Implement `{% include 'template' %}` feature

7 files changed, 125 insertions, 41 deletions

diff --git a/doc-tool/resources/_includes/header.html b/doc-tool/resources/_includes/header.html
new file mode 100644
index 000000000..219cdf7f9
--- /dev/null
+++ b/doc-tool/resources/_includes/header.html
@@ -0,0 +1 @@
+<h1>Some header</h1>
diff --git a/doc-tool/src/dotty/tools/dottydoc/staticsite/LiquidTemplate.scala b/doc-tool/src/dotty/tools/dottydoc/staticsite/LiquidTemplate.scala
new file mode 100644
index 000000000..18ef9ef2a
--- /dev/null
+++ b/doc-tool/src/dotty/tools/dottydoc/staticsite/LiquidTemplate.scala
@@ -0,0 +1,46 @@
+package dotty.tools
+package dottydoc
+package staticsite
+
+import dotc.config.Printers.dottydoc
+
+case class LiquidTemplate(contents: String) extends ResourceFinder {
+  import scala.collection.JavaConverters._
+  import liqp.{ Template, TemplateContext }
+  import liqp.nodes.LNode
+  import liqp.tags.Tag
+
+  def render(params: Map[String, AnyRef], includes: Map[String, String]): String = {
+    Template.parse(contents).`with`(ResourceInclude(params, includes)).render(params.asJava)
+  }
+
+  private case class ResourceInclude(params: Map[String, AnyRef], includes: Map[String, String])
+  extends Tag("include") {
+    val DefaultExtension = ".html"
+
+    private def renderTemplate(template: String) = "dude"
+
+    override def render(ctx: TemplateContext, nodes: LNode*): AnyRef = {
+      val origInclude = asString(nodes(0).render(ctx))
+      val incResource = origInclude match {
+        case fileWithExt if fileWithExt.indexOf('.') > 0 => fileWithExt
+        case file => file + DefaultExtension
+      }
+
+      includes
+        .get(incResource)
+        .map { template =>
+          val additionalParams =
+            // include has `with` clause:
+            if (nodes.length > 1) params + (origInclude -> nodes(1).render(ctx))
+            else params
+
+          Template.parse(template, ctx.flavor).render(additionalParams.asJava)
+        }
+        .getOrElse {
+          /*dottydoc.*/println(s"couldn't find include file '$origInclude'")
+          ""
+        }
+    }
+  }
+}
diff --git a/doc-tool/src/dotty/tools/dottydoc/staticsite/Page.scala b/doc-tool/src/dotty/tools/dottydoc/staticsite/Page.scala
index 0293c3367..c8148c627 100644
--- a/doc-tool/src/dotty/tools/dottydoc/staticsite/Page.scala
+++ b/doc-tool/src/dotty/tools/dottydoc/staticsite/Page.scala
@@ -9,7 +9,6 @@ import dotc.config.Printers.dottydoc
 import com.vladsch.flexmark.html.HtmlRenderer
 import com.vladsch.flexmark.parser.Parser
 import com.vladsch.flexmark.ext.front.matter.AbstractYamlFrontMatterVisitor
-import liqp.{ Template => LiquidTemplate }
 import _root_.java.util.{ Map => JMap }
 
 case class IllegalFrontMatter(message: String) extends Exception(message)
@@ -17,7 +16,7 @@ case class IllegalFrontMatter(message: String) extends Exception(message)
 trait Page {
   import scala.collection.JavaConverters._
 
-
+  def includes: Map[String, String]
   def pageContent: String
   def params: Map[String, AnyRef]
 
@@ -61,9 +60,7 @@ trait Page {
 
     // make accessible via "{{ page.title }}" in templates
     val page = Map("page" ->  _yaml.asJava)
-    _html = LiquidTemplate
-      .parse(withoutYaml)
-      .render((params ++ page).asJava)
+    _html = LiquidTemplate(withoutYaml).render(params ++ page, includes)
   }
 
   /** Takes "page" from `params` map in case this is a second expansion, and
@@ -81,11 +78,11 @@ trait Page {
     .getOrElse(newYaml)
 }
 
-class HtmlPage(fileContents: => String, val params: Map[String, AnyRef]) extends Page {
+class HtmlPage(fileContents: => String, val params: Map[String, AnyRef], val includes: Map[String, String]) extends Page {
   lazy val pageContent = fileContents
 }
 
-class MarkdownPage(fileContents: => String, val params: Map[String, AnyRef]) extends Page {
+class MarkdownPage(fileContents: => String, val params: Map[String, AnyRef], val includes: Map[String, String]) extends Page {
   lazy val pageContent = fileContents
 
   override protected[this] def initFields()(implicit ctx: Context) = {
diff --git a/doc-tool/src/dotty/tools/dottydoc/staticsite/ResourceFinder.scala b/doc-tool/src/dotty/tools/dottydoc/staticsite/ResourceFinder.scala
new file mode 100644
index 000000000..66d31fa18
--- /dev/null
+++ b/doc-tool/src/dotty/tools/dottydoc/staticsite/ResourceFinder.scala
@@ -0,0 +1,16 @@
+package dotty.tools
+package dottydoc
+package staticsite
+
+trait ResourceFinder {
+  /** If, for some reason, the supplied default files cannot be found - this
+    * exception will be thrown in `layouts`.
+    */
+  final case class ResourceNotFoundException(message: String) extends Exception(message)
+
+  protected def getResource(r: String): String =
+    Option(getClass.getResourceAsStream(r)).map(scala.io.Source.fromInputStream)
+      .map(_.mkString)
+      .getOrElse(throw ResourceNotFoundException(r))
+
+}
diff --git a/doc-tool/src/dotty/tools/dottydoc/staticsite/Site.scala b/doc-tool/src/dotty/tools/dottydoc/staticsite/Site.scala
index ac609e6b6..b1962735f 100644
--- a/doc-tool/src/dotty/tools/dottydoc/staticsite/Site.scala
+++ b/doc-tool/src/dotty/tools/dottydoc/staticsite/Site.scala
@@ -7,12 +7,7 @@ import dotc.config.Printers.dottydoc
 import dotc.core.Contexts.Context
 import scala.io.Source
 
-class Site(val root: JFile) {
-
-  /** If, for some reason, the supplied default files cannot be found - this
-    * exception will be thrown in `layouts`.
-    */
-  final case class ResourceNotFoundException(message: String) extends Exception(message)
+class Site(val root: JFile) extends ResourceFinder {
 
   /** Files that define a layout then referred to by `layout: filename-no-ext`
     * in yaml front-matter.
@@ -24,19 +19,10 @@ class Site(val root: JFile) {
     * defaults, the user-defined one will take precedence.
     */
   val layouts: Map[String, String] = {
-    def collectLayouts(dir: JFile): Map[String, String] =
-      dir
-      .listFiles
-      .filter(f => f.getName.endsWith(".md") || f.getName.endsWith(".html"))
-      .map { f =>
-        (f.getName.substring(0, f.getName.lastIndexOf('.')), Source.fromFile(f).mkString)
-      }
-      .toMap
-
     val userDefinedLayouts =
       root
       .listFiles.find(d => d.getName == "_layouts" && d.isDirectory)
-      .map(collectLayouts)
+      .map(collectFiles(_, f => f.endsWith(".md") || f.endsWith(".html")))
       .getOrElse(Map.empty)
 
     val defaultLayouts: Map[String, String] = Map(
@@ -47,10 +33,28 @@ class Site(val root: JFile) {
     defaultLayouts ++ userDefinedLayouts
   }
 
-  private def getResource(r: String): String =
-    Option(getClass.getResourceAsStream(r)).map(scala.io.Source.fromInputStream)
-      .map(_.mkString)
-      .getOrElse(throw ResourceNotFoundException(r))
+  val includes: Map[String, String] = {
+    val userDefinedIncludes =
+      root
+      .listFiles.find(d => d.getName == "_includes" && d.isDirectory)
+      .map(collectFiles(_, f => f.endsWith(".md") || f.endsWith(".html")))
+      .getOrElse(Map.empty)
+
+    val defaultIncludes: Map[String, String] = Map(
+      "header.html" -> "/_includes/header.html"
+    ).mapValues(getResource)
+
+    defaultIncludes ++ userDefinedIncludes
+  }
+
+  private def collectFiles(dir: JFile, includes: String => Boolean): Map[String, String] =
+    dir
+    .listFiles
+    .filter(f => includes(f.getName))
+    .map { f =>
+      (f.getName.substring(0, f.getName.lastIndexOf('.')), Source.fromFile(f).mkString)
+    }
+    .toMap
 
   def render(page: Page, params: Map[String, AnyRef])(implicit ctx: Context): String = {
     page.yaml.get("layout").flatMap(layouts.get(_)) match {
@@ -58,7 +62,7 @@ class Site(val root: JFile) {
         page.html
       case Some(layout) =>
         val newParams = Map("content" -> page.html) ++ params ++ Map("page" -> page.yaml)
-        val expandedTemplate = new HtmlPage(layout, newParams)
+        val expandedTemplate = new HtmlPage(layout, newParams, includes)
         render(expandedTemplate, params)
     }
   }
diff --git a/doc-tool/test/dotty/tools/dottydoc/staticsite/PageTests.scala b/doc-tool/test/dotty/tools/dottydoc/staticsite/PageTests.scala
index 87358d738..6f20e28c2 100644
--- a/doc-tool/test/dotty/tools/dottydoc/staticsite/PageTests.scala
+++ b/doc-tool/test/dotty/tools/dottydoc/staticsite/PageTests.scala
@@ -15,6 +15,7 @@ class PageTests extends DottyDocTest {
          |---
          |
          |great""".stripMargin,
+      Map.empty,
       Map.empty
     )
 
@@ -33,7 +34,8 @@ class PageTests extends DottyDocTest {
          |---
          |
          |{{ content }}""".stripMargin,
-       Map("content" -> "Hello, world!")
+       Map("content" -> "Hello, world!"),
+       Map.empty
     )
 
     assert(
@@ -45,7 +47,8 @@ class PageTests extends DottyDocTest {
 
     val page2 = new MarkdownPage(
       """|{{ content }}""".stripMargin,
-      Map("content" -> "hello")
+      Map("content" -> "hello"),
+      Map.empty
     )
     assert(
       page2.yaml == Map(),
@@ -57,7 +60,8 @@ class PageTests extends DottyDocTest {
       """|{% if product.title == "Awesome Shoes" %}
          |These shoes are awesome!
          |{% endif %}""".stripMargin,
-      Map("product" -> Map("title" -> "Awesome Shoes").asJava)
+      Map("product" -> Map("title" -> "Awesome Shoes").asJava),
+      Map.empty
     )
 
     assertEquals(
@@ -67,7 +71,7 @@ class PageTests extends DottyDocTest {
   }
 
   @Test def simpleHtmlPage = {
-    val p1 = new HtmlPage("""<h1>{{ "hello, world!" }}</h1>""", Map.empty)
+    val p1 = new HtmlPage("""<h1>{{ "hello, world!" }}</h1>""", Map.empty, Map.empty)
     assert(p1.yaml == Map(), "non-empty yaml found")
     assertEquals("<h1>hello, world!</h1>", p1.html)
   }
@@ -79,6 +83,7 @@ class PageTests extends DottyDocTest {
          |---
          |
          |Hello, world!""".stripMargin,
+      Map.empty,
       Map.empty
     )
 
@@ -93,6 +98,7 @@ class PageTests extends DottyDocTest {
          |
          |
          |Hello, world!""".stripMargin,
+      Map.empty,
       Map.empty
     )
 
diff --git a/doc-tool/test/dotty/tools/dottydoc/staticsite/SiteTests.scala b/doc-tool/test/dotty/tools/dottydoc/staticsite/SiteTests.scala
index 2a8b6ac9b..0c6d232f5 100644
--- a/doc-tool/test/dotty/tools/dottydoc/staticsite/SiteTests.scala
+++ b/doc-tool/test/dotty/tools/dottydoc/staticsite/SiteTests.scala
@@ -6,6 +6,12 @@ import org.junit.Test
 import org.junit.Assert._
 
 class SiteTests extends DottyDocTest {
+  private def html(
+    str: String,
+    params: Map[String, AnyRef] = Map.empty,
+    includes: Map[String, String] = Map.empty
+  ) = new HtmlPage(str, params, includes)
+
   @Test def hasCorrectLayoutFiles = {
     val site = new Site(new java.io.File("../doc-tool/resources/"))
 
@@ -20,13 +26,12 @@ class SiteTests extends DottyDocTest {
   @Test def renderHelloInMainLayout = {
     val site = new Site(new java.io.File("../doc-tool/resources/"))
 
-    val renderedPage = site.render(new HtmlPage(
+    val renderedPage = site.render(html(
       """|---
          |layout: main
          |---
          |
-         |Hello, world!""".stripMargin,
-      Map.empty
+         |Hello, world!""".stripMargin
     ), Map.empty)
 
     assert(
@@ -40,12 +45,11 @@ class SiteTests extends DottyDocTest {
   @Test def renderMultipleTemplates = {
     val site = new Site(new java.io.File("../doc-tool/resources/"))
 
-    val renderedPage = site.render(new HtmlPage(
+    val renderedPage = site.render(html(
       """|---
          |layout: index
          |---
-         |Hello, world!""".stripMargin,
-      Map.empty
+         |Hello, world!""".stripMargin
     ), Map.empty)
 
     assert(
@@ -60,13 +64,12 @@ class SiteTests extends DottyDocTest {
   @Test def preservesPageYaml = {
     val site = new Site(new java.io.File("../doc-tool/resources/"))
 
-    val renderedPage = site.render(new HtmlPage(
+    val renderedPage = site.render(html(
       """|---
          |title: Hello, world
          |layout: index
          |---
-         |Hello, world!""".stripMargin,
-      Map.empty
+         |Hello, world!""".stripMargin
     ), Map.empty)
 
     assert(
@@ -78,4 +81,15 @@ class SiteTests extends DottyDocTest {
       "html page did not render properly"
     )
   }
+
+  @Test def include = {
+    val site = new Site(new java.io.File("../doc-tool/resources/"))
+
+    val renderedInclude = site.render(
+      html("""{% include "header.html" %}""", includes = site.includes),
+      Map.empty
+    )
+
+    assertEquals("<h1>Some header</h1>\n", renderedInclude)
+  }
 }