src/ir/ast.rs

@@ -77,7 +77,7 @@ impl Arbitrary for Program {
 #[derive(Debug)]
 pub enum TopLevel {
     Statement(Statement),
-    Function(Variable, Vec<Variable>, Expression),
+    Function(Variable, Vec<Variable>, Vec<Statement>, Expression),
 }
 
 impl<'a, 'b, D, A> Pretty<'a, D, A> for &'b TopLevel
@@ -87,7 +87,7 @@ where
 {
     fn pretty(self, allocator: &'a D) -> pretty::DocBuilder<'a, D, A> {
         match self {
-            TopLevel::Function(name, args, body) => allocator
+            TopLevel::Function(name, args, stmts, body) => allocator
                 .text("function")
                 .append(allocator.space())
                 .append(allocator.text(name.as_ref().to_string()))
@@ -378,6 +378,7 @@ where
 #[derive(Clone, Debug, Eq, PartialEq)]
 pub enum Type {
     Primitive(PrimitiveType),
+    Function(Vec<Type>, Box<Type>),
 }
 
 impl<'a, 'b, D, A> Pretty<'a, D, A> for &'b Type

src/type_infer/ast.rs

@@ -68,7 +68,7 @@ where
 #[derive(Debug)]
 pub enum TopLevel {
     Statement(Statement),
-    Function(Variable, Vec<Variable>, Expression),
+    Function(Variable, Vec<Variable>, Vec<Statement>, Expression),
 }
 
 impl<'a, 'b, D, A> Pretty<'a, D, A> for &'b TopLevel
@@ -78,22 +78,36 @@ where
 {
     fn pretty(self, allocator: &'a D) -> pretty::DocBuilder<'a, D, A> {
         match self {
-            TopLevel::Function(name, args, body) => allocator
+            TopLevel::Function(name, args, stmts, expr) => {
-                .text("function")
+                let base = allocator
-                .append(allocator.space())
+                    .text("function")
-                .append(allocator.text(name.as_ref().to_string()))
+                    .append(allocator.space())
-                .append(allocator.space())
+                    .append(allocator.text(name.as_ref().to_string()))
-                .append(
+                    .append(allocator.space())
-                    allocator
+                    .append(
-                        .intersperse(
+                        pretty_comma_separated(
-                            args.iter().map(|x| allocator.text(x.as_ref().to_string())),
+                            allocator,
-                            ", ",
+                            &args
+                                .iter()
+                                .map(|x| allocator.text(x.as_ref().to_string()))
+                                .collect(),
                         )
                         .parens(),
-                )
+                    )
-                .append(allocator.space())
+                    .append(allocator.space());
-                .append(body.pretty(allocator)),
 
+                let mut body = allocator.nil();
+                for stmt in stmts {
+                    body = body
+                        .append(stmt.pretty(allocator))
+                        .append(allocator.text(";"))
+                        .append(allocator.hardline());
+                }
+                body = body.append(expr.pretty(allocator));
+                body = body.append(allocator.hardline());
+                body = body.braces();
+                base.append(body)
+            }
             TopLevel::Statement(stmt) => stmt.pretty(allocator),
         }
     }
@@ -310,6 +324,7 @@ where
 pub enum Type {
     Variable(Location, ArcIntern<String>),
     Primitive(PrimitiveType),
+    Function(Vec<Type>, Box<Type>),
 }
 
 impl Type {
@@ -327,6 +342,14 @@ where
         match self {
             Type::Variable(_, x) => allocator.text(x.to_string()),
             Type::Primitive(pt) => allocator.text(format!("{}", pt)),
+            Type::Function(args, rettype) => {
+                pretty_comma_separated(allocator, &args.iter().collect())
+                    .parens()
+                    .append(allocator.space())
+                    .append(allocator.text("->"))
+                    .append(allocator.space())
+                    .append(rettype.pretty(allocator))
+            }
         }
     }
 }
@@ -336,6 +359,18 @@ impl fmt::Display for Type {
         match self {
             Type::Variable(_, x) => write!(f, "{}", x),
             Type::Primitive(pt) => pt.fmt(f),
+            Type::Function(args, ret) => {
+                write!(f, "(")?;
+                let mut argiter = args.iter().peekable();
+                while let Some(arg) = argiter.next() {
+                    arg.fmt(f)?;
+                    if argiter.peek().is_some() {
+                        write!(f, ",")?;
+                    }
+                }
+                write!(f, "->")?;
+                ret.fmt(f)
+            }
         }
     }
 }
@@ -373,3 +408,16 @@ pub fn gentype() -> Type {
 
     Type::Variable(Location::manufactured(), name)
 }
+
+fn pretty_comma_separated<'a, D, A, P>(
+    allocator: &'a D,
+    args: &Vec<P>,
+) -> pretty::DocBuilder<'a, D, A>
+where
+    A: 'a,
+    D: ?Sized + DocAllocator<'a, A>,
+    P: Pretty<'a, D, A>,
+{
+    let individuals = args.iter().map(|x| x.pretty(allocator));
+    allocator.intersperse(individuals, ", ")
+}

src/type_infer/convert.rs

@@ -44,8 +44,41 @@ pub fn convert_top_level(
     bindings: &mut HashMap<ArcIntern<String>, Type>,
 ) -> Vec<ir::TopLevel> {
     match top_level {
-        syntax::TopLevel::Function(_, _arg_name, _) => {
+        syntax::TopLevel::Function(name, args, expr) => {
-            unimplemented!()
+            // First, let us figure out what we're going to name this function. If the user
+            // didn't provide one, we'll just call it "function:<something>" for them. (We'll
+            // want a name for this function, eventually, so we might as well do it now.)
+            //
+            // If they did provide a name, see if we're shadowed. IF we are, then we'll have
+            // to specialize the name a bit. Otherwise we'll stick with their name.
+            let funname = match name {
+                None => ir::gensym("function"),
+                Some(unbound) => finalize_name(bindings, renames, unbound),
+            };
+
+            // Now we manufacture types for the inputs and outputs, and then a type for the
+            // function itself. We're not going to make any claims on these types, yet; they're
+            // all just unknown type variables we need to work out.
+            let argtypes: Vec<Type> = args.iter().map(|_| ir::gentype()).collect();
+            let rettype = ir::gentype();
+            let funtype = Type::Function(argtypes.clone(), Box::new(rettype.clone()));
+
+            // Now let's bind these types into the environment. First, we bind our function
+            // namae to the function type we just generated.
+            bindings.insert(funname, funtype);
+            // And then we attach the argument names to the argument types. (We have to go
+            // convert all the names, first.)
+            let iargs: Vec<ArcIntern<String>> =
+                args.iter().map(|x| ArcIntern::new(x.to_string())).collect();
+            assert_eq!(argtypes.len(), iargs.len());
+            for (arg_name, arg_type) in iargs.iter().zip(argtypes) {
+                bindings.insert(arg_name.clone(), arg_type.clone());
+            }
+
+            let (stmts, expr, ty) = convert_expression(expr, constraint_db, renames, bindings);
+            constraint_db.push(Constraint::Equivalent(expr.location().clone(), rettype, ty));
+
+            vec![ir::TopLevel::Function(funname, iargs, stmts, expr)]
         }
         syntax::TopLevel::Statement(stmt) => {
             convert_statement(stmt, constraint_db, renames, bindings)
@@ -93,14 +126,7 @@ fn convert_statement(
         syntax::Statement::Binding(loc, name, expr) => {
             let (mut prereqs, expr, ty) =
                 convert_expression(expr, constraint_db, renames, bindings);
-            let iname = ArcIntern::new(name.to_string());
+            let final_name = finalize_name(bindings, renames, name);
-            let final_name = if bindings.contains_key(&iname) {
-                let new_name = ir::gensym(iname.as_str());
-                renames.insert(iname, new_name.clone());
-                new_name
-            } else {
-                iname
-            };
 
             bindings.insert(final_name.clone(), ty.clone());
             prereqs.push(ir::Statement::Binding(loc, final_name, ty, expr));
@@ -260,6 +286,20 @@ fn simplify_expr(expr: ir::Expression, stmts: &mut Vec<ir::Statement>) -> ir::Va
     }
 }
 
+fn finalize_name(
+    bindings: &HashMap<ArcIntern<String>, Type>,
+    renames: &mut HashMap<ArcIntern<String>, ArcIntern<String>>,
+    name: syntax::Name,
+) -> ArcIntern<String> {
+    if bindings.contains_key(&ArcIntern::new(name.name)) {
+        let new_name = ir::gensym(&name.name);
+        renames.insert(ArcIntern::new(name.name.to_string()), new_name.clone());
+        new_name
+    } else {
+        ArcIntern::new(name.to_string())
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;

src/type_infer/finalize.rs

@@ -16,9 +16,14 @@ pub fn finalize_program(
 
 fn finalize_top_level(item: input::TopLevel, resolutions: &TypeResolutions) -> output::TopLevel {
     match item {
-        input::TopLevel::Function(name, args, body) => {
+        input::TopLevel::Function(name, args, mut body, expr) => output::TopLevel::Function(
-            output::TopLevel::Function(name, args, finalize_expression(body, resolutions))
+            name,
-        }
+            args,
+            body.drain(..)
+                .map(|x| finalize_statement(x, resolutions))
+                .collect(),
+            finalize_expression(expr, resolutions),
+        ),
         input::TopLevel::Statement(stmt) => {
             output::TopLevel::Statement(finalize_statement(stmt, resolutions))
         }
@@ -73,6 +78,12 @@ fn finalize_type(ty: input::Type, resolutions: &TypeResolutions) -> output::Type
             None => panic!("Did not resolve type for type variable {}", tvar),
             Some(pt) => output::Type::Primitive(*pt),
         },
+        input::Type::Function(mut args, ret) => output::Type::Function(
+            args.drain(..)
+                .map(|x| finalize_type(x, resolutions))
+                .collect(),
+            Box::new(finalize_type(*ret, resolutions)),
+        ),
     }
 }
 
@@ -89,6 +100,9 @@ fn finalize_val_or_ref(
 
             match val {
                 input::Value::Unknown(base, value) => match new_type {
+                    output::Type::Function(_, _) => {
+                        panic!("Somehow inferred that a constant was a function")
+                    }
                     output::Type::Primitive(PrimitiveType::U8) => output::ValueOrRef::Value(
                         loc,
                         new_type,