From ae1c06bd22146ac5e38bc513faffe83eaa39096c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Patrick=20F=C3=B6rster?=
 <pfoerster@users.noreply.github.com>
Date: Sat, 22 Dec 2018 21:18:04 +0100
Subject: [PATCH] Parse LaTeX sections

---
 src/main/kotlin/texlab/latex/LatexSection.kt  | 26 ++++++++++++++
 .../kotlin/texlab/latex/LatexSyntaxTree.kt    |  2 ++
 .../kotlin/texlab/latex/LatexSectionTests.kt  | 35 +++++++++++++++++++
 3 files changed, 63 insertions(+)
 create mode 100644 src/main/kotlin/texlab/latex/LatexSection.kt
 create mode 100644 src/test/kotlin/texlab/latex/LatexSectionTests.kt

diff --git a/src/main/kotlin/texlab/latex/LatexSection.kt b/src/main/kotlin/texlab/latex/LatexSection.kt
new file mode 100644
index 00000000..51e880af
--- /dev/null
+++ b/src/main/kotlin/texlab/latex/LatexSection.kt
@@ -0,0 +1,26 @@
+package texlab.latex
+
+data class LatexSection(val command: LatexCommandSyntax, val text: String, val level: Int) {
+    companion object {
+        private val COMMAND_NAMES = arrayOf(
+                "\\chapter", "\\chapter*",
+                "\\section", "\\section*",
+                "\\subsection", "\\subsection*",
+                "\\subsubsection", "\\subsubsection*",
+                "\\paragraph", "\\paragraph*",
+                "\\subparagraph", "\\subparagraph*")
+
+        fun analyze(root: LatexSyntaxNode): List<LatexSection> {
+            return root.descendants()
+                    .filterIsInstance<LatexCommandSyntax>()
+                    .filter { COMMAND_NAMES.contains(it.name.text) }
+                    .mapNotNull { analyze(it) }
+        }
+
+        private fun analyze(command: LatexCommandSyntax): LatexSection? {
+            val text = command.extractText(0) ?: return null
+            val level = COMMAND_NAMES.indexOf(command.name.text) / 2
+            return LatexSection(command, text.words.joinToString(" ") { it.text }, level)
+        }
+    }
+}
diff --git a/src/main/kotlin/texlab/latex/LatexSyntaxTree.kt b/src/main/kotlin/texlab/latex/LatexSyntaxTree.kt
index d666b88f..0c31960f 100644
--- a/src/main/kotlin/texlab/latex/LatexSyntaxTree.kt
+++ b/src/main/kotlin/texlab/latex/LatexSyntaxTree.kt
@@ -7,4 +7,6 @@ class LatexSyntaxTree(text: String) {
     val includes: List<LatexInclude> = LatexInclude.analyze(root)
 
     val environments: List<LatexEnvironment> = LatexEnvironment.analyze(root)
+
+    val sections: List<LatexSection> = LatexSection.analyze(root)
 }
diff --git a/src/test/kotlin/texlab/latex/LatexSectionTests.kt b/src/test/kotlin/texlab/latex/LatexSectionTests.kt
new file mode 100644
index 00000000..d0f67f39
--- /dev/null
+++ b/src/test/kotlin/texlab/latex/LatexSectionTests.kt
@@ -0,0 +1,35 @@
+package texlab.latex
+
+import org.junit.jupiter.api.Assertions.assertEquals
+import org.junit.jupiter.api.Test
+
+class LatexSectionTests {
+
+    @Test
+    fun `it should find numbered sections`() {
+        val text = "\\section{Foo Bar Baz}"
+        val tree = LatexParser.parse(text)
+        val expected = LatexSection(tree.children[0] as LatexCommandSyntax, "Foo Bar Baz", 1)
+        val actual = LatexSection.analyze(tree)
+        assertEquals(1, actual.size)
+        assertEquals(expected, actual[0])
+    }
+
+    @Test
+    fun `it should find unnumbered paragraphs`() {
+        val text = "\\paragraph*{Foo}"
+        val tree = LatexParser.parse(text)
+        val expected = LatexSection(tree.children[0] as LatexCommandSyntax, "Foo", 4)
+        val actual = LatexSection.analyze(tree)
+        assertEquals(1, actual.size)
+        assertEquals(expected, actual[0])
+    }
+
+    @Test
+    fun `it should ignore invalid chapters`() {
+        val text = "\\chapter*"
+        val tree = LatexParser.parse(text)
+        val actual = LatexSection.analyze(tree)
+        assertEquals(0, actual.size)
+    }
+}