Glob documentation (#18789)

Leaving this unlinked for now because I'm not sure where it belongs.
Plan to write up something for regexes too.

docs/src/SUMMARY.md

@@ -16,9 +16,11 @@
 - [Key bindings](./key-bindings.md)
 - [Snippets](./snippets.md)
 - [Themes](./themes.md)
-<!-- - [Fonts](./fonts.md) -->
 - [Vim Mode](./vim.md)
 
+<!-- - [Globs](./globs.md) -->
+<!-- - [Fonts](./fonts.md) -->
+
 # Using Zed
 
 - [Multibuffers](./multibuffers.md)

docs/src/globs.md

@@ -0,0 +1,80 @@
+# Globs
+
+Zed supports the use of [glob](<https://en.wikipedia.org/wiki/Glob_(programming)>) patterns that are the formal name for Unix shell-style path matching wildcards like `*.md` or `docs/src/**/*.md` supported by sh, bash, zsh, etc. A glob is similar but distinct from a [regex (regular expression)](https://en.wikipedia.org/wiki/Regular_expression). You may be In Zed these are commonly used when matching filenames.
+
+## Glob Flavor
+
+Zed uses two different rust crates for matching glob patterns:
+
+- [ignore crate](https://docs.rs/ignore/latest/ignore/) for matching glob patterns stored in `.gitignore` files
+- [glob crate](https://docs.rs/glob/latest/glob/) for matching file paths in Zed
+
+While simple expressions are portable across environments (e.g. running `ls *.py` or `*.tmp` in a gitignore) there is significant divergence in the support for and syntax of more advanced features varies (character classes, exclusions, `**`, etc) across implementations. For the rest of this document we will be describing globs as supported in Zed via the `glob` crate implementation. Please see [References](#references) below for documentation links for glob pattern syntax for `.gitignore`, shells and other programming languages.
+
+The `glob` crate is implemented entirely in rust and does not rely on the `glob` / `fnmatch` interfaces provided by your platforms libc. This means that globs in Zed should behave similarly with across platforms.
+
+## Introduction
+
+A glob "pattern" is used to match a file name or complete file path. For example, when using "Search all files" {#kb project_search::ToggleFocus} you can click the funnel shaped Toggle Filters" button or {#kb project_search::ToggleFilters} and it will show additional search fields for "Include" and "Exclude" which support specifying glob patterns for matching file paths and file names.
+
+When creating a glob pattern you can use one or multiple special characters:
+
+| Special Character | Meaning                                                           |
+| ----------------- | ----------------------------------------------------------------- |
+| `?`               | Matches any single character                                      |
+| `*`               | Matches any (possibly empty) sequence of characters               |
+| `**`              | Matches the current directory and arbitrary subdirectories        |
+| `[abc]`           | Matches any one character in the brackets                         |
+| `[a-z]`           | Matches any of a range of characters (ordered by Unicode)         |
+| `[!...]`          | The negation of `[...]` (matches a character not in the brackets) |
+
+Notes:
+
+1. Shell-style brace-expansions like `{a,b,c}` are not supported.
+2. To match a literal `-` character inside brackets it must come first `[-abc]` or last `[abc-]`.
+3. To match the literal `[` character use `[[]` or put it as the first character in the group `[[abc]`.
+4. To match the literal `]` character use `[]]` or put it as the last character in the group `[abc]]`.
+
+## Examples
+
+### Matching file extensions
+
+If you wanted to only search Markdown files add `*.md` to the "Include" search field.
+
+### Case insensitive matching
+
+Globs in Zed are case-sensitive, so `*.c` will not match `main.C` (even on case-insensitive filesystems like HFS+/APFS on MacOS). Instead use brackets to match characters. So instead of `*.c` use `*.[cC]`.
+
+### Matching directories
+
+If you wanted to search the [zed repository](https://github.com/zed-industries/zed) for examples of [Configuring Language Servers](https://zed.dev/docs/configuring-languages#configuring-language-servers) (under `"lsp"` in Zed settings.json) you could search for `"lsp"` and in the "Include" filter specify `docs/**/*.md`. This would only match files whose path was under the `docs` directory or any nested subdirectories `**/` of that folder with a filename that ends in `.md`.
+
+If instead you wanted to restrict yourself only to [Zed Language-Specific Documentation](https://zed.dev/docs/languages) pages you could define a narrower pattern of: `docs/src/languages/*.md` this would match [`docs/src/languages/rust.md`](https://github.com/zed-industries/zed/blob/main/docs/src/languages/rust.md) and [`docs/src/languages/cpp.md`](https://github.com/zed-industries/zed/blob/main/docs/src/languages/cpp.md) but not [`docs/src/configuring-languages.md`](https://github.com/zed-industries/zed/blob/main/docs/src/configuring-languages.md).
+
+### Implicit Wildcards
+
+When using the "Include" / "Exclude" filters on a Project Search each glob is wrapped in implicit wildcards. For example to exclude any files with license in the path or filename from your search just type type `license` in the exclude box. Behind the scenes Zed transforms `license` to `**license**`. This means that files named `license.*`, `*.license` or inside a `license` subdirectory will all be filtered out. This enables users to easily filter for `*.ts` without having to remember to type `**/*.ts` every time.
+
+Alternatively, if in your Zed settings you wanted a [`file_types`](./configuring-zed.md#file-types) override which only applied to a certain directory you must explicitly include the wildcard globs. For example, if you had a directory of template files with the `html` extension that you wanted to recognize as Jinja2 template you could use the following:
+
+```json
+{
+  "file_types": {
+    "C++": ["[cC]"],
+    "Jinja2": ["**/templates/*.html"]
+  }
+}
+```
+
+## References
+
+While globs in Zed are implemented as described above, when writing code using globs in other languages, please reference your platform's glob documentation:
+
+- [MacOS fnmatch](https://developer.apple.com/library/archive/documentation/System/Conceptual/ManPages_iPhoneOS/man3/fnmatch.3.html) (BSD C Standard Library)
+- [Linux fnmatch](https://www.gnu.org/software/libc/manual/html_node/Wildcard-Matching.html) (GNU C Standard Library)
+- [POSIX fnmatch](https://pubs.opengroup.org/onlinepubs/9699919799/functions/fnmatch.html) (POSIX Specification)
+- [node-glob](https://github.com/isaacs/node-glob) (Node.js `glob` package)
+- [Python glob](https://docs.python.org/3/library/glob.html) (Python Standard Library)
+- [Golang glob](https://pkg.go.dev/path/filepath#Match) (Go Standard Library)
+- [gitignore patterns](https://git-scm.com/docs/gitignore) (Gitignore Pattern Format)
+- [PowerShell: About Wildcards](https://learn.microsoft.com/en-us/powershell/module/microsoft.powershell.core/about/about_wildcards) (Wildcards in PowerShell)