catalog: add indoc! example

fix #667

Author: HerringtonDarkholme

website/catalog/index.md

@@ -34,6 +34,7 @@ Feel free to join our [Discord](https://discord.gg/4YZjf6htSQ) channel and ask @
   * [Avoid Duplicated Exports](/catalog/rust/#avoid-duplicated-exports)
   * [Get number of digits in a `usize`](/catalog/rust/#get-number-of-digits-in-a-usize)
   * [Beware of char offset when iterate over a string](/catalog/rust/#beware-of-char-offset-when-iterate-over-a-string)
+  * [Rewrite `indoc!` macro](/catalog/rust/#rewrite-indoc-macro)
 * [TypeScript](/catalog/typescript/)
   * [Repository of ESLint rules 🔗](https://github.com/ast-grep/eslint/)
   * [No `await` in `Promise.all`](/catalog/typescript/#no-await-in-promise-all-array)

website/catalog/rust/index.md

@@ -4,4 +4,5 @@ This page curates a list of example ast-grep rules to check and to rewrite Rust
 
 <!--@include: ./avoid-duplicated-exports.md-->
 <!--@include: ./boshen-footgun.md-->
-<!--@include: ./get-digit-count-in-usize.md-->
+<!--@include: ./get-digit-count-in-usize.md-->
+<!--@include: ./rewrite-indoc-macro.md-->

website/catalog/rust/rewrite-indoc-macro.md

@@ -0,0 +1,71 @@
+## Rewrite `indoc!` macro <Badge type="tip" text="Has Fix" />
+
+
+* [Playground Link](/playground.html#eyJtb2RlIjoiUGF0Y2giLCJsYW5nIjoicnVzdCIsInF1ZXJ5IjoiaW5kb2MhIHsgciNcIiQkJEFcIiMgfSIsInJld3JpdGUiOiJgJCQkQWAiLCJzdHJpY3RuZXNzIjoicmVsYXhlZCIsInNlbGVjdG9yIjoiIiwiY29uZmlnIjoicnVsZTogXG4gYW55OlxuIC0gcGF0dGVybjogJFYgPT09ICRTRU5TRVRJVkVXT1JEXG4gLSBwYXR0ZXJuOiAkU0VOU0VUSVZFV09SRCA9PT0gJFZcbmNvbnN0cmFpbnRzOlxuICBTRU5TRVRJVkVXT1JEOlxuICAgIHJlZ2V4OiBwYXNzd29yZCIsInNvdXJjZSI6ImZuIG1haW4oKSB7XG4gICAgaW5kb2MhIHtyI1wiXG4gICAgICAgIC5mb28ge1xuICAgICAgICAgICAgb3JkZXI6IDE7XG4gICAgICAgIH1cbiAgICBcIiN9O1xufSJ9)
+
+### Description
+
+This example, created from [a Tweet](https://x.com/zack_overflow/status/1885065128590401551), shows a refactoring operation being performed on Rust source code. The changes involve removing `indoc!` macro declarations while preserving the CSS-like content within them.
+
+Previously, the same refactor is implemented by a _unreadable monster regex_ in vim syntax.
+
+:::details Click to see the original regex (neovim, btw)
+
+```vimscript
+:%s/\v(indoc!|)(| )([|\{)r#"(([^#]+|\n+)+)"#/\4
+```
+I have to confess that I don't understand this regex even if I use neovim, btw.
+
+Let Claude break it down piece by piece:
+
+- `:%s/` - This is a vim/sed substitution command
+- `\v` - Very magic mode in vim, making special characters active by default
+- `(indoc!|)` - Matches either "indoc!" or nothing (optional indoc!)
+- `(| )([\{)` - Matches any spaces, parentheses, or curly braces
+- `r#"` - Matches the literal raw string prefix in Rust
+- `(([^#]+|\n+)+)` - This is the capture group that matches:
+  - `[^#]+` - Any characters that aren't '#'
+  - `|\n+` - Or one or more newlines
+  - The outer `()+` makes it match one or more of these sequences
+- `"#` - Matches the raw string suffix
+- `/\4` - Replaces the entire match with the contents of the 4th capture group
+
+This regex appears to be designed to extract the content from within Rust raw string literals that may or may not be wrapped in the `indoc!` macro.
+
+:::
+
+<!-- Use pattern in the example. Delete this section if use YAML. -->
+### Pattern
+
+```shell
+ast-grep --pattern 'indoc! { r#"$$$A"# }' --rewrite '$$$A' sgtest.rs
+```
+
+### Example
+
+<!-- highlight matched code in curly-brace {lineNum} -->
+```rs {2-6}
+fn main() {
+    indoc! {r#"
+        .foo {
+            order: 1;
+        }
+    "#};
+}
+```
+
+### Diff
+<!-- use // [!code --] and // [!code ++] to annotate diff -->
+```rs
+fn main() {
+    indoc! {r#" // [!code --]
+    `.foo {    // [!code ++]
+        order: 1;
+    }
+    "#}; // [!code --]
+        `; // [!code ++]
+}
+```
+
+### Contributed by
+[Zack in SF](https://x.com/zack_overflow)