rust/src/comp/syntax/parse/lexer.rs
Marijn Haverbeke f26e770745 Make 1-1 parse again
Issue #954

This is not a very elegant fix -- we should probably do something with
constant folding to handle negative-int alt patterns in the future.
2011-10-07 16:46:44 +02:00

804 lines
24 KiB
Rust

import std::{io, int, vec, str, map, option};
import std::map::hashmap;
import std::option::{some, none};
import util::interner;
import util::interner::intern;
import codemap;
type reader =
obj {
fn is_eof() -> bool;
fn curr() -> char;
fn next() -> char;
fn init();
fn bump();
fn get_str_from(uint) -> str;
fn get_interner() -> @interner::interner<str>;
fn get_chpos() -> uint;
fn get_byte_pos() -> uint;
fn get_col() -> uint;
fn get_filemap() -> codemap::filemap;
fn err(str);
};
fn new_reader(cm: codemap::codemap, src: str, filemap: codemap::filemap,
itr: @interner::interner<str>) -> reader {
obj reader(cm: codemap::codemap,
src: str,
len: uint,
mutable col: uint,
mutable pos: uint,
mutable ch: char,
mutable chpos: uint,
mutable strs: [str],
fm: codemap::filemap,
itr: @interner::interner<str>) {
fn is_eof() -> bool { ret ch == -1 as char; }
fn get_str_from(start: uint) -> str {
// I'm pretty skeptical about this subtraction. What if there's a
// multi-byte character before the mark?
ret str::slice(src, start - 1u, pos - 1u);
}
fn get_chpos() -> uint { ret chpos; }
fn get_byte_pos() -> uint { ret pos; }
fn curr() -> char { ret ch; }
fn next() -> char {
if pos < len {
ret str::char_at(src, pos);
} else { ret -1 as char; }
}
fn init() {
if pos < len {
let next = str::char_range_at(src, pos);
pos = next.next;
ch = next.ch;
}
}
fn bump() {
if pos < len {
col += 1u;
chpos += 1u;
if ch == '\n' {
codemap::next_line(fm, chpos, pos + fm.start_pos.byte);
col = 0u;
}
let next = str::char_range_at(src, pos);
pos = next.next;
ch = next.ch;
} else { ch = -1 as char; }
}
fn get_interner() -> @interner::interner<str> { ret itr; }
fn get_col() -> uint { ret col; }
fn get_filemap() -> codemap::filemap { ret fm; }
fn err(m: str) {
codemap::emit_error(some(ast_util::mk_sp(chpos, chpos)), m, cm);
}
}
let strs: [str] = [];
let rd =
reader(cm, src, str::byte_len(src), 0u, 0u, -1 as char,
filemap.start_pos.ch, strs, filemap, itr);
rd.init();
ret rd;
}
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(); }
be 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.
be consume_whitespace_and_comments(rdr);
}
'*' { rdr.bump(); rdr.bump(); be consume_block_comment(rdr); }
_ { ret; }
}
}
}
fn consume_block_comment(rdr: reader) {
let level: int = 1;
while level > 0 {
if rdr.is_eof() { rdr.err("unterminated block comment"); fail; }
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.
be consume_whitespace_and_comments(rdr);
}
fn string_to_int(s: str) -> int {
let negative = false;
if str::char_at(s, 0u) == '-' {
negative = true;
s = str::substr(s, 1u, str::byte_len(s) - 1u);
}
let accum_int: int = 0;
for c: u8 in s { accum_int *= 10; accum_int += dec_digit_val(c as char); }
ret if negative { -accum_int } else { accum_int };
}
fn scan_exponent(rdr: reader) -> option::t<str> {
let c = rdr.curr();
let rslt = "";
if c == 'e' || c == 'E' {
rslt += str::unsafe_from_bytes([c as u8]);
rdr.bump();
c = rdr.curr();
if c == '-' || c == '+' {
rslt += str::unsafe_from_bytes([c as u8]);
rdr.bump();
}
let exponent = scan_dec_digits(rdr);
if str::byte_len(exponent) > 0u {
ret some(rslt + exponent);
} else { rdr.err("scan_exponent: bad fp literal"); fail; }
} else { ret none::<str>; }
}
fn scan_dec_digits_with_prefix(rdr: reader) -> str {
let negative = false;
if rdr.curr() == '-' {
negative = true;
rdr.bump();
}
let digits = scan_dec_digits(rdr);
if negative { str::unshift_char(digits, '-'); }
ret digits;
}
fn scan_dec_digits(rdr: reader) -> str {
let c = rdr.curr();
let rslt: str = "";
while is_dec_digit(c) || c == '_' {
if c != '_' { rslt += str::unsafe_from_bytes([c as u8]); }
rdr.bump();
c = rdr.curr();
}
ret rslt;
}
fn scan_number(c: char, rdr: reader) -> token::token {
let accum_int = 0;
let num_str: str = "";
let n = rdr.next();
if c == '0' && n == 'x' {
rdr.bump();
rdr.bump();
c = rdr.curr();
while is_hex_digit(c) || c == '_' {
if c != '_' { accum_int *= 16; accum_int += hex_digit_val(c); }
rdr.bump();
c = rdr.curr();
}
} else if c == '0' && n == 'b' {
rdr.bump();
rdr.bump();
c = rdr.curr();
while is_bin_digit(c) || c == '_' {
if c != '_' { accum_int *= 2; accum_int += bin_digit_value(c); }
rdr.bump();
c = rdr.curr();
}
} else {
num_str = scan_dec_digits_with_prefix(rdr);
accum_int = string_to_int(num_str);
}
c = rdr.curr();
n = rdr.next();
if c == 'u' || c == 'i' {
let signed: bool = c == 'i';
rdr.bump();
c = rdr.curr();
if c == '8' {
rdr.bump();
if signed {
ret token::LIT_MACH_INT(ast::ty_i8, accum_int);
} else { ret token::LIT_MACH_INT(ast::ty_u8, accum_int); }
}
n = rdr.next();
if c == '1' && n == '6' {
rdr.bump();
rdr.bump();
if signed {
ret token::LIT_MACH_INT(ast::ty_i16, accum_int);
} else { ret token::LIT_MACH_INT(ast::ty_u16, accum_int); }
}
if c == '3' && n == '2' {
rdr.bump();
rdr.bump();
if signed {
ret token::LIT_MACH_INT(ast::ty_i32, accum_int);
} else { ret token::LIT_MACH_INT(ast::ty_u32, accum_int); }
}
if c == '6' && n == '4' {
rdr.bump();
rdr.bump();
if signed {
ret token::LIT_MACH_INT(ast::ty_i64, accum_int);
} else { ret token::LIT_MACH_INT(ast::ty_u64, accum_int); }
}
if signed {
ret token::LIT_INT(accum_int);
} else {
// FIXME: should cast in the target bit-width.
ret token::LIT_UINT(accum_int as uint);
}
}
let is_float = false;
if rdr.curr() == '.' {
is_float = true;
rdr.bump();
let dec_part = scan_dec_digits(rdr);
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_MACH_FLOAT(ast::ty_f32,
intern(*rdr.get_interner(),
num_str));
} else if c == '6' && n == '4' {
rdr.bump();
rdr.bump();
ret token::LIT_MACH_FLOAT(ast::ty_f64,
intern(*rdr.get_interner(),
num_str));
/* 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 */
} else {
is_float = true;
}
}
if is_float {
ret token::LIT_FLOAT(interner::intern::<str>(*rdr.get_interner(),
num_str));
} else {
ret token::LIT_INT(accum_int);
}
}
fn scan_numeric_escape(rdr: reader, n_hex_digits: uint) -> char {
let accum_int = 0;
while n_hex_digits != 0u {
let n = rdr.curr();
rdr.bump();
if !is_hex_digit(n) {
rdr.err(#fmt["illegal numeric character escape: %d", n as int]);
fail;
}
accum_int *= 16;
accum_int += hex_digit_val(n);
n_hex_digits -= 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.get_chpos();
let start_bpos = rdr.get_byte_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 accum_str = "";
let c = rdr.curr();
if is_alpha(c) || c == '_' {
while is_alnum(c) || 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() == ':';
ret token::IDENT(interner::intern::<str>(*rdr.get_interner(),
accum_str), is_mod_name);
}
if is_dec_digit(c) || (c == '-' && is_dec_digit(rdr.next())) {
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::QUES;
}
';' { 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();
if rdr.curr() == '<' { rdr.bump(); ret token::POUND_LT; }
if rdr.curr() == '{' { rdr.bump(); ret token::POUND_LBRACE; }
ret token::POUND;
}
'~' { rdr.bump(); ret token::TILDE; }
':' {
rdr.bump();
if rdr.curr() == ':' {
rdr.bump();
ret token::MOD_SEP;
} else { ret token::COLON; }
}
// 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 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.err(#fmt["unknown character escape: %d", c2 as int]);
fail;
}
}
}
if rdr.curr() != '\'' {
rdr.err("unterminated character constant");
fail;
}
rdr.bump(); // advance curr past token
ret token::LIT_CHAR(c2);
}
'"' {
let n = rdr.get_chpos();
rdr.bump();
while rdr.curr() != '"' {
if rdr.is_eof() {
rdr.err(#fmt["unterminated double quote string: %s",
rdr.get_str_from(n)]);
fail;
}
let ch = rdr.curr();
rdr.bump();
alt ch {
'\\' {
let escaped = rdr.curr();
rdr.bump();
alt escaped {
'n' { str::push_byte(accum_str, '\n' as u8); }
'r' { str::push_byte(accum_str, '\r' as u8); }
't' { str::push_byte(accum_str, '\t' as u8); }
'\\' { str::push_byte(accum_str, '\\' as u8); }
'"' { str::push_byte(accum_str, '"' as u8); }
'\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.err(#fmt["unknown string escape: %d", c2 as int]);
fail;
}
}
}
_ { str::push_char(accum_str, ch); }
}
}
rdr.bump();
ret token::LIT_STR(interner::intern::<str>(*rdr.get_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.err(#fmt["unkown start of token: %d", c as int]); fail; }
}
}
tag cmnt_style {
isolated; // No code on either side of each line of the comment
trailing; // Code exists to the left of the comment
mixed; // Code before /* foo */ and after the comment
blank_line; // Just a manual blank line "\n\n", for layout
}
type cmnt = {style: cmnt_style, lines: [str], pos: uint};
fn read_to_eol(rdr: reader) -> str {
let val = "";
while rdr.curr() != '\n' && !rdr.is_eof() {
str::push_char(val, rdr.curr());
rdr.bump();
}
if rdr.curr() == '\n' { rdr.bump(); }
ret val;
}
fn read_one_line_comment(rdr: reader) -> str {
let val = read_to_eol(rdr);
assert (val[0] == '/' as u8 && val[1] == '/' as u8);
ret val;
}
fn consume_whitespace(rdr: reader) {
while is_whitespace(rdr.curr()) && !rdr.is_eof() { rdr.bump(); }
}
fn consume_non_eol_whitespace(rdr: reader) {
while is_whitespace(rdr.curr()) && rdr.curr() != '\n' && !rdr.is_eof() {
rdr.bump();
}
}
fn push_blank_line_comment(rdr: reader, &comments: [cmnt]) {
log ">>> blank-line comment";
let v: [str] = [];
comments += [{style: blank_line, lines: v, pos: rdr.get_chpos()}];
}
fn consume_whitespace_counting_blank_lines(rdr: reader, &comments: [cmnt]) {
while is_whitespace(rdr.curr()) && !rdr.is_eof() {
if rdr.get_col() == 0u && rdr.curr() == '\n' {
push_blank_line_comment(rdr, comments);
}
rdr.bump();
}
}
fn read_line_comments(rdr: reader, code_to_the_left: bool) -> cmnt {
log ">>> line comments";
let p = rdr.get_chpos();
let lines: [str] = [];
while rdr.curr() == '/' && rdr.next() == '/' {
let line = read_one_line_comment(rdr);
log line;
lines += [line];
consume_non_eol_whitespace(rdr);
}
log "<<< line comments";
ret {style: if code_to_the_left { trailing } else { isolated },
lines: lines,
pos: p};
}
fn all_whitespace(s: str, begin: uint, end: uint) -> bool {
let i: uint = begin;
while i != end { if !is_whitespace(s[i] as char) { ret false; } i += 1u; }
ret true;
}
fn trim_whitespace_prefix_and_push_line(&lines: [str], s: str, col: uint) {
let s1;
if all_whitespace(s, 0u, col) {
if col < str::byte_len(s) {
s1 = str::slice(s, col, str::byte_len(s));
} else { s1 = ""; }
} else { s1 = s; }
log "pushing line: " + s1;
lines += [s1];
}
fn read_block_comment(rdr: reader, code_to_the_left: bool) -> cmnt {
log ">>> block comment";
let p = rdr.get_chpos();
let lines: [str] = [];
let col: uint = rdr.get_col();
rdr.bump();
rdr.bump();
let curr_line = "/*";
let level: int = 1;
while level > 0 {
log #fmt["=== block comment level %d", level];
if rdr.is_eof() { rdr.err("unterminated block comment"); fail; }
if rdr.curr() == '\n' {
trim_whitespace_prefix_and_push_line(lines, curr_line, col);
curr_line = "";
rdr.bump();
} else {
str::push_char(curr_line, rdr.curr());
if rdr.curr() == '/' && rdr.next() == '*' {
rdr.bump();
rdr.bump();
curr_line += "*";
level += 1;
} else {
if rdr.curr() == '*' && rdr.next() == '/' {
rdr.bump();
rdr.bump();
curr_line += "/";
level -= 1;
} else { rdr.bump(); }
}
}
}
if str::byte_len(curr_line) != 0u {
trim_whitespace_prefix_and_push_line(lines, curr_line, col);
}
let style = if code_to_the_left { trailing } else { isolated };
consume_non_eol_whitespace(rdr);
if !rdr.is_eof() && rdr.curr() != '\n' && vec::len(lines) == 1u {
style = mixed;
}
log "<<< block comment";
ret {style: style, lines: lines, pos: p};
}
fn peeking_at_comment(rdr: reader) -> bool {
ret rdr.curr() == '/' && rdr.next() == '/' ||
rdr.curr() == '/' && rdr.next() == '*';
}
fn consume_comment(rdr: reader, code_to_the_left: bool, &comments: [cmnt]) {
log ">>> consume comment";
if rdr.curr() == '/' && rdr.next() == '/' {
comments += [read_line_comments(rdr, code_to_the_left)];
} else if rdr.curr() == '/' && rdr.next() == '*' {
comments += [read_block_comment(rdr, code_to_the_left)];
} else { fail; }
log "<<< consume comment";
}
fn is_lit(t: token::token) -> bool {
ret alt t {
token::LIT_INT(_) { true }
token::LIT_UINT(_) { true }
token::LIT_MACH_INT(_, _) { true }
token::LIT_FLOAT(_) { true }
token::LIT_MACH_FLOAT(_, _) { true }
token::LIT_STR(_) { true }
token::LIT_CHAR(_) { true }
token::LIT_BOOL(_) { true }
_ { false }
}
}
type lit = {lit: str, pos: uint};
fn gather_comments_and_literals(cm: codemap::codemap, path: str,
srdr: io::reader) ->
{cmnts: [cmnt], lits: [lit]} {
let src = str::unsafe_from_bytes(srdr.read_whole_stream());
let itr = @interner::mk::<str>(str::hash, str::eq);
let rdr = new_reader(cm, src, codemap::new_filemap(path, 0u, 0u), itr);
let comments: [cmnt] = [];
let literals: [lit] = [];
let first_read: bool = true;
while !rdr.is_eof() {
while true {
let code_to_the_left = !first_read;
consume_non_eol_whitespace(rdr);
if rdr.curr() == '\n' {
code_to_the_left = false;
consume_whitespace_counting_blank_lines(rdr, comments);
}
while peeking_at_comment(rdr) {
consume_comment(rdr, code_to_the_left, comments);
consume_whitespace_counting_blank_lines(rdr, comments);
}
break;
}
let tok = next_token(rdr);
if is_lit(tok.tok) {
literals += [{lit: rdr.get_str_from(tok.bpos), pos: tok.chpos}];
}
log "tok: " + token::to_str(rdr, tok.tok);
first_read = false;
}
ret {cmnts: comments, lits: literals};
}
// This is a stopgap fix. We will have to do better eventually (issue #954)
fn maybe_untangle_minus_from_lit(r: reader, t: token::token)
-> option::t<token::token> {
fn check_str(r: reader, i: uint) -> option::t<uint> {
let it = r.get_interner(), s = interner::get(*it, i);
if s[0] == '-' as u8 {
some(interner::intern(*it, str::slice(s, 1u, str::byte_len(s))))
} else { none }
}
alt t {
token::LIT_INT(v) {
if v < 0 { ret some(token::LIT_INT(-v)); }
}
token::LIT_UINT(v) {
if v > 0x7fffffffu { ret some(token::LIT_UINT(-(v as int) as uint)); }
}
token::LIT_MACH_INT(m, v) {
if v < 0 { ret some(token::LIT_MACH_INT(m, -v)); }
}
token::LIT_FLOAT(s) {
alt check_str(r, s) {
some(s) { ret some(token::LIT_FLOAT(s)); }
_ {}
}
}
token::LIT_MACH_FLOAT(m, s) {
alt check_str(r, s) {
some(s) { ret some(token::LIT_MACH_FLOAT(m, s)); }
_ {}
}
}
_ {}
}
none
}
//
// Local Variables:
// mode: rust
// fill-column: 78;
// indent-tabs-mode: nil
// c-basic-offset: 4
// buffer-file-coding-system: utf-8-unix
// compile-command: "make -k -C $RBUILD 2>&1 | sed -e 's/\\/x\\//x:\\//g'";
// End:
//