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authorMarijn Suijten <[email protected]>2021-01-03 16:45:49 +0000
committerMarijn Suijten <[email protected]>2021-01-04 09:55:09 +0000
commitd33edb4e9cf1cad1c9ceb7c99859d73993ccba29 (patch)
tree84b93a8b3aa2c1c4e8c17fe72988b2270c80c331
parentb87699d97ac34f95dc09d166d07fc1220b460821 (diff)
ssr: Allow replacing expressions with statements
Now that statements can be matched and replaced (#6587) some usecases require expressions to be replaced with statements as well. This happens when something that can ambiguously be an expression or statement like `if` and loop blocks appear in the last position of a block, as trailing expression. In this case a replacement pattern of the form `if foo(){$a();}==>>$a();` will only substitute `if` blocks in the list of statements but not if they (implicitly) end up in the trailing expression, where they are not wrapped by an EXPR_STMT (but the pattern and template are, as parsing only succeeds for the `stmt ==>> stmt` case). Instead of adding two rules that match an expression - and emit duplicate matching errors - allow the template for expressions to be a statement if it fails to parse as an expression.
-rw-r--r--crates/ssr/src/parsing.rs16
-rw-r--r--crates/ssr/src/tests.rs47
2 files changed, 60 insertions, 3 deletions
diff --git a/crates/ssr/src/parsing.rs b/crates/ssr/src/parsing.rs
index 289affe90..3d5e4feb7 100644
--- a/crates/ssr/src/parsing.rs
+++ b/crates/ssr/src/parsing.rs
@@ -73,12 +73,18 @@ impl ParsedRule {
73 placeholders_by_stand_in: pattern.placeholders_by_stand_in(), 73 placeholders_by_stand_in: pattern.placeholders_by_stand_in(),
74 rules: Vec::new(), 74 rules: Vec::new(),
75 }; 75 };
76 builder.try_add(ast::Expr::parse(&raw_pattern), raw_template.map(ast::Expr::parse)); 76
77 let raw_template_stmt = raw_template.map(ast::Stmt::parse);
78 if let raw_template_expr @ Some(Ok(_)) = raw_template.map(ast::Expr::parse) {
79 builder.try_add(ast::Expr::parse(&raw_pattern), raw_template_expr);
80 } else {
81 builder.try_add(ast::Expr::parse(&raw_pattern), raw_template_stmt.clone());
82 }
77 builder.try_add(ast::Type::parse(&raw_pattern), raw_template.map(ast::Type::parse)); 83 builder.try_add(ast::Type::parse(&raw_pattern), raw_template.map(ast::Type::parse));
78 builder.try_add(ast::Item::parse(&raw_pattern), raw_template.map(ast::Item::parse)); 84 builder.try_add(ast::Item::parse(&raw_pattern), raw_template.map(ast::Item::parse));
79 builder.try_add(ast::Path::parse(&raw_pattern), raw_template.map(ast::Path::parse)); 85 builder.try_add(ast::Path::parse(&raw_pattern), raw_template.map(ast::Path::parse));
80 builder.try_add(ast::Pat::parse(&raw_pattern), raw_template.map(ast::Pat::parse)); 86 builder.try_add(ast::Pat::parse(&raw_pattern), raw_template.map(ast::Pat::parse));
81 builder.try_add(ast::Stmt::parse(&raw_pattern), raw_template.map(ast::Stmt::parse)); 87 builder.try_add(ast::Stmt::parse(&raw_pattern), raw_template_stmt);
82 builder.build() 88 builder.build()
83 } 89 }
84} 90}
@@ -89,7 +95,11 @@ struct RuleBuilder {
89} 95}
90 96
91impl RuleBuilder { 97impl RuleBuilder {
92 fn try_add<T: AstNode>(&mut self, pattern: Result<T, ()>, template: Option<Result<T, ()>>) { 98 fn try_add<T: AstNode, T2: AstNode>(
99 &mut self,
100 pattern: Result<T, ()>,
101 template: Option<Result<T2, ()>>,
102 ) {
93 match (pattern, template) { 103 match (pattern, template) {
94 (Ok(pattern), Some(Ok(template))) => self.rules.push(ParsedRule { 104 (Ok(pattern), Some(Ok(template))) => self.rules.push(ParsedRule {
95 placeholders_by_stand_in: self.placeholders_by_stand_in.clone(), 105 placeholders_by_stand_in: self.placeholders_by_stand_in.clone(),
diff --git a/crates/ssr/src/tests.rs b/crates/ssr/src/tests.rs
index c4149a849..db9cb8ca1 100644
--- a/crates/ssr/src/tests.rs
+++ b/crates/ssr/src/tests.rs
@@ -204,6 +204,53 @@ fn ssr_let_stmt_replace_expr() {
204} 204}
205 205
206#[test] 206#[test]
207fn ssr_blockexpr_replace_stmt_with_stmt() {
208 assert_ssr_transform(
209 "if $a() {$b;} ==>> $b;",
210 "{
211 if foo() {
212 bar();
213 }
214 Ok(())
215}",
216 expect![[r#"{
217 bar();
218 Ok(())
219}"#]],
220 );
221}
222
223#[test]
224fn ssr_blockexpr_match_trailing_expr() {
225 assert_matches(
226 "if $a() {$b;}",
227 "{
228 if foo() {
229 bar();
230 }
231}",
232 &["if foo() {
233 bar();
234 }"],
235 );
236}
237
238#[test]
239fn ssr_blockexpr_replace_trailing_expr_with_stmt() {
240 assert_ssr_transform(
241 "if $a() {$b;} ==>> $b;",
242 "{
243 if foo() {
244 bar();
245 }
246}",
247 expect![["{
248 bar();
249}"]],
250 );
251}
252
253#[test]
207fn ssr_function_to_method() { 254fn ssr_function_to_method() {
208 assert_ssr_transform( 255 assert_ssr_transform(
209 "my_function($a, $b) ==>> ($a).my_method($b)", 256 "my_function($a, $b) ==>> ($a).my_method($b)",