Add help tool

src/bin/dust.rs

@@ -150,7 +150,7 @@ fn run_cli_shell() {
                 let eval_result = eval_with_context(line, &mut context);
 
                 match eval_result {
-                    Ok(_) => {}
+                    Ok(value) => println!("{value}"),
                     Err(error) => eprintln!("{error}"),
                 }
             }

src/tools/general.rs

@@ -2,7 +2,37 @@ use std::{thread::sleep, time::Duration};
 
 use rayon::prelude::{IntoParallelRefIterator, ParallelIterator};
 
-use crate::{Result, Tool, ToolInfo, Value, ValueType};
+use crate::{Result, Table, Tool, ToolInfo, Value, ValueType, TOOL_LIST};
+
+pub struct Help;
+
+impl Tool for Help {
+    fn info(&self) -> ToolInfo<'static> {
+        ToolInfo {
+            identifier: "help",
+            description: "Get help using dust.",
+            group: "general",
+            inputs: vec![ValueType::Empty, ValueType::String],
+        }
+    }
+
+    fn run(&self, argument: &Value) -> Result<Value> {
+        self.check_type(argument)?;
+
+        let mut table = Table::new(vec!["tool".to_string(), "description".to_string()]);
+
+        for tool in TOOL_LIST {
+            let row = vec![
+                Value::String(tool.info().identifier.to_string()),
+                Value::String(tool.info().description.to_string()),
+            ];
+
+            table.insert(row)?;
+        }
+
+        Ok(Value::Table(table))
+    }
+}
 
 pub struct Output;
 

src/tools/mod.rs

@@ -50,7 +50,7 @@ pub mod time;
 /// Master list of all tools.
 ///
 /// This list is used to match identifiers with tools and to provide info to the shell.
-pub const TOOL_LIST: [&'static dyn Tool; 51] = [
+pub const TOOL_LIST: [&'static dyn Tool; 52] = [
     &collections::Count,
     &collections::CreateTable,
     &collections::Insert,
@@ -82,6 +82,7 @@ pub const TOOL_LIST: [&'static dyn Tool; 51] = [
     &filesystem::Trash,
     &filesystem::Watch,
     &filesystem::Write,
+    &general::Help,
     &general::Run,
     &general::Output,
     &general::Repeat,

src/value/value_type.rs

@@ -38,11 +38,9 @@ impl PartialEq for ValueType {
             (ValueType::ListOf(_), ValueType::List) => true,
             (ValueType::List, ValueType::ListOf(_)) => true,
             (ValueType::ListOf(value_type), ValueType::ListExact(exact_list))
-            | (ValueType::ListExact(exact_list), ValueType::ListOf(value_type)) => {
+            | (ValueType::ListExact(exact_list), ValueType::ListOf(value_type)) => exact_list
-                exact_list
                 .iter()
-                    .all(|exact_type| exact_type == value_type.as_ref())
+                .all(|exact_type| exact_type == value_type.as_ref()),
-            }
             (ValueType::List, ValueType::List) => true,
             (ValueType::Empty, ValueType::Empty) => true,
             (ValueType::Map, ValueType::Map) => true,