use std::ops::Index;
use std::sync::Arc;
use rustc_hash::FxHashMap;
use ra_arena::{Arena, RawId, impl_arena_id};
use ra_db::{LocalSyntaxPtr, Cancelable};
use ra_syntax::ast::{self, AstNode, LoopBodyOwner, ArgListOwner, NameOwner};
use crate::{Path, type_ref::{Mutability, TypeRef}, Name, HirDatabase, DefId, Def, name::AsName};
#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
pub struct ExprId(RawId);
impl_arena_id!(ExprId);
/// The body of an item (function, const etc.).
#[derive(Debug, Eq, PartialEq)]
pub struct Body {
exprs: Arena<ExprId, Expr>,
pats: Arena<PatId, Pat>,
/// The patterns for the function's arguments. While the argument types are
/// part of the function signature, the patterns are not (they don't change
/// the external type of the function).
///
/// If this `Body` is for the body of a constant, this will just be
/// empty.
args: Vec<PatId>,
/// The `ExprId` of the actual body expression.
body_expr: ExprId,
}
/// An item body together with the mapping from syntax nodes to HIR expression
/// IDs. This is needed to go from e.g. a position in a file to the HIR
/// expression containing it; but for type inference etc., we want to operate on
/// a structure that is agnostic to the actual positions of expressions in the
/// file, so that we don't recompute the type inference whenever some whitespace
/// is typed.
#[derive(Debug, Eq, PartialEq)]
pub struct BodySyntaxMapping {
body: Arc<Body>,
expr_syntax_mapping: FxHashMap<LocalSyntaxPtr, ExprId>,
expr_syntax_mapping_back: FxHashMap<ExprId, LocalSyntaxPtr>,
pat_syntax_mapping: FxHashMap<LocalSyntaxPtr, PatId>,
pat_syntax_mapping_back: FxHashMap<PatId, LocalSyntaxPtr>,
}
impl Body {
pub fn args(&self) -> &[PatId] {
&self.args
}
pub fn body_expr(&self) -> ExprId {
self.body_expr
}
}
impl Index<ExprId> for Body {
type Output = Expr;
fn index(&self, expr: ExprId) -> &Expr {
&self.exprs[expr]
}
}
impl Index<PatId> for Body {
type Output = Pat;
fn index(&self, pat: PatId) -> &Pat {
&self.pats[pat]
}
}
impl BodySyntaxMapping {
pub fn expr_syntax(&self, expr: ExprId) -> Option<LocalSyntaxPtr> {
self.expr_syntax_mapping_back.get(&expr).cloned()
}
pub fn syntax_expr(&self, ptr: LocalSyntaxPtr) -> Option<ExprId> {
self.expr_syntax_mapping.get(&ptr).cloned()
}
pub fn pat_syntax(&self, pat: PatId) -> Option<LocalSyntaxPtr> {
self.pat_syntax_mapping_back.get(&pat).cloned()
}
pub fn syntax_pat(&self, ptr: LocalSyntaxPtr) -> Option<PatId> {
self.pat_syntax_mapping.get(&ptr).cloned()
}
pub fn body(&self) -> &Arc<Body> {
&self.body
}
}
#[derive(Debug, Clone, Eq, PartialEq)]
pub enum Expr {
/// This is produced if syntax tree does not have a required expression piece.
Missing,
Path(Path),
If {
condition: ExprId,
then_branch: ExprId,
else_branch: Option<ExprId>,
},
Block {
statements: Vec<Statement>,
tail: Option<ExprId>,
},
Loop {
body: ExprId,
},
While {
condition: ExprId,
body: ExprId,
},
For {
iterable: ExprId,
pat: PatId,
body: ExprId,
},
Call {
callee: ExprId,
args: Vec<ExprId>,
},
MethodCall {
receiver: ExprId,
method_name: Name,
args: Vec<ExprId>,
},
Match {
expr: ExprId,
arms: Vec<MatchArm>,
},
Continue,
Break {
expr: Option<ExprId>,
},
Return {
expr: Option<ExprId>,
},
StructLit {
path: Option<Path>,
fields: Vec<StructLitField>,
spread: Option<ExprId>,
},
Field {
expr: ExprId,
name: Name,
},
Try {
expr: ExprId,
},
Cast {
expr: ExprId,
type_ref: TypeRef,
},
Ref {
expr: ExprId,
mutability: Mutability,
},
UnaryOp {
expr: ExprId,
op: Option<UnaryOp>,
},
Lambda {
args: Vec<PatId>,
arg_types: Vec<Option<TypeRef>>,
body: ExprId,
},
}
pub type UnaryOp = ast::PrefixOp;
#[derive(Debug, Clone, Eq, PartialEq)]
pub struct MatchArm {
pub pats: Vec<PatId>,
// guard: Option<ExprId>, // TODO
pub expr: ExprId,
}
#[derive(Debug, Clone, Eq, PartialEq)]
pub struct StructLitField {
pub name: Name,
pub expr: ExprId,
}
#[derive(Debug, Clone, Eq, PartialEq)]
pub enum Statement {
Let {
pat: PatId,
type_ref: Option<TypeRef>,
initializer: Option<ExprId>,
},
Expr(ExprId),
}
impl Expr {
pub fn walk_child_exprs(&self, mut f: impl FnMut(ExprId)) {
match self {
Expr::Missing => {}
Expr::Path(_) => {}
Expr::If {
condition,
then_branch,
else_branch,
} => {
f(*condition);
f(*then_branch);
if let Some(else_branch) = else_branch {
f(*else_branch);
}
}
Expr::Block { statements, tail } => {
for stmt in statements {
match stmt {
Statement::Let { initializer, .. } => {
if let Some(expr) = initializer {
f(*expr);
}
}
Statement::Expr(e) => f(*e),
}
}
if let Some(expr) = tail {
f(*expr);
}
}
Expr::Loop { body } => f(*body),
Expr::While { condition, body } => {
f(*condition);
f(*body);
}
Expr::For { iterable, body, .. } => {
f(*iterable);
f(*body);
}
Expr::Call { callee, args } => {
f(*callee);
for arg in args {
f(*arg);
}
}
Expr::MethodCall { receiver, args, .. } => {
f(*receiver);
for arg in args {
f(*arg);
}
}
Expr::Match { expr, arms } => {
f(*expr);
for arm in arms {
f(arm.expr);
}
}
Expr::Continue => {}
Expr::Break { expr } | Expr::Return { expr } => {
if let Some(expr) = expr {
f(*expr);
}
}
Expr::StructLit { fields, spread, .. } => {
for field in fields {
f(field.expr);
}
if let Some(expr) = spread {
f(*expr);
}
}
Expr::Lambda { body, .. } => {
f(*body);
}
Expr::Field { expr, .. }
| Expr::Try { expr }
| Expr::Cast { expr, .. }
| Expr::Ref { expr, .. }
| Expr::UnaryOp { expr, .. } => {
f(*expr);
}
}
}
}
#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
pub struct PatId(RawId);
impl_arena_id!(PatId);
#[derive(Debug, Clone, Eq, PartialEq)]
pub enum Pat {
Missing,
Bind {
name: Name,
},
TupleStruct {
path: Option<Path>,
args: Vec<PatId>,
},
}
impl Pat {
pub fn walk_child_pats(&self, f: impl FnMut(PatId)) {
match self {
Pat::Missing | Pat::Bind { .. } => {}
Pat::TupleStruct { args, .. } => {
args.iter().map(|pat| *pat).for_each(f);
}
}
}
}
// Queries
pub(crate) fn body_hir(db: &impl HirDatabase, def_id: DefId) -> Cancelable<Arc<Body>> {
Ok(Arc::clone(&body_syntax_mapping(db, def_id)?.body))
}
struct ExprCollector {
exprs: Arena<ExprId, Expr>,
pats: Arena<PatId, Pat>,
expr_syntax_mapping: FxHashMap<LocalSyntaxPtr, ExprId>,
expr_syntax_mapping_back: FxHashMap<ExprId, LocalSyntaxPtr>,
pat_syntax_mapping: FxHashMap<LocalSyntaxPtr, PatId>,
pat_syntax_mapping_back: FxHashMap<PatId, LocalSyntaxPtr>,
}
impl ExprCollector {
fn new() -> Self {
ExprCollector {
exprs: Arena::default(),
pats: Arena::default(),
expr_syntax_mapping: FxHashMap::default(),
expr_syntax_mapping_back: FxHashMap::default(),
pat_syntax_mapping: FxHashMap::default(),
pat_syntax_mapping_back: FxHashMap::default(),
}
}
fn alloc_expr(&mut self, expr: Expr, syntax_ptr: LocalSyntaxPtr) -> ExprId {
let id = self.exprs.alloc(expr);
self.expr_syntax_mapping.insert(syntax_ptr, id);
self.expr_syntax_mapping_back.insert(id, syntax_ptr);
id
}
fn alloc_pat(&mut self, pat: Pat, syntax_ptr: LocalSyntaxPtr) -> PatId {
let id = self.pats.alloc(pat);
self.pat_syntax_mapping.insert(syntax_ptr, id);
self.pat_syntax_mapping_back.insert(id, syntax_ptr);
id
}
fn empty_block(&mut self) -> ExprId {
let block = Expr::Block {
statements: Vec::new(),
tail: None,
};
self.exprs.alloc(block)
}
fn collect_expr(&mut self, expr: ast::Expr) -> ExprId {
let syntax_ptr = LocalSyntaxPtr::new(expr.syntax());
match expr {
ast::Expr::IfExpr(e) => {
if let Some(pat) = e.condition().and_then(|c| c.pat()) {
// if let -- desugar to match
let pat = self.collect_pat(pat);
let match_expr =
self.collect_expr_opt(e.condition().expect("checked above").expr());
let then_branch = self.collect_block_opt(e.then_branch());
let else_branch = e
.else_branch()
.map(|e| self.collect_block(e))
.unwrap_or_else(|| self.empty_block());
let placeholder_pat = self.pats.alloc(Pat::Missing);
let arms = vec![
MatchArm {
pats: vec![pat],
expr: then_branch,
},
MatchArm {
pats: vec![placeholder_pat],
expr: else_branch,
},
];
self.alloc_expr(
Expr::Match {
expr: match_expr,
arms,
},
syntax_ptr,
)
} else {
let condition = self.collect_expr_opt(e.condition().and_then(|c| c.expr()));
let then_branch = self.collect_block_opt(e.then_branch());
let else_branch = e.else_branch().map(|e| self.collect_block(e));
self.alloc_expr(
Expr::If {
condition,
then_branch,
else_branch,
},
syntax_ptr,
)
}
}
ast::Expr::BlockExpr(e) => self.collect_block_opt(e.block()),
ast::Expr::LoopExpr(e) => {
let body = self.collect_block_opt(e.loop_body());
self.alloc_expr(Expr::Loop { body }, syntax_ptr)
}
ast::Expr::WhileExpr(e) => {
let condition = if let Some(condition) = e.condition() {
if condition.pat().is_none() {
self.collect_expr_opt(condition.expr())
} else {
// TODO handle while let
return self.alloc_expr(Expr::Missing, syntax_ptr);
}
} else {
self.exprs.alloc(Expr::Missing)
};
let body = self.collect_block_opt(e.loop_body());
self.alloc_expr(Expr::While { condition, body }, syntax_ptr)
}
ast::Expr::ForExpr(e) => {
let iterable = self.collect_expr_opt(e.iterable());
let pat = self.collect_pat_opt(e.pat());
let body = self.collect_block_opt(e.loop_body());
self.alloc_expr(
Expr::For {
iterable,
pat,
body,
},
syntax_ptr,
)
}
ast::Expr::CallExpr(e) => {
let callee = self.collect_expr_opt(e.expr());
let args = if let Some(arg_list) = e.arg_list() {
arg_list.args().map(|e| self.collect_expr(e)).collect()
} else {
Vec::new()
};
self.alloc_expr(Expr::Call { callee, args }, syntax_ptr)
}
ast::Expr::MethodCallExpr(e) => {
let receiver = self.collect_expr_opt(e.expr());
let args = if let Some(arg_list) = e.arg_list() {
arg_list.args().map(|e| self.collect_expr(e)).collect()
} else {
Vec::new()
};
let method_name = e
.name_ref()
.map(|nr| nr.as_name())
.unwrap_or_else(Name::missing);
self.alloc_expr(
Expr::MethodCall {
receiver,
method_name,
args,
},
syntax_ptr,
)
}
ast::Expr::MatchExpr(e) => {
let expr = self.collect_expr_opt(e.expr());
let arms = if let Some(match_arm_list) = e.match_arm_list() {
match_arm_list
.arms()
.map(|arm| MatchArm {
pats: arm.pats().map(|p| self.collect_pat(p)).collect(),
expr: self.collect_expr_opt(arm.expr()),
})
.collect()
} else {
Vec::new()
};
self.alloc_expr(Expr::Match { expr, arms }, syntax_ptr)
}
ast::Expr::PathExpr(e) => {
let path = e
.path()
.and_then(Path::from_ast)
.map(Expr::Path)
.unwrap_or(Expr::Missing);
self.alloc_expr(path, syntax_ptr)
}
ast::Expr::ContinueExpr(_e) => {
// TODO: labels
self.alloc_expr(Expr::Continue, syntax_ptr)
}
ast::Expr::BreakExpr(e) => {
let expr = e.expr().map(|e| self.collect_expr(e));
self.alloc_expr(Expr::Break { expr }, syntax_ptr)
}
ast::Expr::ParenExpr(e) => {
let inner = self.collect_expr_opt(e.expr());
// make the paren expr point to the inner expression as well
self.expr_syntax_mapping.insert(syntax_ptr, inner);
inner
}
ast::Expr::ReturnExpr(e) => {
let expr = e.expr().map(|e| self.collect_expr(e));
self.alloc_expr(Expr::Return { expr }, syntax_ptr)
}
ast::Expr::StructLit(e) => {
let path = e.path().and_then(Path::from_ast);
let fields = if let Some(nfl) = e.named_field_list() {
nfl.fields()
.map(|field| StructLitField {
name: field
.name_ref()
.map(|nr| nr.as_name())
.unwrap_or_else(Name::missing),
expr: if let Some(e) = field.expr() {
self.collect_expr(e)
} else if let Some(nr) = field.name_ref() {
// field shorthand
let id = self.exprs.alloc(Expr::Path(Path::from_name_ref(nr)));
self.expr_syntax_mapping
.insert(LocalSyntaxPtr::new(nr.syntax()), id);
self.expr_syntax_mapping_back
.insert(id, LocalSyntaxPtr::new(nr.syntax()));
id
} else {
self.exprs.alloc(Expr::Missing)
},
})
.collect()
} else {
Vec::new()
};
let spread = e.spread().map(|s| self.collect_expr(s));
self.alloc_expr(
Expr::StructLit {
path,
fields,
spread,
},
syntax_ptr,
)
}
ast::Expr::FieldExpr(e) => {
let expr = self.collect_expr_opt(e.expr());
let name = e
.name_ref()
.map(|nr| nr.as_name())
.unwrap_or_else(Name::missing);
self.alloc_expr(Expr::Field { expr, name }, syntax_ptr)
}
ast::Expr::TryExpr(e) => {
let expr = self.collect_expr_opt(e.expr());
self.alloc_expr(Expr::Try { expr }, syntax_ptr)
}
ast::Expr::CastExpr(e) => {
let expr = self.collect_expr_opt(e.expr());
let type_ref = TypeRef::from_ast_opt(e.type_ref());
self.alloc_expr(Expr::Cast { expr, type_ref }, syntax_ptr)
}
ast::Expr::RefExpr(e) => {
let expr = self.collect_expr_opt(e.expr());
let mutability = Mutability::from_mutable(e.is_mut());
self.alloc_expr(Expr::Ref { expr, mutability }, syntax_ptr)
}
ast::Expr::PrefixExpr(e) => {
let expr = self.collect_expr_opt(e.expr());
let op = e.op();
self.alloc_expr(Expr::UnaryOp { expr, op }, syntax_ptr)
}
ast::Expr::LambdaExpr(e) => {
let mut args = Vec::new();
let mut arg_types = Vec::new();
if let Some(pl) = e.param_list() {
for param in pl.params() {
let pat = self.collect_pat_opt(param.pat());
let type_ref = param.type_ref().map(TypeRef::from_ast);
args.push(pat);
arg_types.push(type_ref);
}
}
let body = self.collect_expr_opt(e.body());
self.alloc_expr(
Expr::Lambda {
args,
arg_types,
body,
},
syntax_ptr,
)
}
// TODO implement HIR for these:
ast::Expr::Label(_e) => self.alloc_expr(Expr::Missing, syntax_ptr),
ast::Expr::IndexExpr(_e) => self.alloc_expr(Expr::Missing, syntax_ptr),
ast::Expr::TupleExpr(_e) => self.alloc_expr(Expr::Missing, syntax_ptr),
ast::Expr::ArrayExpr(_e) => self.alloc_expr(Expr::Missing, syntax_ptr),
ast::Expr::RangeExpr(_e) => self.alloc_expr(Expr::Missing, syntax_ptr),
ast::Expr::BinExpr(_e) => self.alloc_expr(Expr::Missing, syntax_ptr),
ast::Expr::Literal(_e) => self.alloc_expr(Expr::Missing, syntax_ptr),
}
}
fn collect_expr_opt(&mut self, expr: Option<ast::Expr>) -> ExprId {
if let Some(expr) = expr {
self.collect_expr(expr)
} else {
self.exprs.alloc(Expr::Missing)
}
}
fn collect_block(&mut self, block: ast::Block) -> ExprId {
let statements = block
.statements()
.map(|s| match s {
ast::Stmt::LetStmt(stmt) => {
let pat = self.collect_pat_opt(stmt.pat());
let type_ref = stmt.type_ref().map(TypeRef::from_ast);
let initializer = stmt.initializer().map(|e| self.collect_expr(e));
Statement::Let {
pat,
type_ref,
initializer,
}
}
ast::Stmt::ExprStmt(stmt) => Statement::Expr(self.collect_expr_opt(stmt.expr())),
})
.collect();
let tail = block.expr().map(|e| self.collect_expr(e));
self.alloc_expr(
Expr::Block { statements, tail },
LocalSyntaxPtr::new(block.syntax()),
)
}
fn collect_block_opt(&mut self, block: Option<ast::Block>) -> ExprId {
if let Some(block) = block {
self.collect_block(block)
} else {
self.exprs.alloc(Expr::Missing)
}
}
fn collect_pat(&mut self, pat: ast::Pat) -> PatId {
let syntax_ptr = LocalSyntaxPtr::new(pat.syntax());
match pat {
ast::Pat::BindPat(bp) => {
let name = bp
.name()
.map(|nr| nr.as_name())
.unwrap_or_else(Name::missing);
self.alloc_pat(Pat::Bind { name }, syntax_ptr)
}
ast::Pat::TupleStructPat(p) => {
let path = p.path().and_then(Path::from_ast);
let args = p.args().map(|p| self.collect_pat(p)).collect();
self.alloc_pat(Pat::TupleStruct { path, args }, syntax_ptr)
}
_ => {
// TODO
self.alloc_pat(Pat::Missing, syntax_ptr)
}
}
}
fn collect_pat_opt(&mut self, pat: Option<ast::Pat>) -> PatId {
if let Some(pat) = pat {
self.collect_pat(pat)
} else {
self.pats.alloc(Pat::Missing)
}
}
fn into_body_syntax_mapping(self, args: Vec<PatId>, body_expr: ExprId) -> BodySyntaxMapping {
let body = Body {
exprs: self.exprs,
pats: self.pats,
args,
body_expr,
};
BodySyntaxMapping {
body: Arc::new(body),
expr_syntax_mapping: self.expr_syntax_mapping,
expr_syntax_mapping_back: self.expr_syntax_mapping_back,
pat_syntax_mapping: self.pat_syntax_mapping,
pat_syntax_mapping_back: self.pat_syntax_mapping_back,
}
}
}
pub(crate) fn collect_fn_body_syntax(node: ast::FnDef) -> BodySyntaxMapping {
let mut collector = ExprCollector::new();
let args = if let Some(param_list) = node.param_list() {
let mut args = Vec::new();
if let Some(self_param) = param_list.self_param() {
let self_param = LocalSyntaxPtr::new(
self_param
.self_kw()
.expect("self param without self keyword")
.syntax(),
);
let arg = collector.alloc_pat(
Pat::Bind {
name: Name::self_param(),
},
self_param,
);
args.push(arg);
}
for param in param_list.params() {
let pat = if let Some(pat) = param.pat() {
pat
} else {
continue;
};
args.push(collector.collect_pat(pat));
}
args
} else {
Vec::new()
};
let body = collector.collect_block_opt(node.body());
collector.into_body_syntax_mapping(args, body)
}
pub(crate) fn body_syntax_mapping(
db: &impl HirDatabase,
def_id: DefId,
) -> Cancelable<Arc<BodySyntaxMapping>> {
let def = def_id.resolve(db)?;
let body_syntax_mapping = match def {
Def::Function(f) => {
let node = f.syntax(db);
let node = node.borrowed();
collect_fn_body_syntax(node)
}
// TODO: consts, etc.
_ => panic!("Trying to get body for item type without body"),
};
Ok(Arc::new(body_syntax_mapping))
}