1 files changed, 130 insertions, 0 deletions
diff --git a/document_tree/src/element_categories.rs b/document_tree/src/element_categories.rs
new file mode 100644
index 0000000..24a0798
--- /dev/null
+++ b/document_tree/src/element_categories.rs
@@ -0,0 +1,130 @@
+use std::fmt::{self,Debug,Formatter};
+
+use serde_derive::Serialize;
+
+use crate::elements::*;
+
+pub trait HasChildren<C> {
+	fn with_children(children: Vec<C>) -> Self;
+	fn children(&self) -> &Vec<C>;
+	fn children_mut(&mut self) -> &mut Vec<C>;
+	fn append_child<R: Into<C>>(&mut self, child: R) {
+		self.children_mut().push(child.into());
+	}
+	fn append_children<R: Into<C> + Clone>(&mut self, more: &[R]) {
+		let children = self.children_mut();
+		children.reserve(more.len());
+		for child in more {
+			children.push(child.clone().into());
+		}
+	}
+}
+
+macro_rules! impl_into {
+	([ $( (($subcat:ident :: $entry:ident), $supcat:ident), )+ ]) => {
+		$( impl_into!($subcat::$entry => $supcat); )+
+	};
+	($subcat:ident :: $entry:ident => $supcat:ident ) => {
+		impl Into<$supcat> for $entry {
+			fn into(self) -> $supcat {
+				$supcat::$subcat(Box::new(self.into()))
+			}
+		}
+	};
+}
+
+macro_rules! synonymous_enum {
+	( $subcat:ident : $($supcat:ident),+ ; $midcat:ident : $supsupcat:ident { $($entry:ident),+ $(,)* } ) => {
+		synonymous_enum!($subcat : $( $supcat ),+ , $midcat { $($entry,)* });
+		$( impl_into!($midcat::$entry => $supsupcat); )+
+	};
+	( $subcat:ident : $($supcat:ident),+ { $($entry:ident),+ $(,)* } ) => {
+		synonymous_enum!($subcat { $( $entry, )* });
+		cartesian!(impl_into, [ $( ($subcat::$entry) ),+ ], [ $($supcat),+ ]);
+	};
+	( $name:ident { $( $entry:ident ),+ $(,)* } ) => {
+		#[derive(PartialEq,Serialize,Clone)]
+		pub enum $name { $(
+			$entry(Box<$entry>),
+		)* }
+		
+		impl Debug for $name {
+			fn fmt(&self, fmt: &mut Formatter) -> Result<(), fmt::Error> {
+				match *self {
+					$( $name::$entry(ref inner) => inner.fmt(fmt), )*
+				}
+			}
+		}
+		
+		$( impl Into<$name> for $entry {
+			fn into(self) -> $name {
+				$name::$entry(Box::new(self))
+			}
+		} )*
+	};
+}
+
+synonymous_enum!(StructuralSubElement { Title, Subtitle, Decoration, Docinfo, SubStructure });
+synonymous_enum!(SubStructure: StructuralSubElement { Topic, Sidebar, Transition, Section, BodyElement });
+synonymous_enum!(BodyElement: SubTopic, SubSidebar, SubBlockQuote, SubFootnote, SubFigure; SubStructure: StructuralSubElement {
+	//Simple
+	Paragraph, LiteralBlock, DoctestBlock, MathBlock, Rubric, SubstitutionDefinition, Comment, Pending, Target, Raw, Image,
+	//Compound
+	Compound, Container,
+	BulletList, EnumeratedList, DefinitionList, FieldList, OptionList,
+	LineBlock, BlockQuote, Admonition, Attention, Hint, Note, Caution, Danger, Error, Important, Tip, Warning, Footnote, Citation, SystemMessage, Figure, Table
+});
+
+synonymous_enum!(BibliographicElement { Author, Authors, Organization, Address, Contact, Version, Revision, Status, Date, Copyright, Field });
+
+synonymous_enum!(TextOrInlineElement {
+	String, Emphasis, Strong, Literal, Reference, FootnoteReference, CitationReference, SubstitutionReference, TitleReference, Abbreviation, Acronym, Superscript, Subscript, Inline, Problematic, Generated, Math,
+	//also have non-inline versions. Inline image is no figure child, inline target has content
+	TargetInline, RawInline, ImageInline
+});
+
+//--------------\\
+//Content Models\\
+//--------------\\
+
+synonymous_enum!(AuthorInfo { Author, Organization, Address, Contact });
+synonymous_enum!(DecorationElement { Header, Footer });
+synonymous_enum!(SubTopic { Title, BodyElement });
+synonymous_enum!(SubSidebar { Topic, Title, Subtitle, BodyElement });
+synonymous_enum!(SubDLItem { Term, Classifier, Definition });
+synonymous_enum!(SubField { FieldName, FieldBody });
+synonymous_enum!(SubOptionListItem { OptionGroup, Description });
+synonymous_enum!(SubOption { OptionString, OptionArgument });
+synonymous_enum!(SubLineBlock { LineBlock, Line });
+synonymous_enum!(SubBlockQuote { Attribution, BodyElement });
+synonymous_enum!(SubFootnote { Label, BodyElement });
+synonymous_enum!(SubFigure { Caption, Legend, BodyElement });
+synonymous_enum!(SubTable { Title, TableGroup });
+synonymous_enum!(SubTableGroup { TableColspec, TableHead, TableBody });
+
+#[cfg(test)]
+mod conversion_tests {
+	use std::default::Default;
+	use super::*;
+	
+	#[test]
+	fn basic() {
+		let _: BodyElement = Paragraph::default().into();
+	}
+	
+	#[test]
+	fn more() {
+		let _: SubStructure = Paragraph::default().into();
+	}
+	
+	#[test]
+	fn even_more() {
+		let _: StructuralSubElement = Paragraph::default().into();
+	}
+	
+	#[test]
+	fn super_() {
+		let be: BodyElement = Paragraph::default().into();
+		let _: StructuralSubElement = be.into();
+	}
+}