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lexer.rs
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lexer.rs
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use crate::MiniIter;
/// Tokens are the intermediate representation format in the markdown to html conversion
#[derive(Debug, PartialEq, Eq)]
pub enum Token {
/// String: Body of unstructured text
Plaintext(String),
/// u8: Header level (1..=6). str: Header text. Option<str>: html label
Header(usize, String, Option<String>),
/// str: Text for list entry
UnorderedListEntry(String),
/// str: Text for list entry
OrderedListEntry(String),
/// str: Text to be italicized
Italic(String),
/// str: Text to be bolded
Bold(String),
/// str: Text to be bolded and italicized
BoldItalic(String),
/// Corresponds to a </br> html tag
LineBreak,
/// Corresponds to a newline character
Newline,
/// Corresponds to a <hr /> html tag
HorizontalRule,
/// Used for control flow. Not directly rendered
Tab,
/// Used for control flow. Not directly rendered
DoubleTab,
/// str: Text to be struck through
Strikethrough(String),
/// str: Text to be placed within an inline code tag. eg. <code>str</code>
Code(String),
/// First str: Text to be placed within a multi-line code tag. Second str: Language
CodeBlock(String, String),
/// u8: Block quote level. str: Block quote text
BlockQuote(u8, String),
/// str: Link. Option<str>: Title for link.
Image(String, Option<String>),
/// str: Link. First Option<str>: Title for link. Second Option<str>: Hover text
Link(String, Option<String>, Option<String>),
/// str: Summary. Vec<Token>: Tokens to be rendered in the collapsable section
Detail(String, Vec<Token>),
/// Tuple of Vec<(Alignment, str)>: Which defines the table header and Vec<Vec<(Alignment, Vec<Token>)>> which defines the rows
Table(Vec<(Alignment, String)>, Vec<Vec<(Alignment, Vec<Token>)>>),
/// TaskBox: Boolean state of the checked or unchecked box. str: List item text
TaskListItem(TaskBox, String),
/// First str: Reference id. Second str: Reference text
Footnote(String, String),
}
/// Holds the possible states of a taskbox in a task list
#[derive(Debug, PartialEq, Eq)]
pub enum TaskBox {
Checked,
Unchecked,
}
impl Token{
fn is_usable_in_table(&self) -> bool {
match self {
Token::Code(_) => true,
Token::Link(_, _, _) => true,
Token::Bold(_) => true,
Token::Italic(_) => true,
Token::BoldItalic(_) => true,
Token::Plaintext(_) => true,
_ => false
}
}
}
/// Holds the alignment states for the table token
#[derive(Debug, PartialEq, Eq, Clone)]
pub enum Alignment {
Left,
Right,
Center
}
use std::fmt;
impl fmt::Display for Alignment{
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result{
match self {
Alignment::Left => return write!(f, "left"),
Alignment::Right => return write!(f, "right"),
Alignment::Center => return write!(f, "center"),
}
}
}
#[derive(Debug)]
pub(crate) struct ParseError<'a>{
pub(crate) content: &'a str,
}
pub(crate) fn push_str<'a>(t: &mut Vec<Token>, s: &'a str) {
match t.last_mut() {
Some(Token::Plaintext(token)) => {
token.push_str(s)
}
_ => t.push(Token::Plaintext(s.to_string())),
}
}
pub(crate) fn lex_heading<'a>(char_iter: &mut MiniIter<'a>) -> Result<Token, ParseError<'a>> {
let hashes = char_iter.consume_while_case_holds(&|c| c == "#").unwrap_or("");
if hashes.len() > 6 {
return Err(ParseError{content: hashes});
}
if char_iter.next_if_eq(&" ").is_none() && char_iter.next_if_eq(&"\t").is_none() && char_iter.peek() != Some(&"\n"){
return Err(ParseError{content: hashes});
}
let line = char_iter.consume_while_case_holds(&|c| c != "\n").unwrap_or("");
let mut heading = "";
if line.contains("{#") &&
line.contains('}') {
let (heading, _title) = line.split_once("{").unwrap_or(("",""));
let line = line.strip_prefix(&heading).unwrap()
.strip_prefix("{#").unwrap()
.strip_suffix("}").unwrap();
}
let line_without_optional_trailing_hash_sequence = match line.trim_end().rsplit_once(' ') {
Some((left, right)) => {
match right.chars().all(|c| c == '#') {
true => left,
false => line,
}
},
None => line,
};
if line.chars().all(|c| c == '#') {
return Ok(Token::Header(hashes.len(), "".to_string(), None));
}
let parsed_line = crate::render_ignore(line_without_optional_trailing_hash_sequence.trim_end_matches(&[' ', '\t']), &['#'])
.strip_prefix("<p>").unwrap_or("")
.strip_suffix("</p>\n").unwrap_or("").trim().to_string();
println!("line: {:?}", line);
println!("parsed_line: {:?}", parsed_line);
println!("line_without_optional_trailing_hash_sequence: {:?}", line_without_optional_trailing_hash_sequence);
if heading != "" {
return Ok(Token::Header(hashes.len(), heading.trim().to_string(), Some(parsed_line)));
}
return Ok(Token::Header(hashes.len(), parsed_line, None));
}
pub(crate) fn lex_asterisk_underscore<'a>(char_iter: &mut MiniIter<'a>) -> Result<Token, ParseError<'a>> {
let start_index = char_iter.get_index();
let asterunds = char_iter.consume_while_case_holds(&|c| c == "*" || c == "_").unwrap_or("");
if asterunds.len() == 1 && char_iter.next_if_eq(&" ").is_some(){
let s = char_iter.consume_while_case_holds(&|c| c != "\n").unwrap_or("");
char_iter.next();
return Ok(Token::UnorderedListEntry(s.to_string()))
}
if asterunds.chars().all(|x| x == '*') && char_iter.peek() == Some(&"\n"){
return Ok(Token::HorizontalRule)
}
match asterunds.len() {
1 => {
let s = char_iter.consume_while_case_holds(&|c| c != "*" && c != "_").unwrap_or("");
if char_iter.peek() != Some("*") || char_iter.peek() != Some(&"_"){
char_iter.next();
return Ok(Token::Italic(s.to_string()))
} else {
return Err(ParseError{content: char_iter.get_substring_from(start_index).unwrap_or("")});
}
},
2 => {
let s = char_iter.consume_while_case_holds(&|c| c != "*" && c != "_").unwrap_or("");
let trailing_astunds = char_iter.consume_while_case_holds(&|c| c == "*" || c == "_").unwrap_or("");
if trailing_astunds.len() == 2 {
return Ok(Token::Bold(s.to_string()))
} else {
return Err(ParseError{content: char_iter.get_substring_from(start_index).unwrap_or("")});
}
},
3 => {
let s = char_iter.consume_while_case_holds(&|c| c != "*" && c != "_").unwrap_or("");
let trailing_astunds = char_iter.consume_while_case_holds(&|c| c == "*" || c == "_").unwrap_or("");
if trailing_astunds.len() == 3 {
return Ok(Token::BoldItalic(s.to_string()))
} else {
return Err(ParseError{content: char_iter.get_substring_from(start_index).unwrap_or("")});
}
},
_ => {
if asterunds.chars().all(|x| x == '*') || asterunds.chars().all(|x| x == '_'){
return Ok(Token::HorizontalRule)
} else {
return Err(ParseError{content: asterunds})
}
}
}
}
pub(crate) fn lex_tabs_spaces<'a>(char_iter: &mut MiniIter<'a>, tokens: &Vec<Token>) -> Result<Token, ParseError<'a>> {
let start_index = char_iter.get_index();
let whitespace = char_iter.consume_while_case_holds(&|c| c == "\t" || c == " ");
match whitespace {
None => return Err(ParseError{content: ""}),
Some(s) if (1..=3).contains(&s.len()) && !s.contains("\t") => return Err(ParseError{content: s}),
Some(s) if s.len() >= 2 &&
!s.contains("\t") &&
char_iter.peek() == Some("\n") => return Ok(Token::LineBreak),
Some(_s) => {},
}
let whitespace = whitespace.unwrap_or("");
let line = char_iter.consume_until_tail_is("\n").unwrap_or("");
match whitespace {
" " if (matches!(tokens.last(), Some(Token::Plaintext(_))) && line.contains('#')) => return Err(ParseError{content: line}),
" " if (matches!(tokens.last(), Some(Token::Newline)) && line.contains('#')) => return Err(ParseError{content: line}),
"\t" | " " => return Ok(Token::Code(line.to_string())),
_ => {},
}
if char_iter.peek() == Some("\t") || char_iter.peek() == Some(" ") {
match lex_tabs_spaces(char_iter, tokens) {
Ok(Token::CodeBlock(_content, _lang)) => {
return Ok(Token::CodeBlock(char_iter.get_substring_from(start_index).unwrap_or("").to_string(),"".to_string()))},
Err(e) => return Err(e),
Ok(_) => return Err(ParseError{content: ""}),
}
}
return Err(ParseError{content: char_iter.get_substring_from(start_index).unwrap_or("")})
}
pub(crate) fn lex_backticks<'a>(char_iter: &mut MiniIter<'a>) -> Result<Token, ParseError<'a>> {
let start_index = char_iter.get_index();
let leading_ticks = char_iter.consume_while_case_holds(&|c| c == "`").unwrap_or("");
let mut lang = "";
if leading_ticks.len() == 3 {
if char_iter.next_if_eq("\n") != Some(&"\n") {
lang = char_iter.consume_while_case_holds(&|c| c != "\n").unwrap_or("");
char_iter.next();
}
let s = char_iter.consume_while_case_holds(&|c| c != "`").unwrap_or("");
let trailing_ticks = char_iter.consume_while_case_holds(&|c| c == "`").unwrap_or("");
if leading_ticks.len() != trailing_ticks.len() {
return Err(ParseError{content: char_iter.get_substring_from(start_index).unwrap_or("")})
} else {
return Ok(Token::CodeBlock(s.to_string(), lang.to_string()))
}
}
// let s = char_iter.consume_while_case_holds(&|c| c != "`" && c!= "\n").unwrap_or("");
let tail = &(0..leading_ticks.len() as u64).map(|_| "`").collect::<String>();
let s = char_iter.consume_until_tail_is(tail).unwrap_or("");
if !s.ends_with(tail) {
return Err(ParseError{content: char_iter.get_substring_from(start_index).unwrap_or("")})
} else {
let s = s.trim_end_matches(tail);
if s.starts_with(' ') && s.ends_with(' ') {
return Ok(Token::Code(s.trim_start_matches(' ').trim_end_matches(' ').to_string()))
}
return Ok(Token::Code(s.to_string()))
}
// leading_ticks.len() == 3. Check for lang
}
pub(crate) fn lex_newlines<'a>(char_iter: &mut MiniIter<'a>, tokens: &Vec<Token>) -> Result<Token, ParseError<'a>> {
match char_iter.consume_while_case_holds(&|c| c == "\n") {
Some(s) if s.len() >= 2 => return Ok(Token::Newline),
Some(s) if s.len() < 2 => return Err(ParseError{content: s}),
_ => return Err(ParseError{content: ""}),
}
}
pub(crate) fn lex_blockquotes<'a>(char_iter: &mut MiniIter<'a>) -> Result<Token, ParseError<'a>> {
let right_arrows = char_iter.consume_while_case_holds(&|c| c == ">").unwrap_or("");
match char_iter.next_if_eq(" ") {
Some(" ") => {},
_ => {return Err(ParseError{content: right_arrows})}
}
let s = char_iter.consume_while_case_holds(&|c| c != "\n").unwrap_or("");
char_iter.next_if_eq(&"\n");
Ok(Token::BlockQuote(right_arrows.len() as u8, s.to_string()))
}
pub(crate) fn lex_images<'a>(char_iter: &mut MiniIter<'a>) -> Result<Token, ParseError<'a>> {
let start_index = char_iter.get_index();
if char_iter.next_if_eq("!") != Some(&"!"){
return Err(ParseError{content: ""})
}
let link_result = lex_links(char_iter);
match link_result {
Err(_e) => return Err(ParseError{content: char_iter.get_substring_from(start_index).unwrap_or("")}),
Ok(Token::Link(link, title, _)) => return Ok(Token::Image(link, title)),
_ => return Err(ParseError{content: "Non link token returned from lex_links"})
}
}
pub(crate) fn lex_links<'a>(char_iter: &mut MiniIter<'a>) -> Result<Token, ParseError<'a>> {
let start_index = char_iter.get_index();
if char_iter.next_if_eq("[") != Some(&"[") {
return Err(ParseError{content: ""})
}
let title = char_iter.consume_while_case_holds(&|c| c != "]").unwrap_or("");
if char_iter.next_if_eq("]") != Some(&"]") {
return Err(ParseError{content: char_iter.get_substring_from(start_index).unwrap_or("")})
}
// Parse footnotes big and small
if title.starts_with("^") && char_iter.next_if_eq(":") == Some(&":") {
let ref_id = title.strip_prefix("^").unwrap_or("");
let note_index = char_iter.get_index();
loop {
char_iter.consume_while_case_holds(&|c| c != "\n");
char_iter.next();
if char_iter.peek() != Some(&" ") && char_iter.peek() != Some(&"\t") {
break;
}
if char_iter.next_if_eq("\t") == Some(&"\t") {
continue;
}
if char_iter.peek() == Some(&" ") {
let spaces = char_iter.consume_while_case_holds(&|c| c == " ").unwrap_or("");
match spaces.len() {
2 | 4 => {},
_ => {return Err(ParseError{content: char_iter.get_substring_from(start_index).unwrap_or("")})},
}
continue
}
break;
}
if ref_id.contains(char::is_whitespace){
return Err(ParseError{content: char_iter.get_substring_from(start_index).unwrap_or("")})
}
return Ok(Token::Footnote(ref_id.to_string(), char_iter.get_substring_from(note_index).unwrap_or("").trim().to_string()));
}
if char_iter.next_if_eq("(") != Some(&"(") {
return Err(ParseError{content: char_iter.get_substring_from(start_index).unwrap_or("")})
}
let link = char_iter.consume_while_case_holds(&|c| c != ")" && c != " ").unwrap_or("");
if char_iter.peek() != Some(&")") && char_iter.peek() != Some(&" ") {
return Err(ParseError{content: char_iter.get_substring_from(start_index).unwrap_or("")})
}
if char_iter.next_if_eq(")") == Some(&")") {
return Ok(Token::Link(link.to_string(), Some(title.to_string()), None));
}
if char_iter.peek() == Some(&" ") {
let hover = char_iter.consume_while_case_holds(&|c| c != ")").unwrap_or("");
char_iter.skip_while(|c| c != &"\n").next();
return Ok(Token::Link(link.to_string(), Some(title.to_string()), Some(hover.to_string())));
}
Err(ParseError{content: ""})
}
pub(crate) fn lex_side_carrot<'a>(char_iter: &mut MiniIter<'a>) -> Result<Token, ParseError<'a>> {
match char_iter.next_if_eq("<") {
Some("<") => {
let s = char_iter.consume_while_case_holds(&|c| c != ">").unwrap_or("");
match (s, char_iter.next_if_eq(">")) {
("details", Some(">")) => {
char_iter.next_if_eq(&"\r");
if !char_iter.next_if_eq(&"\n").is_some(){
return Err(ParseError{content: s});
}
return parse_details(char_iter)
},
(_, Some(">")) => return Ok(Token::Link(s.to_string(), None, None)),
(_, _) => return Err(ParseError{content: s}),
}
}
_ => return Err(ParseError{content: ""})
}
}
pub(crate) fn lex_plus_minus<'a>(char_iter: &mut MiniIter<'a>) -> Result<Token, ParseError<'a>> {
let start_index = char_iter.get_index();
let s = char_iter.consume_while_case_holds(&|c| c == "-" || c == "+").unwrap_or("");
match s.len() {
3..=usize::MAX => { return Ok(Token::HorizontalRule)},
2 => {return Err(ParseError{content: char_iter.get_substring_from(start_index).unwrap_or("")})},
1 => {},
_ => {return Err(ParseError{content: "string length error"})},
}
let line = char_iter.consume_while_case_holds(&|c| c != "\n").unwrap_or("");
if line.starts_with(" [ ] "){return Ok(Token::TaskListItem(TaskBox::Unchecked, line[5..].to_string()))}
else if line.starts_with(" [x] ") || line.starts_with(" [X] "){return Ok(Token::TaskListItem(TaskBox::Checked, line[5..].to_string()))}
else if line.starts_with(" "){return Ok(Token::UnorderedListEntry(line[1..].to_string()))}
else {return Err(ParseError{content: char_iter.get_substring_from(start_index).unwrap_or("")})}
}
pub(crate) fn lex_numbers<'a>(char_iter: &mut MiniIter<'a>) -> Result<Token, ParseError<'a>> {
let start_index = char_iter.get_index();
let c = char_iter.next().unwrap();
match char_iter.next_if_eq(".") {
Some(".") => {
if char_iter.next_if_eq(" ") != Some(&" "){
return Err(ParseError{content: char_iter.get_substring_from(start_index).unwrap_or("")})
}
let s = char_iter.consume_while_case_holds(&|c| c != "\n").unwrap_or("");
return Ok(Token::OrderedListEntry(s.to_string()))
},
_ => return Err(ParseError{content: c})
}
}
pub(crate) fn lex_tilde<'a>(char_iter: &mut MiniIter<'a>) -> Result<Token, ParseError<'a>> {
let start_index = char_iter.get_index();
let lead_tildes = match char_iter.consume_while_case_holds(&|s| s == "~") {
Some(s) => s,
None => return Err(ParseError{content: "Failure to parse ~"}),
};
match lead_tildes.len() {
1 => return Err(ParseError{content: lead_tildes}),
2 => {
let line = char_iter.consume_while_case_holds(&|s| s != "~").unwrap_or("");
let tail_tildes = char_iter.consume_while_case_holds(&|s| s == "~").unwrap_or("");
if lead_tildes.len() != tail_tildes.len() {
return Err(ParseError{content: char_iter.get_substring_from(start_index).unwrap_or("")})
}
return Ok(Token::Strikethrough(line.to_string()));
}
_ => return Err(ParseError{content: lead_tildes}),
}
}
fn parse_details<'a>(char_iter: &mut MiniIter<'a>) -> Result<Token, ParseError<'a>>{
let mut summary_line = char_iter.consume_while_case_holds(&|c| c != "\n" && c != "\r").unwrap_or("");
char_iter.next_if_eq("\r");
if (!summary_line.starts_with("<summary>") || !summary_line.ends_with("</summary>")) && !summary_line.len() >= 20 {
return Err(ParseError{content: summary_line});
}
summary_line = summary_line.strip_prefix("<summary>").unwrap()
.strip_suffix("</summary>").unwrap_or("");
let remaining_text_index = char_iter.get_index();
let mut remaining_text = char_iter.consume_until_tail_is("</details>").unwrap_or("");
if remaining_text.contains("<details>") {
let mut opens = remaining_text.matches("<details>").count();
let mut closes = remaining_text.matches("</details>").count();
while opens == closes {
char_iter.consume_until_tail_is("</details>").unwrap_or("");
remaining_text = char_iter.get_substring_from(remaining_text_index).unwrap_or("");
opens = remaining_text.matches("<details>").count();
closes = remaining_text.matches("</details>").count();
}
}
let inner_tokens = crate::lex(remaining_text.strip_suffix("</details>").unwrap_or(""), &[]);
Ok(Token::Detail(summary_line.to_string(), inner_tokens))
}
pub(crate) fn lex_pipes<'a>(char_iter: &mut MiniIter<'a>) -> Result<Token, ParseError<'a>> {
let start_index = char_iter.get_index();
let mut lines = Vec::new();
while char_iter.next_if_eq(&"|") == Some("|") {
lines.push(char_iter.consume_while_case_holds(&|c| c != "\n").unwrap_or(""));
char_iter.next();
}
if lines.len() < 3 {
return Err(ParseError{content: char_iter.get_substring_from(start_index).unwrap_or("")})
}
if !lines.iter().all(|l| l.matches("|").count() == lines[0].matches("|").count()) {
return Err(ParseError{content: char_iter.get_substring_from(start_index).unwrap_or("")})
}
let headings: Vec<_> = lines.remove(0).split("|")
.filter(|&x| x != "")
.map(|x| x.trim().to_string())
.collect();
let alignments: Vec<_> = lines.remove(0).split("|")
.filter(|&x| x != "")
.map(|x|
{
match (x.trim().starts_with(":"), x.trim().ends_with(":")) {
(true, false) => Alignment::Left,
(true, true) => Alignment::Center,
(false, true) => Alignment::Right,
_ => Alignment::Left,
}}
)
.collect();
let mut rows = Vec::new();
for l in lines.into_iter() {
let elements: Vec<&str> = l.split("|")
.filter(|&x| x != "")
.map(|x| x.trim())
.collect();
let mut r = Vec::new();
for e in elements.into_iter() {
let mut inner_tokens = crate::lex(&e, &[]);
inner_tokens.retain(|token| token.is_usable_in_table());
r.push(inner_tokens);
}
rows.push(alignments.clone().into_iter().zip(r.into_iter()).collect());
}
Ok(Token::Table(alignments.into_iter().zip(headings.into_iter()).collect(), rows))
}