use crate::lexers::Token;
pub struct Lexer {
input: Vec<char>,
pub position: usize,
pub read_position: usize,
pub ch: char,
}
fn is_letter(ch: char) -> bool {
ch.is_alphabetic() || ch == '_'
}
impl Lexer {
pub fn new(input: Vec<char>) -> Self {
Self {
input,
position: 0,
read_position: 0,
ch: '\0',
}
}
pub fn read_char(&mut self) {
if self.read_position >= self.input.len() {
self.ch = '\0';
} else {
self.ch = self.input[self.read_position];
}
self.position = self.read_position;
self.read_position += 1;
}
pub fn next_token(&mut self) -> Token {
let read_identifier = |l: &mut Lexer| -> Vec<char> {
let position = l.position;
while l.position < l.input.len() && is_letter(l.ch) {
l.read_char();
}
l.input[position..l.position].to_vec()
};
let read_number = |l: &mut Lexer| -> Vec<char> {
let position = l.position;
while l.position < l.input.len() && l.ch.is_numeric() {
l.read_char();
}
l.input[position..l.position].to_vec()
};
let tok: Token;
match self.ch {
'\n' => {
tok = Token::ENDL(self.ch);
}
'\0' => {
tok = Token::EOF;
}
_ => {
return if is_letter(self.ch) {
#[allow(unused_variables)]
let start_position = self.position;
#[allow(unused_mut)]
let mut identifier: Vec<char> = read_identifier(self);
match get_keyword_token(&identifier) {
Ok(keyword_token) => keyword_token,
Err(_) => Token::IDENT(identifier),
}
} else if self.ch.is_numeric() {
let identifier: Vec<char> = read_number(self);
Token::IDENT(identifier)
} else {
Token::ILLEGAL
}
}
}
self.read_char();
tok
}
}
pub fn get_keyword_token(identifier: &Vec<char>) -> Result<Token, String> {
let id: String = identifier.into_iter().collect();
match &id[..] {
_ => Err(String::from("Not a keyword")),
}
}
pub fn render_html(input: Vec<char>) -> String {
let mut l = Lexer::new(input);
l.read_char();
let mut html = String::new();
let mut line = 1;
html.push_str("<table class=\"highlight-table\">\n");
html.push_str("<tbody>\n");
html.push_str("<tr>");
html.push_str(&format!(
"<td class=\"hl-num\" data-line=\"{}\"></td><td>",
line
));
loop {
let token = l.next_token();
if token == Token::EOF {
html.push_str("</td></tr>\n");
break;
}
match token {
Token::IDENT(value) => {
html.push_str(&value.iter().collect::<String>());
}
Token::ENDL(_) => {
line = line + 1;
html.push_str("</td></tr>\n");
html.push_str(&format!(
"<tr><td class=\"hl-num\" data-line=\"{}\"></td><td>",
line
));
}
_ => {
if l.ch == '<' {
html.push_str("<");
l.read_char();
continue;
}
if l.ch == '>' {
html.push_str(">");
l.read_char();
continue;
}
html.push(l.ch);
l.read_char();
}
}
}
html.push_str("</tbody>\n");
html.push_str("</table>");
html
}