Add wrap and get and cell_path parsing

crates/nu-command/src/default_context.rs

@@ -5,10 +5,7 @@ use nu_protocol::{
     Signature,
 };
 
-use crate::{
-    Alias, Benchmark, BuildString, Def, Do, Each, External, For, From, FromJson, Git, GitCheckout,
-    Help, If, Length, Let, LetEnv, Lines, ListGitBranches, Ls, Module, Ps, Sys, Table, Use, Where,
-};
+use crate::*;
 
 pub fn create_default_context() -> Rc<RefCell<EngineState>> {
     let engine_state = Rc::new(RefCell::new(EngineState::new()));
@@ -26,6 +23,7 @@ pub fn create_default_context() -> Rc<RefCell<EngineState>> {
         working_set.add_decl(Box::new(For));
         working_set.add_decl(Box::new(From));
         working_set.add_decl(Box::new(FromJson));
+        working_set.add_decl(Box::new(Get));
         working_set.add_decl(Box::new(Help));
         working_set.add_decl(Box::new(If));
         working_set.add_decl(Box::new(Length));
@@ -39,6 +37,7 @@ pub fn create_default_context() -> Rc<RefCell<EngineState>> {
         working_set.add_decl(Box::new(Table));
         working_set.add_decl(Box::new(Use));
         working_set.add_decl(Box::new(Where));
+        working_set.add_decl(Box::new(Wrap));
 
         // This is a WIP proof of concept
         working_set.add_decl(Box::new(ListGitBranches));

crates/nu-command/src/filesystem/ls.rs

@@ -63,8 +63,8 @@ impl Command for Ls {
                                     } else {
                                         Value::Nothing { span: call_span }
                                     },
-                                    Value::Int {
-                                        val: filesize as i64,
+                                    Value::Filesize {
+                                        val: filesize,
                                         span: call_span,
                                     },
                                 ],

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

@@ -0,0 +1,35 @@
+use nu_engine::CallExt;
+use nu_protocol::ast::{Call, CellPath};
+use nu_protocol::engine::{Command, EvaluationContext};
+use nu_protocol::{Signature, SyntaxShape, Value};
+
+pub struct Get;
+
+impl Command for Get {
+    fn name(&self) -> &str {
+        "get"
+    }
+
+    fn usage(&self) -> &str {
+        "Extract data using a cell path."
+    }
+
+    fn signature(&self) -> nu_protocol::Signature {
+        Signature::build("wrap").required(
+            "cell_path",
+            SyntaxShape::CellPath,
+            "the cell path to the data",
+        )
+    }
+
+    fn run(
+        &self,
+        context: &EvaluationContext,
+        call: &Call,
+        input: Value,
+    ) -> Result<nu_protocol::Value, nu_protocol::ShellError> {
+        let cell_path: CellPath = call.req(context, 0)?;
+
+        input.follow_cell_path(&cell_path.members)
+    }
+}

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

@@ -1,11 +1,15 @@
 mod each;
 mod for_;
+mod get;
 mod length;
 mod lines;
 mod where_;
+mod wrap;
 
 pub use each::Each;
 pub use for_::For;
+pub use get::Get;
 pub use length::Length;
 pub use lines::Lines;
 pub use where_::Where;
+pub use wrap::Wrap;

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

@@ -0,0 +1,59 @@
+use nu_engine::CallExt;
+use nu_protocol::ast::Call;
+use nu_protocol::engine::{Command, EvaluationContext};
+use nu_protocol::{IntoValueStream, Signature, SyntaxShape, Value};
+
+pub struct Wrap;
+
+impl Command for Wrap {
+    fn name(&self) -> &str {
+        "wrap"
+    }
+
+    fn usage(&self) -> &str {
+        "Wrap the value into a column."
+    }
+
+    fn signature(&self) -> nu_protocol::Signature {
+        Signature::build("wrap").required("name", SyntaxShape::String, "the name of the column")
+    }
+
+    fn run(
+        &self,
+        context: &EvaluationContext,
+        call: &Call,
+        input: Value,
+    ) -> Result<nu_protocol::Value, nu_protocol::ShellError> {
+        let span = call.head;
+        let name: String = call.req(context, 0)?;
+
+        match input {
+            Value::List { vals, .. } => Ok(Value::List {
+                vals: vals
+                    .into_iter()
+                    .map(move |x| Value::Record {
+                        cols: vec![name.clone()],
+                        vals: vec![x],
+                        span,
+                    })
+                    .collect(),
+                span,
+            }),
+            Value::Stream { stream, .. } => Ok(Value::Stream {
+                stream: stream
+                    .map(move |x| Value::Record {
+                        cols: vec![name.clone()],
+                        vals: vec![x],
+                        span,
+                    })
+                    .into_value_stream(),
+                span,
+            }),
+            _ => Ok(Value::Record {
+                cols: vec![name],
+                vals: vec![input],
+                span,
+            }),
+        }
+    }
+}

crates/nu-command/src/system/sys.rs

@@ -274,10 +274,11 @@ pub fn host(sys: &mut System, span: Span) -> Option<Value> {
             span,
         });
     }
-    // dict.insert_untagged(
-    //     "uptime",
-    //     UntaggedValue::duration(1000000000 * sys.uptime() as i64),
-    // );
+    cols.push("uptime".into());
+    vals.push(Value::Duration {
+        val: 1000000000 * sys.uptime() as u64,
+        span,
+    });
 
     let mut users = vec![];
     for user in sys.users() {

crates/nu-command/src/viewers/table.rs

@@ -63,7 +63,7 @@ impl Command for Table {
                     output.push(vec![
                         StyledString {
                             contents: c,
-                            style: nu_table::TextStyle::default_header(),
+                            style: nu_table::TextStyle::default_field(),
                         },
                         StyledString {
                             contents: v.into_string(),

crates/nu-engine/src/call_ext.rs

@@ -14,6 +14,14 @@ pub trait CallExt {
         context: &EvaluationContext,
         starting_pos: usize,
     ) -> Result<Vec<T>, ShellError>;
+
+    fn opt<T: FromValue>(
+        &self,
+        context: &EvaluationContext,
+        pos: usize,
+    ) -> Result<Option<T>, ShellError>;
+
+    fn req<T: FromValue>(&self, context: &EvaluationContext, pos: usize) -> Result<T, ShellError>;
 }
 
 impl CallExt for Call {
@@ -44,4 +52,29 @@ impl CallExt for Call {
 
         Ok(output)
     }
+
+    fn opt<T: FromValue>(
+        &self,
+        context: &EvaluationContext,
+        pos: usize,
+    ) -> Result<Option<T>, ShellError> {
+        if let Some(expr) = self.nth(pos) {
+            let result = eval_expression(context, &expr)?;
+            FromValue::from_value(&result).map(Some)
+        } else {
+            Ok(None)
+        }
+    }
+
+    fn req<T: FromValue>(&self, context: &EvaluationContext, pos: usize) -> Result<T, ShellError> {
+        if let Some(expr) = self.nth(pos) {
+            let result = eval_expression(context, &expr)?;
+            FromValue::from_value(&result)
+        } else {
+            Err(ShellError::AccessBeyondEnd(
+                self.positional.len(),
+                self.head,
+            ))
+        }
+    }
 }

crates/nu-engine/src/eval.rs

@@ -156,6 +156,10 @@ pub fn eval_expression(
         Expr::Var(var_id) => context
             .get_var(*var_id)
             .map_err(move |_| ShellError::VariableNotFoundAtRuntime(expr.span)),
+        Expr::CellPath(cell_path) => Ok(Value::CellPath {
+            val: cell_path.clone(),
+            span: expr.span,
+        }),
         Expr::FullCellPath(cell_path) => {
             let value = eval_expression(context, &cell_path.head)?;
 

crates/nu-engine/src/from_value.rs

@@ -1,6 +1,7 @@
 // use std::path::PathBuf;
 
 // use nu_path::expand_path;
+use nu_protocol::ast::CellPath;
 use nu_protocol::ShellError;
 use nu_protocol::{Range, Spanned, Value};
 
@@ -110,28 +111,25 @@ impl FromValue for ColumnPath {
     }
 }
 
-impl FromValue for bool {
+*/
+
+impl FromValue for CellPath {
     fn from_value(v: &Value) -> Result<Self, ShellError> {
         match v {
-            Value {
-                value: UntaggedValue::Primitive(Primitive::Boolean(b)),
-                ..
-            } => Ok(*b),
-            Value {
-                value: UntaggedValue::Row(_),
-                ..
-            } => {
-                let mut shell_error = ShellError::type_error("boolean", v.spanned_type_name());
-                shell_error.notes.push(
-                    "Note: you can access columns using dot. eg) $it.column or (ls).column".into(),
-                );
-                Err(shell_error)
-            }
-            v => Err(ShellError::type_error("boolean", v.spanned_type_name())),
+            Value::CellPath { val, .. } => Ok(val.clone()),
+            v => Err(ShellError::CantConvert("cell path".into(), v.span())),
+        }
+    }
+}
+
+impl FromValue for bool {
+    fn from_value(v: &Value) -> Result<Self, ShellError> {
+        match v {
+            Value::Bool { val, .. } => Ok(*val),
+            v => Err(ShellError::CantConvert("bool".into(), v.span())),
         }
     }
 }
-*/
 
 impl FromValue for Spanned<bool> {
     fn from_value(v: &Value) -> Result<Self, ShellError> {

crates/nu-parser/src/flatten.rs

@@ -79,6 +79,16 @@ pub fn flatten_expression(
         Expr::Float(_) => {
             vec![(expr.span, FlatShape::Float)]
         }
+        Expr::CellPath(cell_path) => {
+            let mut output = vec![];
+            for path_element in &cell_path.members {
+                match path_element {
+                    PathMember::String { span, .. } => output.push((*span, FlatShape::String)),
+                    PathMember::Int { span, .. } => output.push((*span, FlatShape::Int)),
+                }
+            }
+            output
+        }
         Expr::FullCellPath(cell_path) => {
             let mut output = vec![];
             output.extend(flatten_expression(working_set, &cell_path.head));

crates/nu-parser/src/parser.rs

@@ -6,8 +6,8 @@ use crate::{
 
 use nu_protocol::{
     ast::{
-        Block, Call, Expr, Expression, FullCellPath, ImportPattern, ImportPatternMember, Operator,
-        PathMember, Pipeline, RangeInclusion, RangeOperator, Statement,
+        Block, Call, CellPath, Expr, Expression, FullCellPath, ImportPattern, ImportPatternMember,
+        Operator, PathMember, Pipeline, RangeInclusion, RangeOperator, Statement,
     },
     engine::StateWorkingSet,
     span, Flag, PositionalArg, Signature, Span, SyntaxShape, Type, VarId,
@@ -1157,6 +1157,62 @@ pub fn parse_variable_expr(
     }
 }
 
+pub fn parse_cell_path(
+    working_set: &mut StateWorkingSet,
+    tokens: impl Iterator<Item = Token>,
+    mut expect_dot: bool,
+    span: Span,
+) -> (Vec<PathMember>, Option<ParseError>) {
+    let mut error = None;
+    let mut tail = vec![];
+
+    for path_element in tokens {
+        let bytes = working_set.get_span_contents(path_element.span);
+
+        if expect_dot {
+            expect_dot = false;
+            if bytes.len() != 1 || bytes[0] != b'.' {
+                error = error.or_else(|| Some(ParseError::Expected('.'.into(), path_element.span)));
+            }
+        } else {
+            expect_dot = true;
+
+            match parse_int(bytes, path_element.span) {
+                (
+                    Expression {
+                        expr: Expr::Int(val),
+                        span,
+                        ..
+                    },
+                    None,
+                ) => tail.push(PathMember::Int {
+                    val: val as usize,
+                    span,
+                }),
+                _ => {
+                    let (result, err) = parse_string(working_set, path_element.span);
+                    error = error.or(err);
+                    match result {
+                        Expression {
+                            expr: Expr::String(string),
+                            span,
+                            ..
+                        } => {
+                            tail.push(PathMember::String { val: string, span });
+                        }
+                        _ => {
+                            error =
+                                error.or_else(|| Some(ParseError::Expected("string".into(), span)));
+                        }
+                    }
+                }
+            }
+        }
+    }
+
+    (tail, error)
+}
+
 pub fn parse_full_cell_path(
     working_set: &mut StateWorkingSet,
     implicit_head: Option<VarId>,
@@ -1173,7 +1229,7 @@ pub fn parse_full_cell_path(
     let mut tokens = tokens.into_iter().peekable();
     if let Some(head) = tokens.peek() {
         let bytes = working_set.get_span_contents(head.span);
-        let (head, mut expect_dot) = if bytes.starts_with(b"(") {
+        let (head, expect_dot) = if bytes.starts_with(b"(") {
             let mut start = head.span.start;
             let mut end = head.span.end;
 
@@ -1247,52 +1303,8 @@ pub fn parse_full_cell_path(
             );
         };
 
-        let mut tail = vec![];
-
-        for path_element in tokens {
-            let bytes = working_set.get_span_contents(path_element.span);
-
-            if expect_dot {
-                expect_dot = false;
-                if bytes.len() != 1 || bytes[0] != b'.' {
-                    error =
-                        error.or_else(|| Some(ParseError::Expected('.'.into(), path_element.span)));
-                }
-            } else {
-                expect_dot = true;
-
-                match parse_int(bytes, path_element.span) {
-                    (
-                        Expression {
-                            expr: Expr::Int(val),
-                            span,
-                            ..
-                        },
-                        None,
-                    ) => tail.push(PathMember::Int {
-                        val: val as usize,
-                        span,
-                    }),
-                    _ => {
-                        let (result, err) = parse_string(working_set, path_element.span);
-                        error = error.or(err);
-                        match result {
-                            Expression {
-                                expr: Expr::String(string),
-                                span,
-                                ..
-                            } => {
-                                tail.push(PathMember::String { val: string, span });
-                            }
-                            _ => {
-                                error = error
-                                    .or_else(|| Some(ParseError::Expected("string".into(), span)));
-                            }
-                        }
-                    }
-                }
-            }
-        }
+        let (tail, err) = parse_cell_path(working_set, tokens, expect_dot, span);
+        error = error.or(err);
 
         (
             Expression {
@@ -2351,6 +2363,28 @@ pub fn parse_value(
                 )
             }
         }
+        SyntaxShape::CellPath => {
+            let source = working_set.get_span_contents(span);
+            let mut error = None;
+
+            let (tokens, err) = lex(source, span.start, &[b'\n'], &[b'.']);
+            error = error.or(err);
+
+            let tokens = tokens.into_iter().peekable();
+
+            let (cell_path, err) = parse_cell_path(working_set, tokens, false, span);
+            error = error.or(err);
+
+            (
+                Expression {
+                    expr: Expr::CellPath(CellPath { members: cell_path }),
+                    span,
+                    ty: Type::CellPath,
+                    custom_completion: None,
+                },
+                error,
+            )
+        }
         SyntaxShape::Any => {
             if bytes.starts_with(b"[") {
                 parse_value(working_set, span, &SyntaxShape::Table)

crates/nu-protocol/src/ast/call.rs

@@ -45,4 +45,8 @@ impl Call {
 
         None
     }
+
+    pub fn nth(&self, pos: usize) -> Option<Expression> {
+        self.positional.get(pos).cloned()
+    }
 }

crates/nu-protocol/src/ast/cell_path.rs

@@ -1,13 +1,14 @@
 use super::Expression;
 use crate::Span;
+use serde::{Deserialize, Serialize};
 
-#[derive(Debug, Clone)]
+#[derive(Debug, Clone, Serialize, Deserialize)]
 pub enum PathMember {
     String { val: String, span: Span },
     Int { val: usize, span: Span },
 }
 
-#[derive(Debug, Clone)]
+#[derive(Debug, Clone, Serialize, Deserialize)]
 pub struct CellPath {
     pub members: Vec<PathMember>,
 }

crates/nu-protocol/src/ast/expr.rs

@@ -1,4 +1,4 @@
-use super::{Call, Expression, FullCellPath, Operator, RangeOperator};
+use super::{Call, CellPath, Expression, FullCellPath, Operator, RangeOperator};
 use crate::{BlockId, Signature, Span, VarId};
 
 #[derive(Debug, Clone)]
@@ -24,6 +24,7 @@ pub enum Expr {
     Table(Vec<Expression>, Vec<Vec<Expression>>),
     Keyword(Vec<u8>, Span, Box<Expression>),
     String(String), // FIXME: improve this in the future?
+    CellPath(CellPath),
     FullCellPath(Box<FullCellPath>),
     Signature(Box<Signature>),
     Garbage,

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

@@ -9,7 +9,7 @@ pub use stream::*;
 
 use std::fmt::Debug;
 
-use crate::ast::PathMember;
+use crate::ast::{CellPath, PathMember};
 use crate::{span, BlockId, Span, Type};
 
 use crate::ShellError;
@@ -72,6 +72,10 @@ pub enum Value {
         val: Vec<u8>,
         span: Span,
     },
+    CellPath {
+        val: CellPath,
+        span: Span,
+    },
 }
 
 impl Value {
@@ -99,6 +103,7 @@ impl Value {
             Value::Stream { span, .. } => *span,
             Value::Nothing { span, .. } => *span,
             Value::Binary { span, .. } => *span,
+            Value::CellPath { span, .. } => *span,
         }
     }
 
@@ -119,6 +124,7 @@ impl Value {
             Value::Nothing { span, .. } => *span = new_span,
             Value::Error { .. } => {}
             Value::Binary { span, .. } => *span = new_span,
+            Value::CellPath { span, .. } => *span = new_span,
         }
 
         self
@@ -143,6 +149,7 @@ impl Value {
             Value::Stream { .. } => Type::ValueStream,
             Value::Error { .. } => Type::Error,
             Value::Binary { .. } => Type::Binary,
+            Value::CellPath { .. } => Type::CellPath,
         }
     }
 
@@ -184,6 +191,7 @@ impl Value {
             Value::Nothing { .. } => String::new(),
             Value::Error { error } => format!("{:?}", error),
             Value::Binary { val, .. } => format!("{:?}", val),
+            Value::CellPath { val, .. } => format!("{:?}", val),
         }
     }
 
@@ -215,6 +223,7 @@ impl Value {
             Value::Nothing { .. } => String::new(),
             Value::Error { error } => format!("{:?}", error),
             Value::Binary { val, .. } => format!("{:?}", val),
+            Value::CellPath { val, .. } => format!("{:?}", val),
         }
     }
 

crates/nu-table/src/table.rs

@@ -240,6 +240,10 @@ impl TextStyle {
             .bold(Some(true))
     }
 
+    pub fn default_field() -> TextStyle {
+        TextStyle::new().fg(Color::Green).bold(Some(true))
+    }
+
     pub fn with_attributes(bo: bool, al: Alignment, co: Color) -> TextStyle {
         TextStyle::new().alignment(al).fg(co).bold(Some(bo))
     }

src/tests.rs

@@ -396,3 +396,16 @@ fn from_json_2() -> TestResult {
         "Sally",
     )
 }
+
+#[test]
+fn wrap() -> TestResult {
+    run_test(r#"([1, 2, 3] | wrap foo).foo.1"#, "2")
+}
+
+#[test]
+fn get() -> TestResult {
+    run_test(
+        r#"[[name, grade]; [Alice, A], [Betty, B]] | get grade.1"#,
+        "B",
+    )
+}