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|
use std::{
fmt,
collections::HashMap,
};
use libsyntax2::{
SyntaxNodeRef, SyntaxNode, SmolStr, AstNode,
ast::{self, NameOwner},
algo::{ancestors, generate, walk::preorder}
};
type ScopeId = usize;
#[derive(Debug)]
pub struct FnScopes {
scopes: Vec<ScopeData>,
scope_for: HashMap<SyntaxNode, ScopeId>,
}
impl FnScopes {
pub fn new(fn_def: ast::FnDef) -> FnScopes {
let mut scopes = FnScopes {
scopes: Vec::new(),
scope_for: HashMap::new()
};
let root = scopes.root_scope();
fn_def.param_list().into_iter()
.flat_map(|it| it.params())
.filter_map(|it| it.pat())
.for_each(|it| scopes.add_bindings(root, it));
if let Some(body) = fn_def.body() {
compute_block_scopes(body, &mut scopes, root)
}
scopes
}
pub fn entries(&self, scope: ScopeId) -> &[ScopeEntry] {
&self.scopes[scope].entries
}
pub fn scope_chain<'a>(&'a self, node: SyntaxNodeRef) -> impl Iterator<Item=ScopeId> + 'a {
generate(self.scope_for(node), move |&scope| self.scopes[scope].parent)
}
fn root_scope(&mut self) -> ScopeId {
let res = self.scopes.len();
self.scopes.push(ScopeData { parent: None, entries: vec![] });
res
}
fn new_scope(&mut self, parent: ScopeId) -> ScopeId {
let res = self.scopes.len();
self.scopes.push(ScopeData { parent: Some(parent), entries: vec![] });
res
}
fn add_bindings(&mut self, scope: ScopeId, pat: ast::Pat) {
let entries = preorder(pat.syntax())
.filter_map(ast::BindPat::cast)
.filter_map(ScopeEntry::new);
self.scopes[scope].entries.extend(entries);
}
fn set_scope(&mut self, node: SyntaxNodeRef, scope: ScopeId) {
self.scope_for.insert(node.owned(), scope);
}
fn scope_for(&self, node: SyntaxNodeRef) -> Option<ScopeId> {
ancestors(node)
.filter_map(|it| self.scope_for.get(&it.owned()).map(|&scope| scope))
.next()
}
}
pub struct ScopeEntry {
syntax: SyntaxNode
}
impl ScopeEntry {
fn new(pat: ast::BindPat) -> Option<ScopeEntry> {
if pat.name().is_some() {
Some(ScopeEntry { syntax: pat.syntax().owned() })
} else {
None
}
}
pub fn name(&self) -> SmolStr {
self.ast().name()
.unwrap()
.text()
}
fn ast(&self) -> ast::BindPat {
ast::BindPat::cast(self.syntax.borrowed())
.unwrap()
}
}
impl fmt::Debug for ScopeEntry {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
f.debug_struct("ScopeEntry")
.field("name", &self.name())
.field("syntax", &self.syntax)
.finish()
}
}
fn compute_block_scopes(block: ast::Block, scopes: &mut FnScopes, mut scope: ScopeId) {
for stmt in block.statements() {
match stmt {
ast::Stmt::LetStmt(stmt) => {
scope = scopes.new_scope(scope);
if let Some(pat) = stmt.pat() {
scopes.add_bindings(scope, pat);
}
if let Some(expr) = stmt.initializer() {
scopes.set_scope(expr.syntax(), scope)
}
}
ast::Stmt::ExprStmt(expr_stmt) => {
if let Some(expr) = expr_stmt.expr() {
scopes.set_scope(expr.syntax(), scope);
compute_expr_scopes(expr, scopes, scope);
}
}
}
}
if let Some(expr) = block.expr() {
scopes.set_scope(expr.syntax(), scope);
compute_expr_scopes(expr, scopes, scope);
}
}
fn compute_expr_scopes(expr: ast::Expr, scopes: &mut FnScopes, scope: ScopeId) {
match expr {
ast::Expr::IfExpr(e) => {
let cond_scope = e.condition().and_then(|cond| {
compute_cond_scopes(cond, scopes, scope)
});
if let Some(block) = e.then_branch() {
compute_block_scopes(block, scopes, cond_scope.unwrap_or(scope));
}
if let Some(block) = e.else_branch() {
compute_block_scopes(block, scopes, scope);
}
},
ast::Expr::WhileExpr(e) => {
let cond_scope = e.condition().and_then(|cond| {
compute_cond_scopes(cond, scopes, scope)
});
if let Some(block) = e.body() {
compute_block_scopes(block, scopes, cond_scope.unwrap_or(scope));
}
},
ast::Expr::BlockExpr(e) => {
if let Some(block) = e.block() {
compute_block_scopes(block, scopes, scope);
}
}
ast::Expr::ForExpr(e) => {
if let Some(expr) = e.iterable() {
compute_expr_scopes(expr, scopes, scope);
}
let mut scope = scope;
if let Some(pat) = e.pat() {
scope = scopes.new_scope(scope);
scopes.add_bindings(scope, pat);
}
if let Some(block) = e.body() {
compute_block_scopes(block, scopes, scope);
}
},
_ => {
expr.syntax().children()
.filter_map(ast::Expr::cast)
.for_each(|expr| compute_expr_scopes(expr, scopes, scope))
}
};
fn compute_cond_scopes(cond: ast::Condition, scopes: &mut FnScopes, scope: ScopeId) -> Option<ScopeId> {
if let Some(expr) = cond.expr() {
compute_expr_scopes(expr, scopes, scope);
}
if let Some(pat) = cond.pat() {
let s = scopes.new_scope(scope);
scopes.add_bindings(s, pat);
Some(s)
} else {
None
}
}
}
#[derive(Debug)]
struct ScopeData {
parent: Option<ScopeId>,
entries: Vec<ScopeEntry>
}
|
