From 9e4bf553d3681a359e1d2f41eeaf8cefe6462fb1 Mon Sep 17 00:00:00 2001
From: Tom Alexander <tom@fizz.buzz>
Date: Sat, 15 Apr 2023 17:56:07 -0400
Subject: [PATCH] First attempt at implementing drawers.

---
 org_mode_samples/drawer/Makefile   | 23 ++++++++++
 org_mode_samples/drawer/simple.org |  9 ++++
 src/parser/drawer.rs               | 70 +++++++++++++++++++++++++++++-
 src/parser/greater_element.rs      |  2 +-
 4 files changed, 102 insertions(+), 2 deletions(-)
 create mode 100644 org_mode_samples/drawer/Makefile
 create mode 100644 org_mode_samples/drawer/simple.org

diff --git a/org_mode_samples/drawer/Makefile b/org_mode_samples/drawer/Makefile
new file mode 100644
index 0000000..c47a86c
--- /dev/null
+++ b/org_mode_samples/drawer/Makefile
@@ -0,0 +1,23 @@
+SHELL := bash
+.ONESHELL:
+.SHELLFLAGS := -eu -o pipefail -c
+.DELETE_ON_ERROR:
+MAKEFLAGS += --warn-undefined-variables
+MAKEFLAGS += --no-builtin-rules
+SRCFILES := $(wildcard *.org)
+OUTFILES := $(patsubst %.org,%.tree.txt,$(SRCFILES))
+
+ifeq ($(origin .RECIPEPREFIX), undefined)
+  $(error This Make does not support .RECIPEPREFIX. Please use GNU Make 4.0 or later)
+endif
+.RECIPEPREFIX = >
+
+.PHONY: all
+all: $(OUTFILES)
+
+.PHONY: clean
+clean:
+> rm -rf $(OUTFILES)
+
+%.tree.txt: %.org ../common.el ../dump_org_ast.bash
+> ../dump_org_ast.bash $< $@
diff --git a/org_mode_samples/drawer/simple.org b/org_mode_samples/drawer/simple.org
new file mode 100644
index 0000000..50adaa3
--- /dev/null
+++ b/org_mode_samples/drawer/simple.org
@@ -0,0 +1,9 @@
+* Headline
+before
+:candle:
+inside
+
+the drawer
+:end:
+
+after
diff --git a/src/parser/drawer.rs b/src/parser/drawer.rs
index 1443521..2c417e8 100644
--- a/src/parser/drawer.rs
+++ b/src/parser/drawer.rs
@@ -1,8 +1,76 @@
+use nom::branch::alt;
+use nom::bytes::complete::tag;
+use nom::bytes::complete::take_while;
+use nom::character::complete::line_ending;
+use nom::character::complete::space0;
+use nom::combinator::eof;
+use nom::combinator::recognize;
+use nom::multi::many_till;
+use nom::sequence::tuple;
+
 use super::Context;
+use crate::parser::element::element;
 use crate::parser::error::Res;
+use crate::parser::parser_context::ChainBehavior;
+use crate::parser::parser_context::ContextElement;
+use crate::parser::parser_context::ExitMatcherNode;
+use crate::parser::parser_with_context::parser_with_context;
+use crate::parser::util::exit_matcher_parser;
+use crate::parser::util::get_consumed;
+use crate::parser::util::maybe_consume_trailing_whitespace_if_not_exiting;
+use crate::parser::util::start_of_line;
+use crate::parser::util::WORD_CONSTITUENT_CHARACTERS;
 use crate::parser::Drawer;
 
 #[tracing::instrument(ret, level = "debug")]
 pub fn drawer<'r, 's>(context: Context<'r, 's>, input: &'s str) -> Res<&'s str, Drawer<'s>> {
-    todo!()
+    start_of_line(context, input)?;
+    let (remaining, _leading_whitespace) = space0(input)?;
+    let (remaining, (_open_colon, drawer_name, _close_colon, _new_line)) = tuple((
+        tag(":"),
+        name,
+        tag(":"),
+        recognize(tuple((space0, line_ending))),
+    ))(remaining)?;
+
+    let parser_context = context
+        .with_additional_node(ContextElement::ConsumeTrailingWhitespace(true))
+        .with_additional_node(ContextElement::ExitMatcherNode(ExitMatcherNode {
+            exit_matcher: ChainBehavior::AndParent(Some(&drawer_end)),
+        }));
+
+    let element_matcher = parser_with_context!(element)(&parser_context);
+    let exit_matcher = parser_with_context!(exit_matcher_parser)(&parser_context);
+    let (remaining, (children, _exit_contents)) =
+        many_till(element_matcher, exit_matcher)(remaining)?;
+    let (remaining, _end) = drawer_end(&parser_context, remaining)?;
+
+    let (remaining, _trailing_ws) =
+        maybe_consume_trailing_whitespace_if_not_exiting(context, remaining)?;
+    let source = get_consumed(input, remaining);
+
+    Ok((
+        remaining,
+        Drawer {
+            source,
+            name: drawer_name,
+            children,
+        },
+    ))
+}
+
+#[tracing::instrument(ret, level = "debug")]
+fn name<'s>(input: &'s str) -> Res<&'s str, &'s str> {
+    take_while(|c| WORD_CONSTITUENT_CHARACTERS.contains(c) || "-_".contains(c))(input)
+}
+
+#[tracing::instrument(ret, level = "debug")]
+fn drawer_end<'r, 's>(context: Context<'r, 's>, input: &'s str) -> Res<&'s str, &'s str> {
+    start_of_line(context, input)?;
+    recognize(tuple((
+        space0,
+        tag(":end:"),
+        space0,
+        alt((line_ending, eof)),
+    )))(input)
 }
diff --git a/src/parser/greater_element.rs b/src/parser/greater_element.rs
index 2d1f92a..c9e5975 100644
--- a/src/parser/greater_element.rs
+++ b/src/parser/greater_element.rs
@@ -32,6 +32,6 @@ pub struct FootnoteDefinition<'s> {
 #[derive(Debug)]
 pub struct Drawer<'s> {
     pub source: &'s str,
-    pub label: &'s str,
+    pub name: &'s str,
     pub children: Vec<Element<'s>>,
 }