Added ExcerptGetter and fixed potential FrontMatter bug.

cli/src/main/groovy/com/jessebrault/ssg/StaticSiteGeneratorCli.groovy

@@ -11,6 +11,7 @@ import com.jessebrault.ssg.specialpage.SpecialPageType
 import com.jessebrault.ssg.template.GspTemplateRenderer
 import com.jessebrault.ssg.template.TemplateFileTemplatesProvider
 import com.jessebrault.ssg.template.TemplateType
+import com.jessebrault.ssg.text.MarkdownExcerptGetter
 import com.jessebrault.ssg.text.MarkdownFrontMatterGetter
 import com.jessebrault.ssg.text.MarkdownTextRenderer
 import com.jessebrault.ssg.text.TextFileTextsProvider
@@ -85,7 +86,7 @@ class StaticSiteGeneratorCli implements Callable<Integer> {
         context.updateLoggers()
 
         // Configure
-        def markdownText = new TextType(['.md'], new MarkdownTextRenderer(), new MarkdownFrontMatterGetter())
+        def markdownText = new TextType(['.md'], new MarkdownTextRenderer(), new MarkdownFrontMatterGetter(), new MarkdownExcerptGetter())
         def gspTemplate = new TemplateType(['.gsp'], new GspTemplateRenderer())
         def gspPart = new PartType(['.gsp'], new GspPartRenderer())
         def gspSpecialPage = new SpecialPageType(['.gsp'], new GspSpecialPageRenderer())

lib/src/main/groovy/com/jessebrault/ssg/text/EmbeddableText.groovy

@@ -30,7 +30,18 @@ class EmbeddableText {
         def result = this.text.type.frontMatterGetter.get(this.text)
         if (result.v1.size() > 0) {
             this.onDiagnostics.call(result.v1)
-            new FrontMatter([:])
+            new FrontMatter(this.text, [:])
+        } else {
+            result.v2
+        }
+    }
+
+    @Memoized
+    String getExcerpt(int limit) {
+        def result = this.text.type.excerptGetter.getExcerpt(this.text, limit)
+        if (result.v1.size() > 0) {
+            this.onDiagnostics.call(result.v1)
+            ''
         } else {
             result.v2
         }

lib/src/main/groovy/com/jessebrault/ssg/text/ExcerptGetter.groovy

@@ -0,0 +1,7 @@
+package com.jessebrault.ssg.text
+
+import com.jessebrault.ssg.Diagnostic
+
+interface ExcerptGetter {
+    Tuple2<Collection<Diagnostic>, String> getExcerpt(Text text, int limit)
+}

lib/src/main/groovy/com/jessebrault/ssg/text/MarkdownExcerptGetter.groovy

@@ -0,0 +1,54 @@
+package com.jessebrault.ssg.text
+
+import com.jessebrault.ssg.Diagnostic
+import org.commonmark.ext.front.matter.YamlFrontMatterExtension
+import org.commonmark.node.AbstractVisitor
+import org.commonmark.parser.Parser
+
+class MarkdownExcerptGetter implements ExcerptGetter {
+
+    private static class ExcerptVisitor extends AbstractVisitor {
+
+        final int limit
+        List<String> words = []
+
+        ExcerptVisitor(int limit) {
+            this.limit = limit
+        }
+
+        @Override
+        void visit(org.commonmark.node.Text text) {
+            if (this.words.size() <= limit) {
+                def textWords = text.literal.split('\\s+').toList()
+                def taken = textWords.take(this.limit - this.words.size())
+                this.words.addAll(taken)
+            }
+        }
+
+        String getResult() {
+            this.words.take(this.limit).join(' ')
+        }
+
+    }
+
+    private static final Parser parser = Parser.builder()
+            .extensions([YamlFrontMatterExtension.create()])
+            .build()
+
+    @Override
+    Tuple2<Collection<Diagnostic>, String> getExcerpt(Text text, int limit) {
+        try {
+            def node = parser.parse(text.text)
+            def visitor = new ExcerptVisitor(limit)
+            node.accept(visitor)
+            new Tuple2<>([], visitor.result)
+        } catch (Exception e) {
+            def diagnostic = new Diagnostic(
+                    "There was an exception while getting the excerpt for ${ text }:\n${ e }",
+                    e
+            )
+            new Tuple2<>([diagnostic], '')
+        }
+    }
+
+}

lib/src/main/groovy/com/jessebrault/ssg/text/TextType.groovy

@@ -12,10 +12,11 @@ class TextType {
     Collection<String> ids
     TextRenderer renderer
     FrontMatterGetter frontMatterGetter
+    ExcerptGetter excerptGetter
 
     @Override
     String toString() {
-        "TextType(ids: ${ this.ids }, renderer: ${ this.renderer }, frontMatterGetter: ${ this.renderer })"
+        "TextType(ids: ${ this.ids }, renderer: ${ this.renderer }, frontMatterGetter: ${ this.renderer }, excerptGetter: ${ this.excerptGetter })"
     }
 
 }

lib/src/test/groovy/com/jessebrault/ssg/SimpleStaticSiteGeneratorIntegrationTests.groovy

@@ -9,6 +9,7 @@ import com.jessebrault.ssg.specialpage.SpecialPageType
 import com.jessebrault.ssg.template.GspTemplateRenderer
 import com.jessebrault.ssg.template.TemplateFileTemplatesProvider
 import com.jessebrault.ssg.template.TemplateType
+import com.jessebrault.ssg.text.MarkdownExcerptGetter
 import com.jessebrault.ssg.text.MarkdownFrontMatterGetter
 import com.jessebrault.ssg.text.MarkdownTextRenderer
 import com.jessebrault.ssg.text.TextFileTextsProvider
@@ -35,7 +36,7 @@ class SimpleStaticSiteGeneratorIntegrationTests {
         this.partsDir = File.createTempDir()
         this.specialPagesDir = File.createTempDir()
 
-        def markdownTextType = new TextType(['.md'], new MarkdownTextRenderer(), new MarkdownFrontMatterGetter())
+        def markdownTextType = new TextType(['.md'], new MarkdownTextRenderer(), new MarkdownFrontMatterGetter(), new MarkdownExcerptGetter())
         def gspTemplateType = new TemplateType(['.gsp'], new GspTemplateRenderer())
         def gspPartType = new PartType(['.gsp'], new GspPartRenderer())
         def gspSpecialPageType = new SpecialPageType(['.gsp'], new GspSpecialPageRenderer())

lib/src/test/groovy/com/jessebrault/ssg/specialpage/GspSpecialPageRendererTests.groovy

@@ -4,6 +4,7 @@ import com.jessebrault.ssg.part.Part
 import com.jessebrault.ssg.part.PartRenderer
 import com.jessebrault.ssg.part.PartType
 import com.jessebrault.ssg.text.FrontMatterGetter
+import com.jessebrault.ssg.text.MarkdownExcerptGetter
 import com.jessebrault.ssg.text.Text
 import com.jessebrault.ssg.text.TextRenderer
 import com.jessebrault.ssg.text.TextType
@@ -59,7 +60,7 @@ class GspSpecialPageRendererTests {
     @Test
     void rendersText(@Mock TextRenderer textRenderer, @Mock FrontMatterGetter frontMatterGetter) {
         when(textRenderer.render(any(), any())).thenReturn(new Tuple2<>([], '<p><strong>Hello, World!</strong></p>\n'))
-        def textType = new TextType([], textRenderer, frontMatterGetter)
+        def textType = new TextType([], textRenderer, frontMatterGetter, new MarkdownExcerptGetter())
         def text = new Text('', 'test', textType)
 
         def specialPage = new SpecialPage("<%= texts.find { it.path == 'test' }.render() %>", null, null)

lib/src/test/groovy/com/jessebrault/ssg/text/ExcerptGetterTests.groovy

@@ -0,0 +1,43 @@
+package com.jessebrault.ssg.text
+
+import org.junit.jupiter.api.Test
+
+import static org.junit.jupiter.api.Assertions.assertEquals
+
+class ExcerptGetterTests {
+
+    ExcerptGetter excerptGetter = new MarkdownExcerptGetter()
+
+    @Test
+    void takesAllIfTextLessThanLimit() {
+        def text = new Text('One Two Three Four Five', null, null)
+        def result = this.excerptGetter.getExcerpt(text, 10)
+        assertEquals(0, result.v1.size())
+        assertEquals('One Two Three Four Five', result.v2)
+    }
+
+    @Test
+    void takesTheLimit() {
+        def text = new Text('One Two Three Four Five', null, null)
+        def result = this.excerptGetter.getExcerpt(text, 2)
+        assertEquals(0, result.v1.size())
+        assertEquals('One Two', result.v2)
+    }
+
+    @Test
+    void worksWithHeading() {
+        def text = new Text('# Heading\nOne Two Three', null, null)
+        def result = this.excerptGetter.getExcerpt(text, 1)
+        assertEquals(0, result.v1.size())
+        assertEquals('Heading', result.v2)
+    }
+
+    @Test
+    void worksWithFrontMatter() {
+        def text = new Text('---\ntest: hello\n---\nOne Two Three', null, null)
+        def result = this.excerptGetter.getExcerpt(text, 1)
+        assertEquals(0, result.v1.size())
+        assertEquals('One', result.v2)
+    }
+
+}

lib/src/test/groovy/com/jessebrault/ssg/text/TextFileTextsProviderTests.groovy

@@ -7,7 +7,7 @@ import static org.junit.jupiter.api.Assertions.assertEquals
 
 class TextFileTextsProviderTests {
 
-    private static final TextType markdownType = new TextType(['.md'], null, null)
+    private static final TextType markdownType = new TextType(['.md'], null, null, null)
 
     private File textsDir
     private TextsProvider textsProvider