From 311dbb854536dd526cdbcadc6d270f9a37e4b816 Mon Sep 17 00:00:00 2001 From: Ekaterina Babshukova Date: Sat, 5 Oct 2019 17:48:31 +0300 Subject: [PATCH] remove `visitor` module --- crates/ra_assists/src/assists/split_import.rs | 6 +- crates/ra_syntax/src/algo.rs | 2 - crates/ra_syntax/src/algo/visit.rs | 112 ------------------ crates/ra_syntax/src/lib.rs | 43 ++++--- docs/dev/architecture.md | 4 +- docs/user/features.md | 4 +- 6 files changed, 27 insertions(+), 144 deletions(-) delete mode 100644 crates/ra_syntax/src/algo/visit.rs diff --git a/crates/ra_assists/src/assists/split_import.rs b/crates/ra_assists/src/assists/split_import.rs index 19d429daf5..fe3e64af50 100644 --- a/crates/ra_assists/src/assists/split_import.rs +++ b/crates/ra_assists/src/assists/split_import.rs @@ -51,13 +51,13 @@ mod tests { fn split_import_works_with_trees() { check_assist( split_import, - "use algo:<|>:visitor::{Visitor, visit}", - "use algo::{<|>visitor::{Visitor, visit}}", + "use crate:<|>:db::{RootDatabase, FileSymbol}", + "use crate::{<|>db::{RootDatabase, FileSymbol}}", ) } #[test] fn split_import_target() { - check_assist_target(split_import, "use algo::<|>visitor::{Visitor, visit}", "::"); + check_assist_target(split_import, "use crate::<|>db::{RootDatabase, FileSymbol}", "::"); } } diff --git a/crates/ra_syntax/src/algo.rs b/crates/ra_syntax/src/algo.rs index d55534ede8..7cfea70f97 100644 --- a/crates/ra_syntax/src/algo.rs +++ b/crates/ra_syntax/src/algo.rs @@ -1,7 +1,5 @@ //! FIXME: write short doc here -pub mod visit; - use std::ops::RangeInclusive; use itertools::Itertools; diff --git a/crates/ra_syntax/src/algo/visit.rs b/crates/ra_syntax/src/algo/visit.rs deleted file mode 100644 index 4df275ba4f..0000000000 --- a/crates/ra_syntax/src/algo/visit.rs +++ /dev/null @@ -1,112 +0,0 @@ -//! FIXME: write short doc here - -use crate::{AstNode, SyntaxNode}; - -use std::marker::PhantomData; - -pub fn visitor<'a, T>() -> impl Visitor<'a, Output = T> { - EmptyVisitor { ph: PhantomData } -} - -pub fn visitor_ctx<'a, T, C>(ctx: C) -> impl VisitorCtx<'a, Output = T, Ctx = C> { - EmptyVisitorCtx { ph: PhantomData, ctx } -} - -pub trait Visitor<'a>: Sized { - type Output; - fn accept(self, node: &'a SyntaxNode) -> Option; - fn visit(self, f: F) -> Vis - where - N: AstNode + 'a, - F: FnOnce(N) -> Self::Output, - { - Vis { inner: self, f, ph: PhantomData } - } -} - -pub trait VisitorCtx<'a>: Sized { - type Output; - type Ctx; - fn accept(self, node: &'a SyntaxNode) -> Result; - fn visit(self, f: F) -> VisCtx - where - N: AstNode + 'a, - F: FnOnce(N, Self::Ctx) -> Self::Output, - { - VisCtx { inner: self, f, ph: PhantomData } - } -} - -#[derive(Debug)] -struct EmptyVisitor { - ph: PhantomData T>, -} - -impl<'a, T> Visitor<'a> for EmptyVisitor { - type Output = T; - - fn accept(self, _node: &'a SyntaxNode) -> Option { - None - } -} - -#[derive(Debug)] -struct EmptyVisitorCtx { - ctx: C, - ph: PhantomData T>, -} - -impl<'a, T, C> VisitorCtx<'a> for EmptyVisitorCtx { - type Output = T; - type Ctx = C; - - fn accept(self, _node: &'a SyntaxNode) -> Result { - Err(self.ctx) - } -} - -#[derive(Debug)] -pub struct Vis { - inner: V, - f: F, - ph: PhantomData, -} - -impl<'a, V, N, F> Visitor<'a> for Vis -where - V: Visitor<'a>, - N: AstNode + 'a, - F: FnOnce(N) -> >::Output, -{ - type Output = >::Output; - - fn accept(self, node: &'a SyntaxNode) -> Option { - let Vis { inner, f, .. } = self; - inner.accept(node).or_else(|| N::cast(node.clone()).map(f)) - } -} - -#[derive(Debug)] -pub struct VisCtx { - inner: V, - f: F, - ph: PhantomData, -} - -impl<'a, V, N, F> VisitorCtx<'a> for VisCtx -where - V: VisitorCtx<'a>, - N: AstNode + 'a, - F: FnOnce(N, >::Ctx) -> >::Output, -{ - type Output = >::Output; - type Ctx = >::Ctx; - - fn accept(self, node: &'a SyntaxNode) -> Result { - let VisCtx { inner, f, .. } = self; - inner.accept(node).or_else(|ctx| match N::cast(node.clone()) { - None => Err(ctx), - Some(node) => Ok(f(node, ctx)), - }) - } -} diff --git a/crates/ra_syntax/src/lib.rs b/crates/ra_syntax/src/lib.rs index 09230ccb2c..c315ba5528 100644 --- a/crates/ra_syntax/src/lib.rs +++ b/crates/ra_syntax/src/lib.rs @@ -160,6 +160,17 @@ impl SourceFile { } } +#[macro_export] +macro_rules! match_ast { + (match $node:ident { + $( ast::$ast:ident($it:ident) => $res:block, )* + _ => $catch_all:expr, + }) => {{ + $( if let Some($it) = ast::$ast::cast($node.clone()) $res else )* + { $catch_all } + }}; +} + /// This test does not assert anything and instead just shows off the crate's /// API. #[test] @@ -294,8 +305,7 @@ fn api_walkthrough() { // To recursively process the tree, there are three approaches: // 1. explicitly call getter methods on AST nodes. // 2. use descendants and `AstNode::cast`. - // 3. use descendants and the visitor. - // 4. use descendants and `match_ast!`. + // 3. use descendants and `match_ast!`. // // Here's how the first one looks like: let exprs_cast: Vec = file @@ -305,29 +315,18 @@ fn api_walkthrough() { .map(|expr| expr.syntax().text().to_string()) .collect(); - // An alternative is to use a visitor. The visitor does not do traversal - // automatically (so it's more akin to a generic lambda) and is constructed - // from closures. This seems more flexible than a single generated visitor - // trait. - use algo::visit::{visitor, Visitor}; + // An alternative is to use a macro. let mut exprs_visit = Vec::new(); for node in file.syntax().descendants() { - if let Some(result) = - visitor().visit::(|expr| expr.syntax().text().to_string()).accept(&node) - { - exprs_visit.push(result); + match_ast! { + match node { + ast::Expr(it) => { + let res = it.syntax().text().to_string(); + exprs_visit.push(res); + }, + _ => (), + } } } assert_eq!(exprs_cast, exprs_visit); } - -#[macro_export] -macro_rules! match_ast { - (match $node:ident { - $( ast::$ast:ident($it:ident) => $res:block, )* - _ => $catch_all:expr, - }) => {{ - $( if let Some($it) = ast::$ast::cast($node.clone()) $res else )* - { $catch_all } - }}; -} diff --git a/docs/dev/architecture.md b/docs/dev/architecture.md index 1201f6e5a0..1ffabc6efb 100644 --- a/docs/dev/architecture.md +++ b/docs/dev/architecture.md @@ -79,9 +79,7 @@ Rust syntax tree structure and parser. See - `grammar.ron` RON description of the grammar, which is used to generate `syntax_kinds` and `ast` modules, using `cargo gen-syntax` command. - `algo`: generic tree algorithms, including `walk` for O(1) stack - space tree traversal (this is cool) and `visit` for type-driven - visiting the nodes (this is double plus cool, if you understand how - `Visitor` works, you understand the design of syntax trees). + space tree traversal (this is cool). Tests for ra_syntax are mostly data-driven: `test_data/parser` contains subdirectories with a bunch of `.rs` (test vectors) and `.txt` files with corresponding syntax trees. During testing, we check diff --git a/docs/user/features.md b/docs/user/features.md index 0ce8f577b3..757a02838e 100644 --- a/docs/user/features.md +++ b/docs/user/features.md @@ -367,9 +367,9 @@ impl VariantData { ```rust // before: -use algo:<|>:visitor::{Visitor, visit}; +use crate:<|>:db::{RootDatabase, FileSymbol}; // after: -use algo::{<|>visitor::{Visitor, visit}}; +use crate::{<|>db::{RootDatabase, FileSymbol}}; ``` - Flip binary expression