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use crate::error::{NxsError, Result};
#[derive(Debug, Clone, PartialEq)]
pub enum Token {
// Sigils + their values
Int(i64),
Float(f64),
Bool(bool),
Keyword(String),
Str(String),
Time(i64), // unix nanoseconds
Binary(Vec<u8>),
Link(i32),
Macro(String),
Null,
// Structure
Ident(String),
Colon,
LBrace,
RBrace,
LBracket,
RBracket,
Comma,
LParen,
RParen,
Eof,
}
pub struct Lexer {
input: Vec<char>,
pos: usize,
}
impl Lexer {
pub fn new(input: &str) -> Self {
Lexer {
input: input.chars().collect(),
pos: 0,
}
}
fn peek(&self) -> Option<char> {
self.input.get(self.pos).copied()
}
fn advance(&mut self) -> Option<char> {
let c = self.input.get(self.pos).copied();
self.pos += 1;
c
}
fn skip_whitespace_and_comments(&mut self) {
while let Some(c) = self.peek() {
if c == '#' {
while let Some(c) = self.peek() {
self.advance();
if c == '\n' {
break;
}
}
} else if c.is_whitespace() {
self.advance();
} else {
break;
}
}
}
fn read_while<F: Fn(char) -> bool>(&mut self, pred: F) -> String {
let mut s = String::new();
while let Some(c) = self.peek() {
if pred(c) {
s.push(c);
self.advance();
} else {
break;
}
}
s
}
fn read_string(&mut self) -> Result<String> {
// opening `"` already consumed
let mut s = String::new();
loop {
match self.advance() {
None => return Err(NxsError::ParseError("unterminated string".into())),
Some('"') => break,
Some('\\') => match self.advance() {
Some('\\') => s.push('\\'),
Some('"') => s.push('"'),
Some('n') => s.push('\n'),
Some('r') => s.push('\r'),
Some('t') => s.push('\t'),
Some('0') => s.push('\0'),
Some('u') => {
let hex: String = (0..4).filter_map(|_| self.advance()).collect();
let code = u32::from_str_radix(&hex, 16)
.map_err(|_| NxsError::ParseError(format!("bad \\u escape: {hex}")))?;
let ch = char::from_u32(code).ok_or_else(|| {
NxsError::ParseError(format!("invalid unicode: {code}"))
})?;
s.push(ch);
}
Some('U') => {
let hex: String = (0..8).filter_map(|_| self.advance()).collect();
let code = u32::from_str_radix(&hex, 16)
.map_err(|_| NxsError::ParseError(format!("bad \\U escape: {hex}")))?;
let ch = char::from_u32(code).ok_or_else(|| {
NxsError::ParseError(format!("invalid unicode: {code}"))
})?;
s.push(ch);
}
Some(c) => return Err(NxsError::BadEscape(c)),
None => return Err(NxsError::ParseError("unterminated escape".into())),
},
Some(c) => s.push(c),
}
}
Ok(s)
}
fn read_binary(&mut self) -> Result<Vec<u8>> {
// opening `<` already consumed; expect hex digits until `>`
let mut hex = String::new();
loop {
match self.advance() {
Some('>') => break,
Some(c) if c.is_ascii_hexdigit() || c.is_whitespace() => {
if c.is_ascii_hexdigit() {
hex.push(c);
}
}
Some(c) => {
return Err(NxsError::ParseError(format!(
"unexpected char in binary: '{c}'"
)));
}
None => return Err(NxsError::ParseError("unterminated binary literal".into())),
}
}
if hex.len() % 2 != 0 {
return Err(NxsError::ParseError(
"binary hex must have even number of digits".into(),
));
}
(0..hex.len())
.step_by(2)
.map(|i| {
u8::from_str_radix(&hex[i..i + 2], 16)
.map_err(|_| NxsError::ParseError(format!("bad hex byte: {}", &hex[i..i + 2])))
})
.collect()
}
fn read_macro_expr(&mut self) -> String {
// consume to end of line or comma or closing brace
let mut s = String::new();
while let Some(c) = self.peek() {
if c == '\n' || c == ',' || c == '}' {
break;
}
s.push(c);
self.advance();
}
s.trim().to_string()
}
pub fn tokenize(&mut self) -> Result<Vec<Token>> {
let mut tokens = Vec::new();
loop {
self.skip_whitespace_and_comments();
match self.peek() {
None => {
tokens.push(Token::Eof);
break;
}
Some(c) => {
self.advance();
let tok = match c {
'{' => Token::LBrace,
'}' => Token::RBrace,
'[' => Token::LBracket,
']' => Token::RBracket,
'(' => Token::LParen,
')' => Token::RParen,
':' => Token::Colon,
',' => Token::Comma,
// Sigils
'=' => {
let neg = if self.peek() == Some('-') {
self.advance();
true
} else {
false
};
let s = self.read_while(|c| c.is_ascii_digit());
let n: i64 = s
.parse()
.map_err(|_| NxsError::ParseError(format!("bad int: {s}")))?;
Token::Int(if neg { -n } else { n })
}
'~' => {
let neg = if self.peek() == Some('-') {
self.advance();
true
} else {
false
};
let s = self.read_while(|c| {
c.is_ascii_digit()
|| c == '.'
|| c == 'e'
|| c == 'E'
|| c == '+'
|| c == '-'
});
let f: f64 = s
.parse()
.map_err(|_| NxsError::ParseError(format!("bad float: {s}")))?;
Token::Float(if neg { -f } else { f })
}
'?' => {
let s = self.read_while(|c| c.is_alphabetic());
match s.as_str() {
"true" => Token::Bool(true),
"false" => Token::Bool(false),
_ => return Err(NxsError::ParseError(format!("bad bool: {s}"))),
}
}
'$' => {
let s = self.read_while(|c| c.is_alphanumeric() || c == '_');
Token::Keyword(s)
}
'"' => Token::Str(self.read_string()?),
'@' => {
// peek: if digit, it's a timestamp; otherwise it's a macro ref (handled in parser)
if self.peek().map(|c| c.is_ascii_digit()).unwrap_or(false) {
// parse ISO-8601 date as nanoseconds: YYYY-MM-DD or full RFC3339
let s = self.read_while(|c| {
!c.is_whitespace() && c != ',' && c != '}' && c != ']'
});
let ns = parse_temporal(&s)?;
Token::Time(ns)
} else {
// macro ref — return @ + ident as a raw string for the macro parser
let ident = self.read_while(|c| c.is_alphanumeric() || c == '_');
Token::Macro(format!("@{ident}"))
}
}
'<' => Token::Binary(self.read_binary()?),
'&' => {
let neg = if self.peek() == Some('-') {
self.advance();
true
} else {
false
};
let s = self.read_while(|c| c.is_ascii_digit());
let n: i32 = s.parse().map_err(|_| {
NxsError::ParseError(format!("bad link offset: {s}"))
})?;
Token::Link(if neg { -n } else { n })
}
'!' => Token::Macro(self.read_macro_expr()),
'^' => Token::Null,
// Identifier (key name)
c if c.is_alphabetic() || c == '_' => {
let mut s = c.to_string();
s.push_str(
&self.read_while(|c| c.is_alphanumeric() || c == '_' || c == '-'),
);
Token::Ident(s)
}
other => return Err(NxsError::UnknownSigil(other)),
};
tokens.push(tok);
}
}
}
Ok(tokens)
}
}
fn parse_temporal(s: &str) -> Result<i64> {
// Support YYYY-MM-DD
if s.len() == 10 && s.chars().nth(4) == Some('-') {
let year: i64 = s[0..4]
.parse()
.map_err(|_| NxsError::ParseError(format!("bad date: {s}")))?;
let month: i64 = s[5..7]
.parse()
.map_err(|_| NxsError::ParseError(format!("bad date: {s}")))?;
let day: i64 = s[8..10]
.parse()
.map_err(|_| NxsError::ParseError(format!("bad date: {s}")))?;
// Days since epoch (very simplified, good enough for POC)
let days = days_since_epoch(year, month, day);
return days
.checked_mul(86_400_000_000_000i64)
.ok_or_else(|| NxsError::ParseError(format!("temporal overflow: {s}")))
.map(Some)
.map(|v| v.unwrap());
}
// Support raw nanosecond integer
s.parse::<i64>()
.map_err(|_| NxsError::ParseError(format!("bad temporal: {s}")))
}
fn days_since_epoch(year: i64, month: i64, day: i64) -> i64 {
// Julian Day Number → days since Unix epoch (1970-01-01)
let a = (14 - month) / 12;
let y = year + 4800 - a;
let m = month + 12 * a - 3;
let jdn = day + (153 * m + 2) / 5 + 365 * y + y / 4 - y / 100 + y / 400 - 32045;
jdn - 2_440_588 // JDN of 1970-01-01
}