Implement functio declaration & calling

src/ast.rs

@@ -60,7 +60,7 @@ pub enum StmtKind {
 
     Functio {
         iden: Iden,
-        args: Vec<Iden>,
+        params: Vec<Iden>,
         body: Block,
     },
     BfFunctio {

src/error.rs

@@ -20,6 +20,7 @@ pub enum ErrorKind {
     TopLevelBreak,
     ArithmeticError,
     BfInterpretError(InterpretError),
+    MismatchedArgumentError,
     MissingLhs,
 }
 

src/interpret.rs

@@ -76,7 +76,7 @@ impl ExecEnv {
                 // It's an error to issue a `break` outside of a
                 // `loop` statement.
                 kind: ErrorKind::TopLevelBreak,
-                span: span,
+                span,
             }),
         }
     }
@@ -203,11 +203,13 @@ impl ExecEnv {
 
                 self.decl_var(&iden.iden, init);
             }
-            StmtKind::Functio {
+            StmtKind::Functio { iden, params, body } => self.decl_var(
-                iden: _,
+                &iden.iden,
-                args: _,
+                Value::Functio(Functio::AbleFunctio {
-                body: _,
+                    params: params.iter().map(|iden| iden.iden.to_string()).collect(),
-            } => todo!(),
+                    body: body.block.to_owned(),
+                }),
+            ),
             StmtKind::BfFunctio {
                 iden,
                 tape_len,
@@ -235,49 +237,19 @@ impl ExecEnv {
             }
             StmtKind::Call { iden, args } => {
                 let func = self.get_var(&iden)?;
-                match func {
-                    Value::Functio(func) => {
-                        match func {
-                            Functio::BfFunctio {
-                                instructions,
-                                tape_len,
-                            } => {
-                                let mut input: Vec<u8> = vec![];
-                                for arg in args {
-                                    self.eval_expr(arg)?.bf_write(&mut input);
-                                }
-                                println!("input = {:?}", input);
-                                let mut output = vec![];
 
-                                crate::brian::Interpreter::from_ascii_with_tape_limit(
+                let args = args
-                                    &instructions,
+                    .iter()
-                                    &input as &[_],
+                    .map(|arg| self.eval_expr(arg))
-                                    tape_len,
+                    .collect::<Result<_, _>>()?;
-                                )
-                                .interpret_with_output(&mut output)
-                                .map_err(|e| Error {
-                                    kind: ErrorKind::BfInterpretError(e),
-                                    span: stmt.span.clone(),
-                                })?;
 
-                                // I guess Brainfuck functions write
+                if let Value::Functio(func) = func {
-                                // output to stdout? It's not quite
+                    self.fn_call(func, args, &stmt.span)?;
-                                // clear to me what else to do. ~~Alex
+                } else {
-                                stdout()
-                                    .write_all(&output)
-                                    .expect("Failed to write to stdout");
-                            }
-                            Functio::AbleFunctio(_) => {
-                                todo!()
-                            }
-                        }
-                    }
-                    _ => {
                     return Err(Error {
                         kind: ErrorKind::TypeError(iden.iden.to_owned()),
                         span: stmt.span.clone(),
-                        })
+                    });
-                    }
                 }
             }
             StmtKind::Loop { body } => loop {
@@ -313,6 +285,65 @@ impl ExecEnv {
         Ok(HaltStatus::Finished)
     }
 
+    /// Call a function with the given arguments (i.e., actual
+    /// parameters). If the function invocation fails for some reason,
+    /// report the error at `span`.
+    fn fn_call(
+        &mut self,
+        func: Functio,
+        args: Vec<Value>,
+        span: &Range<usize>,
+    ) -> Result<(), Error> {
+        match func {
+            Functio::BfFunctio {
+                instructions,
+                tape_len,
+            } => {
+                let mut input: Vec<u8> = vec![];
+                for arg in args {
+                    arg.bf_write(&mut input);
+                }
+                println!("input = {:?}", input);
+                let mut output = vec![];
+
+                crate::brian::Interpreter::from_ascii_with_tape_limit(
+                    &instructions,
+                    &input as &[_],
+                    tape_len,
+                )
+                .interpret_with_output(&mut output)
+                .map_err(|e| Error {
+                    kind: ErrorKind::BfInterpretError(e),
+                    span: span.to_owned(),
+                })?;
+
+                stdout()
+                    .write_all(&output)
+                    .expect("Failed to write to stdout");
+            }
+            Functio::AbleFunctio { params, body } => {
+                if params.len() != args.len() {
+                    return Err(Error {
+                        kind: ErrorKind::MismatchedArgumentError,
+                        span: span.to_owned(),
+                    });
+                }
+
+                self.stack.push(Default::default());
+
+                for (param, arg) in params.iter().zip(args.iter()) {
+                    self.decl_var(param, arg.to_owned());
+                }
+
+                let res = self.eval_stmts_hs(&body, false);
+
+                self.stack.pop();
+                res?;
+            }
+        }
+        Ok(())
+    }
+
     /// Get the value of a variable. Throw an error if the variable is
     /// inaccessible or banned.
     fn get_var(&self, name: &Iden) -> Result<Value, Error> {

src/parser.rs

@@ -347,7 +347,7 @@ impl<'source> Parser<'source> {
 
         self.require(Token::LeftParen)?;
 
-        let mut args = vec![];
+        let mut params = vec![];
         loop {
             match self
                 .lexer
@@ -356,7 +356,7 @@ impl<'source> Parser<'source> {
             {
                 Token::RightParen => break,
                 Token::Identifier(i) => {
-                    args.push(Iden::new(i, self.lexer.span()));
+                    params.push(Iden::new(i, self.lexer.span()));
 
                     // Require comma (next) or right paren (end) after identifier
                     match self
@@ -380,7 +380,7 @@ impl<'source> Parser<'source> {
 
         let body = self.get_block()?;
 
-        Ok(StmtKind::Functio { iden, args, body })
+        Ok(StmtKind::Functio { iden, params, body })
     }
 
     /// Parse BF function declaration

src/variables.rs

@@ -40,7 +40,10 @@ pub enum Functio {
         instructions: Vec<u8>,
         tape_len: usize,
     },
-    AbleFunctio(Vec<Stmt>),
+    AbleFunctio {
+        params: Vec<String>,
+        body: Vec<Stmt>,
+    },
 }
 
 #[derive(Debug, PartialEq, Clone)]
@@ -76,7 +79,7 @@ impl Value {
     /// break a significant amount of AbleScript code. If more types
     /// are added in the future, they should be assigned the remaining
     /// discriminant bytes from 06..FF.
-    pub fn bf_write(&mut self, stream: &mut impl Write) {
+    pub fn bf_write(&self, stream: &mut impl Write) {
         match self {
             Value::Nul => stream.write_all(&[0]),
             Value::Str(s) => stream
@@ -108,7 +111,7 @@ impl Value {
                         .and_then(|_| stream.write_all(&(instructions.len() as u32).to_le_bytes()))
                         .and_then(|_| stream.write_all(&instructions))
                 }
-                Functio::AbleFunctio(_) => {
+                Functio::AbleFunctio { params: _, body: _ } => {
                     todo!()
                 }
             }),
@@ -158,7 +161,10 @@ impl Display for Value {
             Value::Bool(v) => write!(f, "{}", v),
             Value::Abool(v) => write!(f, "{}", v),
             Value::Functio(v) => match v {
-                Functio::BfFunctio { instructions, tape_len } => {
+                Functio::BfFunctio {
+                    instructions,
+                    tape_len,
+                } => {
                     write!(
                         f,
                         "({}) {}",
@@ -167,10 +173,15 @@ impl Display for Value {
                             .expect("Brainfuck functio source should be UTF-8")
                     )
                 }
-                Functio::AbleFunctio(source) => {
+                Functio::AbleFunctio { params, body } => {
-                    // TODO: what's the proper way to display an
+                    write!(
-                    // AbleScript functio?
+                        f,
-                    write!(f, "{:?}", source)
+                        "({}) -> {:?}",
+                        params.join(", "),
+                        // Maybe we should have a pretty-printer for
+                        // statement blocks at some point?
+                        body,
+                    )
                 }
             },
         }