1 files changed, 247 insertions, 0 deletions
diff --git a/src/paragraph/part.rs b/src/paragraph/part.rs
new file mode 100644
index 0000000..5e5a846
--- /dev/null
+++ b/src/paragraph/part.rs
@@ -0,0 +1,247 @@
+use crate::emphasis::{Emphasis, Error as EmphasisError};
+use crate::itemized_list::{Error as ItemizedListError, ItemizedList};
+use crate::paragraph::{Error as ParagraphError, Paragraph};
+use crate::table::{Error as TableError, Informal as InformalTable, Table};
+use crate::variable_list::{Error as VariableListError, VariableList};
+use crate::xml::element::{Elements, FromElements, Tagged};
+
+/// Paragraph part.
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub enum Part
+{
+    /// Text part.
+    Text(String),
+
+    /// <constant>..</constant> part.
+    Constant(String),
+
+    /// <function>..</function> part.
+    Function(String),
+
+    /// <parameter>..</parameter> part.
+    Parameter(String),
+
+    /// Emphasis part.
+    Emphasis(Emphasis),
+
+    /// Code part.
+    Code(String),
+
+    /// Inline equation part.
+    InlineEquation(String),
+
+    /// Program listing part.
+    ProgramListing(String),
+
+    /// Reference entry citation part.
+    Entry(String),
+
+    /// Variable list part.
+    VariableList(VariableList),
+
+    /// Itemized list part.
+    ItemizedList(ItemizedList),
+
+    /// Informal table part.
+    InformalTable(InformalTable),
+
+    /// Paragraph part.
+    Paragraph(Paragraph),
+
+    /// Footnote part.
+    Footnote(Paragraph),
+
+    /// Table part.
+    Table(Table),
+
+    /// Informal equation part.
+    InformalEquation(String),
+
+    /// Superscript part.
+    Superscript(String),
+}
+
+impl FromElements for Part
+{
+    type Error = Error;
+
+    fn from_elements(elements: &Elements) -> Result<Self, Self::Error>
+    {
+        if let Some(tagged_element) = elements.get_first_tagged() {
+            return Self::from_tagged_element(tagged_element);
+        }
+
+        let text = elements
+            .get_first_text_element()
+            .ok_or(Self::Error::ExpectedTextElement)?;
+
+        Ok(Self::Text(text.clone()))
+    }
+}
+
+impl Part
+{
+    fn from_tagged_element(
+        tagged_element: &Tagged,
+    ) -> Result<Self, <Self as FromElements>::Error>
+    {
+        let create: fn(String) -> Self = match tagged_element.name() {
+            "constant" => Self::Constant,
+            "function" => Self::Function,
+            "parameter" => Self::Parameter,
+            "code" => Self::Code,
+            "inlineequation" => Self::InlineEquation,
+            "programlisting" => Self::ProgramListing,
+            "citerefentry" => Self::Entry,
+            "superscript" => Self::Superscript,
+            "variablelist" | "itemizedlist" | "informaltable" | "para" | "footnote"
+            | "table" | "informalequation" | "emphasis" => |_| {
+                unreachable!();
+            },
+            _ => {
+                return Err(<Self as FromElements>::Error::UnknownPart(
+                    tagged_element.name().to_string(),
+                ));
+            }
+        };
+
+        if tagged_element.name() == "citerefentry" {
+            let title_element = tagged_element
+                .child_elements()
+                .get_first_tagged_with_name("refentrytitle")
+                .ok_or(<Self as FromElements>::Error::NoEntryTitleFound)?;
+
+            let title = title_element
+                .child_elements()
+                .get_first_text_element()
+                .ok_or(<Self as FromElements>::Error::NoTextInTagged)?;
+
+            return Ok(Self::Entry(title.clone()));
+        }
+
+        if tagged_element.name() == "variablelist" {
+            let variable_list =
+                VariableList::from_elements(tagged_element.child_elements())?;
+
+            return Ok(Self::VariableList(variable_list));
+        }
+
+        if tagged_element.name() == "itemizedlist" {
+            let itemized_list =
+                ItemizedList::from_elements(tagged_element.child_elements())?;
+
+            return Ok(Self::ItemizedList(itemized_list));
+        }
+
+        if tagged_element.name() == "informaltable" {
+            let informal_table =
+                InformalTable::from_elements(tagged_element.child_elements())
+                    .map_err(|err| Error::InvalidInformalTable(Box::new(err)))?;
+
+            return Ok(Self::InformalTable(informal_table));
+        }
+
+        if tagged_element.name() == "inlineequation" {
+            return Ok(Self::InlineEquation(
+                tagged_element
+                    .child_elements()
+                    .into_iter()
+                    .map(ToString::to_string)
+                    .collect::<String>(),
+            ));
+        }
+
+        if tagged_element.name() == "para" {
+            return Ok(Self::Paragraph(
+                Paragraph::from_elements(tagged_element.child_elements())
+                    .map_err(|err| Error::InvalidParagraph(Box::new(err)))?,
+            ));
+        }
+
+        if tagged_element.name() == "footnote" {
+            return Ok(Self::Footnote(
+                Paragraph::from_elements(tagged_element.child_elements())
+                    .map_err(|err| Error::InvalidFootnote(Box::new(err)))?,
+            ));
+        }
+
+        if tagged_element.name() == "table" {
+            let table = Table::from_elements(tagged_element.child_elements())
+                .map_err(|err| Error::InvalidInformalTable(Box::new(err)))?;
+
+            return Ok(Self::Table(table));
+        }
+
+        if tagged_element.name() == "informalequation" {
+            return Ok(Self::InlineEquation(
+                tagged_element
+                    .child_elements()
+                    .into_iter()
+                    .map(ToString::to_string)
+                    .collect::<String>(),
+            ));
+        }
+
+        if tagged_element.name() == "emphasis" {
+            return Ok(Self::Emphasis(Emphasis::from_tagged_element(
+                tagged_element,
+            )?));
+        }
+
+        let text_element = tagged_element
+            .child_elements()
+            .get_first_text_element()
+            .ok_or(<Self as FromElements>::Error::NoTextInTagged)?;
+
+        Ok(create(text_element.clone()))
+    }
+}
+
+/// [`Part`] error.
+#[derive(Debug, thiserror::Error)]
+pub enum Error
+{
+    /// Expected a text element.
+    #[error("Expected a text element")]
+    ExpectedTextElement,
+
+    /// A input element is a unknown paragraph part.
+    #[error("Input element with name '{0}' is a unknown paragraph part")]
+    UnknownPart(String),
+
+    /// No text was found in tagged input element.
+    #[error("No text was found in tagged input element")]
+    NoTextInTagged,
+
+    /// No entry title found.
+    #[error("No entry title found")]
+    NoEntryTitleFound,
+
+    /// Invalid variable list.
+    #[error("Invalid variable list")]
+    InvalidVariableList(#[from] VariableListError),
+
+    /// Invalid itemized list.
+    #[error("Invalid itemized list")]
+    InvalidItemizedList(#[from] ItemizedListError),
+
+    /// Invalid informal table.
+    #[error("Invalid informal table")]
+    InvalidInformalTable(#[source] Box<TableError>),
+
+    /// Invalid paragraph.
+    #[error("Invalid paragraph")]
+    InvalidParagraph(#[source] Box<ParagraphError>),
+
+    /// Invalid footnote.
+    #[error("Invalid footnote")]
+    InvalidFootnote(#[source] Box<ParagraphError>),
+
+    /// Invalid table.
+    #[error("Invalid table")]
+    InvalidTable(#[source] Box<TableError>),
+
+    /// Invalid emphasis.
+    #[error("Invalid emphasis")]
+    InvalidEmphasis(#[from] EmphasisError),
+}