Semicolon (#1613)

* WIP on blocks

* Getting further

* add some tests

crates/nu-cli/src/cli.rs

@@ -1,5 +1,5 @@
+use crate::commands::classified::block::run_block;
 use crate::commands::classified::external::{MaybeTextCodec, StringOrBinary};
-use crate::commands::classified::pipeline::run_pipeline;
 use crate::commands::plugin::JsonRpc;
 use crate::commands::plugin::{PluginCommand, PluginSink};
 use crate::commands::whole_stream_command;
@@ -710,12 +710,12 @@ async fn process_line(
             debug!("=== Parsed ===");
             debug!("{:#?}", result);
 
-            let pipeline = nu_parser::classify_pipeline(&result, ctx.registry());
+            let classified_block = nu_parser::classify_block(&result, ctx.registry());
 
-            debug!("{:#?}", pipeline);
+            debug!("{:#?}", classified_block);
             //println!("{:#?}", pipeline);
 
-            if let Some(failure) = pipeline.failed {
+            if let Some(failure) = classified_block.failed {
                 return LineResult::Error(line.to_string(), failure.into());
             }
 
@@ -725,10 +725,13 @@ async fn process_line(
             // ...and it doesn't have any arguments
             // ...and we're in the CLI
             // ...then change to this directory
-            if cli_mode && pipeline.commands.list.len() == 1 {
+            if cli_mode
+                && classified_block.block.block.len() == 1
+                && classified_block.block.block[0].list.len() == 1
+            {
                 if let ClassifiedCommand::Internal(InternalCommand {
                     ref name, ref args, ..
-                }) = pipeline.commands.list[0]
+                }) = classified_block.block.block[0].list[0]
                 {
                     let internal_name = name;
                     let name = args
@@ -826,7 +829,7 @@ async fn process_line(
                 InputStream::empty()
             };
 
-            match run_pipeline(pipeline, ctx, input_stream, &Scope::empty()).await {
+            match run_block(&classified_block.block, ctx, input_stream, &Scope::empty()).await {
                 Ok(input) => {
                     // Running a pipeline gives us back a stream that we can then
                     // work through. At the top level, we just want to pull on the
@@ -896,12 +899,10 @@ mod tests {
 
     #[quickcheck]
     fn quickcheck_parse(data: String) -> bool {
-        if let Ok(lite_pipeline) = nu_parser::lite_parse(&data, 0) {
+        if let Ok(lite_block) = nu_parser::lite_parse(&data, 0) {
             let context = crate::context::Context::basic().unwrap();
-            let _ = nu_parser::classify_pipeline(&lite_pipeline, context.registry());
-            true
-        } else {
-            false
+            let _ = nu_parser::classify_block(&lite_block, context.registry());
         }
+        true
     }
 }

crates/nu-cli/src/commands/classified/block.rs

@@ -0,0 +1,97 @@
+use crate::commands::classified::expr::run_expression_block;
+use crate::commands::classified::external::run_external_command;
+use crate::commands::classified::internal::run_internal_command;
+use crate::context::Context;
+use crate::prelude::*;
+use crate::stream::InputStream;
+use futures::stream::TryStreamExt;
+use nu_errors::ShellError;
+use nu_protocol::hir::{Block, ClassifiedCommand, Commands};
+use nu_protocol::{ReturnSuccess, Scope, UntaggedValue, Value};
+use std::sync::atomic::Ordering;
+
+pub(crate) async fn run_block(
+    block: &Block,
+    ctx: &mut Context,
+    mut input: InputStream,
+    scope: &Scope,
+) -> Result<InputStream, ShellError> {
+    let mut output: Result<InputStream, ShellError> = Ok(InputStream::empty());
+    for pipeline in &block.block {
+        match output {
+            Ok(inp) if inp.is_empty() => {}
+            Ok(inp) => {
+                let mut output_stream = inp.to_output_stream();
+
+                loop {
+                    match output_stream.try_next().await {
+                        Ok(Some(ReturnSuccess::Value(Value {
+                            value: UntaggedValue::Error(e),
+                            ..
+                        }))) => return Err(e),
+                        Ok(Some(_item)) => {
+                            if ctx.ctrl_c.load(Ordering::SeqCst) {
+                                break;
+                            }
+                        }
+                        Ok(None) => break,
+                        Err(e) => return Err(e),
+                    }
+                }
+                if !ctx.get_errors().is_empty() {
+                    return Ok(InputStream::empty());
+                }
+            }
+            Err(e) => {
+                return Err(e);
+            }
+        }
+        output = run_pipeline(pipeline, ctx, input, scope).await;
+
+        input = InputStream::empty();
+    }
+
+    output
+}
+
+async fn run_pipeline(
+    commands: &Commands,
+    ctx: &mut Context,
+    mut input: InputStream,
+    scope: &Scope,
+) -> Result<InputStream, ShellError> {
+    let mut iter = commands.list.clone().into_iter().peekable();
+
+    loop {
+        let item: Option<ClassifiedCommand> = iter.next();
+        let next: Option<&ClassifiedCommand> = iter.peek();
+
+        input = match (item, next) {
+            (Some(ClassifiedCommand::Dynamic(_)), _) | (_, Some(ClassifiedCommand::Dynamic(_))) => {
+                return Err(ShellError::unimplemented("Dynamic commands"))
+            }
+
+            (Some(ClassifiedCommand::Expr(expr)), _) => {
+                run_expression_block(*expr, ctx, input, scope)?
+            }
+            (Some(ClassifiedCommand::Error(err)), _) => return Err(err.into()),
+            (_, Some(ClassifiedCommand::Error(err))) => return Err(err.clone().into()),
+
+            (Some(ClassifiedCommand::Internal(left)), _) => {
+                run_internal_command(left, ctx, input, scope)?
+            }
+
+            (Some(ClassifiedCommand::External(left)), None) => {
+                run_external_command(left, ctx, input, scope, true).await?
+            }
+
+            (Some(ClassifiedCommand::External(left)), _) => {
+                run_external_command(left, ctx, input, scope, false).await?
+            }
+
+            (None, _) => break,
+        };
+    }
+
+    Ok(input)
+}

crates/nu-cli/src/commands/classified/internal.rs

@@ -120,12 +120,12 @@ pub(crate) fn run_internal_command(
                             FilesystemShell::with_location(location, context.registry().clone()),
                         ));
                     }
-                    CommandAction::AddAlias(name, args, commands) => {
+                    CommandAction::AddAlias(name, args, block) => {
                         context.add_commands(vec![
                             per_item_command(AliasCommand::new(
                                 name,
                                 args,
-                                commands,
+                                block,
                             ))
                         ]);
                     }

crates/nu-cli/src/commands/classified/mod.rs

@@ -1,8 +1,8 @@
+pub(crate) mod block;
 mod dynamic;
 pub(crate) mod expr;
 pub(crate) mod external;
 pub(crate) mod internal;
-pub(crate) mod pipeline;
 
 #[allow(unused_imports)]
 pub(crate) use dynamic::Command as DynamicCommand;

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

@@ -1,4 +1,4 @@
-use crate::commands::classified::pipeline::run_pipeline;
+use crate::commands::classified::block::run_block;
 use crate::commands::PerItemCommand;
 use crate::context::CommandRegistry;
 use crate::prelude::*;
@@ -6,10 +6,7 @@ use crate::prelude::*;
 use futures::stream::once;
 
 use nu_errors::ShellError;
-use nu_protocol::{
-    hir::ClassifiedPipeline, CallInfo, ReturnSuccess, Scope, Signature, SyntaxShape, UntaggedValue,
-    Value,
-};
+use nu_protocol::{CallInfo, ReturnSuccess, Scope, Signature, SyntaxShape, UntaggedValue, Value};
 
 pub struct Each;
 
@@ -50,8 +47,8 @@ impl PerItemCommand for Each {
                     let input_clone = input.clone();
                     let input_stream = once(async { Ok(input) }).to_input_stream();
 
-                    let result = run_pipeline(
-                        ClassifiedPipeline::new(block.clone(), None),
+                    let result = run_block(
+                        block,
                         &mut context,
                         input_stream,
                         &Scope::new(input_clone),

crates/nu-cli/src/commands/run_alias.rs

@@ -1,18 +1,15 @@
-use crate::commands::classified::pipeline::run_pipeline;
+use crate::commands::classified::block::run_block;
 use crate::prelude::*;
 
 use derive_new::new;
 use nu_errors::ShellError;
-use nu_protocol::{
-    hir::ClassifiedPipeline, hir::Commands, CallInfo, ReturnSuccess, Scope, Signature, SyntaxShape,
-    Value,
-};
+use nu_protocol::{hir::Block, CallInfo, ReturnSuccess, Scope, Signature, SyntaxShape, Value};
 
 #[derive(new)]
 pub struct AliasCommand {
     name: String,
     args: Vec<String>,
-    block: Commands,
+    block: Block,
 }
 
 impl PerItemCommand for AliasCommand {
@@ -60,8 +57,8 @@ impl PerItemCommand for AliasCommand {
             let input_clone = Ok(input.clone());
             let input_stream = futures::stream::once(async { input_clone }).boxed().to_input_stream();
 
-            let result = run_pipeline(
-                ClassifiedPipeline::new(block.clone(), None),
+            let result = run_block(
+                &block,
                 &mut context,
                 input_stream,
                 &scope

crates/nu-cli/src/commands/skip_while.rs

@@ -40,25 +40,34 @@ impl WholeStreamCommand for SkipWhile {
             Value {
                 value: UntaggedValue::Block(block),
                 tag,
-            } => match block.list.get(0) {
-                Some(item) => match item {
-                    ClassifiedCommand::Expr(expr) => expr.clone(),
-                    _ => {
-                        return Err(ShellError::labeled_error(
-                            "Expected a condition",
-                            "expected a condition",
-                            tag,
-                        ))
-                    }
-                },
-                None => {
+            } => {
+                if block.block.len() != 1 {
                     return Err(ShellError::labeled_error(
                         "Expected a condition",
                         "expected a condition",
                         tag,
                     ));
                 }
-            },
+                match block.block[0].list.get(0) {
+                    Some(item) => match item {
+                        ClassifiedCommand::Expr(expr) => expr.clone(),
+                        _ => {
+                            return Err(ShellError::labeled_error(
+                                "Expected a condition",
+                                "expected a condition",
+                                tag,
+                            ))
+                        }
+                    },
+                    None => {
+                        return Err(ShellError::labeled_error(
+                            "Expected a condition",
+                            "expected a condition",
+                            tag,
+                        ));
+                    }
+                }
+            }
             Value { tag, .. } => {
                 return Err(ShellError::labeled_error(
                     "Expected a condition",

crates/nu-cli/src/commands/where_.rs

@@ -40,25 +40,34 @@ impl PerItemCommand for Where {
             Value {
                 value: UntaggedValue::Block(block),
                 tag,
-            } => match block.list.get(0) {
-                Some(item) => match item {
-                    ClassifiedCommand::Expr(expr) => expr.clone(),
-                    _ => {
-                        return Err(ShellError::labeled_error(
-                            "Expected a condition",
-                            "expected a condition",
-                            tag,
-                        ))
-                    }
-                },
-                None => {
+            } => {
+                if block.block.len() != 1 {
                     return Err(ShellError::labeled_error(
                         "Expected a condition",
                         "expected a condition",
                         tag,
                     ));
                 }
-            },
+                match block.block[0].list.get(0) {
+                    Some(item) => match item {
+                        ClassifiedCommand::Expr(expr) => expr.clone(),
+                        _ => {
+                            return Err(ShellError::labeled_error(
+                                "Expected a condition",
+                                "expected a condition",
+                                tag,
+                            ))
+                        }
+                    },
+                    None => {
+                        return Err(ShellError::labeled_error(
+                            "Expected a condition",
+                            "expected a condition",
+                            tag,
+                        ));
+                    }
+                }
+            }
             Value { tag, .. } => {
                 return Err(ShellError::labeled_error(
                     "Expected a condition",

crates/nu-cli/src/deserializer.rs

@@ -1,7 +1,7 @@
 use log::trace;
 use nu_errors::{CoerceInto, ShellError};
 use nu_protocol::{
-    hir::Commands, CallInfo, ColumnPath, Primitive, RangeInclusion, ShellTypeName, UntaggedValue,
+    hir::Block, CallInfo, ColumnPath, Primitive, RangeInclusion, ShellTypeName, UntaggedValue,
     Value,
 };
 use nu_source::{HasSpan, Spanned, SpannedItem, Tagged, TaggedItem};
@@ -369,7 +369,7 @@ impl<'de, 'a> de::Deserializer<'de> for &'a mut ConfigDeserializer<'de> {
                     ))
                 }
             };
-            return visit::<Commands, _>(block, name, fields, visitor);
+            return visit::<Block, _>(block, name, fields, visitor);
         }
 
         if name == "ColumnPath" {

crates/nu-cli/src/shell/completer.rs

@@ -34,14 +34,9 @@ impl NuCompleter {
 
         // See if we're a flag
         if pos > 0 && replace_pos < line_chars.len() && line_chars[replace_pos] == '-' {
-            if let Ok(lite_pipeline) = nu_parser::lite_parse(line, 0) {
-                completions = self.get_matching_arguments(
-                    &lite_pipeline,
-                    &line_chars,
-                    line,
-                    replace_pos,
-                    pos,
-                );
+            if let Ok(lite_block) = nu_parser::lite_parse(line, 0) {
+                completions =
+                    self.get_matching_arguments(&lite_block, &line_chars, line, replace_pos, pos);
             } else {
                 completions = self.file_completer.complete(line, pos, context)?.1;
             }
@@ -96,7 +91,7 @@ impl NuCompleter {
 
     fn get_matching_arguments(
         &self,
-        lite_parse: &nu_parser::LitePipeline,
+        lite_block: &nu_parser::LiteBlock,
         line_chars: &[char],
         line: &str,
         replace_pos: usize,
@@ -109,23 +104,25 @@ impl NuCompleter {
         let replace_string = (replace_pos..pos).map(|_| " ").collect::<String>();
         line_copy.replace_range(replace_pos..pos, &replace_string);
 
-        let result = nu_parser::classify_pipeline(&lite_parse, &self.commands);
+        let result = nu_parser::classify_block(&lite_block, &self.commands);
 
-        for command in result.commands.list {
-            if let nu_protocol::hir::ClassifiedCommand::Internal(
-                nu_protocol::hir::InternalCommand { args, .. },
-            ) = command
-            {
-                if replace_pos >= args.span.start() && replace_pos <= args.span.end() {
-                    if let Some(named) = args.named {
-                        for (name, _) in named.iter() {
-                            let full_flag = format!("--{}", name);
+        for pipeline in &result.block.block {
+            for command in &pipeline.list {
+                if let nu_protocol::hir::ClassifiedCommand::Internal(
+                    nu_protocol::hir::InternalCommand { args, .. },
+                ) = command
+                {
+                    if replace_pos >= args.span.start() && replace_pos <= args.span.end() {
+                        if let Some(named) = &args.named {
+                            for (name, _) in named.iter() {
+                                let full_flag = format!("--{}", name);
 
-                            if full_flag.starts_with(&substring) {
-                                matching_arguments.push(rustyline::completion::Pair {
-                                    display: full_flag.clone(),
-                                    replacement: full_flag,
-                                });
+                                if full_flag.starts_with(&substring) {
+                                    matching_arguments.push(rustyline::completion::Pair {
+                                        display: full_flag.clone(),
+                                        replacement: full_flag,
+                                    });
+                                }
                             }
                         }
                     }

crates/nu-cli/src/shell/helper.rs

@@ -61,15 +61,15 @@ impl Highlighter for Helper {
     }
 
     fn highlight<'l>(&self, line: &'l str, _pos: usize) -> Cow<'l, str> {
-        let lite_pipeline = nu_parser::lite_parse(line, 0);
+        let lite_block = nu_parser::lite_parse(line, 0);
 
-        match lite_pipeline {
+        match lite_block {
             Err(_) => Cow::Borrowed(line),
-            Ok(lp) => {
+            Ok(lb) => {
                 let classified =
-                    nu_parser::classify_pipeline(&lp, &self.context.registry().clone_box());
+                    nu_parser::classify_block(&lb, &self.context.registry().clone_box());
 
-                let shapes = nu_parser::shapes(&classified.commands);
+                let shapes = nu_parser::shapes(&classified.block);
                 let mut painter = Painter::new(line);
 
                 for shape in shapes {

crates/nu-cli/tests/commands/mod.rs

@@ -30,6 +30,7 @@ mod rename;
 mod reverse;
 mod rm;
 mod save;
+mod semicolon;
 mod sort_by;
 mod split_by;
 mod split_column;

crates/nu-cli/tests/commands/semicolon.rs

@@ -0,0 +1,29 @@
+use nu_test_support::playground::Playground;
+use nu_test_support::{nu, pipeline};
+
+#[test]
+fn semicolon_allows_lhs_to_complete() {
+    Playground::setup("create_test_1", |dirs, _sandbox| {
+        let actual = nu!(
+            cwd: dirs.test(),
+            "touch i_will_be_created_semi.txt; echo done"
+        );
+
+        let path = dirs.test().join("i_will_be_created_semi.txt");
+
+        assert!(path.exists());
+        assert_eq!(actual, "done");
+    })
+}
+
+#[test]
+fn semicolon_lhs_error_stops_processing() {
+    let actual = nu!(
+    cwd: "tests/fixtures/formats", pipeline(
+    r#"
+        where 1 1; echo done
+    "#
+    ));
+
+    assert!(!actual.contains("done"));
+}

crates/nu-parser/src/lib.rs

@@ -6,7 +6,7 @@ mod shapes;
 mod signature;
 
 pub use crate::files::Files;
-pub use crate::lite_parse::{lite_parse, LitePipeline};
-pub use crate::parse::{classify_pipeline, garbage};
+pub use crate::lite_parse::{lite_parse, LiteBlock};
+pub use crate::parse::{classify_block, garbage};
 pub use crate::shapes::shapes;
 pub use crate::signature::{Signature, SignatureRegistry};

crates/nu-parser/src/lite_parse.rs

@@ -29,11 +29,16 @@ impl LiteCommand {
     }
 }
 
-#[derive(Debug)]
+#[derive(Debug, Clone)]
 pub struct LitePipeline {
     pub commands: Vec<LiteCommand>,
 }
 
+#[derive(Debug, Clone)]
+pub struct LiteBlock {
+    pub block: Vec<LitePipeline>,
+}
+
 fn skip_whitespace(src: &mut Input) {
     while let Some((_, x)) = src.peek() {
         if x.is_whitespace() {
@@ -58,7 +63,8 @@ fn bare(src: &mut Input, span_offset: usize) -> Result<Spanned<String>, ParseErr
     let mut inside_quote = false;
     let mut block_level = vec![];
 
-    for (_, c) in src {
+    while let Some((_, c)) = src.peek() {
+        let c = *c;
         if inside_quote {
             if c == delimiter {
                 inside_quote = false;
@@ -84,10 +90,11 @@ fn bare(src: &mut Input, span_offset: usize) -> Result<Spanned<String>, ParseErr
             if let Some('(') = block_level.last() {
                 let _ = block_level.pop();
             }
-        } else if block_level.is_empty() && c.is_whitespace() {
+        } else if block_level.is_empty() && (c.is_whitespace() || c == '|' || c == ';') {
             break;
         }
         bare.push(c);
+        let _ = src.next();
     }
 
     let span = Span::new(
@@ -139,16 +146,14 @@ fn quoted(
 fn command(src: &mut Input, span_offset: usize) -> Result<LiteCommand, ParseError> {
     let command = bare(src, span_offset)?;
     if command.item.is_empty() {
-        Err(ParseError::unexpected_eof(
-            "unexpected end of input",
-            command.span,
-        ))
+        Err(ParseError::unexpected_eof("command", command.span))
     } else {
         Ok(LiteCommand::new(command))
     }
 }
 
-fn pipeline(src: &mut Input, span_offset: usize) -> Result<LitePipeline, ParseError> {
+fn pipeline(src: &mut Input, span_offset: usize) -> Result<LiteBlock, ParseError> {
+    let mut block = vec![];
     let mut commands = vec![];
 
     skip_whitespace(src);
@@ -167,6 +172,10 @@ fn pipeline(src: &mut Input, span_offset: usize) -> Result<LitePipeline, ParseEr
             if let Some((_, c)) = src.peek() {
                 // The first character tells us a lot about each argument
                 match c {
+                    ';' => {
+                        // this is the end of the command and the end of the pipeline
+                        break;
+                    }
                     '|' => {
                         let _ = src.next();
                         if let Some((pos, next_c)) = src.peek() {
@@ -202,21 +211,35 @@ fn pipeline(src: &mut Input, span_offset: usize) -> Result<LitePipeline, ParseEr
         }
         commands.push(cmd);
         skip_whitespace(src);
+
+        if let Some((_, ';')) = src.peek() {
+            let _ = src.next();
+
+            if !commands.is_empty() {
+                block.push(LitePipeline { commands });
+                commands = vec![];
+            }
+        }
     }
 
-    Ok(LitePipeline { commands })
+    if !commands.is_empty() {
+        block.push(LitePipeline { commands });
+    }
+
+    Ok(LiteBlock { block })
 }
 
-pub fn lite_parse(src: &str, span_offset: usize) -> Result<LitePipeline, ParseError> {
+pub fn lite_parse(src: &str, span_offset: usize) -> Result<LiteBlock, ParseError> {
     pipeline(&mut src.char_indices().peekable(), span_offset)
 }
 
 #[test]
 fn lite_simple_1() -> Result<(), ParseError> {
     let result = lite_parse("foo", 0)?;
-    assert_eq!(result.commands.len(), 1);
-    assert_eq!(result.commands[0].name.span.start(), 0);
-    assert_eq!(result.commands[0].name.span.end(), 3);
+    assert_eq!(result.block.len(), 1);
+    assert_eq!(result.block[0].commands.len(), 1);
+    assert_eq!(result.block[0].commands[0].name.span.start(), 0);
+    assert_eq!(result.block[0].commands[0].name.span.end(), 3);
 
     Ok(())
 }
@@ -224,9 +247,10 @@ fn lite_simple_1() -> Result<(), ParseError> {
 #[test]
 fn lite_simple_offset() -> Result<(), ParseError> {
     let result = lite_parse("foo", 10)?;
-    assert_eq!(result.commands.len(), 1);
-    assert_eq!(result.commands[0].name.span.start(), 10);
-    assert_eq!(result.commands[0].name.span.end(), 13);
+    assert_eq!(result.block.len(), 1);
+    assert_eq!(result.block[0].commands.len(), 1);
+    assert_eq!(result.block[0].commands[0].name.span.start(), 10);
+    assert_eq!(result.block[0].commands[0].name.span.end(), 13);
 
     Ok(())
 }

crates/nu-parser/src/parse.rs

@@ -1,13 +1,14 @@
 use std::path::Path;
 
-use crate::lite_parse::{lite_parse, LiteCommand, LitePipeline};
+use crate::lite_parse::{lite_parse, LiteBlock, LiteCommand, LitePipeline};
 use crate::path::expand_path;
 use crate::signature::SignatureRegistry;
 use log::trace;
 use nu_errors::{ArgumentError, ParseError};
 use nu_protocol::hir::{
-    self, Binary, ClassifiedCommand, ClassifiedPipeline, Commands, Expression, Flag, FlagKind,
-    InternalCommand, Member, NamedArguments, Operator, SpannedExpression, Unit,
+    self, Binary, Block, ClassifiedBlock, ClassifiedCommand, ClassifiedPipeline, Commands,
+    Expression, Flag, FlagKind, InternalCommand, Member, NamedArguments, Operator,
+    SpannedExpression, Unit,
 };
 use nu_protocol::{NamedType, PositionalType, Signature, SyntaxShape, UnspannedPathMember};
 use nu_source::{Span, Spanned, SpannedItem};
@@ -416,11 +417,19 @@ fn parse_arg(
                     let mut error = None;
 
                     // We haven't done much with the inner string, so let's go ahead and work with it
-                    let lite_pipeline = match lite_parse(&string, lite_arg.span.start() + 1) {
-                        Ok(lp) => lp,
+                    let lite_block = match lite_parse(&string, lite_arg.span.start() + 1) {
+                        Ok(lb) => lb,
                         Err(e) => return (garbage(lite_arg.span), Some(e)),
                     };
 
+                    if lite_block.block.len() != 1 {
+                        return (
+                            garbage(lite_arg.span),
+                            Some(ParseError::mismatch("table", lite_arg.clone())),
+                        );
+                    }
+
+                    let lite_pipeline = lite_block.block[0].clone();
                     let mut output = vec![];
                     for lite_inner in &lite_pipeline.commands {
                         let (arg, err) = parse_arg(SyntaxShape::Any, registry, &lite_inner.name);
@@ -462,17 +471,17 @@ fn parse_arg(
                     let string: String = chars.collect();
 
                     // We haven't done much with the inner string, so let's go ahead and work with it
-                    let lite_pipeline = match lite_parse(&string, lite_arg.span.start() + 1) {
+                    let lite_block = match lite_parse(&string, lite_arg.span.start() + 1) {
                         Ok(lp) => lp,
                         Err(e) => return (garbage(lite_arg.span), Some(e)),
                     };
 
-                    let classified_block = classify_pipeline(&lite_pipeline, registry);
+                    let classified_block = classify_block(&lite_block, registry);
                     let error = classified_block.failed;
 
                     (
                         SpannedExpression::new(
-                            Expression::Block(classified_block.commands),
+                            Expression::Block(classified_block.block),
                             lite_arg.span,
                         ),
                         error,
@@ -586,11 +595,20 @@ fn parse_parenthesized_expression(
             let string: String = chars.collect();
 
             // We haven't done much with the inner string, so let's go ahead and work with it
-            let mut lite_pipeline = match lite_parse(&string, lite_arg.span.start() + 1) {
-                Ok(lp) => lp,
+            let lite_block = match lite_parse(&string, lite_arg.span.start() + 1) {
+                Ok(lb) => lb,
                 Err(e) => return (garbage(lite_arg.span), Some(e)),
             };
 
+            if lite_block.block.len() != 1 {
+                return (
+                    garbage(lite_arg.span),
+                    Some(ParseError::mismatch("math expression", lite_arg.clone())),
+                );
+            }
+
+            let mut lite_pipeline = lite_block.block[0].clone();
+
             let mut collection = vec![];
             for lite_cmd in lite_pipeline.commands.iter_mut() {
                 collection.push(lite_cmd.name.clone());
@@ -796,8 +814,10 @@ fn parse_positional_argument(
                     let span = arg.span;
                     let mut commands = hir::Commands::new(span);
                     commands.push(ClassifiedCommand::Expr(Box::new(arg)));
+                    let mut block = hir::Block::new(span);
+                    block.push(commands);
 
-                    let arg = SpannedExpression::new(Expression::Block(commands), span);
+                    let arg = SpannedExpression::new(Expression::Block(block), span);
 
                     idx = new_idx;
                     if error.is_none() {
@@ -971,10 +991,10 @@ fn parse_internal_command(
 /// Convert a lite-ly parsed pipeline into a fully classified pipeline, ready to be evaluated.
 /// This conversion does error-recovery, so the result is allowed to be lossy. A lossy unit is designated as garbage.
 /// Errors are returned as part of a side-car error rather than a Result to allow both error and lossy result simultaneously.
-pub fn classify_pipeline(
+fn classify_pipeline(
     lite_pipeline: &LitePipeline,
     registry: &dyn SignatureRegistry,
-) -> ClassifiedPipeline {
+) -> (ClassifiedPipeline, Option<ParseError>) {
     // FIXME: fake span
     let mut commands = Commands::new(Span::new(0, 0));
     let mut error = None;
@@ -1054,7 +1074,23 @@ pub fn classify_pipeline(
         }
     }
 
-    ClassifiedPipeline::new(commands, error)
+    (ClassifiedPipeline::new(commands), error)
+}
+
+pub fn classify_block(lite_block: &LiteBlock, registry: &dyn SignatureRegistry) -> ClassifiedBlock {
+    // FIXME: fake span
+    let mut block = Block::new(Span::new(0, 0));
+
+    let mut error = None;
+    for lite_pipeline in &lite_block.block {
+        let (pipeline, err) = classify_pipeline(lite_pipeline, registry);
+        block.push(pipeline.commands);
+        if error.is_none() {
+            error = err;
+        }
+    }
+
+    ClassifiedBlock::new(block, error)
 }
 
 /// Parse out arguments from spanned expressions

crates/nu-parser/src/shapes.rs

@@ -62,43 +62,45 @@ pub fn expression_to_flat_shape(e: &SpannedExpression) -> Vec<Spanned<FlatShape>
 }
 
 /// Converts a series of commands into a vec of spanned shapes ready for color-highlighting
-pub fn shapes(commands: &Commands) -> Vec<Spanned<FlatShape>> {
+pub fn shapes(commands: &Block) -> Vec<Spanned<FlatShape>> {
     let mut output = vec![];
 
-    for command in &commands.list {
-        match command {
-            ClassifiedCommand::Internal(internal) => {
-                output.append(&mut expression_to_flat_shape(&internal.args.head));
+    for pipeline in &commands.block {
+        for command in &pipeline.list {
+            match command {
+                ClassifiedCommand::Internal(internal) => {
+                    output.append(&mut expression_to_flat_shape(&internal.args.head));
 
-                if let Some(positionals) = &internal.args.positional {
-                    for positional_arg in positionals {
-                        output.append(&mut expression_to_flat_shape(positional_arg));
+                    if let Some(positionals) = &internal.args.positional {
+                        for positional_arg in positionals {
+                            output.append(&mut expression_to_flat_shape(positional_arg));
+                        }
                     }
-                }
 
-                if let Some(named) = &internal.args.named {
-                    for (_, named_arg) in named.iter() {
-                        match named_arg {
-                            NamedValue::PresentSwitch(span) => {
-                                output.push(FlatShape::Flag.spanned(*span));
+                    if let Some(named) = &internal.args.named {
+                        for (_, named_arg) in named.iter() {
+                            match named_arg {
+                                NamedValue::PresentSwitch(span) => {
+                                    output.push(FlatShape::Flag.spanned(*span));
+                                }
+                                NamedValue::Value(span, expr) => {
+                                    output.push(FlatShape::Flag.spanned(*span));
+                                    output.append(&mut expression_to_flat_shape(expr));
+                                }
+                                _ => {}
                             }
-                            NamedValue::Value(span, expr) => {
-                                output.push(FlatShape::Flag.spanned(*span));
-                                output.append(&mut expression_to_flat_shape(expr));
-                            }
-                            _ => {}
                         }
                     }
                 }
-            }
-            ClassifiedCommand::External(external) => {
-                output.push(FlatShape::ExternalCommand.spanned(external.name_tag.span));
-                for arg in external.args.iter() {
-                    output.push(FlatShape::ExternalWord.spanned(arg.tag.span));
+                ClassifiedCommand::External(external) => {
+                    output.push(FlatShape::ExternalCommand.spanned(external.name_tag.span));
+                    for arg in external.args.iter() {
+                        output.push(FlatShape::ExternalWord.spanned(arg.tag.span));
+                    }
                 }
+                ClassifiedCommand::Expr(expr) => output.append(&mut expression_to_flat_shape(expr)),
+                _ => {}
             }
-            ClassifiedCommand::Expr(expr) => output.append(&mut expression_to_flat_shape(expr)),
-            _ => {}
         }
     }
 

crates/nu-protocol/src/hir.rs

@@ -44,16 +44,27 @@ impl InternalCommand {
 }
 
 #[derive(Debug, Clone, PartialEq, PartialOrd, Eq, Ord, Hash, Serialize, Deserialize)]
-pub struct ClassifiedPipeline {
-    pub commands: Commands,
+pub struct ClassifiedBlock {
+    pub block: Block,
     // this is not a Result to make it crystal clear that these shapes
     // aren't intended to be used directly with `?`
     pub failed: Option<ParseError>,
 }
 
+impl ClassifiedBlock {
+    pub fn new(block: Block, failed: Option<ParseError>) -> ClassifiedBlock {
+        ClassifiedBlock { block, failed }
+    }
+}
+
+#[derive(Debug, Clone, PartialEq, PartialOrd, Eq, Ord, Hash, Serialize, Deserialize)]
+pub struct ClassifiedPipeline {
+    pub commands: Commands,
+}
+
 impl ClassifiedPipeline {
-    pub fn new(commands: Commands, failed: Option<ParseError>) -> ClassifiedPipeline {
-        ClassifiedPipeline { commands, failed }
+    pub fn new(commands: Commands) -> ClassifiedPipeline {
+        ClassifiedPipeline { commands }
     }
 }
 
@@ -83,6 +94,25 @@ impl Commands {
     }
 }
 
+#[derive(Debug, Clone, PartialEq, PartialOrd, Eq, Ord, Hash, Serialize, Deserialize)]
+pub struct Block {
+    pub block: Vec<Commands>,
+    pub span: Span,
+}
+
+impl Block {
+    pub fn new(span: Span) -> Block {
+        Block {
+            block: vec![],
+            span,
+        }
+    }
+
+    pub fn push(&mut self, commands: Commands) {
+        self.block.push(commands);
+    }
+}
+
 #[derive(Debug, Ord, PartialOrd, Eq, PartialEq, Clone, Hash, Deserialize, Serialize)]
 pub struct ExternalStringCommand {
     pub name: Spanned<String>,
@@ -766,7 +796,7 @@ pub enum Expression {
     Variable(Variable),
     Binary(Box<Binary>),
     Range(Box<Range>),
-    Block(hir::Commands),
+    Block(hir::Block),
     List(Vec<SpannedExpression>),
     Path(Box<Path>),
 

crates/nu-protocol/src/return_value.rs

@@ -1,4 +1,4 @@
-use crate::hir::Commands;
+use crate::hir::Block;
 use crate::value::Value;
 use nu_errors::ShellError;
 use nu_source::{b, DebugDocBuilder, PrettyDebug};
@@ -22,7 +22,7 @@ pub enum CommandAction {
     /// Enter the help shell, which allows exploring the help system
     EnterHelpShell(Value),
     /// Enter the help shell, which allows exploring the help system
-    AddAlias(String, Vec<String>, Commands),
+    AddAlias(String, Vec<String>, Block),
     /// Go to the previous shell in the shell ring buffer
     PreviousShell,
     /// Go to the next shell in the shell ring buffer

crates/nu-protocol/src/value.rs

@@ -37,8 +37,8 @@ pub enum UntaggedValue {
     /// An error value that represents an error that occurred as the values in the pipeline were built
     Error(ShellError),
 
-    /// A block of Nu code, eg `{ ls | get name }`
-    Block(hir::Commands),
+    /// A block of Nu code, eg `{ ls | get name ; echo "done" }`
+    Block(hir::Block),
 }
 
 impl UntaggedValue {

crates/nu-value-ext/src/lib.rs

@@ -228,7 +228,7 @@ pub fn insert_data_at_path(value: &Value, path: &str, new_value: Value) -> Optio
                         if let UntaggedValue::Row(o) = &mut next.value {
                             o.entries.insert(
                                 split_path[idx + 1].to_string(),
-                                new_value.value.clone().into_value(&value.tag),
+                                new_value.value.into_value(&value.tag),
                             );
                         }
                         return Some(new_obj.clone());