refactor(users/glittershark): Rename to grfn r/2485

Rename my //users directory and all places that refer to glittershark to
grfn, including nix references and documentation.

This may require some extra attention inside of gerrit's database after
it lands to allow me to actually push things.

Change-Id: I4728b7ec2c60024392c1c1fa6e0d4a59b3e266fa
Reviewed-on: https://cl.tvl.fyi/c/depot/+/2933
Tested-by: BuildkiteCI
Reviewed-by: tazjin <mail@tazj.in>
Reviewed-by: lukegb <lukegb@tvl.fyi>
Reviewed-by: glittershark <grfn@gws.fyi>

3 files changed, 525 insertions, 0 deletions

diff --git a/users/grfn/achilles/src/passes/hir/mod.rs b/users/grfn/achilles/src/passes/hir/mod.rs
new file mode 100644
index 000000000000..845bfcb7ab6a
--- /dev/null
+++ b/users/grfn/achilles/src/passes/hir/mod.rs
@@ -0,0 +1,197 @@
+use std::collections::HashMap;
+
+use crate::ast::hir::{Binding, Decl, Expr};
+use crate::ast::{BinaryOperator, Ident, Literal, UnaryOperator};
+
+pub(crate) mod monomorphize;
+pub(crate) mod strip_positive_units;
+
+pub(crate) trait Visitor<'a, 'ast, T: 'ast>: Sized + 'a {
+    type Error;
+
+    fn visit_type(&mut self, _type: &mut T) -> Result<(), Self::Error> {
+        Ok(())
+    }
+
+    fn visit_ident(&mut self, _ident: &mut Ident<'ast>) -> Result<(), Self::Error> {
+        Ok(())
+    }
+
+    fn visit_literal(&mut self, _literal: &mut Literal<'ast>) -> Result<(), Self::Error> {
+        Ok(())
+    }
+
+    fn visit_unary_operator(&mut self, _op: &mut UnaryOperator) -> Result<(), Self::Error> {
+        Ok(())
+    }
+
+    fn visit_binary_operator(&mut self, _op: &mut BinaryOperator) -> Result<(), Self::Error> {
+        Ok(())
+    }
+
+    fn visit_binding(&mut self, binding: &mut Binding<'ast, T>) -> Result<(), Self::Error> {
+        self.visit_ident(&mut binding.ident)?;
+        self.visit_type(&mut binding.type_)?;
+        self.visit_expr(&mut binding.body)?;
+        Ok(())
+    }
+
+    fn post_visit_call(
+        &mut self,
+        _fun: &mut Expr<'ast, T>,
+        _type_args: &mut HashMap<Ident<'ast>, T>,
+        _args: &mut Vec<Expr<'ast, T>>,
+    ) -> Result<(), Self::Error> {
+        Ok(())
+    }
+
+    fn pre_visit_call(
+        &mut self,
+        _fun: &mut Expr<'ast, T>,
+        _type_args: &mut HashMap<Ident<'ast>, T>,
+        _args: &mut Vec<Expr<'ast, T>>,
+    ) -> Result<(), Self::Error> {
+        Ok(())
+    }
+
+    fn pre_visit_expr(&mut self, _expr: &mut Expr<'ast, T>) -> Result<(), Self::Error> {
+        Ok(())
+    }
+
+    fn visit_expr(&mut self, expr: &mut Expr<'ast, T>) -> Result<(), Self::Error> {
+        self.pre_visit_expr(expr)?;
+        match expr {
+            Expr::Ident(id, t) => {
+                self.visit_ident(id)?;
+                self.visit_type(t)?;
+            }
+            Expr::Literal(lit, t) => {
+                self.visit_literal(lit)?;
+                self.visit_type(t)?;
+            }
+            Expr::UnaryOp { op, rhs, type_ } => {
+                self.visit_unary_operator(op)?;
+                self.visit_expr(rhs)?;
+                self.visit_type(type_)?;
+            }
+            Expr::BinaryOp {
+                lhs,
+                op,
+                rhs,
+                type_,
+            } => {
+                self.visit_expr(lhs)?;
+                self.visit_binary_operator(op)?;
+                self.visit_expr(rhs)?;
+                self.visit_type(type_)?;
+            }
+            Expr::Let {
+                bindings,
+                body,
+                type_,
+            } => {
+                for binding in bindings.iter_mut() {
+                    self.visit_binding(binding)?;
+                }
+                self.visit_expr(body)?;
+                self.visit_type(type_)?;
+            }
+            Expr::If {
+                condition,
+                then,
+                else_,
+                type_,
+            } => {
+                self.visit_expr(condition)?;
+                self.visit_expr(then)?;
+                self.visit_expr(else_)?;
+                self.visit_type(type_)?;
+            }
+            Expr::Fun {
+                args,
+                body,
+                type_args,
+                type_,
+            } => {
+                for (ident, t) in args {
+                    self.visit_ident(ident)?;
+                    self.visit_type(t)?;
+                }
+                for ta in type_args {
+                    self.visit_ident(ta)?;
+                }
+                self.visit_expr(body)?;
+                self.visit_type(type_)?;
+            }
+            Expr::Call {
+                fun,
+                args,
+                type_args,
+                type_,
+            } => {
+                self.pre_visit_call(fun, type_args, args)?;
+                self.visit_expr(fun)?;
+                for arg in args.iter_mut() {
+                    self.visit_expr(arg)?;
+                }
+                self.visit_type(type_)?;
+                self.post_visit_call(fun, type_args, args)?;
+            }
+        }
+
+        Ok(())
+    }
+
+    fn post_visit_decl(&mut self, decl: &'a Decl<'ast, T>) -> Result<(), Self::Error> {
+        Ok(())
+    }
+
+    fn post_visit_fun_decl(
+        &mut self,
+        _name: &mut Ident<'ast>,
+        _type_args: &mut Vec<Ident>,
+        _args: &mut Vec<(Ident, T)>,
+        _body: &mut Box<Expr<T>>,
+        _type_: &mut T,
+    ) -> Result<(), Self::Error> {
+        Ok(())
+    }
+
+    fn visit_decl(&mut self, decl: &'a mut Decl<'ast, T>) -> Result<(), Self::Error> {
+        match decl {
+            Decl::Fun {
+                name,
+                type_args,
+                args,
+                body,
+                type_,
+            } => {
+                self.visit_ident(name)?;
+                for type_arg in type_args.iter_mut() {
+                    self.visit_ident(type_arg)?;
+                }
+                for (arg, t) in args.iter_mut() {
+                    self.visit_ident(arg)?;
+                    self.visit_type(t)?;
+                }
+                self.visit_expr(body)?;
+                self.visit_type(type_)?;
+                self.post_visit_fun_decl(name, type_args, args, body, type_)?;
+            }
+            Decl::Extern {
+                name,
+                arg_types,
+                ret_type,
+            } => {
+                self.visit_ident(name)?;
+                for arg_t in arg_types {
+                    self.visit_type(arg_t)?;
+                }
+                self.visit_type(ret_type)?;
+            }
+        }
+
+        self.post_visit_decl(decl)?;
+        Ok(())
+    }
+}
diff --git a/users/grfn/achilles/src/passes/hir/monomorphize.rs b/users/grfn/achilles/src/passes/hir/monomorphize.rs
new file mode 100644
index 000000000000..251a988f4f6f
--- /dev/null
+++ b/users/grfn/achilles/src/passes/hir/monomorphize.rs
@@ -0,0 +1,139 @@
+use std::cell::RefCell;
+use std::collections::{HashMap, HashSet};
+use std::convert::TryInto;
+use std::mem;
+
+use void::{ResultVoidExt, Void};
+
+use crate::ast::hir::{Decl, Expr};
+use crate::ast::{self, Ident};
+
+use super::Visitor;
+
+#[derive(Default)]
+pub(crate) struct Monomorphize<'a, 'ast> {
+    decls: HashMap<&'a Ident<'ast>, &'a Decl<'ast, ast::Type<'ast>>>,
+    extra_decls: Vec<Decl<'ast, ast::Type<'ast>>>,
+    remove_decls: HashSet<Ident<'ast>>,
+}
+
+impl<'a, 'ast> Monomorphize<'a, 'ast> {
+    pub(crate) fn new() -> Self {
+        Default::default()
+    }
+}
+
+impl<'a, 'ast> Visitor<'a, 'ast, ast::Type<'ast>> for Monomorphize<'a, 'ast> {
+    type Error = Void;
+
+    fn post_visit_call(
+        &mut self,
+        fun: &mut Expr<'ast, ast::Type<'ast>>,
+        type_args: &mut HashMap<Ident<'ast>, ast::Type<'ast>>,
+        args: &mut Vec<Expr<'ast, ast::Type<'ast>>>,
+    ) -> Result<(), Self::Error> {
+        let new_fun = match fun {
+            Expr::Ident(id, _) => {
+                let decl: Decl<_> = (**self.decls.get(id).unwrap()).clone();
+                let name = RefCell::new(id.to_string());
+                let type_args = mem::take(type_args);
+                let mut monomorphized = decl
+                    .traverse_type(|ty| -> Result<_, Void> {
+                        Ok(ty.clone().traverse_type_vars(|v| {
+                            let concrete = type_args.get(&v).unwrap();
+                            name.borrow_mut().push_str(&concrete.to_string());
+                            concrete.clone()
+                        }))
+                    })
+                    .void_unwrap();
+                let name: Ident = name.into_inner().try_into().unwrap();
+                if name != *id {
+                    self.remove_decls.insert(id.clone());
+                    monomorphized.set_name(name.clone());
+                    let type_ = monomorphized.type_().unwrap().clone();
+                    self.extra_decls.push(monomorphized);
+                    Some(Expr::Ident(name, type_))
+                } else {
+                    None
+                }
+            }
+            _ => todo!(),
+        };
+        if let Some(new_fun) = new_fun {
+            *fun = new_fun;
+        }
+        Ok(())
+    }
+
+    fn post_visit_decl(
+        &mut self,
+        decl: &'a Decl<'ast, ast::Type<'ast>>,
+    ) -> Result<(), Self::Error> {
+        self.decls.insert(decl.name(), decl);
+        Ok(())
+    }
+}
+
+pub(crate) fn run_toplevel<'a>(toplevel: &mut Vec<Decl<'a, ast::Type<'a>>>) {
+    let mut pass = Monomorphize::new();
+    for decl in toplevel.iter_mut() {
+        pass.visit_decl(decl).void_unwrap();
+    }
+    let remove_decls = mem::take(&mut pass.remove_decls);
+    let mut extra_decls = mem::take(&mut pass.extra_decls);
+    toplevel.retain(|decl| !remove_decls.contains(decl.name()));
+    extra_decls.append(toplevel);
+    *toplevel = extra_decls;
+}
+
+#[cfg(test)]
+mod tests {
+    use std::convert::TryFrom;
+
+    use super::*;
+    use crate::parser::toplevel;
+    use crate::tc::typecheck_toplevel;
+
+    #[test]
+    fn call_id_decl() {
+        let (_, program) = toplevel(
+            "ty id : fn a -> a
+             fn id x = x
+
+             ty main : fn -> int
+             fn main = id 0",
+        )
+        .unwrap();
+        let mut program = typecheck_toplevel(program).unwrap();
+        run_toplevel(&mut program);
+
+        let find_decl = |ident: &str| {
+            program.iter().find(|decl| {
+                matches!(decl, Decl::Fun {name, ..} if name == &Ident::try_from(ident).unwrap())
+            }).unwrap()
+        };
+
+        let main = find_decl("main");
+        let body = match main {
+            Decl::Fun { body, .. } => body,
+            _ => unreachable!(),
+        };
+
+        let expected_type = ast::Type::Function(ast::FunctionType {
+            args: vec![ast::Type::Int],
+            ret: Box::new(ast::Type::Int),
+        });
+
+        match &**body {
+            Expr::Call { fun, .. } => {
+                let fun = match &**fun {
+                    Expr::Ident(fun, _) => fun,
+                    _ => unreachable!(),
+                };
+                let called_decl = find_decl(fun.into());
+                assert_eq!(called_decl.type_().unwrap(), &expected_type);
+            }
+            _ => unreachable!(),
+        }
+    }
+}
diff --git a/users/grfn/achilles/src/passes/hir/strip_positive_units.rs b/users/grfn/achilles/src/passes/hir/strip_positive_units.rs
new file mode 100644
index 000000000000..91b56551c82d
--- /dev/null
+++ b/users/grfn/achilles/src/passes/hir/strip_positive_units.rs
@@ -0,0 +1,189 @@
+use std::collections::HashMap;
+use std::mem;
+
+use ast::hir::Binding;
+use ast::Literal;
+use void::{ResultVoidExt, Void};
+
+use crate::ast::hir::{Decl, Expr};
+use crate::ast::{self, Ident};
+
+use super::Visitor;
+
+/// Strip all values with a unit type in positive (non-return) position
+pub(crate) struct StripPositiveUnits {}
+
+impl<'a, 'ast> Visitor<'a, 'ast, ast::Type<'ast>> for StripPositiveUnits {
+    type Error = Void;
+
+    fn pre_visit_expr(
+        &mut self,
+        expr: &mut Expr<'ast, ast::Type<'ast>>,
+    ) -> Result<(), Self::Error> {
+        let mut extracted = vec![];
+        if let Expr::Call { args, .. } = expr {
+            // TODO(grfn): replace with drain_filter once it's stabilized
+            let mut i = 0;
+            while i != args.len() {
+                if args[i].type_() == &ast::Type::Unit {
+                    let expr = args.remove(i);
+                    if !matches!(expr, Expr::Literal(Literal::Unit, _)) {
+                        extracted.push(expr)
+                    };
+                } else {
+                    i += 1
+                }
+            }
+        }
+
+        if !extracted.is_empty() {
+            let body = mem::replace(expr, Expr::Literal(Literal::Unit, ast::Type::Unit));
+            *expr = Expr::Let {
+                bindings: extracted
+                    .into_iter()
+                    .map(|expr| Binding {
+                        ident: Ident::from_str_unchecked("___discarded"),
+                        type_: expr.type_().clone(),
+                        body: expr,
+                    })
+                    .collect(),
+                type_: body.type_().clone(),
+                body: Box::new(body),
+            };
+        }
+
+        Ok(())
+    }
+
+    fn post_visit_call(
+        &mut self,
+        _fun: &mut Expr<'ast, ast::Type<'ast>>,
+        _type_args: &mut HashMap<Ident<'ast>, ast::Type<'ast>>,
+        args: &mut Vec<Expr<'ast, ast::Type<'ast>>>,
+    ) -> Result<(), Self::Error> {
+        args.retain(|arg| arg.type_() != &ast::Type::Unit);
+        Ok(())
+    }
+
+    fn visit_type(&mut self, type_: &mut ast::Type<'ast>) -> Result<(), Self::Error> {
+        if let ast::Type::Function(ft) = type_ {
+            ft.args.retain(|a| a != &ast::Type::Unit);
+        }
+        Ok(())
+    }
+
+    fn post_visit_fun_decl(
+        &mut self,
+        _name: &mut Ident<'ast>,
+        _type_args: &mut Vec<Ident>,
+        args: &mut Vec<(Ident, ast::Type<'ast>)>,
+        _body: &mut Box<Expr<ast::Type<'ast>>>,
+        _type_: &mut ast::Type<'ast>,
+    ) -> Result<(), Self::Error> {
+        args.retain(|(_, ty)| ty != &ast::Type::Unit);
+        Ok(())
+    }
+}
+
+pub(crate) fn run_toplevel<'a>(toplevel: &mut Vec<Decl<'a, ast::Type<'a>>>) {
+    let mut pass = StripPositiveUnits {};
+    for decl in toplevel.iter_mut() {
+        pass.visit_decl(decl).void_unwrap();
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::parser::toplevel;
+    use crate::tc::typecheck_toplevel;
+    use pretty_assertions::assert_eq;
+
+    #[test]
+    fn unit_only_arg() {
+        let (_, program) = toplevel(
+            "ty f : fn () -> int
+             fn f _ = 1
+
+             ty main : fn -> int
+             fn main = f ()",
+        )
+        .unwrap();
+
+        let (_, expected) = toplevel(
+            "ty f : fn -> int
+             fn f = 1
+
+             ty main : fn -> int
+             fn main = f()",
+        )
+        .unwrap();
+        let expected = typecheck_toplevel(expected).unwrap();
+
+        let mut program = typecheck_toplevel(program).unwrap();
+        run_toplevel(&mut program);
+
+        assert_eq!(program, expected);
+    }
+
+    #[test]
+    fn unit_and_other_arg() {
+        let (_, program) = toplevel(
+            "ty f : fn (), int -> int
+             fn f _ x = x
+
+             ty main : fn -> int
+             fn main = f () 1",
+        )
+        .unwrap();
+
+        let (_, expected) = toplevel(
+            "ty f : fn int -> int
+             fn f x = x
+
+             ty main : fn -> int
+             fn main = f 1",
+        )
+        .unwrap();
+        let expected = typecheck_toplevel(expected).unwrap();
+
+        let mut program = typecheck_toplevel(program).unwrap();
+        run_toplevel(&mut program);
+
+        assert_eq!(program, expected);
+    }
+
+    #[test]
+    fn unit_expr_and_other_arg() {
+        let (_, program) = toplevel(
+            "ty f : fn (), int -> int
+             fn f _ x = x
+
+             ty g : fn int -> ()
+             fn g _ = ()
+
+             ty main : fn -> int
+             fn main = f (g 2) 1",
+        )
+        .unwrap();
+
+        let (_, expected) = toplevel(
+            "ty f : fn int -> int
+             fn f x = x
+
+             ty g : fn int -> ()
+             fn g _ = ()
+
+             ty main : fn -> int
+             fn main = let ___discarded = g 2 in f 1",
+        )
+        .unwrap();
+        assert_eq!(expected.len(), 6);
+        let expected = typecheck_toplevel(expected).unwrap();
+
+        let mut program = typecheck_toplevel(program).unwrap();
+        run_toplevel(&mut program);
+
+        assert_eq!(program, expected);
+    }
+}