internal: Add SyntaxFactory to ease generating nodes with syntax mappings

crates/syntax/src/ast/syntax_factory/constructors.rs

@@ -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
+    }
+}