;
 
     let name = args.call_info.name_tag.clone();
-    let args = args.evaluate_once()?;
 
     let args = ExecArgs {
         command: args.req(0)?,

crates/nu-command/src/commands/exit.rs

@@ -44,15 +44,13 @@ impl WholeStreamCommand for Exit {
 }
 
 pub fn exit(args: CommandArgs) -> Result<ActionStream, ShellError> {
-    let args = args.evaluate_once()?;
+    let code = if let Some(value) = args.opt::<i64>(0)? {
-
+        value as i32
-    let code = if let Some(value) = args.call_info.args.nth(0) {
-        value.as_i32()?
     } else {
         0
     };
 
-    let command_action = if args.call_info.args.has("now") {
+    let command_action = if args.has_flag("now") {
         CommandAction::Exit(code)
     } else {
         CommandAction::LeaveShell(code)

crates/nu-command/src/commands/first.rs

@@ -47,7 +47,6 @@ impl WholeStreamCommand for First {
 }
 
 fn first(args: CommandArgs) -> Result<ActionStream, ShellError> {
-    let args = args.evaluate_once()?;
     let rows: Option<Tagged<usize>> = args.opt(0)?;
     let input = args.input;
 

crates/nu-command/src/commands/flatten.rs

@@ -48,7 +48,6 @@ impl WholeStreamCommand for Command {
 
 fn flatten(args: CommandArgs) -> Result<ActionStream, ShellError> {
     let tag = args.call_info.name_tag.clone();
-    let args = args.evaluate_once()?;
     let columns: Vec<Tagged<String>> = args.rest(0)?;
     let input = args.input;
 

crates/nu-command/src/commands/for_in.rs

@@ -111,8 +111,7 @@ pub(crate) fn make_indexed_item(index: usize, item: Value) -> Value {
 fn for_in(raw_args: CommandArgs) -> Result<OutputStream, ShellError> {
     let context = Arc::new(EvaluationContext::from_args(&raw_args));
     let external_redirection = raw_args.call_info.args.external_redirection;
-    //let args = raw_args.evaluate_once()?;
+    //
-
     let numbered: bool = raw_args.call_info.switch_present("numbered");
     let positional = raw_args
         .call_info

crates/nu-command/src/commands/format/command.rs

@@ -40,7 +40,6 @@ impl WholeStreamCommand for Format {
 
 fn format_command(args: CommandArgs) -> Result<OutputStream, ShellError> {
     let ctx = Arc::new(EvaluationContext::from_args(&args));
-    let args = args.evaluate_once()?;
     let pattern: Tagged<String> = args.req(0)?;
 
     let format_pattern = format(&pattern);

crates/nu-command/src/commands/format/format_filesize.rs

@@ -83,9 +83,7 @@ fn process_row(
     }
 }
 
-fn filesize(raw_args: CommandArgs) -> Result<OutputStream, ShellError> {
+fn filesize(args: CommandArgs) -> Result<OutputStream, ShellError> {
-    let args = raw_args.evaluate_once()?;
-
     let field: ColumnPath = args.req(0)?;
     let format: Tagged<String> = args.req(1)?;
     let field = Arc::new(field);

crates/nu-command/src/commands/from_csv.rs

@@ -62,7 +62,6 @@ impl WholeStreamCommand for FromCsv {
 
 fn from_csv(args: CommandArgs) -> Result<OutputStream, ShellError> {
     let name = args.call_info.name_tag.clone();
-    let args = args.evaluate_once()?;
 
     let noheaders = args.has_flag("noheaders");
     let separator: Option<Value> = args.get_flag("separator")?;

crates/nu-command/src/commands/from_eml.rs

@@ -68,7 +68,6 @@ fn headerfieldvalue_to_value(tag: &Tag, value: &HeaderFieldValue) -> UntaggedVal
 
 fn from_eml(args: CommandArgs) -> Result<OutputStream, ShellError> {
     let tag = args.call_info.name_tag.clone();
-    let args = args.evaluate_once()?;
 
     let preview_body: Option<Tagged<usize>> = args.get_flag("preview-body")?;
 

crates/nu-command/src/commands/from_ics.rs

@@ -28,7 +28,6 @@ impl WholeStreamCommand for FromIcs {
 }
 
 fn from_ics(args: CommandArgs) -> Result<OutputStream, ShellError> {
-    let args = args.evaluate_once()?;
     let tag = args.name_tag();
     let input = args.input;
 

crates/nu-command/src/commands/from_ini.rs

@@ -60,7 +60,6 @@ pub fn from_ini_string_to_value(
 }
 
 fn from_ini(args: CommandArgs) -> Result<OutputStream, ShellError> {
-    let args = args.evaluate_once()?;
     let tag = args.name_tag();
     let input = args.input;
     let concat_string = input.collect_string(tag.clone())?;

crates/nu-command/src/commands/from_json.rs

@@ -65,7 +65,6 @@ pub fn from_json_string_to_value(s: String, tag: impl Into<Tag>) -> nu_json::Res
 fn from_json(args: CommandArgs) -> Result<OutputStream, ShellError> {
     let name_tag = args.call_info.name_tag.clone();
 
-    let args = args.evaluate_once()?;
     let objects = args.has_flag("objects");
 
     let concat_string = args.input.collect_string(name_tag.clone())?;

crates/nu-command/src/commands/from_ods.rs

@@ -52,14 +52,10 @@ fn from_ods(args: CommandArgs) -> Result<OutputStream, ShellError> {
     let tag = args.call_info.name_tag.clone();
     let span = tag.span;
 
-    let args = args.evaluate_once()?;
-
     let mut sel_sheets = vec![];
 
-    if let Some(s) = args.call_info.args.get("sheets") {
+    if let Some(columns) = args.get_flag::<Vec<Value>>("sheets")? {
-        if let UntaggedValue::Table(columns) = s.value.clone() {
+        sel_sheets = convert_columns(columns.as_slice())?;
-            sel_sheets = convert_columns(columns.as_slice())?;
-        }
     }
 
     let bytes = args.input.collect_binary(tag.clone())?;

crates/nu-command/src/commands/from_ssv.rs

@@ -237,7 +237,6 @@ fn from_ssv_string_to_value(
 
 fn from_ssv(args: CommandArgs) -> Result<OutputStream, ShellError> {
     let name = args.call_info.name_tag.clone();
-    let args = args.evaluate_once()?;
 
     let noheaders = args.has_flag("noheaders");
     let aligned_columns = args.has_flag("aligned-columns");

crates/nu-command/src/commands/from_toml.rs

@@ -61,7 +61,6 @@ pub fn from_toml_string_to_value(s: String, tag: impl Into<Tag>) -> Result<Value
 }
 
 pub fn from_toml(args: CommandArgs) -> Result<OutputStream, ShellError> {
-    let args = args.evaluate_once()?;
     let tag = args.name_tag();
     let input = args.input;
 

crates/nu-command/src/commands/from_tsv.rs

@@ -30,7 +30,6 @@ impl WholeStreamCommand for FromTsv {
 
 fn from_tsv(args: CommandArgs) -> Result<OutputStream, ShellError> {
     let name = args.call_info.name_tag.clone();
-    let args = args.evaluate_once()?;
     let noheaders = args.has_flag("noheaders");
     let input = args.input;
 

crates/nu-command/src/commands/from_url.rs

@@ -24,7 +24,6 @@ impl WholeStreamCommand for FromUrl {
 }
 
 fn from_url(args: CommandArgs) -> Result<OutputStream, ShellError> {
-    let args = args.evaluate_once()?;
     let tag = args.name_tag();
     let input = args.input;
 

crates/nu-command/src/commands/from_vcf.rs

@@ -26,7 +26,6 @@ impl WholeStreamCommand for FromVcf {
 }
 
 fn from_vcf(args: CommandArgs) -> Result<OutputStream, ShellError> {
-    let args = args.evaluate_once()?;
     let tag = args.name_tag();
     let input = args.input;
 

crates/nu-command/src/commands/from_xlsx.rs

@@ -58,14 +58,10 @@ fn from_xlsx(args: CommandArgs) -> Result<OutputStream, ShellError> {
     let tag = args.call_info.name_tag.clone();
     let span = tag.span;
 
-    let args = args.evaluate_once()?;
-
     let mut sel_sheets = vec![];
 
-    if let Some(s) = args.call_info.args.get("sheets") {
+    if let Some(columns) = args.get_flag::<Vec<Value>>("sheets")? {
-        if let UntaggedValue::Table(columns) = s.value.clone() {
+        sel_sheets = convert_columns(columns.as_slice())?;
-            sel_sheets = convert_columns(columns.as_slice())?;
-        }
     }
 
     let value = args.input.collect_binary(tag.clone())?;

crates/nu-command/src/commands/from_xml.rs

@@ -95,7 +95,6 @@ pub fn from_xml_string_to_value(s: String, tag: impl Into<Tag>) -> Result<Value,
 }
 
 fn from_xml(args: CommandArgs) -> Result<OutputStream, ShellError> {
-    let args = args.evaluate_once()?;
     let tag = args.name_tag();
     let input = args.input;
 

crates/nu-command/src/commands/from_yaml.rs

@@ -132,7 +132,6 @@ pub fn from_yaml_string_to_value(s: String, tag: impl Into<Tag>) -> Result<Value
 }
 
 fn from_yaml(args: CommandArgs) -> Result<OutputStream, ShellError> {
-    let args = args.evaluate_once()?;
     let tag = args.name_tag();
     let input = args.input;
 

crates/nu-command/src/commands/get.rs

@@ -49,7 +49,6 @@ impl WholeStreamCommand for Command {
 }
 
 pub fn get(args: CommandArgs) -> Result<ActionStream, ShellError> {
-    let args = args.evaluate_once()?;
     let column_paths: Vec<ColumnPath> = args.rest(0)?;
     let mut input = args.input;
 

crates/nu-command/src/commands/group_by.rs

@@ -126,7 +126,6 @@ enum Grouper {
 pub fn group_by(args: CommandArgs) -> Result<OutputStream, ShellError> {
     let name = args.call_info.name_tag.clone();
     let context = Arc::new(EvaluationContext::from_args(&args));
-    let args = args.evaluate_once()?;
 
     let grouper = args.opt(0)?;
     let values: Vec<Value> = args.input.collect();

crates/nu-command/src/commands/group_by_date.rs

@@ -54,7 +54,6 @@ enum GroupByColumn {
 
 pub fn group_by_date(args: CommandArgs) -> Result<OutputStream, ShellError> {
     let name = args.call_info.name_tag.clone();
-    let args = args.evaluate_once()?;
     let column_name: Option<Tagged<String>> = args.opt(0)?;
     let format: Option<Tagged<String>> = args.get_flag("format")?;
 

crates/nu-command/src/commands/hash_/base64_.rs

@@ -87,7 +87,6 @@ impl WholeStreamCommand for SubCommand {
 
 fn operate(args: CommandArgs) -> Result<OutputStream, ShellError> {
     let name_tag = args.call_info.name_tag.clone();
-    let args = args.evaluate_once()?;
 
     let encode = args.has_flag("encode");
     let decode = args.has_flag("decode");

crates/nu-command/src/commands/hash_/md5_.rs

@@ -50,7 +50,6 @@ impl WholeStreamCommand for SubCommand {
 }
 
 fn operate(args: CommandArgs) -> Result<OutputStream, ShellError> {
-    let args = args.evaluate_once()?;
     let column_paths: Vec<ColumnPath> = args.rest(0)?;
 
     Ok(args

crates/nu-command/src/commands/help.rs

@@ -34,7 +34,6 @@ impl WholeStreamCommand for Help {
 fn help(args: CommandArgs) -> Result<ActionStream, ShellError> {
     let name = args.call_info.name_tag.clone();
     let scope = args.scope().clone();
-    let args = args.evaluate_once()?;
 
     let rest: Vec<Tagged<String>> = args.rest(0)?;
 

crates/nu-command/src/commands/histogram.rs

@@ -59,21 +59,10 @@ impl WholeStreamCommand for Histogram {
 
 pub fn histogram(args: CommandArgs) -> Result<ActionStream, ShellError> {
     let name = args.call_info.name_tag.clone();
-    let (input, args) = args.evaluate_once()?.parts();
 
-    let values: Vec<Value> = input.collect();
+    let mut columns = args.rest::<ColumnPath>(0)?;
-
+    let evaluate_with = args.get_flag::<ColumnPath>("use")?.map(evaluator);
-    let mut columns = args
+    let values: Vec<Value> = args.input.collect();
-        .positional_iter()
-        .map(|c| c.as_column_path())
-        .filter_map(Result::ok)
-        .collect::<Vec<_>>();
-
-    let evaluate_with = if let Some(path) = args.get("use") {
-        Some(evaluator(path.as_column_path()?.item))
-    } else {
-        None
-    };
 
     let column_grouper = if !columns.is_empty() {
         columns

crates/nu-command/src/commands/history.rs

@@ -28,7 +28,6 @@ impl WholeStreamCommand for History {
 fn history(args: CommandArgs) -> Result<ActionStream, ShellError> {
     let tag = args.call_info.name_tag.clone();
     let ctx = EvaluationContext::from_args(&args);
-    let args = args.evaluate_once()?;
 
     let clear = args.has_flag("clear");
 

crates/nu-command/src/commands/if_.rs

@@ -57,12 +57,11 @@ impl WholeStreamCommand for If {
         ]
     }
 }
-fn if_command(raw_args: CommandArgs) -> Result<OutputStream, ShellError> {
+fn if_command(args: CommandArgs) -> Result<OutputStream, ShellError> {
-    let tag = raw_args.call_info.name_tag.clone();
+    let tag = args.call_info.name_tag.clone();
-    let external_redirection = raw_args.call_info.args.external_redirection;
+    let external_redirection = args.call_info.args.external_redirection;
-    let context = Arc::new(EvaluationContext::from_args(&raw_args));
+    let context = Arc::new(args.context.clone());
 
-    let args = raw_args.evaluate_once()?;
     let condition: CapturedBlock = args.req(0)?;
     let then_case: CapturedBlock = args.req(1)?;
     let else_case: CapturedBlock = args.req(2)?;

crates/nu-command/src/commands/insert.rs

@@ -154,7 +154,6 @@ fn process_row(
 
 fn insert(args: CommandArgs) -> Result<ActionStream, ShellError> {
     let context = Arc::new(EvaluationContext::from_args(&args));
-    let args = args.evaluate_once()?;
     let column: ColumnPath = args.req(0)?;
     let value: Value = args.req(1)?;
     let input = args.input;

crates/nu-command/src/commands/into/binary.rs

@@ -113,7 +113,6 @@ impl WholeStreamCommand for SubCommand {
 }
 
 fn into_binary(args: CommandArgs) -> Result<OutputStream, ShellError> {
-    let args = args.evaluate_once()?;
     let skip: Option<Value> = args.get_flag("skip")?;
     let bytes: Option<Value> = args.get_flag("bytes")?;
     let column_paths: Vec<ColumnPath> = args.rest(0)?;

crates/nu-command/src/commands/into/int.rs

@@ -79,7 +79,6 @@ impl WholeStreamCommand for SubCommand {
 }
 
 fn into_int(args: CommandArgs) -> Result<OutputStream, ShellError> {
-    let args = args.evaluate_once()?;
     let column_paths: Vec<ColumnPath> = args.rest(0)?;
 
     Ok(args

crates/nu-command/src/commands/into/string.rs

@@ -81,8 +81,6 @@ impl WholeStreamCommand for SubCommand {
 }
 
 fn into_string(args: CommandArgs) -> Result<OutputStream, ShellError> {
-    let args = args.evaluate_once()?;
-
     let decimals: Option<Tagged<u64>> = args.get_flag("decimals")?;
     let column_paths: Vec<ColumnPath> = args.rest(0)?;
 

crates/nu-command/src/commands/keep/command.rs

@@ -49,7 +49,6 @@ impl WholeStreamCommand for Command {
 }
 
 fn keep(args: CommandArgs) -> Result<OutputStream, ShellError> {
-    let args = args.evaluate_once()?;
     let rows: Option<Tagged<usize>> = args.opt(0)?;
 
     let rows_desired = if let Some(quantity) = rows {