Reinstate the index option

This wasn't needed for AWS as you can configure a custom 404 page, but
Cloudflare Pages expects a "404.html" file somewhere and you can't
change this behaviour.

Changelog: added

README.md

@@ -49,7 +49,10 @@ To build the site, you can use the following methods on the `Site` type:
   (relative to the output directory). This is useful when generating files using
   arbitrary logic, such as an Atom feed.
 - `page(pattern, index, func)`: finds Markdown files matching `pattern`, turning
-  them into HTML files by calling the `func` closure.
+  them into HTML files by calling the `func` closure. If `index` is set to
+  `true`, the output is `NAME/index.html` (e.g. `articles/foo/index.html`). If
+  `index` is `false`, the output is instead `NAME.html` (e.g.
+  `articles/foo.html`).
 
 For example:
 
@@ -80,7 +83,7 @@ import wobsite.(Site, Page)
 class async Main {
   fn async main {
     Site.build fn (site) {
-      site.page('/index.md') fn {
+      site.page('/index.md', index: false) fn {
         recover fn (_, page: Page) { Result.Ok(page.to_html([])) }
       }
     }

src/wobsite.inko

@@ -498,19 +498,27 @@ class pub Site {
   # typical setting, this closure converts the Markdown to HTML and wraps it in
   # a layout of sorts.
   #
-  # Input files are mapped to output files as follows:
+  # Input files are mapped to output files as follows when using `index: true`:
   #
-  # - `./source/index.md` results in `./public/index.html`
-  # - `./source/foo.md` results in `./public/foo/index.html`
-  # - `./source/foo/bar/index.md` results in `./public/foo/bar/index.html`
-  # - `./source/foo/bar.md` results in `./public/foo/bar/index.html`
+  # - `./source/index.md` becomes `./public/index.html`
+  # - `./source/foo.md` becomes `./public/foo/index.html`
+  # - `./source/foo/bar/index.md` becomes `./public/foo/bar/index.html`
+  # - `./source/foo/bar.md` becomes `./public/foo/bar/index.html`
+  #
+  # When using `index: false`, the mapping is instead as follows:
+  #
+  # - `./source/index.md` becomes `./public/index.html`
+  # - `./source/foo.md` becomes `./public/foo.html`
+  # - `./source/foo/bar/index.md` becomes `./public/foo/bar.html`
+  # - `./source/foo/bar.md` becomes `./public/foo/bar.html`
   fn pub mut page(
     pattern: String,
+    index: Bool,
     builder: fn -> uni fn (ref Files, Page) -> Result[html.Document, String],
   ) {
     @files.matching(pattern).each fn (path) {
       @pending += 1
-      spawn.page(recover path.clone, builder.call)
+      spawn.page(recover path.clone, index, builder.call)
     }
   }
 
@@ -593,11 +601,12 @@ class async Worker {
 
   fn async page(
     source: uni Path,
+    index: Bool,
     layout: uni fn (ref Files, Page) -> Result[html.Document, String],
   ) {
     let source = recover source
     let rel_source = source.strip_prefix(@files.source).unwrap
-    let target = if rel_source.tail == INDEX_FILE {
+    let target = if rel_source.tail == INDEX_FILE or index.false? {
       @files.output.join(rel_source.with_extension('html'))
     } else {
       @files.output.join(rel_source.with_extension('').join('index.html'))

test/test_wobsite.inko

@@ -414,14 +414,38 @@ test'
 
     let site = Site.new(dir.path.clone, dir.path.clone).unwrap
 
-    site.page('*.md') fn {
+    site.page('*.md', index: true) fn {
       recover fn (_, page: Page) { Result.Ok(page.to_html([])) }
     }
 
     t.true(site.wait.ok?)
     t.equal(read(dir.path.join('foo/index.html')), Result.Ok("<p>\ntest</p>"))
   }
 
+  t.test('Site.page with a regular Markdown file and index: false') fn (t) {
+    let dir = TempPath.directory(t.id)
+    let md = '\
+---
+{
+  "title": "test",
+  "date": "2024-01-01T13:00:00Z"
+}
+---
+
+test'
+
+    write(dir.path.join('foo.md'), md)
+
+    let site = Site.new(dir.path.clone, dir.path.clone).unwrap
+
+    site.page('*.md', index: false) fn {
+      recover fn (_, page: Page) { Result.Ok(page.to_html([])) }
+    }
+
+    t.true(site.wait.ok?)
+    t.equal(read(dir.path.join('foo.html')), Result.Ok("<p>\ntest</p>"))
+  }
+
   t.test('Site.page with the index Markdown file') fn (t) {
     let dir = TempPath.directory(t.id)
     let md = '\
@@ -438,7 +462,31 @@ test'
 
     let site = Site.new(dir.path.clone, dir.path.clone).unwrap
 
-    site.page('*.md') fn {
+    site.page('*.md', index: true) fn {
+      recover fn (_, page: Page) { Result.Ok(page.to_html([])) }
+    }
+
+    t.true(site.wait.ok?)
+    t.equal(read(dir.path.join('index.html')), Result.Ok("<p>\ntest</p>"))
+  }
+
+  t.test('Site.page with the index Markdown file and index: false') fn (t) {
+    let dir = TempPath.directory(t.id)
+    let md = '\
+---
+{
+  "title": "test",
+  "date": "2024-01-01T13:00:00Z"
+}
+---
+
+test'
+
+    write(dir.path.join('index.md'), md)
+
+    let site = Site.new(dir.path.clone, dir.path.clone).unwrap
+
+    site.page('*.md', index: false) fn {
       recover fn (_, page: Page) { Result.Ok(page.to_html([])) }
     }
 
@@ -461,7 +509,7 @@ test'
 
     let site = Site.new(dir.path.clone, dir.path.clone).unwrap
 
-    site.page('*.md') fn {
+    site.page('*.md', index: true) fn {
       recover fn (_, page: Page) { Result.Ok(page.to_html([])) }
     }
 
@@ -484,7 +532,7 @@ test'
 
     let site = Site.new(dir.path.clone, Path.new('/dev/null/invalid')).unwrap
 
-    site.page('*.md') fn {
+    site.page('*.md', index: true) fn {
       recover fn (_, page: Page) { Result.Ok(page.to_html([])) }
     }