builtin echo returns

src/builtins.rs

@@ -1,3 +1,33 @@
-pub trait BuiltinFn {
+use crate::{
-    fn call(&self, args: Vec<&str>);
+    error::ExecError,
+    syntax::{self, State},
+};
+
+pub enum Builtin {
+    Echo,
+}
+
+impl Builtin {
+    pub fn lookup(name: &str) -> Option<Self> {
+        match name {
+            "echo" => Some(Self::Echo),
+            _ => None,
+        }
+    }
+
+    pub fn call(
+        &self,
+        _: &mut State,
+        args: &Vec<syntax::Value>,
+    ) -> Result<syntax::Value, ExecError> {
+        match self {
+            Builtin::Echo => {
+                let args: Result<Vec<String>, ExecError> =
+                    args.into_iter().map(|arg| arg.try_as_string()).collect();
+                let args = args?;
+                println!("{}", args.join(" "));
+                Ok(syntax::Value::None)
+            }
+        }
+    }
 }

src/error.rs

@@ -20,7 +20,8 @@ pub enum LexError {
     #[error("a word character was expected but none was encountered")]
     ExpectedWordCharacter,
 
-    #[error("unexpected character: {0:?}")]
+    // #[error("unexpected character {0.glyph} at {0.position}")]
+    #[error("unexpected character {g} at {pos:?}", g = .0.glyph, pos = .0.position)]
     UnexpectedCharacter(Glyph),
 
     #[error("unexpected eof")]

src/line.rs

@@ -5,7 +5,7 @@ pub struct Line {
     /// the current contents of the line
     chars: Vec<char>,
 
-    /// the cursor position of our dit head within the vector of characters that we store as chars
+    /// the cursor position of our head within the vector of characters that we store as chars
     cursor: usize,
 }
 

src/output.rs

@@ -150,10 +150,16 @@ impl Writer {
 
 impl Write for Writer {
     fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        let mut written = 0;
         unsafe {
-            Error::check(Console::WriteConsoleA(self.output, buf, None, None))?;
+            Error::check(Console::WriteConsoleA(
-        }
+                self.output,
-        Ok(0)
+                buf,
+                Some(&mut written),
+                None,
+            ))?;
+        }
+        Ok(written as usize)
     }
 
     fn flush(&mut self) -> io::Result<()> {

src/shell.rs

@@ -166,9 +166,9 @@ impl Shell {
 
     fn render_error_helper<E: Error>(&mut self, e: E, depth: u8) -> io::Result<()> {
         if depth > 0 {
-            println!("  {e}");
+            writeln!(self.output, "  {e}")?;
         } else {
-            println!("{e}:");
+            writeln!(self.output, "{e}:")?;
         }
         if let Some(cause) = e.source() {
             self.render_error_helper(cause, depth + 1)?;

src/syntax.rs

@@ -1,5 +1,5 @@
 use crate::{
-    builtins::BuiltinFn,
+    builtins::Builtin,
     error::{ExecError, ParseError},
     lex::{Lexer, Token},
     log::debug,
@@ -11,14 +11,12 @@ use std::{
 };
 
 pub struct State {
-    builtins: HashMap<&'static str, Box<dyn BuiltinFn>>,
     variables: HashMap<&'static str, syntax::Value>,
 }
 
 impl State {
     pub fn new() -> Self {
         Self {
-            builtins: HashMap::new(),
             variables: HashMap::new(),
         }
     }
@@ -54,7 +52,7 @@ pub enum Value {
 }
 
 impl Eval for Value {
-    fn eval(&self, ctx: &mut State) -> Result<Value, ExecError> {
+    fn eval(&self, _: &mut State) -> Result<Value, ExecError> {
         Ok(self.clone())
     }
 }
@@ -69,6 +67,16 @@ impl Value {
             )),
         }
     }
+
+    pub fn try_as_string(&self) -> Result<String, ExecError> {
+        match self {
+            Value::None => Err(ExecError::type_error("expected text value, saw None value")),
+            Value::Text(v) => Ok(v.clone()),
+            Value::ExitStatus(_) => Err(ExecError::type_error(
+                "expected text value, saw ExitStatus value",
+            )),
+        }
+    }
 }
 
 #[derive(Debug)]
@@ -100,9 +108,12 @@ pub struct Command {
     args: Vec<Element>,
 }
 
-impl Eval for Command {
+impl Command {
-    fn eval(&self, ctx: &mut State) -> Result<Value, ExecError> {
+    fn eval_args(&self, ctx: &mut State) -> Result<Vec<Value>, ExecError> {
-        let name = self.name.eval(ctx)?.try_to_string()?;
+        self.args.iter().map(|elem| elem.eval(ctx)).collect()
+    }
+
+    fn exec_command(&self, ctx: &mut State, name: &str) -> Result<Value, ExecError> {
         let mut proc = process::Command::new(&name);
 
         if self.args.len() > 0 {
@@ -114,16 +125,32 @@ impl Eval for Command {
             proc.args(args);
         }
         let mut child = proc.spawn().map_err(|e| ExecError::ProcessSpawnError {
-            name: name.clone(),
+            name: name.to_string(),
             source: e,
         })?;
         let pid = child.id();
         let status = child.wait().map_err(|e| ExecError::ProcessWaitError {
-            name,
+            name: name.to_string(),
             pid,
             source: e,
         })?;
-        return Ok(Value::ExitStatus(status));
+        Ok(Value::ExitStatus(status))
+    }
+}
+
+impl Eval for Command {
+    fn eval(&self, ctx: &mut State) -> Result<Value, ExecError> {
+        let name = self.name.eval(ctx)?.try_to_string()?;
+
+        match Builtin::lookup(&name) {
+            Some(builtin) => {
+                let args = self.eval_args(ctx)?;
+                // let args: Vec<&str> = args.into_iter().map(|arg| arg).collect();
+
+                builtin.call(ctx, &args)
+            }
+            None => self.exec_command(ctx, &name),
+        }
     }
 }
 
@@ -199,11 +226,3 @@ mod test {
         //Ok(())
     }
 }
-
-/*
-
-> ls
-  command
-    name: ls
-
-*/