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internal: Add SyntaxFactory to ease generating nodes with syntax ma…
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…ppings
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DropDemBits committed Sep 26, 2024
1 parent 2904b35 commit b9a0502
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Showing 5 changed files with 186 additions and 101 deletions.
1 change: 1 addition & 0 deletions src/tools/rust-analyzer/crates/syntax/src/ast.rs
Original file line number Diff line number Diff line change
Expand Up @@ -8,6 +8,7 @@ pub mod make;
mod node_ext;
mod operators;
pub mod prec;
pub mod syntax_factory;
mod token_ext;
mod traits;

Expand Down
45 changes: 45 additions & 0 deletions src/tools/rust-analyzer/crates/syntax/src/ast/syntax_factory.rs
Original file line number Diff line number Diff line change
@@ -0,0 +1,45 @@
//! Builds upon [`crate::ast::make`] constructors to create ast fragments with
//! optional syntax mappings.
//!
//! Instead of forcing make constructors to perform syntax mapping, we instead
//! let [`SyntaxFactory`] handle constructing the mappings. Care must be taken
//! to remember to feed the syntax mappings into a [`SyntaxEditor`](crate::syntax_editor::SyntaxEditor),
//! if applicable.
mod constructors;

use std::cell::{RefCell, RefMut};

use crate::syntax_editor::SyntaxMapping;

pub struct SyntaxFactory {
// Stored in a refcell so that the factory methods can be &self
mappings: Option<RefCell<SyntaxMapping>>,
}

impl SyntaxFactory {
/// Creates a new [`SyntaxFactory`], generating mappings between input nodes and generated nodes.
pub fn new() -> Self {
Self { mappings: Some(RefCell::new(SyntaxMapping::new())) }
}

/// Creates a [`SyntaxFactory`] without generating mappings.
pub fn without_mappings() -> Self {
Self { mappings: None }
}

/// Gets all of the tracked syntax mappings, if any.
pub fn finish_with_mappings(self) -> SyntaxMapping {
self.mappings.unwrap_or_default().into_inner()
}

fn mappings(&self) -> Option<RefMut<'_, SyntaxMapping>> {
self.mappings.as_ref().map(|it| it.borrow_mut())
}
}

impl Default for SyntaxFactory {
fn default() -> Self {
Self::without_mappings()
}
}
Original file line number Diff line number Diff line change
@@ -0,0 +1,110 @@
//! Wrappers over [`make`] constructors
use itertools::Itertools;

use crate::{
ast::{self, make, HasName},
syntax_editor::SyntaxMappingBuilder,
AstNode,
};

use super::SyntaxFactory;

impl SyntaxFactory {
pub fn name(&self, name: &str) -> ast::Name {
make::name(name).clone_for_update()
}

pub fn ident_pat(&self, ref_: bool, mut_: bool, name: ast::Name) -> ast::IdentPat {
let ast = make::ident_pat(ref_, mut_, name.clone()).clone_for_update();

if let Some(mut mapping) = self.mappings() {
let mut builder = SyntaxMappingBuilder::new(ast.syntax().clone());
builder.map_node(name.syntax().clone(), ast.name().unwrap().syntax().clone());
builder.finish(&mut mapping);
}

ast
}

pub fn block_expr(
&self,
stmts: impl IntoIterator<Item = ast::Stmt>,
tail_expr: Option<ast::Expr>,
) -> ast::BlockExpr {
let stmts = stmts.into_iter().collect_vec();
let input = stmts.iter().map(|it| it.syntax().clone()).collect_vec();

let ast = make::block_expr(stmts, tail_expr.clone()).clone_for_update();

if let Some((mut mapping, stmt_list)) = self.mappings().zip(ast.stmt_list()) {
let mut builder = SyntaxMappingBuilder::new(stmt_list.syntax().clone());

builder.map_children(
input.into_iter(),
stmt_list.statements().map(|it| it.syntax().clone()),
);

if let Some((input, output)) = tail_expr.zip(stmt_list.tail_expr()) {
builder.map_node(input.syntax().clone(), output.syntax().clone());
}

builder.finish(&mut mapping);
}

ast
}

pub fn expr_path(&self, path: ast::Path) -> ast::Expr {
let ast::Expr::PathExpr(ast) = make::expr_path(path.clone()).clone_for_update() else {
unreachable!()
};

if let Some(mut mapping) = self.mappings() {
let mut builder = SyntaxMappingBuilder::new(ast.syntax().clone());
builder.map_node(path.syntax().clone(), ast.path().unwrap().syntax().clone());
builder.finish(&mut mapping);
}

ast.into()
}

pub fn expr_ref(&self, expr: ast::Expr, exclusive: bool) -> ast::Expr {
let ast::Expr::RefExpr(ast) = make::expr_ref(expr.clone(), exclusive).clone_for_update()
else {
unreachable!()
};

if let Some(mut mapping) = self.mappings() {
let mut builder = SyntaxMappingBuilder::new(ast.syntax().clone());
builder.map_node(expr.syntax().clone(), ast.expr().unwrap().syntax().clone());
builder.finish(&mut mapping);
}

ast.into()
}

pub fn let_stmt(
&self,
pattern: ast::Pat,
ty: Option<ast::Type>,
initializer: Option<ast::Expr>,
) -> ast::LetStmt {
let ast =
make::let_stmt(pattern.clone(), ty.clone(), initializer.clone()).clone_for_update();

if let Some(mut mapping) = self.mappings() {
let mut builder = SyntaxMappingBuilder::new(ast.syntax().clone());
builder.map_node(pattern.syntax().clone(), ast.pat().unwrap().syntax().clone());
if let Some(input) = ty {
builder.map_node(input.syntax().clone(), ast.ty().unwrap().syntax().clone());
}
if let Some(input) = initializer {
builder
.map_node(input.syntax().clone(), ast.initializer().unwrap().syntax().clone());
}
builder.finish(&mut mapping);
}

ast
}
}
123 changes: 27 additions & 96 deletions src/tools/rust-analyzer/crates/syntax/src/syntax_editor.rs
Original file line number Diff line number Diff line change
Expand Up @@ -100,6 +100,10 @@ impl SyntaxEditor {
pub fn finish(self) -> SyntaxEdit {
edit_algo::apply_edits(self)
}

pub fn add_mappings(&mut self, other: SyntaxMapping) {
self.mappings.merge(other);
}
}

/// Represents a completed [`SyntaxEditor`] operation.
Expand Down Expand Up @@ -319,85 +323,14 @@ fn is_ancestor_or_self_of_element(node: &SyntaxElement, ancestor: &SyntaxNode) -
#[cfg(test)]
mod tests {
use expect_test::expect;
use itertools::Itertools;

use crate::{
ast::{self, make, HasName},
ast::{self, make, syntax_factory::SyntaxFactory},
AstNode,
};

use super::*;

fn make_ident_pat(
editor: Option<&mut SyntaxEditor>,
ref_: bool,
mut_: bool,
name: ast::Name,
) -> ast::IdentPat {
let ast = make::ident_pat(ref_, mut_, name.clone()).clone_for_update();

if let Some(editor) = editor {
let mut mapping = SyntaxMappingBuilder::new(ast.syntax().clone());
mapping.map_node(name.syntax().clone(), ast.name().unwrap().syntax().clone());
mapping.finish(editor);
}

ast
}

fn make_let_stmt(
editor: Option<&mut SyntaxEditor>,
pattern: ast::Pat,
ty: Option<ast::Type>,
initializer: Option<ast::Expr>,
) -> ast::LetStmt {
let ast =
make::let_stmt(pattern.clone(), ty.clone(), initializer.clone()).clone_for_update();

if let Some(editor) = editor {
let mut mapping = SyntaxMappingBuilder::new(ast.syntax().clone());
mapping.map_node(pattern.syntax().clone(), ast.pat().unwrap().syntax().clone());
if let Some(input) = ty {
mapping.map_node(input.syntax().clone(), ast.ty().unwrap().syntax().clone());
}
if let Some(input) = initializer {
mapping
.map_node(input.syntax().clone(), ast.initializer().unwrap().syntax().clone());
}
mapping.finish(editor);
}

ast
}

fn make_block_expr(
editor: Option<&mut SyntaxEditor>,
stmts: impl IntoIterator<Item = ast::Stmt>,
tail_expr: Option<ast::Expr>,
) -> ast::BlockExpr {
let stmts = stmts.into_iter().collect_vec();
let input = stmts.iter().map(|it| it.syntax().clone()).collect_vec();

let ast = make::block_expr(stmts, tail_expr.clone()).clone_for_update();

if let Some((editor, stmt_list)) = editor.zip(ast.stmt_list()) {
let mut mapping = SyntaxMappingBuilder::new(stmt_list.syntax().clone());

mapping.map_children(
input.into_iter(),
stmt_list.statements().map(|it| it.syntax().clone()),
);

if let Some((input, output)) = tail_expr.zip(stmt_list.tail_expr()) {
mapping.map_node(input.syntax().clone(), output.syntax().clone());
}

mapping.finish(editor);
}

ast
}

#[test]
fn basic_usage() {
let root = make::match_arm(
Expand All @@ -417,6 +350,7 @@ mod tests {
let to_replace = root.syntax().descendants().find_map(ast::BinExpr::cast).unwrap();

let mut editor = SyntaxEditor::new(root.syntax().clone());
let make = SyntaxFactory::new();

let name = make::name("var_name");
let name_ref = make::name_ref("var_name").clone_for_update();
Expand All @@ -425,21 +359,20 @@ mod tests {
editor.add_annotation(name.syntax(), placeholder_snippet);
editor.add_annotation(name_ref.syntax(), placeholder_snippet);

let make_ident_pat = make_ident_pat(Some(&mut editor), false, false, name);
let make_let_stmt = make_let_stmt(
Some(&mut editor),
make_ident_pat.into(),
None,
Some(to_replace.clone().into()),
);
let new_block = make_block_expr(
Some(&mut editor),
[make_let_stmt.into()],
let new_block = make.block_expr(
[make
.let_stmt(
make.ident_pat(false, false, name.clone()).into(),
None,
Some(to_replace.clone().into()),
)
.into()],
Some(to_wrap.clone().into()),
);

editor.replace(to_replace.syntax(), name_ref.syntax());
editor.replace(to_wrap.syntax(), new_block.syntax());
editor.add_mappings(make.finish_with_mappings());

let edit = editor.finish();

Expand Down Expand Up @@ -473,11 +406,11 @@ mod tests {
let second_let = root.syntax().descendants().find_map(ast::LetStmt::cast).unwrap();

let mut editor = SyntaxEditor::new(root.syntax().clone());
let make = SyntaxFactory::without_mappings();

editor.insert(
Position::first_child_of(root.stmt_list().unwrap().syntax()),
make_let_stmt(
None,
make.let_stmt(
make::ext::simple_ident_pat(make::name("first")).into(),
None,
Some(make::expr_literal("1").into()),
Expand All @@ -487,8 +420,7 @@ mod tests {

editor.insert(
Position::after(second_let.syntax()),
make_let_stmt(
None,
make.let_stmt(
make::ext::simple_ident_pat(make::name("third")).into(),
None,
Some(make::expr_literal("3").into()),
Expand Down Expand Up @@ -528,19 +460,17 @@ mod tests {
let second_let = root.syntax().descendants().find_map(ast::LetStmt::cast).unwrap();

let mut editor = SyntaxEditor::new(root.syntax().clone());
let make = SyntaxFactory::new();

let new_block_expr =
make_block_expr(Some(&mut editor), [], Some(ast::Expr::BlockExpr(inner_block.clone())));
let new_block_expr = make.block_expr([], Some(ast::Expr::BlockExpr(inner_block.clone())));

let first_let = make_let_stmt(
Some(&mut editor),
let first_let = make.let_stmt(
make::ext::simple_ident_pat(make::name("first")).into(),
None,
Some(make::expr_literal("1").into()),
);

let third_let = make_let_stmt(
Some(&mut editor),
let third_let = make.let_stmt(
make::ext::simple_ident_pat(make::name("third")).into(),
None,
Some(make::expr_literal("3").into()),
Expand All @@ -552,6 +482,7 @@ mod tests {
);
editor.insert(Position::after(second_let.syntax()), third_let.syntax());
editor.replace(inner_block.syntax(), new_block_expr.syntax());
editor.add_mappings(make.finish_with_mappings());

let edit = editor.finish();

Expand Down Expand Up @@ -581,12 +512,11 @@ mod tests {
let inner_block = root.clone();

let mut editor = SyntaxEditor::new(root.syntax().clone());
let make = SyntaxFactory::new();

let new_block_expr =
make_block_expr(Some(&mut editor), [], Some(ast::Expr::BlockExpr(inner_block.clone())));
let new_block_expr = make.block_expr([], Some(ast::Expr::BlockExpr(inner_block.clone())));

let first_let = make_let_stmt(
Some(&mut editor),
let first_let = make.let_stmt(
make::ext::simple_ident_pat(make::name("first")).into(),
None,
Some(make::expr_literal("1").into()),
Expand All @@ -597,6 +527,7 @@ mod tests {
first_let.syntax(),
);
editor.replace(inner_block.syntax(), new_block_expr.syntax());
editor.add_mappings(make.finish_with_mappings());

let edit = editor.finish();

Expand Down
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