Add a simple scope variable

Cargo.lock

@@ -163,6 +163,28 @@ dependencies = [
  "chrono",
 ]
 
+[[package]]
+name = "chrono-tz"
+version = "0.6.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "64c01c1c607d25c71bbaa67c113d6c6b36c434744b4fd66691d711b5b1bc0c8b"
+dependencies = [
+ "chrono",
+ "chrono-tz-build",
+ "phf",
+]
+
+[[package]]
+name = "chrono-tz-build"
+version = "0.0.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "db058d493fb2f65f41861bfed7e3fe6335264a9f0f92710cab5bdf01fef09069"
+dependencies = [
+ "parse-zoneinfo",
+ "phf",
+ "phf_codegen",
+]
+
 [[package]]
 name = "console"
 version = "0.15.0"
@@ -622,6 +644,8 @@ version = "0.1.0"
 dependencies = [
  "bytesize",
  "chrono",
+ "chrono-humanize",
+ "chrono-tz",
  "dialoguer",
  "glob",
  "lscolors",
@@ -636,6 +660,7 @@ dependencies = [
  "sysinfo",
  "terminal_size",
  "thiserror",
+ "titlecase",
  "trash",
  "unicode-segmentation",
 ]
@@ -801,6 +826,54 @@ dependencies = [
  "winapi",
 ]
 
+[[package]]
+name = "parse-zoneinfo"
+version = "0.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c705f256449c60da65e11ff6626e0c16a0a0b96aaa348de61376b249bc340f41"
+dependencies = [
+ "regex",
+]
+
+[[package]]
+name = "phf"
+version = "0.10.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b9fc3db1018c4b59d7d582a739436478b6035138b6aecbce989fc91c3e98409f"
+dependencies = [
+ "phf_shared",
+]
+
+[[package]]
+name = "phf_codegen"
+version = "0.10.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4fb1c3a8bc4dd4e5cfce29b44ffc14bedd2ee294559a294e2a4d4c9e9a6a13cd"
+dependencies = [
+ "phf_generator",
+ "phf_shared",
+]
+
+[[package]]
+name = "phf_generator"
+version = "0.10.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5d5285893bb5eb82e6aaf5d59ee909a06a16737a8970984dd7746ba9283498d6"
+dependencies = [
+ "phf_shared",
+ "rand",
+]
+
+[[package]]
+name = "phf_shared"
+version = "0.10.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b6796ad771acdc0123d2a88dc428b5e38ef24456743ddb1744ed628f9815c096"
+dependencies = [
+ "siphasher",
+ "uncased",
+]
+
 [[package]]
 name = "ppv-lite86"
 version = "0.2.15"
@@ -1096,6 +1169,12 @@ dependencies = [
  "libc",
 ]
 
+[[package]]
+name = "siphasher"
+version = "0.3.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "533494a8f9b724d33625ab53c6c4800f7cc445895924a8ef649222dcb76e938b"
+
 [[package]]
 name = "sized-chunks"
 version = "0.6.5"
@@ -1263,6 +1342,16 @@ dependencies = [
  "winapi",
 ]
 
+[[package]]
+name = "titlecase"
+version = "1.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f565e410cfc24c2f2a89960b023ca192689d7f77d3f8d4f4af50c2d8affe1117"
+dependencies = [
+ "lazy_static",
+ "regex",
+]
+
 [[package]]
 name = "trash"
 version = "1.3.0"
@@ -1278,6 +1367,15 @@ version = "1.14.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "b63708a265f51345575b27fe43f9500ad611579e764c79edbc2037b1121959ec"
 
+[[package]]
+name = "uncased"
+version = "0.9.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5baeed7327e25054889b9bd4f975f32e5f4c5d434042d59ab6cd4142c0a76ed0"
+dependencies = [
+ "version_check",
+]
+
 [[package]]
 name = "unicode-linebreak"
 version = "0.1.2"

crates/nu-command/src/default_context.rs

@@ -95,16 +95,6 @@ pub fn create_default_context() -> EngineState {
 
         let sig = Signature::build("exit");
         working_set.add_decl(sig.predeclare());
-        let sig = Signature::build("vars");
-        working_set.add_decl(sig.predeclare());
-        let sig = Signature::build("decls");
-        working_set.add_decl(sig.predeclare());
-        let sig = Signature::build("blocks");
-        working_set.add_decl(sig.predeclare());
-        let sig = Signature::build("stack");
-        working_set.add_decl(sig.predeclare());
-        let sig = Signature::build("contents");
-        working_set.add_decl(sig.predeclare());
 
         working_set.render()
     };

crates/nu-engine/src/eval.rs

@@ -371,12 +371,12 @@ pub fn eval_block(
 }
 
 pub fn eval_variable(
-    _engine_state: &EngineState,
+    engine_state: &EngineState,
     stack: &Stack,
     var_id: VarId,
     span: Span,
 ) -> Result<Value, ShellError> {
-    if var_id == 0 {
+    if var_id == nu_protocol::NU_VARIABLE_ID {
         // $nu
         let mut output_cols = vec![];
         let mut output_vals = vec![];
@@ -425,6 +425,71 @@ pub fn eval_variable(
             output_vals.push(Value::String { val: cwd, span })
         }
 
+        Ok(Value::Record {
+            cols: output_cols,
+            vals: output_vals,
+            span,
+        })
+    } else if var_id == nu_protocol::SCOPE_VARIABLE_ID {
+        let mut output_cols = vec![];
+        let mut output_vals = vec![];
+
+        let mut vars = vec![];
+        let mut commands = vec![];
+        let mut aliases = vec![];
+        let mut modules = vec![];
+
+        for frame in &engine_state.scope {
+            for var in &frame.vars {
+                vars.push(Value::String {
+                    val: String::from_utf8_lossy(var.0).to_string(),
+                    span,
+                });
+            }
+
+            for command in &frame.decls {
+                commands.push(Value::String {
+                    val: String::from_utf8_lossy(command.0).to_string(),
+                    span,
+                });
+            }
+
+            for alias in &frame.aliases {
+                aliases.push(Value::String {
+                    val: String::from_utf8_lossy(alias.0).to_string(),
+                    span,
+                });
+            }
+
+            for module in &frame.modules {
+                modules.push(Value::String {
+                    val: String::from_utf8_lossy(module.0).to_string(),
+                    span,
+                });
+            }
+        }
+
+        output_cols.push("vars".to_string());
+        output_vals.push(Value::List { vals: vars, span });
+
+        output_cols.push("commands".to_string());
+        output_vals.push(Value::List {
+            vals: commands,
+            span,
+        });
+
+        output_cols.push("aliases".to_string());
+        output_vals.push(Value::List {
+            vals: aliases,
+            span,
+        });
+
+        output_cols.push("modules".to_string());
+        output_vals.push(Value::List {
+            vals: modules,
+            span,
+        });
+
         Ok(Value::Record {
             cols: output_cols,
             vals: output_vals,

crates/nu-parser/src/parser.rs

@@ -1198,7 +1198,17 @@ pub fn parse_variable_expr(
     } else if contents == b"$nu" {
         return (
             Expression {
-                expr: Expr::Var(0),
+                expr: Expr::Var(nu_protocol::NU_VARIABLE_ID),
+                span,
+                ty: Type::Unknown,
+                custom_completion: None,
+            },
+            None,
+        );
+    } else if contents == b"$scope" {
+        return (
+            Expression {
+                expr: Expr::Var(nu_protocol::SCOPE_VARIABLE_ID),
                 span,
                 ty: Type::Unknown,
                 custom_completion: None,

crates/nu-protocol/src/engine/engine_state.rs

@@ -6,17 +6,6 @@ use std::{
     sync::{atomic::AtomicBool, Arc},
 };
 
-#[derive(Clone)]
-pub struct EngineState {
-    files: im::Vector<(String, usize, usize)>,
-    file_contents: im::Vector<(Vec<u8>, usize, usize)>,
-    vars: im::Vector<Type>,
-    decls: im::Vector<Box<dyn Command + 'static>>,
-    blocks: im::Vector<Block>,
-    pub scope: im::Vector<ScopeFrame>,
-    pub ctrlc: Option<Arc<AtomicBool>>,
-}
-
 // Tells whether a decl etc. is visible or not
 // TODO: When adding new exportables (env vars, aliases, etc.), parametrize the ID type with generics
 #[derive(Debug, Clone)]
@@ -62,9 +51,9 @@ impl Visibility {
 pub struct ScopeFrame {
     pub vars: HashMap<Vec<u8>, VarId>,
     predecls: HashMap<Vec<u8>, DeclId>, // temporary storage for predeclarations
-    decls: HashMap<Vec<u8>, DeclId>,
-    aliases: HashMap<Vec<u8>, Vec<Span>>,
-    modules: HashMap<Vec<u8>, BlockId>,
+    pub decls: HashMap<Vec<u8>, DeclId>,
+    pub aliases: HashMap<Vec<u8>, Vec<Span>>,
+    pub modules: HashMap<Vec<u8>, BlockId>,
     visibility: Visibility,
 }
 
@@ -91,18 +80,26 @@ impl Default for ScopeFrame {
     }
 }
 
-impl Default for EngineState {
-    fn default() -> Self {
-        Self::new()
-    }
+#[derive(Clone)]
+pub struct EngineState {
+    files: im::Vector<(String, usize, usize)>,
+    file_contents: im::Vector<(Vec<u8>, usize, usize)>,
+    vars: im::Vector<Type>,
+    decls: im::Vector<Box<dyn Command + 'static>>,
+    blocks: im::Vector<Block>,
+    pub scope: im::Vector<ScopeFrame>,
+    pub ctrlc: Option<Arc<AtomicBool>>,
 }
 
+pub const NU_VARIABLE_ID: usize = 0;
+pub const SCOPE_VARIABLE_ID: usize = 1;
+
 impl EngineState {
     pub fn new() -> Self {
         Self {
             files: im::vector![],
             file_contents: im::vector![],
-            vars: im::vector![Type::Unknown],
+            vars: im::vector![Type::Unknown, Type::Unknown],
             decls: im::vector![],
             blocks: im::vector![],
             scope: im::vector![ScopeFrame::new()],
@@ -319,6 +316,12 @@ impl EngineState {
     }
 }
 
+impl Default for EngineState {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
 pub struct StateWorkingSet<'a> {
     pub permanent_state: &'a EngineState,
     pub delta: StateDelta,

crates/nu-protocol/src/lib.rs

@@ -11,6 +11,7 @@ mod ty;
 mod value;
 pub use value::Value;
 
+pub use engine::{NU_VARIABLE_ID, SCOPE_VARIABLE_ID};
 pub use example::*;
 pub use id::*;
 pub use pipeline_data::*;

src/main.rs

@@ -225,21 +225,6 @@ fn main() -> Result<()> {
                 Ok(Signal::Success(s)) => {
                     if s.trim() == "exit" {
                         break;
-                    } else if s.trim() == "vars" {
-                        engine_state.print_vars();
-                        continue;
-                    } else if s.trim() == "decls" {
-                        engine_state.print_decls();
-                        continue;
-                    } else if s.trim() == "blocks" {
-                        engine_state.print_blocks();
-                        continue;
-                    } else if s.trim() == "stack" {
-                        stack.print_stack();
-                        continue;
-                    } else if s.trim() == "contents" {
-                        engine_state.print_contents();
-                        continue;
                     }
 
                     eval_source(

src/tests.rs

@@ -801,3 +801,8 @@ fn long_flag() -> TestResult {
 fn help_works_with_missing_requirements() -> TestResult {
     run_test(r#"each --help | lines | length"#, "10")
 }
+
+#[test]
+fn scope_variable() -> TestResult {
+    run_test(r"let x = 3; $scope.vars.0", "$x")
+}