yog_script_analyze/typeck/

types.rs

//! Each expression's type, as the checker found it: what a compiler needs
//! to write the code (a local's declaration, a value boxed, a switch's
//! result) and an editor to show.

use std::collections::HashMap;

use super::model::Type;
use crate::ast::Expr;

/// The types of a checked file's expressions. An expression is known by
/// its node in the file's tree — which, once checked, isn't changed — so
/// two that share a place (a macro's output, all at its call) stay apart.
#[derive(Debug, Default)]
pub struct Types {
    types: HashMap<usize, Type>,
    /// The operators a type declares that expressions are (`a + b`, `-a`,
    /// `(Energy)n`), by expression.
    operators: HashMap<usize, OperatorUse>,
    /// The implicit conversions values go through where they're handed
    /// on, by expression.
    conversions: HashMap<usize, OperatorUse>,
    /// The types values are recast to where they go by variance only (the
    /// JVM's generics have none), by expression.
    recasts: HashMap<usize, Type>,
    /// The lambdas given where an expression tree is wanted
    /// (`Expression<Func<i32, bool>>`), by the lambda.
    quoted: HashMap<usize, Quoted>,
    /// What each `foreach`'s items are, by what it goes through.
    items: HashMap<usize, Type>,
    /// The type of each name a pattern binds (`let r`, `Monster m`), by the name.
    bindings: HashMap<usize, Type>,
    /// The constructor each `new T(…)` chose: which of the type's, its body's
    /// in order and then its primary one, by the `new`.
    constructors: HashMap<usize, usize>,
    /// A `new` whose constructor's `params` takes its arguments from one on
    /// (the call's expanded form): from where, and the array's item type.
    constructor_rests: HashMap<usize, (usize, Type)>,
    /// The method each call chose, by the call.
    methods: HashMap<usize, MethodUse>,
    /// Calls across sides, by the call.
    messages: HashMap<usize, Message>,
    /// The operators `op=` applies (`v += w` on a `Vec`), by the place it
    /// writes.
    assigned: HashMap<usize, OperatorUse>,
    /// The names that are a local's or a parameter's (not a member's), by
    /// the name's expression.
    locals: std::collections::HashSet<usize>,
    /// The bound a type parameter's value is reached through, by the
    /// value (`t.Score()` of `where T : IScore`: `IScore`).
    bounded: HashMap<usize, Type>,
    /// The locals each lambda handed to another thread takes from its
    /// owner (not `Copy`): moved there, by the lambda.
    moved_away: HashMap<usize, Vec<String>>,
    /// The strings written for message templates, by the string.
    templates: HashMap<usize, super::templates::MessageTemplate>,
    /// What each lambda captures, by the lambda (`threads/captures.rs`).
    captures: HashMap<usize, Vec<super::threads::Capture>>,
}

/// A lambda given as an expression tree: its delegate's type, and the
/// parameters and result the delegate gives it.
#[derive(Debug, Clone, PartialEq)]
pub struct Quoted {
    pub delegate: Type,
    pub params: Vec<Type>,
    pub ret: Type,
}

/// An operator or a conversion a type declares, as used: the type, its
/// method (`op_Addition`, `op_Implicit`).
#[derive(Debug, Clone, PartialEq)]
pub struct OperatorUse {
    pub owner: Type,
    pub method: String,
}

/// A method as a call chose it: its type (none: the file's), its name,
/// which of the type's methods of that name (in declaration order), its
/// parameters and result as declared (its type parameters unbound).
/// A call across sides: the file's method it runs on the other side, and
/// which way it goes.
#[derive(Debug, Clone, PartialEq)]
pub struct Message {
    pub method: String,
    /// From a client to the server (else from the server to a client).
    pub to_server: bool,
}

#[derive(Debug, Clone, PartialEq)]
pub struct MethodUse {
    pub owner: Option<String>,
    /// Its type's arity (`ValueTuple<T1, T2>`'s 2): one of its name.
    pub owner_arity: usize,
    pub name: String,
    pub overload: usize,
    pub params: Vec<Type>,
    pub ret: Type,
    /// Its parameters as the call takes them (its type parameters bound).
    pub taken: Vec<Type>,
    /// Its own type parameters' types in this call, in order.
    pub type_args: Vec<Type>,
    /// An extension method (`xs.Where(…)`): the receiver its first argument.
    pub extension: bool,
    /// How many type parameters of its own it has (`F<A, B>`: 2).
    pub generics: usize,
    /// Its `params` parameter takes the arguments from this one on, packed
    /// in an array of its item type (the call's expanded form).
    pub rest_from: Option<usize>,
}

impl Types {
    /// The type `e`'s value is recast to, going where it's wanted by
    /// variance (`IEnumerable<string>` as an `IEnumerable<object>`).
    /// Lambda `e` as an expression tree, when it's given as one.
    pub fn quoted(&self, e: &Expr) -> Option<&Quoted> {
        self.quoted.get(&key(e))
    }

    pub(super) fn set_quoted(&mut self, e: &Expr, quoted: Quoted) {
        self.quoted.insert(key(e), quoted);
    }

    pub fn recast(&self, e: &Expr) -> Option<&Type> {
        self.recasts.get(&key(e))
    }

    pub(super) fn set_recast(&mut self, e: &Expr, to: Type) {
        self.recasts.insert(key(e), to);
    }

    /// The method call `e` chose, when it's an own one.
    /// What `foreach` over `iter` gives each time.
    pub fn item(&self, iter: &Expr) -> Option<&Type> {
        self.items.get(&key(iter))
    }

    pub(super) fn set_item(&mut self, iter: &Expr, t: Type) {
        self.items.insert(key(iter), t);
    }

    /// The type of name `n` a pattern binds.
    pub fn binding(&self, n: &crate::ast::Name) -> Option<&Type> {
        self.bindings.get(&(std::ptr::from_ref(n) as usize))
    }

    pub(super) fn set_binding(&mut self, n: &crate::ast::Name, t: Type) {
        self.bindings.insert(std::ptr::from_ref(n) as usize, t);
    }

    /// Which of its type's constructors `new` expression `e` chose.
    pub fn constructor(&self, e: &Expr) -> Option<usize> {
        self.constructors.get(&key(e)).copied()
    }

    /// Where `new` expression `e`'s `params` arguments start, and their
    /// item type, when it packs them.
    pub fn constructor_rest(&self, e: &Expr) -> Option<&(usize, Type)> {
        self.constructor_rests.get(&key(e))
    }

    pub(super) fn set_constructor_rest(&mut self, e: &Expr, from: usize, item: Type) {
        self.constructor_rests.insert(key(e), (from, item));
    }

    pub(super) fn set_constructor(&mut self, e: &Expr, index: usize) {
        self.constructors.insert(key(e), index);
    }

    pub fn method(&self, e: &Expr) -> Option<&MethodUse> {
        self.methods.get(&key(e))
    }

    /// Call `e` across sides, when it's one.
    pub fn message(&self, e: &Expr) -> Option<&Message> {
        self.messages.get(&key(e))
    }

    pub(super) fn set_message(&mut self, e: &Expr, m: Message) {
        self.messages.insert(key(e), m);
    }

    /// Whether name `e` is a local's or a parameter's (not a member's).
    pub fn is_local(&self, e: &Expr) -> bool {
        self.locals.contains(&key(e))
    }

    /// What lambda `e` captures: locals of the code around it, `this`,
    /// statics it reaches.
    pub(super) fn captures(&self, e: &Expr) -> &[super::threads::Capture] {
        self.captures.get(&key(e)).map_or(&[], Vec::as_slice)
    }

    /// The locals lambda `e` takes with it to another thread: moved away
    /// from the code around it.
    pub fn moved_away(&self, e: &Expr) -> &[String] {
        self.moved_away.get(&key(e)).map_or(&[], Vec::as_slice)
    }

    pub(super) fn set_moved_away(&mut self, e: &Expr, names: Vec<String>) {
        self.moved_away.insert(key(e), names);
    }

    /// Lambda `lambda` (by its key) captures `c` (once, by its name).
    pub(super) fn capture(&mut self, lambda: usize, c: super::threads::Capture) {
        let all = self.captures.entry(lambda).or_default();
        if !all.iter().any(|o| o.name == c.name) {
            all.push(c);
        }
    }

    /// The bound value `e` (of a type parameter) is reached through.
    pub fn bounded(&self, e: &Expr) -> Option<&Type> {
        self.bounded.get(&key(e))
    }

    pub(super) fn set_bounded(&mut self, e: &Expr, t: Type) {
        self.bounded.insert(key(e), t);
    }

    /// String `e` written for a message template, if it's one.
    pub fn template(&self, e: &Expr) -> Option<&super::templates::MessageTemplate> {
        self.templates.get(&key(e))
    }

    pub(super) fn set_template(&mut self, e: &Expr, t: super::templates::MessageTemplate) {
        self.set(e, Type::String);
        self.templates.insert(key(e), t);
    }

    pub(super) fn key_of(e: &Expr) -> usize {
        key(e)
    }

    pub(super) fn set_local(&mut self, e: &Expr) {
        self.locals.insert(key(e));
    }

    pub(super) fn set_method(&mut self, e: &Expr, used: MethodUse) {
        self.methods.insert(key(e), used);
    }

    /// `e`'s type, if it was checked.
    pub fn of(&self, e: &Expr) -> Option<&Type> {
        self.types.get(&key(e))
    }

    /// The declared operator `e` is, if it's one.
    pub fn operator(&self, e: &Expr) -> Option<&OperatorUse> {
        self.operators.get(&key(e))
    }

    /// The implicit conversion `e`'s value goes through, if any.
    pub fn conversion(&self, e: &Expr) -> Option<&OperatorUse> {
        self.conversions.get(&key(e))
    }

    /// The declared operator `place op= …` applies, if it's one.
    pub fn assigned(&self, place: &Expr) -> Option<&OperatorUse> {
        self.assigned.get(&key(place))
    }

    pub(super) fn set(&mut self, e: &Expr, t: Type) {
        self.types.insert(key(e), t);
    }

    pub(super) fn set_operator(&mut self, e: &Expr, used: OperatorUse) {
        self.operators.insert(key(e), used);
    }

    pub(super) fn set_assigned(&mut self, place: &Expr, used: OperatorUse) {
        self.assigned.insert(key(place), used);
    }

    pub(super) fn set_conversion(&mut self, e: &Expr, used: OperatorUse) {
        self.conversions.insert(key(e), used);
    }
}

/// A node's address: its identity in the tree.
fn key(e: &Expr) -> usize {
    std::ptr::from_ref(e) as usize
}