/
lexer.rs
541 lines (499 loc) · 15.8 KB
/
lexer.rs
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import util::interner;
import util::interner::intern;
import diagnostic;
export reader, new_reader, next_token, is_whitespace;
type reader = @{
span_diagnostic: diagnostic::span_handler,
src: @str,
mut col: uint,
mut pos: uint,
mut curr: char,
mut chpos: uint,
filemap: codemap::filemap,
interner: @interner::interner<str>
};
impl reader for reader {
fn is_eof() -> bool { self.curr == -1 as char }
fn get_str_from(start: uint) -> str unsafe {
// I'm pretty skeptical about this subtraction. What if there's a
// multi-byte character before the mark?
ret str::slice(*self.src, start - 1u, self.pos - 1u);
}
fn next() -> char {
if self.pos < (*self.src).len() {
ret str::char_at(*self.src, self.pos);
} else { ret -1 as char; }
}
fn bump() {
if self.pos < (*self.src).len() {
self.col += 1u;
self.chpos += 1u;
if self.curr == '\n' {
codemap::next_line(self.filemap, self.chpos, self.pos);
self.col = 0u;
}
let next = str::char_range_at(*self.src, self.pos);
self.pos = next.next;
self.curr = next.ch;
} else {
if (self.curr != -1 as char) {
self.col += 1u;
self.chpos += 1u;
self.curr = -1 as char;
}
}
}
fn fatal(m: str) -> ! {
self.span_diagnostic.span_fatal(
ast_util::mk_sp(self.chpos, self.chpos),
m)
}
}
fn new_reader(span_diagnostic: diagnostic::span_handler,
filemap: codemap::filemap,
itr: @interner::interner<str>) -> reader {
let r = @{span_diagnostic: span_diagnostic, src: filemap.src,
mut col: 0u, mut pos: 0u, mut curr: -1 as char,
mut chpos: filemap.start_pos.ch,
filemap: filemap, interner: itr};
if r.pos < (*filemap.src).len() {
let next = str::char_range_at(*r.src, r.pos);
r.pos = next.next;
r.curr = next.ch;
}
ret r;
}
fn dec_digit_val(c: char) -> int { ret (c as int) - ('0' as int); }
fn hex_digit_val(c: char) -> int {
if in_range(c, '0', '9') { ret (c as int) - ('0' as int); }
if in_range(c, 'a', 'f') { ret (c as int) - ('a' as int) + 10; }
if in_range(c, 'A', 'F') { ret (c as int) - ('A' as int) + 10; }
fail;
}
fn bin_digit_value(c: char) -> int { if c == '0' { ret 0; } ret 1; }
fn is_whitespace(c: char) -> bool {
ret c == ' ' || c == '\t' || c == '\r' || c == '\n';
}
fn may_begin_ident(c: char) -> bool { ret is_alpha(c) || c == '_'; }
fn in_range(c: char, lo: char, hi: char) -> bool { ret lo <= c && c <= hi; }
fn is_alpha(c: char) -> bool {
ret in_range(c, 'a', 'z') || in_range(c, 'A', 'Z');
}
fn is_dec_digit(c: char) -> bool { ret in_range(c, '0', '9'); }
fn is_alnum(c: char) -> bool { ret is_alpha(c) || is_dec_digit(c); }
fn is_hex_digit(c: char) -> bool {
ret in_range(c, '0', '9') || in_range(c, 'a', 'f') ||
in_range(c, 'A', 'F');
}
fn is_bin_digit(c: char) -> bool { ret c == '0' || c == '1'; }
fn consume_whitespace_and_comments(rdr: reader) {
while is_whitespace(rdr.curr) { rdr.bump(); }
ret consume_any_line_comment(rdr);
}
fn consume_any_line_comment(rdr: reader) {
if rdr.curr == '/' {
alt rdr.next() {
'/' {
while rdr.curr != '\n' && !rdr.is_eof() { rdr.bump(); }
// Restart whitespace munch.
ret consume_whitespace_and_comments(rdr);
}
'*' { rdr.bump(); rdr.bump(); ret consume_block_comment(rdr); }
_ { ret; }
}
} else if rdr.curr == '#' {
if rdr.next() == '!' {
let cmap = codemap::new_codemap();
(*cmap).files.push(rdr.filemap);
let loc = codemap::lookup_char_pos_adj(cmap, rdr.chpos);
if loc.line == 1u && loc.col == 0u {
while rdr.curr != '\n' && !rdr.is_eof() { rdr.bump(); }
ret consume_whitespace_and_comments(rdr);
}
}
}
}
fn consume_block_comment(rdr: reader) {
let mut level: int = 1;
while level > 0 {
if rdr.is_eof() { rdr.fatal("unterminated block comment"); }
if rdr.curr == '/' && rdr.next() == '*' {
rdr.bump();
rdr.bump();
level += 1;
} else {
if rdr.curr == '*' && rdr.next() == '/' {
rdr.bump();
rdr.bump();
level -= 1;
} else { rdr.bump(); }
}
}
// restart whitespace munch.
ret consume_whitespace_and_comments(rdr);
}
fn scan_exponent(rdr: reader) -> option<str> {
let mut c = rdr.curr;
let mut rslt = "";
if c == 'e' || c == 'E' {
str::push_char(rslt, c);
rdr.bump();
c = rdr.curr;
if c == '-' || c == '+' {
str::push_char(rslt, c);
rdr.bump();
}
let exponent = scan_digits(rdr, 10u);
if str::len(exponent) > 0u {
ret some(rslt + exponent);
} else { rdr.fatal("scan_exponent: bad fp literal"); }
} else { ret none::<str>; }
}
fn scan_digits(rdr: reader, radix: uint) -> str {
let mut rslt = "";
loop {
let c = rdr.curr;
if c == '_' { rdr.bump(); cont; }
alt char::to_digit(c, radix) {
some(d) {
str::push_char(rslt, c);
rdr.bump();
}
_ { ret rslt; }
}
};
}
fn scan_number(c: char, rdr: reader) -> token::token {
let mut num_str, base = 10u, c = c, n = rdr.next();
if c == '0' && n == 'x' {
rdr.bump();
rdr.bump();
base = 16u;
} else if c == '0' && n == 'b' {
rdr.bump();
rdr.bump();
base = 2u;
}
num_str = scan_digits(rdr, base);
c = rdr.curr;
n = rdr.next();
if c == 'u' || c == 'i' {
let signed = c == 'i';
let mut tp = {
if signed { either::left(ast::ty_i) }
else { either::right(ast::ty_u) }
};
rdr.bump();
c = rdr.curr;
if c == '8' {
rdr.bump();
tp = if signed { either::left(ast::ty_i8) }
else { either::right(ast::ty_u8) };
}
n = rdr.next();
if c == '1' && n == '6' {
rdr.bump();
rdr.bump();
tp = if signed { either::left(ast::ty_i16) }
else { either::right(ast::ty_u16) };
} else if c == '3' && n == '2' {
rdr.bump();
rdr.bump();
tp = if signed { either::left(ast::ty_i32) }
else { either::right(ast::ty_u32) };
} else if c == '6' && n == '4' {
rdr.bump();
rdr.bump();
tp = if signed { either::left(ast::ty_i64) }
else { either::right(ast::ty_u64) };
}
if str::len(num_str) == 0u {
rdr.fatal("no valid digits found for number");
}
let parsed = option::get(u64::from_str_radix(num_str, base as u64));
alt tp {
either::left(t) { ret token::LIT_INT(parsed as i64, t); }
either::right(t) { ret token::LIT_UINT(parsed, t); }
}
}
let mut is_float = false;
if rdr.curr == '.' && !(is_alpha(rdr.next()) || rdr.next() == '_') {
is_float = true;
rdr.bump();
let dec_part = scan_digits(rdr, 10u);
num_str += "." + dec_part;
}
alt scan_exponent(rdr) {
some(s) {
is_float = true;
num_str += s;
}
none {}
}
if rdr.curr == 'f' {
rdr.bump();
c = rdr.curr;
n = rdr.next();
if c == '3' && n == '2' {
rdr.bump();
rdr.bump();
ret token::LIT_FLOAT(intern(*rdr.interner, num_str),
ast::ty_f32);
} else if c == '6' && n == '4' {
rdr.bump();
rdr.bump();
ret token::LIT_FLOAT(intern(*rdr.interner, num_str),
ast::ty_f64);
/* FIXME: if this is out of range for either a 32-bit or
64-bit float, it won't be noticed till the back-end (Issue #2252)
*/
} else {
is_float = true;
}
}
if is_float {
ret token::LIT_FLOAT(interner::intern(*rdr.interner, num_str),
ast::ty_f);
} else {
if str::len(num_str) == 0u {
rdr.fatal("no valid digits found for number");
}
let parsed = option::get(u64::from_str_radix(num_str, base as u64));
ret token::LIT_INT(parsed as i64, ast::ty_i);
}
}
fn scan_numeric_escape(rdr: reader, n_hex_digits: uint) -> char {
let mut accum_int = 0, i = n_hex_digits;
while i != 0u {
let n = rdr.curr;
rdr.bump();
if !is_hex_digit(n) {
rdr.fatal(#fmt["illegal numeric character escape: %d", n as int]);
}
accum_int *= 16;
accum_int += hex_digit_val(n);
i -= 1u;
}
ret accum_int as char;
}
fn next_token(rdr: reader) -> {tok: token::token, chpos: uint, bpos: uint} {
consume_whitespace_and_comments(rdr);
let start_chpos = rdr.chpos;
let start_bpos = rdr.pos;
let tok = if rdr.is_eof() { token::EOF } else { next_token_inner(rdr) };
ret {tok: tok, chpos: start_chpos, bpos: start_bpos};
}
fn next_token_inner(rdr: reader) -> token::token {
let mut accum_str = "";
let mut c = rdr.curr;
if (c >= 'a' && c <= 'z')
|| (c >= 'A' && c <= 'Z')
|| c == '_'
|| (c > 'z' && char::is_XID_start(c)) {
while (c >= 'a' && c <= 'z')
|| (c >= 'A' && c <= 'Z')
|| (c >= '0' && c <= '9')
|| c == '_'
|| (c > 'z' && char::is_XID_continue(c)) {
str::push_char(accum_str, c);
rdr.bump();
c = rdr.curr;
}
if str::eq(accum_str, "_") { ret token::UNDERSCORE; }
let is_mod_name = c == ':' && rdr.next() == ':';
// FIXME: perform NFKC normalization here. (Issue #2253)
ret token::IDENT(interner::intern::<str>(*rdr.interner,
accum_str), is_mod_name);
}
if is_dec_digit(c) {
ret scan_number(c, rdr);
}
fn binop(rdr: reader, op: token::binop) -> token::token {
rdr.bump();
if rdr.curr == '=' {
rdr.bump();
ret token::BINOPEQ(op);
} else { ret token::BINOP(op); }
}
alt c {
// One-byte tokens.
';' { rdr.bump(); ret token::SEMI; }
',' { rdr.bump(); ret token::COMMA; }
'.' {
rdr.bump();
if rdr.curr == '.' && rdr.next() == '.' {
rdr.bump();
rdr.bump();
ret token::ELLIPSIS;
}
ret token::DOT;
}
'(' { rdr.bump(); ret token::LPAREN; }
')' { rdr.bump(); ret token::RPAREN; }
'{' { rdr.bump(); ret token::LBRACE; }
'}' { rdr.bump(); ret token::RBRACE; }
'[' { rdr.bump(); ret token::LBRACKET; }
']' { rdr.bump(); ret token::RBRACKET; }
'@' { rdr.bump(); ret token::AT; }
'#' { rdr.bump(); ret token::POUND; }
'~' { rdr.bump(); ret token::TILDE; }
':' {
rdr.bump();
if rdr.curr == ':' {
rdr.bump();
ret token::MOD_SEP;
} else { ret token::COLON; }
}
'$' { rdr.bump(); ret token::DOLLAR; }
// Multi-byte tokens.
'=' {
rdr.bump();
if rdr.curr == '=' {
rdr.bump();
ret token::EQEQ;
} else { ret token::EQ; }
}
'!' {
rdr.bump();
if rdr.curr == '=' {
rdr.bump();
ret token::NE;
} else { ret token::NOT; }
}
'<' {
rdr.bump();
alt rdr.curr {
'=' { rdr.bump(); ret token::LE; }
'<' { ret binop(rdr, token::LSL); }
'-' {
rdr.bump();
alt rdr.curr {
'>' { rdr.bump(); ret token::DARROW; }
_ { ret token::LARROW; }
}
}
_ { ret token::LT; }
}
}
'>' {
rdr.bump();
alt rdr.curr {
'=' { rdr.bump(); ret token::GE; }
'>' {
if rdr.next() == '>' {
rdr.bump();
ret binop(rdr, token::ASR);
} else { ret binop(rdr, token::LSR); }
}
_ { ret token::GT; }
}
}
'\'' {
rdr.bump();
let mut c2 = rdr.curr;
rdr.bump();
if c2 == '\\' {
let escaped = rdr.curr;
rdr.bump();
alt escaped {
'n' { c2 = '\n'; }
'r' { c2 = '\r'; }
't' { c2 = '\t'; }
'\\' { c2 = '\\'; }
'\'' { c2 = '\''; }
'x' { c2 = scan_numeric_escape(rdr, 2u); }
'u' { c2 = scan_numeric_escape(rdr, 4u); }
'U' { c2 = scan_numeric_escape(rdr, 8u); }
c2 {
rdr.fatal(#fmt["unknown character escape: %d", c2 as int]);
}
}
}
if rdr.curr != '\'' {
rdr.fatal("unterminated character constant");
}
rdr.bump(); // advance curr past token
ret token::LIT_INT(c2 as i64, ast::ty_char);
}
'"' {
let n = rdr.chpos;
rdr.bump();
while rdr.curr != '"' {
if rdr.is_eof() {
rdr.fatal(#fmt["unterminated double quote string: %s",
rdr.get_str_from(n)]);
}
let ch = rdr.curr;
rdr.bump();
alt ch {
'\\' {
let escaped = rdr.curr;
rdr.bump();
alt escaped {
'n' { str::push_char(accum_str, '\n'); }
'r' { str::push_char(accum_str, '\r'); }
't' { str::push_char(accum_str, '\t'); }
'\\' { str::push_char(accum_str, '\\'); }
'"' { str::push_char(accum_str, '"'); }
'\n' { consume_whitespace(rdr); }
'x' {
str::push_char(accum_str, scan_numeric_escape(rdr, 2u));
}
'u' {
str::push_char(accum_str, scan_numeric_escape(rdr, 4u));
}
'U' {
str::push_char(accum_str, scan_numeric_escape(rdr, 8u));
}
c2 {
rdr.fatal(#fmt["unknown string escape: %d", c2 as int]);
}
}
}
_ { str::push_char(accum_str, ch); }
}
}
rdr.bump();
ret token::LIT_STR(interner::intern::<str>(*rdr.interner,
accum_str));
}
'-' {
if rdr.next() == '>' {
rdr.bump();
rdr.bump();
ret token::RARROW;
} else { ret binop(rdr, token::MINUS); }
}
'&' {
if rdr.next() == '&' {
rdr.bump();
rdr.bump();
ret token::ANDAND;
} else { ret binop(rdr, token::AND); }
}
'|' {
alt rdr.next() {
'|' { rdr.bump(); rdr.bump(); ret token::OROR; }
_ { ret binop(rdr, token::OR); }
}
}
'+' { ret binop(rdr, token::PLUS); }
'*' { ret binop(rdr, token::STAR); }
'/' { ret binop(rdr, token::SLASH); }
'^' { ret binop(rdr, token::CARET); }
'%' { ret binop(rdr, token::PERCENT); }
c { rdr.fatal(#fmt["unknown start of token: %d", c as int]); }
}
}
fn consume_whitespace(rdr: reader) {
while is_whitespace(rdr.curr) && !rdr.is_eof() { rdr.bump(); }
}
//
// Local Variables:
// mode: rust
// fill-column: 78;
// indent-tabs-mode: nil
// c-basic-offset: 4
// buffer-file-coding-system: utf-8-unix
// End:
//