simple keybinding parsing (#768)

Cargo.lock

@@ -2851,7 +2851,7 @@ dependencies = [
 [[package]]
 name = "reedline"
 version = "0.2.0"
-source = "git+https://github.com/nushell/reedline?branch=main#32338dc18aaa1633bf636717c334f22dae8e374a"
+source = "git+https://github.com/nushell/reedline?branch=main#b0ff0eb4d1f062a03b76ef0ac28a2ccaada32a52"
 dependencies = [
  "chrono",
  "crossterm",

crates/nu-protocol/src/config.rs

@@ -38,6 +38,37 @@ impl EnvConversion {
     }
 }
 
+/// Definition of a parsed keybinding from the config object
+#[derive(Serialize, Deserialize, Clone, Debug)]
+pub struct ParsedKeybinding {
+    pub modifier: String,
+    pub keycode: String,
+    pub event: EventType,
+    pub mode: EventMode,
+}
+
+impl Default for ParsedKeybinding {
+    fn default() -> Self {
+        Self {
+            modifier: "".to_string(),
+            keycode: "".to_string(),
+            event: EventType::Single("".to_string()),
+            mode: EventMode::Emacs,
+        }
+    }
+}
+
+#[derive(Serialize, Deserialize, Clone, Debug)]
+pub enum EventType {
+    Single(String),
+}
+
+#[derive(Serialize, Deserialize, Clone, Debug)]
+pub enum EventMode {
+    Emacs,
+    Vi,
+}
+
 #[derive(Serialize, Deserialize, Clone, Debug)]
 pub struct Config {
     pub filesize_metric: bool,
@@ -55,6 +86,7 @@ pub struct Config {
     pub max_history_size: i64,
     pub log_level: String,
     pub menu_config: HashMap<String, Value>,
+    pub keybindings: Vec<ParsedKeybinding>,
 }
 
 impl Default for Config {
@@ -75,6 +107,7 @@ impl Default for Config {
             max_history_size: 1000,
             log_level: String::new(),
             menu_config: HashMap::new(),
+            keybindings: Vec::new(),
         }
     }
 }
@@ -161,6 +194,7 @@ impl Value {
                 "menu_config" => {
                     config.menu_config = create_map(value, &config)?;
                 }
+                "keybindings" => config.keybindings = create_keybindings(value, &config)?,
                 _ => {}
             }
         }
@@ -180,6 +214,24 @@ fn create_map(value: &Value, config: &Config) -> Result<HashMap<String, Value>,
                 vals: inner_vals,
                 span,
             } => {
+                let val = color_value_string(span, inner_cols, inner_vals, config);
+                hm.insert(k.to_string(), val);
+            }
+            _ => {
+                hm.insert(k.to_string(), v.clone());
+            }
+        }
+    }
+
+    Ok(hm)
+}
+
+fn color_value_string(
+    span: &Span,
+    inner_cols: &[String],
+    inner_vals: &[Value],
+    config: &Config,
+) -> Value {
     // make a string from our config.color_config section that
     // looks like this: { fg: "#rrggbb" bg: "#rrggbb" attr: "abc", }
     // the real key here was to have quotes around the values but not
@@ -187,7 +239,6 @@ fn create_map(value: &Value, config: &Config) -> Result<HashMap<String, Value>,
 
     // maybe there's a better way to generate this but i'm not sure
     // what it is.
-                let key = k.to_string();
     let val: String = inner_cols
         .iter()
         .zip(inner_vals)
@@ -198,18 +249,109 @@ fn create_map(value: &Value, config: &Config) -> Result<HashMap<String, Value>,
         .collect();
 
     // now insert the braces at the front and the back to fake the json string
-                let val = Value::String {
+    Value::String {
         val: format!("{{{}}}", val),
         span: *span,
-                };
-
-                hm.insert(key, val);
     }
-            _ => {
-                hm.insert(k.to_string(), v.clone());
-            }
-        }
-    }
-
-    Ok(hm)
+}
+
+// Parses the config object to extract the strings that will compose a keybinding for reedline
+fn create_keybindings(value: &Value, config: &Config) -> Result<Vec<ParsedKeybinding>, ShellError> {
+    match value {
+        Value::Record { cols, vals, .. } => {
+            let mut keybinding = ParsedKeybinding::default();
+
+            for (col, val) in cols.iter().zip(vals.iter()) {
+                match col.as_str() {
+                    "modifier" => keybinding.modifier = val.clone().into_string("", config),
+                    "keycode" => keybinding.keycode = val.clone().into_string("", config),
+                    "mode" => {
+                        keybinding.mode = match val.clone().into_string("", config).as_str() {
+                            "emacs" => EventMode::Emacs,
+                            "vi" => EventMode::Vi,
+                            e => {
+                                return Err(ShellError::UnsupportedConfigValue(
+                                    "emacs or vi".to_string(),
+                                    e.to_string(),
+                                    val.span()?,
+                                ))
+                            }
+                        };
+                    }
+                    "event" => match val {
+                        Value::Record {
+                            cols: event_cols,
+                            vals: event_vals,
+                            span: event_span,
+                        } => {
+                            let event_type_idx = event_cols
+                                .iter()
+                                .position(|key| key == "type")
+                                .ok_or_else(|| {
+                                    ShellError::MissingConfigValue("type".to_string(), *event_span)
+                                })?;
+
+                            let event_idx = event_cols
+                                .iter()
+                                .position(|key| key == "event")
+                                .ok_or_else(|| {
+                                    ShellError::MissingConfigValue("event".to_string(), *event_span)
+                                })?;
+
+                            let event_type =
+                                event_vals[event_type_idx].clone().into_string("", config);
+
+                            // Extracting the event type information from the record based on the type
+                            match event_type.as_str() {
+                                "single" => {
+                                    let event_value =
+                                        event_vals[event_idx].clone().into_string("", config);
+
+                                    keybinding.event = EventType::Single(event_value)
+                                }
+                                e => {
+                                    return Err(ShellError::UnsupportedConfigValue(
+                                        "single".to_string(),
+                                        e.to_string(),
+                                        *event_span,
+                                    ))
+                                }
+                            };
+                        }
+                        e => {
+                            return Err(ShellError::UnsupportedConfigValue(
+                                "record type".to_string(),
+                                format!("{:?}", e.get_type()),
+                                e.span()?,
+                            ))
+                        }
+                    },
+                    "name" => {} // don't need to store name
+                    e => {
+                        return Err(ShellError::UnsupportedConfigValue(
+                            "name, mode, modifier, keycode or event".to_string(),
+                            e.to_string(),
+                            val.span()?,
+                        ))
+                    }
+                }
+            }
+
+            Ok(vec![keybinding])
+        }
+        Value::List { vals, .. } => {
+            let res = vals
+                .iter()
+                .map(|inner_value| create_keybindings(inner_value, config))
+                .collect::<Result<Vec<Vec<ParsedKeybinding>>, ShellError>>();
+
+            let res = res?
+                .into_iter()
+                .flatten()
+                .collect::<Vec<ParsedKeybinding>>();
+
+            Ok(res)
+        }
+        _ => Ok(Vec::new()),
+    }
 }

src/config_files.rs

@@ -0,0 +1,83 @@
+use crate::utils::{eval_source, report_error};
+use nu_protocol::engine::{EngineState, Stack, StateDelta, StateWorkingSet};
+use std::path::PathBuf;
+
+const NUSHELL_FOLDER: &str = "nushell";
+const PLUGIN_FILE: &str = "plugin.nu";
+const CONFIG_FILE: &str = "config.nu";
+const HISTORY_FILE: &str = "history.txt";
+
+pub(crate) fn read_plugin_file(engine_state: &mut EngineState, stack: &mut Stack) {
+    // Reading signatures from signature file
+    // The plugin.nu file stores the parsed signature collected from each registered plugin
+    if let Some(mut plugin_path) = nu_path::config_dir() {
+        // Path to store plugins signatures
+        plugin_path.push(NUSHELL_FOLDER);
+        plugin_path.push(PLUGIN_FILE);
+        engine_state.plugin_signatures = Some(plugin_path.clone());
+
+        let plugin_filename = plugin_path.to_string_lossy().to_owned();
+
+        if let Ok(contents) = std::fs::read_to_string(&plugin_path) {
+            eval_source(engine_state, stack, &contents, &plugin_filename);
+        }
+    }
+}
+
+pub(crate) fn read_config_file(engine_state: &mut EngineState, stack: &mut Stack) {
+    // Load config startup file
+    if let Some(mut config_path) = nu_path::config_dir() {
+        config_path.push(NUSHELL_FOLDER);
+
+        // Create config directory if it does not exist
+        if !config_path.exists() {
+            if let Err(err) = std::fs::create_dir_all(&config_path) {
+                eprintln!("Failed to create config directory: {}", err);
+            }
+        } else {
+            config_path.push(CONFIG_FILE);
+
+            if config_path.exists() {
+                // FIXME: remove this message when we're ready
+                println!("Loading config from: {:?}", config_path);
+                let config_filename = config_path.to_string_lossy().to_owned();
+
+                if let Ok(contents) = std::fs::read_to_string(&config_path) {
+                    eval_source(engine_state, stack, &contents, &config_filename);
+                    // Merge the delta in case env vars changed in the config
+                    match nu_engine::env::current_dir(engine_state, stack) {
+                        Ok(cwd) => {
+                            if let Err(e) =
+                                engine_state.merge_delta(StateDelta::new(), Some(stack), cwd)
+                            {
+                                let working_set = StateWorkingSet::new(engine_state);
+                                report_error(&working_set, &e);
+                            }
+                        }
+                        Err(e) => {
+                            let working_set = StateWorkingSet::new(engine_state);
+                            report_error(&working_set, &e);
+                        }
+                    }
+                }
+            }
+        }
+    }
+}
+
+pub(crate) fn create_history_path() -> Option<PathBuf> {
+    nu_path::config_dir().and_then(|mut history_path| {
+        history_path.push(NUSHELL_FOLDER);
+        history_path.push(HISTORY_FILE);
+
+        if !history_path.exists() {
+            // Creating an empty file to store the history
+            match std::fs::File::create(&history_path) {
+                Ok(_) => Some(history_path),
+                Err(_) => None,
+            }
+        } else {
+            Some(history_path)
+        }
+    })
+}

src/eval_file.rs

@@ -0,0 +1,167 @@
+use log::trace;
+use miette::{IntoDiagnostic, Result};
+use nu_engine::{convert_env_values, eval_block};
+use nu_parser::parse;
+use nu_protocol::{
+    engine::{EngineState, StateDelta, StateWorkingSet},
+    Config, PipelineData, Span, Value, CONFIG_VARIABLE_ID,
+};
+use std::path::PathBuf;
+
+use crate::utils::{gather_parent_env_vars, report_error};
+
+/// Main function used when a file path is found as argument for nu
+pub(crate) fn evaluate(
+    path: String,
+    init_cwd: PathBuf,
+    engine_state: &mut EngineState,
+) -> Result<()> {
+    // First, set up env vars as strings only
+    gather_parent_env_vars(engine_state);
+
+    let file = std::fs::read(&path).into_diagnostic()?;
+
+    let (block, delta) = {
+        let mut working_set = StateWorkingSet::new(engine_state);
+        trace!("parsing file: {}", path);
+
+        let (output, err) = parse(&mut working_set, Some(&path), &file, false);
+        if let Some(err) = err {
+            report_error(&working_set, &err);
+
+            std::process::exit(1);
+        }
+        (output, working_set.render())
+    };
+
+    if let Err(err) = engine_state.merge_delta(delta, None, &init_cwd) {
+        let working_set = StateWorkingSet::new(engine_state);
+        report_error(&working_set, &err);
+    }
+
+    let mut stack = nu_protocol::engine::Stack::new();
+
+    // Set up our initial config to start from
+    stack.vars.insert(
+        CONFIG_VARIABLE_ID,
+        Value::Record {
+            cols: vec![],
+            vals: vec![],
+            span: Span { start: 0, end: 0 },
+        },
+    );
+
+    let config = match stack.get_config() {
+        Ok(config) => config,
+        Err(e) => {
+            let working_set = StateWorkingSet::new(engine_state);
+
+            report_error(&working_set, &e);
+            Config::default()
+        }
+    };
+
+    // Merge the delta in case env vars changed in the config
+    match nu_engine::env::current_dir(engine_state, &stack) {
+        Ok(cwd) => {
+            if let Err(e) = engine_state.merge_delta(StateDelta::new(), Some(&mut stack), cwd) {
+                let working_set = StateWorkingSet::new(engine_state);
+                report_error(&working_set, &e);
+            }
+        }
+        Err(e) => {
+            let working_set = StateWorkingSet::new(engine_state);
+            report_error(&working_set, &e);
+        }
+    }
+
+    // Translate environment variables from Strings to Values
+    if let Some(e) = convert_env_values(engine_state, &stack, &config) {
+        let working_set = StateWorkingSet::new(engine_state);
+        report_error(&working_set, &e);
+        std::process::exit(1);
+    }
+
+    match eval_block(
+        engine_state,
+        &mut stack,
+        &block,
+        PipelineData::new(Span::new(0, 0)), // Don't try this at home, 0 span is ignored
+    ) {
+        Ok(pipeline_data) => {
+            for item in pipeline_data {
+                if let Value::Error { error } = item {
+                    let working_set = StateWorkingSet::new(engine_state);
+
+                    report_error(&working_set, &error);
+
+                    std::process::exit(1);
+                }
+                println!("{}", item.into_string("\n", &config));
+            }
+
+            // Next, let's check if there are any flags we want to pass to the main function
+            let args: Vec<String> = std::env::args().skip(2).collect();
+
+            if args.is_empty() && engine_state.find_decl(b"main").is_none() {
+                return Ok(());
+            }
+
+            let args = format!("main {}", args.join(" ")).as_bytes().to_vec();
+
+            let (block, delta) = {
+                let mut working_set = StateWorkingSet::new(engine_state);
+                let (output, err) = parse(&mut working_set, Some("<cmdline>"), &args, false);
+                if let Some(err) = err {
+                    report_error(&working_set, &err);
+
+                    std::process::exit(1);
+                }
+                (output, working_set.render())
+            };
+
+            let cwd = nu_engine::env::current_dir_str(engine_state, &stack)?;
+
+            if let Err(err) = engine_state.merge_delta(delta, Some(&mut stack), &cwd) {
+                let working_set = StateWorkingSet::new(engine_state);
+                report_error(&working_set, &err);
+            }
+
+            match eval_block(
+                engine_state,
+                &mut stack,
+                &block,
+                PipelineData::new(Span::new(0, 0)), // Don't try this at home, 0 span is ignored
+            ) {
+                Ok(pipeline_data) => {
+                    for item in pipeline_data {
+                        if let Value::Error { error } = item {
+                            let working_set = StateWorkingSet::new(engine_state);
+
+                            report_error(&working_set, &error);
+
+                            std::process::exit(1);
+                        }
+                        println!("{}", item.into_string("\n", &config));
+                    }
+                }
+                Err(err) => {
+                    let working_set = StateWorkingSet::new(engine_state);
+
+                    report_error(&working_set, &err);
+
+                    std::process::exit(1);
+                }
+            }
+        }
+        Err(err) => {
+            let working_set = StateWorkingSet::new(engine_state);
+
+            report_error(&working_set, &err);
+
+            std::process::exit(1);
+        }
+    }
+
+    Ok(())
+}

src/fuzzy_completion.rs

@@ -0,0 +1,57 @@
+use dialoguer::{
+    console::{Style, Term},
+    theme::ColorfulTheme,
+    Select,
+};
+use reedline::{Completer, CompletionActionHandler, LineBuffer};
+
+pub(crate) struct FuzzyCompletion {
+    pub completer: Box<dyn Completer>,
+}
+
+impl CompletionActionHandler for FuzzyCompletion {
+    fn handle(&mut self, present_buffer: &mut LineBuffer) {
+        let completions = self
+            .completer
+            .complete(present_buffer.get_buffer(), present_buffer.offset());
+
+        if completions.is_empty() {
+            // do nothing
+        } else if completions.len() == 1 {
+            let span = completions[0].0;
+
+            let mut offset = present_buffer.offset();
+            offset += completions[0].1.len() - (span.end - span.start);
+
+            // TODO improve the support for multiline replace
+            present_buffer.replace(span.start..span.end, &completions[0].1);
+            present_buffer.set_insertion_point(offset);
+        } else {
+            let selections: Vec<_> = completions.iter().map(|(_, string)| string).collect();
+
+            let _ = crossterm::terminal::disable_raw_mode();
+            println!();
+            let theme = ColorfulTheme {
+                active_item_style: Style::new().for_stderr().on_green().black(),
+                ..Default::default()
+            };
+            let result = Select::with_theme(&theme)
+                .default(0)
+                .items(&selections[..])
+                .interact_on_opt(&Term::stdout())
+                .unwrap_or(None);
+            let _ = crossterm::terminal::enable_raw_mode();
+
+            if let Some(result) = result {
+                let span = completions[result].0;
+
+                let mut offset = present_buffer.offset();
+                offset += completions[result].1.len() - (span.end - span.start);
+
+                // TODO improve the support for multiline replace
+                present_buffer.replace(span.start..span.end, &completions[result].1);
+                present_buffer.set_insertion_point(offset);
+            }
+        }
+    }
+}

src/prompt_update.rs

@@ -0,0 +1,99 @@
+use nu_cli::NushellPrompt;
+use nu_engine::eval_block;
+use nu_protocol::{
+    engine::{EngineState, Stack},
+    Config, PipelineData, Span,
+};
+use reedline::Prompt;
+
+// Name of environment variable where the prompt could be stored
+pub(crate) const PROMPT_COMMAND: &str = "PROMPT_COMMAND";
+pub(crate) const PROMPT_COMMAND_RIGHT: &str = "PROMPT_COMMAND_RIGHT";
+pub(crate) const PROMPT_INDICATOR: &str = "PROMPT_INDICATOR";
+pub(crate) const PROMPT_INDICATOR_VI_INSERT: &str = "PROMPT_INDICATOR_VI_INSERT";
+pub(crate) const PROMPT_INDICATOR_VI_VISUAL: &str = "PROMPT_INDICATOR_VI_VISUAL";
+pub(crate) const PROMPT_MULTILINE_INDICATOR: &str = "PROMPT_MULTILINE_INDICATOR";
+
+pub(crate) fn get_prompt_indicators(
+    config: &Config,
+    engine_state: &EngineState,
+    stack: &Stack,
+) -> (String, String, String, String) {
+    let prompt_indicator = match stack.get_env_var(engine_state, PROMPT_INDICATOR) {
+        Some(pi) => pi.into_string("", config),
+        None => "〉".to_string(),
+    };
+
+    let prompt_vi_insert = match stack.get_env_var(engine_state, PROMPT_INDICATOR_VI_INSERT) {
+        Some(pvii) => pvii.into_string("", config),
+        None => ": ".to_string(),
+    };
+
+    let prompt_vi_visual = match stack.get_env_var(engine_state, PROMPT_INDICATOR_VI_VISUAL) {
+        Some(pviv) => pviv.into_string("", config),
+        None => "v ".to_string(),
+    };
+
+    let prompt_multiline = match stack.get_env_var(engine_state, PROMPT_MULTILINE_INDICATOR) {
+        Some(pm) => pm.into_string("", config),
+        None => "::: ".to_string(),
+    };
+
+    (
+        prompt_indicator,
+        prompt_vi_insert,
+        prompt_vi_visual,
+        prompt_multiline,
+    )
+}
+
+fn get_prompt_string(
+    prompt: &str,
+    config: &Config,
+    engine_state: &EngineState,
+    stack: &mut Stack,
+) -> Option<String> {
+    stack
+        .get_env_var(engine_state, prompt)
+        .and_then(|v| v.as_block().ok())
+        .and_then(|block_id| {
+            let block = engine_state.get_block(block_id);
+            eval_block(
+                engine_state,
+                stack,
+                block,
+                PipelineData::new(Span::new(0, 0)), // Don't try this at home, 0 span is ignored
+            )
+            .ok()
+        })
+        .and_then(|pipeline_data| pipeline_data.collect_string("", config).ok())
+}
+
+pub(crate) fn update_prompt<'prompt>(
+    config: &Config,
+    engine_state: &EngineState,
+    stack: &Stack,
+    nu_prompt: &'prompt mut NushellPrompt,
+) -> &'prompt dyn Prompt {
+    // get the other indicators
+    let (
+        prompt_indicator_string,
+        prompt_vi_insert_string,
+        prompt_vi_visual_string,
+        prompt_multiline_string,
+    ) = get_prompt_indicators(config, engine_state, stack);
+
+    let mut stack = stack.clone();
+
+    // apply the other indicators
+    nu_prompt.update_all_prompt_strings(
+        get_prompt_string(PROMPT_COMMAND, config, engine_state, &mut stack),
+        get_prompt_string(PROMPT_COMMAND_RIGHT, config, engine_state, &mut stack),
+        prompt_indicator_string,
+        prompt_vi_insert_string,
+        prompt_vi_visual_string,
+        prompt_multiline_string,
+    );
+
+    nu_prompt as &dyn Prompt
+}

src/reedline_config.rs

@@ -0,0 +1,104 @@
+use crossterm::event::{KeyCode, KeyModifiers};
+use nu_color_config::lookup_ansi_color_style;
+use nu_protocol::{Config, EventType, ParsedKeybinding, ShellError};
+use reedline::{
+    default_emacs_keybindings, ContextMenuInput, EditCommand, Keybindings, ReedlineEvent,
+};
+
+// This creates an input object for the context menu based on the dictionary
+// stored in the config variable
+pub(crate) fn create_menu_input(config: &Config) -> ContextMenuInput {
+    let mut input = ContextMenuInput::default();
+
+    input = match config
+        .menu_config
+        .get("columns")
+        .and_then(|value| value.as_integer().ok())
+    {
+        Some(value) => input.with_columns(value as u16),
+        None => input,
+    };
+
+    input = input.with_col_width(
+        config
+            .menu_config
+            .get("col_width")
+            .and_then(|value| value.as_integer().ok())
+            .map(|value| value as usize),
+    );
+
+    input = match config
+        .menu_config
+        .get("col_padding")
+        .and_then(|value| value.as_integer().ok())
+    {
+        Some(value) => input.with_col_padding(value as usize),
+        None => input,
+    };
+
+    input = match config
+        .menu_config
+        .get("text_style")
+        .and_then(|value| value.as_string().ok())
+    {
+        Some(value) => input.with_text_style(lookup_ansi_color_style(&value)),
+        None => input,
+    };
+
+    input = match config
+        .menu_config
+        .get("selected_text_style")
+        .and_then(|value| value.as_string().ok())
+    {
+        Some(value) => input.with_selected_text_style(lookup_ansi_color_style(&value)),
+        None => input,
+    };
+
+    input
+}
+
+pub(crate) fn create_keybindings(
+    parsed_keybindings: &[ParsedKeybinding],
+) -> Result<Keybindings, ShellError> {
+    let mut keybindings = default_emacs_keybindings();
+
+    // temporal keybinding with multiple events
+    keybindings.add_binding(
+        KeyModifiers::SHIFT,
+        KeyCode::BackTab,
+        ReedlineEvent::Multiple(vec![
+            ReedlineEvent::Edit(vec![EditCommand::InsertChar('p')]),
+            ReedlineEvent::Enter,
+        ]),
+    );
+
+    for keybinding in parsed_keybindings {
+        let modifier = match keybinding.modifier.as_str() {
+            "CONTROL" => KeyModifiers::CONTROL,
+            "SHIFT" => KeyModifiers::CONTROL,
+            _ => unimplemented!(),
+        };
+
+        let keycode = match keybinding.keycode.as_str() {
+            c if c.starts_with("Char_") => {
+                let char = c.replace("Char_", "");
+                let char = char.chars().next().expect("correct");
+                KeyCode::Char(char)
+            }
+            "down" => KeyCode::Down,
+            _ => unimplemented!(),
+        };
+
+        let event = match &keybinding.event {
+            EventType::Single(name) => match name.as_str() {
+                "Complete" => ReedlineEvent::Complete,
+                "ContextMenu" => ReedlineEvent::ContextMenu,
+                _ => unimplemented!(),
+            },
+        };
+
+        keybindings.add_binding(modifier, keycode, event);
+    }
+
+    Ok(keybindings)
+}

src/repl.rs

@@ -0,0 +1,257 @@
+use std::sync::{
+    atomic::{AtomicBool, Ordering},
+    Arc,
+};
+
+use crate::utils::{eval_source, gather_parent_env_vars, report_error};
+use crate::{config_files, prompt_update, reedline_config};
+use log::trace;
+use miette::{IntoDiagnostic, Result};
+use nu_cli::{NuCompleter, NuHighlighter, NuValidator, NushellPrompt};
+use nu_color_config::get_color_config;
+use nu_engine::convert_env_values;
+use nu_parser::lex;
+use nu_protocol::{
+    engine::{EngineState, StateWorkingSet},
+    Config, ShellError, Span, Value, CONFIG_VARIABLE_ID,
+};
+use reedline::{DefaultHinter, Emacs, Vi};
+
+pub(crate) fn evaluate(ctrlc: Arc<AtomicBool>, engine_state: &mut EngineState) -> Result<()> {
+    use crate::logger::{configure, logger};
+    use reedline::{FileBackedHistory, Reedline, Signal};
+
+    let mut entry_num = 0;
+
+    let mut nu_prompt = NushellPrompt::new();
+    let mut stack = nu_protocol::engine::Stack::new();
+
+    // First, set up env vars as strings only
+    gather_parent_env_vars(engine_state);
+
+    // Set up our initial config to start from
+    stack.vars.insert(
+        CONFIG_VARIABLE_ID,
+        Value::Record {
+            cols: vec![],
+            vals: vec![],
+            span: Span::new(0, 0),
+        },
+    );
+
+    #[cfg(feature = "plugin")]
+    config_files::read_plugin_file(engine_state, &mut stack);
+
+    config_files::read_config_file(engine_state, &mut stack);
+    let history_path = config_files::create_history_path();
+
+    // Load config struct form config variable
+    let config = match stack.get_config() {
+        Ok(config) => config,
+        Err(e) => {
+            let working_set = StateWorkingSet::new(engine_state);
+
+            report_error(&working_set, &e);
+            Config::default()
+        }
+    };
+
+    logger(|builder| {
+        configure(&config.log_level, builder)?;
+        // trace_filters(self, builder)?;
+        // debug_filters(self, builder)?;
+
+        Ok(())
+    })?;
+
+    // Translate environment variables from Strings to Values
+    if let Some(e) = convert_env_values(engine_state, &stack, &config) {
+        let working_set = StateWorkingSet::new(engine_state);
+        report_error(&working_set, &e);
+    }
+
+    loop {
+        let config = match stack.get_config() {
+            Ok(config) => config,
+            Err(e) => {
+                let working_set = StateWorkingSet::new(engine_state);
+
+                report_error(&working_set, &e);
+                Config::default()
+            }
+        };
+
+        //Reset the ctrl-c handler
+        ctrlc.store(false, Ordering::SeqCst);
+
+        let keybindings = reedline_config::create_keybindings(&config.keybindings)?;
+        let edit_mode = Box::new(Emacs::new(keybindings));
+
+        let line_editor = Reedline::create()
+            .into_diagnostic()?
+            // .with_completion_action_handler(Box::new(fuzzy_completion::FuzzyCompletion {
+            //     completer: Box::new(NuCompleter::new(engine_state.clone())),
+            // }))
+            // .with_completion_action_handler(Box::new(
+            //     ListCompletionHandler::default().with_completer(Box::new(completer)),
+            // ))
+            .with_highlighter(Box::new(NuHighlighter {
+                engine_state: engine_state.clone(),
+                config: config.clone(),
+            }))
+            .with_animation(config.animate_prompt)
+            .with_validator(Box::new(NuValidator {
+                engine_state: engine_state.clone(),
+            }))
+            .with_edit_mode(edit_mode)
+            .with_ansi_colors(config.use_ansi_coloring)
+            .with_menu_completer(
+                Box::new(NuCompleter::new(engine_state.clone())),
+                reedline_config::create_menu_input(&config),
+            );
+
+        //FIXME: if config.use_ansi_coloring is false then we should
+        // turn off the hinter but I don't see any way to do that yet.
+
+        let color_hm = get_color_config(&config);
+
+        let line_editor = if let Some(history_path) = history_path.clone() {
+            let history = std::fs::read_to_string(&history_path);
+            if history.is_ok() {
+                line_editor
+                    .with_hinter(Box::new(
+                        DefaultHinter::default()
+                            .with_history()
+                            .with_style(color_hm["hints"]),
+                    ))
+                    .with_history(Box::new(
+                        FileBackedHistory::with_file(
+                            config.max_history_size as usize,
+                            history_path.clone(),
+                        )
+                        .into_diagnostic()?,
+                    ))
+                    .into_diagnostic()?
+            } else {
+                line_editor
+            }
+        } else {
+            line_editor
+        };
+
+        // The line editor default mode is emacs mode. For the moment we only
+        // need to check for vi mode
+        let mut line_editor = if config.edit_mode == "vi" {
+            let edit_mode = Box::new(Vi::default());
+            line_editor.with_edit_mode(edit_mode)
+        } else {
+            line_editor
+        };
+
+        let prompt = prompt_update::update_prompt(&config, engine_state, &stack, &mut nu_prompt);
+
+        entry_num += 1;
+
+        let input = line_editor.read_line(prompt);
+        match input {
+            Ok(Signal::Success(s)) => {
+                let tokens = lex(s.as_bytes(), 0, &[], &[], false);
+                // Check if this is a single call to a directory, if so auto-cd
+                let cwd = nu_engine::env::current_dir_str(engine_state, &stack)?;
+                let path = nu_path::expand_path_with(&s, &cwd);
+
+                let orig = s.clone();
+
+                if (orig.starts_with('.')
+                    || orig.starts_with('~')
+                    || orig.starts_with('/')
+                    || orig.starts_with('\\'))
+                    && path.is_dir()
+                    && tokens.0.len() == 1
+                {
+                    // We have an auto-cd
+                    let (path, span) = {
+                        if !path.exists() {
+                            let working_set = StateWorkingSet::new(engine_state);
+
+                            report_error(
+                                &working_set,
+                                &ShellError::DirectoryNotFound(tokens.0[0].span),
+                            );
+                        }
+
+                        let path = nu_path::canonicalize_with(path, &cwd)
+                            .expect("internal error: cannot canonicalize known path");
+                        (path.to_string_lossy().to_string(), tokens.0[0].span)
+                    };
+
+                    //FIXME: this only changes the current scope, but instead this environment variable
+                    //should probably be a block that loads the information from the state in the overlay
+                    stack.add_env_var(
+                        "PWD".into(),
+                        Value::String {
+                            val: path.clone(),
+                            span: Span { start: 0, end: 0 },
+                        },
+                    );
+                    let cwd = Value::String { val: cwd, span };
+
+                    let shells = stack.get_env_var(engine_state, "NUSHELL_SHELLS");
+                    let mut shells = if let Some(v) = shells {
+                        v.as_list()
+                            .map(|x| x.to_vec())
+                            .unwrap_or_else(|_| vec![cwd])
+                    } else {
+                        vec![cwd]
+                    };
+
+                    let current_shell = stack.get_env_var(engine_state, "NUSHELL_CURRENT_SHELL");
+                    let current_shell = if let Some(v) = current_shell {
+                        v.as_integer().unwrap_or_default() as usize
+                    } else {
+                        0
+                    };
+
+                    shells[current_shell] = Value::String { val: path, span };
+
+                    stack.add_env_var("NUSHELL_SHELLS".into(), Value::List { vals: shells, span });
+                } else {
+                    trace!("eval source: {}", s);
+
+                    eval_source(
+                        engine_state,
+                        &mut stack,
+                        &s,
+                        &format!("entry #{}", entry_num),
+                    );
+                }
+                // FIXME: permanent state changes like this hopefully in time can be removed
+                // and be replaced by just passing the cwd in where needed
+                if let Some(cwd) = stack.get_env_var(engine_state, "PWD") {
+                    let path = cwd.as_string()?;
+                    let _ = std::env::set_current_dir(path);
+                    engine_state.env_vars.insert("PWD".into(), cwd);
+                }
+            }
+            Ok(Signal::CtrlC) => {
+                // `Reedline` clears the line content. New prompt is shown
+            }
+            Ok(Signal::CtrlD) => {
+                // When exiting clear to a new line
+                println!();
+                break;
+            }
+            Ok(Signal::CtrlL) => {
+                line_editor.clear_screen().into_diagnostic()?;
+            }
+            Err(err) => {
+                let message = err.to_string();
+                if !message.contains("duration") {
+                    println!("Error: {:?}", err);
+                }
+            }
+        }
+    }
+
+    Ok(())
+}

src/utils.rs

@@ -0,0 +1,395 @@
+use log::trace;
+use nu_cli::CliError;
+use nu_engine::eval_block;
+use nu_parser::{lex, parse, trim_quotes, Token, TokenContents};
+use nu_protocol::{
+    ast::Call,
+    engine::{EngineState, Stack, StateWorkingSet},
+    PipelineData, ShellError, Span, Value,
+};
+use std::{io::Write, path::PathBuf};
+
+// This fill collect environment variables from std::env and adds them to a stack.
+//
+// In order to ensure the values have spans, it first creates a dummy file, writes the collected
+// env vars into it (in a "NAME"="value" format, quite similar to the output of the Unix 'env'
+// tool), then uses the file to get the spans. The file stays in memory, no filesystem IO is done.
+pub(crate) fn gather_parent_env_vars(engine_state: &mut EngineState) {
+    // Some helper functions
+    fn get_surround_char(s: &str) -> Option<char> {
+        if s.contains('"') {
+            if s.contains('\'') {
+                None
+            } else {
+                Some('\'')
+            }
+        } else {
+            Some('"')
+        }
+    }
+
+    fn report_capture_error(engine_state: &EngineState, env_str: &str, msg: &str) {
+        let working_set = StateWorkingSet::new(engine_state);
+        report_error(
+            &working_set,
+            &ShellError::LabeledError(
+                format!("Environment variable was not captured: {}", env_str),
+                msg.into(),
+            ),
+        );
+    }
+
+    fn put_env_to_fake_file(
+        name: &str,
+        val: &str,
+        fake_env_file: &mut String,
+        engine_state: &EngineState,
+    ) {
+        let (c_name, c_val) =
+            if let (Some(cn), Some(cv)) = (get_surround_char(name), get_surround_char(val)) {
+                (cn, cv)
+            } else {
+                // environment variable with its name or value containing both ' and " is ignored
+                report_capture_error(
+                    engine_state,
+                    &format!("{}={}", name, val),
+                    "Name or value should not contain both ' and \" at the same time.",
+                );
+                return;
+            };
+
+        fake_env_file.push(c_name);
+        fake_env_file.push_str(name);
+        fake_env_file.push(c_name);
+        fake_env_file.push('=');
+        fake_env_file.push(c_val);
+        fake_env_file.push_str(val);
+        fake_env_file.push(c_val);
+        fake_env_file.push('\n');
+    }
+
+    let mut fake_env_file = String::new();
+
+    // Make sure we always have PWD
+    if std::env::var("PWD").is_err() {
+        match std::env::current_dir() {
+            Ok(cwd) => {
+                put_env_to_fake_file(
+                    "PWD",
+                    &cwd.to_string_lossy(),
+                    &mut fake_env_file,
+                    engine_state,
+                );
+            }
+            Err(e) => {
+                // Could not capture current working directory
+                let working_set = StateWorkingSet::new(engine_state);
+                report_error(
+                    &working_set,
+                    &ShellError::LabeledError(
+                        "Current directory not found".to_string(),
+                        format!("Retrieving current directory failed: {:?}", e),
+                    ),
+                );
+            }
+        }
+    }
+
+    // Write all the env vars into a fake file
+    for (name, val) in std::env::vars() {
+        put_env_to_fake_file(&name, &val, &mut fake_env_file, engine_state);
+    }
+
+    // Lex the fake file, assign spans to all environment variables and add them
+    // to stack
+    let span_offset = engine_state.next_span_start();
+
+    engine_state.add_file(
+        "Host Environment Variables".to_string(),
+        fake_env_file.as_bytes().to_vec(),
+    );
+
+    let (tokens, _) = lex(fake_env_file.as_bytes(), span_offset, &[], &[], true);
+
+    for token in tokens {
+        if let Token {
+            contents: TokenContents::Item,
+            span: full_span,
+        } = token
+        {
+            let contents = engine_state.get_span_contents(&full_span);
+            let (parts, _) = lex(contents, full_span.start, &[], &[b'='], true);
+
+            let name = if let Some(Token {
+                contents: TokenContents::Item,
+                span,
+            }) = parts.get(0)
+            {
+                let bytes = engine_state.get_span_contents(span);
+
+                if bytes.len() < 2 {
+                    report_capture_error(
+                        engine_state,
+                        &String::from_utf8_lossy(contents),
+                        "Got empty name.",
+                    );
+
+                    continue;
+                }
+
+                let bytes = trim_quotes(bytes);
+                String::from_utf8_lossy(bytes).to_string()
+            } else {
+                report_capture_error(
+                    engine_state,
+                    &String::from_utf8_lossy(contents),
+                    "Got empty name.",
+                );
+
+                continue;
+            };
+
+            let value = if let Some(Token {
+                contents: TokenContents::Item,
+                span,
+            }) = parts.get(2)
+            {
+                let bytes = engine_state.get_span_contents(span);
+
+                if bytes.len() < 2 {
+                    report_capture_error(
+                        engine_state,
+                        &String::from_utf8_lossy(contents),
+                        "Got empty value.",
+                    );
+
+                    continue;
+                }
+
+                let bytes = trim_quotes(bytes);
+
+                Value::String {
+                    val: String::from_utf8_lossy(bytes).to_string(),
+                    span: *span,
+                }
+            } else {
+                report_capture_error(
+                    engine_state,
+                    &String::from_utf8_lossy(contents),
+                    "Got empty value.",
+                );
+
+                continue;
+            };
+
+            // stack.add_env_var(name, value);
+            engine_state.env_vars.insert(name, value);
+        }
+    }
+}
+
+fn print_pipeline_data(
+    input: PipelineData,
+    engine_state: &EngineState,
+    stack: &mut Stack,
+) -> Result<(), ShellError> {
+    // If the table function is in the declarations, then we can use it
+    // to create the table value that will be printed in the terminal
+
+    let config = stack.get_config().unwrap_or_default();
+
+    match input {
+        PipelineData::StringStream(stream, _, _) => {
+            for s in stream {
+                print!("{}", s?);
+                let _ = std::io::stdout().flush();
+            }
+            return Ok(());
+        }
+        PipelineData::ByteStream(stream, _, _) => {
+            let mut address_offset = 0;
+            for v in stream {
+                let cfg = nu_pretty_hex::HexConfig {
+                    title: false,
+                    address_offset,
+                    ..Default::default()
+                };
+
+                let v = v?;
+                address_offset += v.len();
+
+                let s = if v.iter().all(|x| x.is_ascii()) {
+                    format!("{}", String::from_utf8_lossy(&v))
+                } else {
+                    nu_pretty_hex::config_hex(&v, cfg)
+                };
+                println!("{}", s);
+            }
+            return Ok(());
+        }
+        _ => {}
+    }
+
+    match engine_state.find_decl("table".as_bytes()) {
+        Some(decl_id) => {
+            let table =
+                engine_state
+                    .get_decl(decl_id)
+                    .run(engine_state, stack, &Call::new(), input)?;
+
+            for item in table {
+                let stdout = std::io::stdout();
+
+                if let Value::Error { error } = item {
+                    return Err(error);
+                }
+
+                let mut out = item.into_string("\n", &config);
+                out.push('\n');
+
+                match stdout.lock().write_all(out.as_bytes()) {
+                    Ok(_) => (),
+                    Err(err) => eprintln!("{}", err),
+                };
+            }
+        }
+        None => {
+            for item in input {
+                let stdout = std::io::stdout();
+
+                if let Value::Error { error } = item {
+                    return Err(error);
+                }
+
+                let mut out = item.into_string("\n", &config);
+                out.push('\n');
+
+                match stdout.lock().write_all(out.as_bytes()) {
+                    Ok(_) => (),
+                    Err(err) => eprintln!("{}", err),
+                };
+            }
+        }
+    };
+
+    Ok(())
+}
+
+pub(crate) fn eval_source(
+    engine_state: &mut EngineState,
+    stack: &mut Stack,
+    source: &str,
+    fname: &str,
+) -> bool {
+    trace!("eval_source");
+
+    let (block, delta) = {
+        let mut working_set = StateWorkingSet::new(engine_state);
+        let (output, err) = parse(
+            &mut working_set,
+            Some(fname), // format!("entry #{}", entry_num)
+            source.as_bytes(),
+            false,
+        );
+        if let Some(err) = err {
+            report_error(&working_set, &err);
+            return false;
+        }
+
+        (output, working_set.render())
+    };
+
+    let cwd = match nu_engine::env::current_dir_str(engine_state, stack) {
+        Ok(p) => PathBuf::from(p),
+        Err(e) => {
+            let working_set = StateWorkingSet::new(engine_state);
+            report_error(&working_set, &e);
+            get_init_cwd()
+        }
+    };
+
+    if let Err(err) = engine_state.merge_delta(delta, Some(stack), &cwd) {
+        let working_set = StateWorkingSet::new(engine_state);
+        report_error(&working_set, &err);
+    }
+
+    match eval_block(
+        engine_state,
+        stack,
+        &block,
+        PipelineData::new(Span::new(0, 0)), // Don't try this at home, 0 span is ignored
+    ) {
+        Ok(pipeline_data) => {
+            if let Err(err) = print_pipeline_data(pipeline_data, engine_state, stack) {
+                let working_set = StateWorkingSet::new(engine_state);
+
+                report_error(&working_set, &err);
+
+                return false;
+            }
+
+            // reset vt processing, aka ansi because illbehaved externals can break it
+            #[cfg(windows)]
+            {
+                let _ = enable_vt_processing();
+            }
+        }
+        Err(err) => {
+            let working_set = StateWorkingSet::new(engine_state);
+
+            report_error(&working_set, &err);
+
+            return false;
+        }
+    }
+
+    true
+}
+
+#[cfg(windows)]
+pub fn enable_vt_processing() -> Result<(), ShellError> {
+    use crossterm_winapi::{ConsoleMode, Handle};
+
+    pub const ENABLE_PROCESSED_OUTPUT: u32 = 0x0001;
+    pub const ENABLE_VIRTUAL_TERMINAL_PROCESSING: u32 = 0x0004;
+    // let mask = ENABLE_VIRTUAL_TERMINAL_PROCESSING;
+
+    let console_mode = ConsoleMode::from(Handle::current_out_handle()?);
+    let old_mode = console_mode.mode()?;
+
+    // researching odd ansi behavior in windows terminal repo revealed that
+    // enable_processed_output and enable_virtual_terminal_processing should be used
+    // also, instead of checking old_mode & mask, just set the mode already
+
+    // if old_mode & mask == 0 {
+    console_mode
+        .set_mode(old_mode | ENABLE_PROCESSED_OUTPUT | ENABLE_VIRTUAL_TERMINAL_PROCESSING)?;
+    // }
+
+    Ok(())
+}
+
+pub fn report_error(
+    working_set: &StateWorkingSet,
+    error: &(dyn miette::Diagnostic + Send + Sync + 'static),
+) {
+    eprintln!("Error: {:?}", CliError(error, working_set));
+    // reset vt processing, aka ansi because illbehaved externals can break it
+    #[cfg(windows)]
+    {
+        let _ = enable_vt_processing();
+    }
+}
+
+pub(crate) fn get_init_cwd() -> PathBuf {
+    match std::env::current_dir() {
+        Ok(cwd) => cwd,
+        Err(_) => match std::env::var("PWD".to_string()) {
+            Ok(cwd) => PathBuf::from(cwd),
+            Err(_) => match nu_path::home_dir() {
+                Some(cwd) => cwd,
+                None => PathBuf::new(),
+            },
+        },
+    }
+}