Implement parser for subscript/superscript with braces.

This commit is contained in:
Tom Alexander 2023-07-24 16:29:31 -04:00
parent f717d5e7df
commit 23d587c699
Signed by: talexander
GPG Key ID: D3A179C9A53C0EDE
2 changed files with 101 additions and 0 deletions

View File

@ -194,6 +194,18 @@ pub enum ContextElement<'r, 's> {
/// unbalanced brackets can be detected in the middle of an
/// object.
InlineSourceBlockBracket(InlineSourceBlockBracket<'s>),
/// Stores the current bracket or parenthesis depth inside a
/// superscript or superscript.
///
/// Inside the braces of a subscript or superscript there must be
/// balanced braces {}, so this stores the amount of opening
/// braces subtracted by the amount of closing braces within the
/// definition must equal zero.
///
/// A reference to the position in the string is also included so
/// unbalanced braces can be detected in the middle of an object.
SubscriptSuperscriptBrace(SubscriptSuperscriptBrace<'s>),
}
pub struct ExitMatcherNode<'r> {
@ -225,6 +237,12 @@ pub struct InlineSourceBlockBracket<'s> {
pub depth: usize,
}
#[derive(Debug)]
pub struct SubscriptSuperscriptBrace<'s> {
pub position: &'s str,
pub depth: usize,
}
impl<'r> std::fmt::Debug for ExitMatcherNode<'r> {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
let mut formatter = f.debug_struct("ExitMatcherNode");

View File

@ -16,7 +16,13 @@ use super::Object;
use crate::error::CustomError;
use crate::error::MyError;
use crate::error::Res;
use crate::parser::exiting::ExitClass;
use crate::parser::object_parser::standard_set_object;
use crate::parser::parser_context::ContextElement;
use crate::parser::parser_context::ExitMatcherNode;
use crate::parser::parser_context::SubscriptSuperscriptBrace;
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::get_one_before;
use crate::parser::Subscript;
@ -79,6 +85,9 @@ fn script_body<'r, 's>(context: Context<'r, 's>, input: &'s str) -> Res<&'s str,
map(parser_with_context!(script_alphanum)(context), |body| {
ScriptBody::Braceless(body)
}),
map(parser_with_context!(script_with_braces)(context), |body| {
ScriptBody::WithBraces(body)
}),
))(input)
}
@ -119,3 +128,77 @@ fn end_script_alphanum_character<'r, 's>(
)))(remaining)?;
Ok((remaining, final_char))
}
#[tracing::instrument(ret, level = "debug")]
fn script_with_braces<'r, 's>(
context: Context<'r, 's>,
input: &'s str,
) -> Res<&'s str, Vec<Object<'s>>> {
let (remaining, _) = tag("{")(input)?;
let parser_context = context
.with_additional_node(ContextElement::SubscriptSuperscriptBrace(
SubscriptSuperscriptBrace {
position: remaining,
depth: 0,
},
))
.with_additional_node(ContextElement::ExitMatcherNode(ExitMatcherNode {
class: ExitClass::Beta,
exit_matcher: &script_with_braces_end,
}));
let (remaining, (children, _exit_contents)) = many_till(
parser_with_context!(standard_set_object)(&parser_context),
parser_with_context!(exit_matcher_parser)(&parser_context),
)(remaining)?;
let (remaining, _) = tag("}")(remaining)?;
Ok((remaining, children))
}
#[tracing::instrument(ret, level = "debug")]
fn script_with_braces_end<'r, 's>(
context: Context<'r, 's>,
input: &'s str,
) -> Res<&'s str, &'s str> {
let context_depth = get_bracket_depth(context)
.expect("This function should only be called from inside a subscript or superscript.");
let text_since_context_entry = get_consumed(context_depth.position, input);
let mut current_depth = context_depth.depth;
for c in text_since_context_entry.chars() {
match c {
'{' => {
current_depth += 1;
}
'}' if current_depth == 0 => {
panic!("Exceeded subscript or superscript brace depth.")
}
'}' if current_depth > 0 => {
current_depth -= 1;
}
_ => {}
}
}
if current_depth == 0 {
let close_bracket = tag::<&str, &str, CustomError<&str>>("}")(input);
if close_bracket.is_ok() {
return close_bracket;
}
}
return Err(nom::Err::Error(CustomError::MyError(MyError(
"Not a valid end for subscript or superscript.",
))));
}
#[tracing::instrument(ret, level = "debug")]
fn get_bracket_depth<'r, 's>(
context: Context<'r, 's>,
) -> Option<&'r SubscriptSuperscriptBrace<'s>> {
for node in context.iter() {
match node.get_data() {
ContextElement::SubscriptSuperscriptBrace(depth) => return Some(depth),
_ => {}
}
}
None
}