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Improve lexing of float literals

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Closes #575
This commit is contained in:
Marijn Haverbeke 2011-09-13 17:43:01 +02:00
parent f72573cce8
commit 577d6dd602
1 changed files with 36 additions and 39 deletions
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75
src/comp/syntax/parse/lexer.rs
View file

@ -195,7 +195,7 @@ fn scan_dec_digits(rdr: reader) -> str {
fn scan_number(c: char, rdr: reader) -> token::token {
let accum_int = 0;
let dec_str: str = "";
let num_str: str = "";
let is_dec_integer: bool = false;
let n = rdr.next();
if c == '0' && n == 'x' {
@ -216,8 +216,8 @@ fn scan_number(c: char, rdr: reader) -> token::token {
rdr.bump();
c = rdr.curr();
}
} else { dec_str = scan_dec_digits(rdr); is_dec_integer = true; }
if is_dec_integer { accum_int = digits_to_string(dec_str); }
} else { num_str = scan_dec_digits(rdr); is_dec_integer = true; }
if is_dec_integer { accum_int = digits_to_string(num_str); }
c = rdr.curr();
n = rdr.next();
if c == 'u' || c == 'i' {
@ -256,53 +256,50 @@ fn scan_number(c: char, rdr: reader) -> token::token {
ret token::LIT_INT(accum_int);
} else {
// FIXME: should cast in the target bit-width.
ret token::LIT_UINT(accum_int as uint);
}
}
c = rdr.curr();
if c == '.' {
// Parse a floating-point number.
let is_float = false;
if rdr.curr() == '.' {
is_float = true;
rdr.bump();
let dec_part = scan_dec_digits(rdr);
let float_str = dec_str + "." + dec_part;
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();
let exponent_str = scan_exponent(rdr);
alt exponent_str { some(s) { float_str += s; } none. { } }
c = rdr.curr();
if c == 'f' {
n = rdr.next();
if c == '3' && n == '2' {
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(),
float_str));
} else if c == '6' && n == '4' {
rdr.bump();
rdr.bump();
ret token::LIT_MACH_FLOAT(ast::ty_f64,
intern(*rdr.get_interner(),
float_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 */
}
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 {
ret token::LIT_FLOAT(interner::intern::<str>(*rdr.get_interner(),
float_str));
is_float = true;
}
}
let maybe_exponent = scan_exponent(rdr);
alt maybe_exponent {
some(s) {
if is_float {
ret token::LIT_FLOAT(interner::intern::<str>(*rdr.get_interner(),
dec_str + s));
}
none. { ret token::LIT_INT(accum_int); }
num_str));
} else {
ret token::LIT_INT(accum_int);
}
}