From eb304836c4b1cf3ee1c60c9618d2e9fca15838ce Mon Sep 17 00:00:00 2001
From: Eric Scouten <git@scouten.me>
Date: Wed, 27 Dec 2023 13:20:38 -0800
Subject: [PATCH] Add a Block enum type which will eventually represent all
 possible block types in AsciiDoc

---
 src/blocks/block.rs        | 35 ++++++++++++++
 src/blocks/mod.rs          |  6 ++-
 src/tests/blocks/block.rs  | 95 ++++++++++++++++++++++++++++++++++++++
 src/tests/blocks/mod.rs    |  3 +-
 src/tests/blocks/simple.rs |  2 +-
 5 files changed, 138 insertions(+), 3 deletions(-)
 create mode 100644 src/blocks/block.rs
 create mode 100644 src/tests/blocks/block.rs

diff --git a/src/blocks/block.rs b/src/blocks/block.rs
new file mode 100644
index 0000000..ce414bc
--- /dev/null
+++ b/src/blocks/block.rs
@@ -0,0 +1,35 @@
+use nom::IResult;
+
+use super::SimpleBlock;
+use crate::{primitives::consume_empty_lines, Span};
+
+/// Block elements form the main structure of an AsciiDoc document, starting
+/// with the document itself.
+///
+/// A block element (aka block) is a discrete, line-oriented chunk of content in
+/// an AsciiDoc document. Once parsed, that chunk of content becomes a block
+/// element in the parsed document model. Certain blocks may contain other
+/// blocks, so we say that blocks can be nested. The converter visits each block
+/// in turn, in document order, converting it to a corresponding chunk of
+/// output.
+#[derive(Clone, Debug, Eq, PartialEq)]
+pub enum Block<'a> {
+    /// A block that’s treated as contiguous lines of paragraph text (and
+    /// subject to normal substitutions) (e.g., a paragraph block).
+    Simple(SimpleBlock<'a>),
+}
+
+impl<'a> Block<'a> {
+    #[allow(dead_code)]
+    /// Parse a block of any type and return a `Block` that describes it.
+    ///
+    /// Consumes any blank lines before and after the block.
+    pub(crate) fn parse(i: Span<'a>) -> IResult<Span, Self> {
+        let i = consume_empty_lines(i);
+
+        // TEMPORARY: So far, we only know SimpleBlock.
+        // Later we'll start to try to discern other block types.
+        let (rem, simple_block) = SimpleBlock::parse(i)?;
+        Ok((rem, Self::Simple(simple_block)))
+    }
+}
diff --git a/src/blocks/mod.rs b/src/blocks/mod.rs
index a94714a..4f5d38a 100644
--- a/src/blocks/mod.rs
+++ b/src/blocks/mod.rs
@@ -8,4 +8,8 @@
 //! in turn, in document order, converting it to a corresponding chunk of
 //! output.
 
-pub(crate) mod simple;
+mod block;
+pub use block::Block;
+
+mod simple;
+pub use simple::SimpleBlock;
diff --git a/src/tests/blocks/block.rs b/src/tests/blocks/block.rs
new file mode 100644
index 0000000..4b632bf
--- /dev/null
+++ b/src/tests/blocks/block.rs
@@ -0,0 +1,95 @@
+mod simple {
+    use nom::{
+        error::{Error, ErrorKind},
+        Err,
+    };
+
+    use crate::{
+        blocks::{Block, SimpleBlock},
+        Span,
+    };
+
+    #[test]
+    fn empty_source() {
+        let expected_err = Err::Error(Error::new(Span::new("", true), ErrorKind::TakeTill1));
+
+        let actual_err = Block::parse(Span::new("", true)).unwrap_err();
+
+        assert_eq!(expected_err, actual_err);
+    }
+
+    #[test]
+    fn only_spaces() {
+        let err = Block::parse(Span::new("    ", true)).unwrap_err();
+
+        let Err::Error(e) = err else {
+            panic!("Expected Err::Error: {err:#?}");
+        };
+
+        assert_eq!(e.code, ErrorKind::TakeTill1);
+
+        let span = e.input;
+        assert_eq!(span.data(), &"");
+        assert_eq!(span.line(), 1);
+        assert_eq!(span.col(), 5);
+    }
+
+    #[test]
+    fn single_line() {
+        let expected = Block::Simple(SimpleBlock {
+            inlines: vec![Span::new("abc", true)],
+        });
+
+        let (rem, block) = Block::parse(Span::new("abc", true)).unwrap();
+
+        assert_eq!(rem.line(), 1);
+        assert_eq!(rem.col(), 4);
+        assert_eq!(*rem.data(), "");
+
+        assert_eq!(block, expected);
+    }
+
+    #[test]
+    fn multiple_lines() {
+        let (rem, block) = Block::parse(Span::new("abc\ndef", true)).unwrap();
+
+        assert_eq!(rem.line(), 2);
+        assert_eq!(rem.col(), 4);
+        assert_eq!(*rem.data(), "");
+
+        let Block::Simple(block) = block;
+        // else { // ADD THIS ONCE WE HAVE OTHER BLOCK TYPES
+        //panic!("Expected a SimpleBlock: {block:#?}");
+        //};
+
+        assert_eq!(block.inlines.len(), 2);
+
+        assert_eq!(block.inlines[0].line(), 1);
+        assert_eq!(block.inlines[0].col(), 1);
+        assert_eq!(*block.inlines[0].data(), "abc");
+
+        assert_eq!(block.inlines[1].line(), 2);
+        assert_eq!(block.inlines[1].col(), 1);
+        assert_eq!(*block.inlines[1].data(), "def");
+    }
+
+    #[test]
+    fn consumes_blank_lines_after() {
+        let expected = SimpleBlock {
+            inlines: vec![Span::new("abc", true)],
+        };
+
+        let (rem, block) = Block::parse(Span::new("abc\n\ndef", true)).unwrap();
+
+        assert_eq!(rem.line(), 3);
+        assert_eq!(rem.col(), 1);
+        assert_eq!(*rem.data(), "def");
+
+        let Block::Simple(block) = block;
+        // else { // ADD THIS ONCE WE HAVE OTHER BLOCK TYPES
+        //panic!("Expected a SimpleBlock: {block:#?}");
+        //};
+
+        assert_eq!(block, expected);
+    }
+}
diff --git a/src/tests/blocks/mod.rs b/src/tests/blocks/mod.rs
index 6d0ed9e..68a05a7 100644
--- a/src/tests/blocks/mod.rs
+++ b/src/tests/blocks/mod.rs
@@ -1 +1,2 @@
-pub(crate) mod simple;
+mod block;
+mod simple;
diff --git a/src/tests/blocks/simple.rs b/src/tests/blocks/simple.rs
index c27e6e6..1b78f68 100644
--- a/src/tests/blocks/simple.rs
+++ b/src/tests/blocks/simple.rs
@@ -3,7 +3,7 @@ use nom::{
     Err,
 };
 
-use crate::{blocks::simple::SimpleBlock, Span};
+use crate::{blocks::SimpleBlock, Span};
 
 #[test]
 fn empty_source() {