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- better documentation

Browse Source 
- code cleanup

R=rsc,austin
DELTA=28  (12 added, 2 deleted, 14 changed)
OCL=31808
CL=31810
This commit is contained in:
Robert Griesemer 2009-07-17 16:22:55 -07:00
parent 3321470488
commit 821897bc96
1 changed files with 25 additions and 15 deletions
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40
src/pkg/bignum/bignum.go
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@ -809,7 +809,8 @@ func muladd1(x Natural, d, c digit) Natural {
// NatFromString returns the natural number corresponding to the
// longest possible prefix of s representing a natural number in a
// given conversion base, the actual conversion base used, and the
// prefix length.
// prefix length. The syntax of natural numbers follows the syntax
// of unsigned integer literals in Go.
//
// If the base argument is 0, the string prefix determines the actual
// conversion base. A prefix of ``0x'' or ``0X'' selects base 16; the
@ -1322,7 +1323,8 @@ func (x *Integer) Format(h fmt.State, c int) {
// IntFromString returns the integer corresponding to the
// longest possible prefix of s representing an integer in a
// given conversion base, the actual conversion base used, and
// the prefix length.
// the prefix length. The syntax of integers follows the syntax
// of signed integer literals in Go.
//
// If the base argument is 0, the string prefix determines the actual
// conversion base. A prefix of ``0x'' or ``0X'' selects base 16; the
@ -1499,14 +1501,24 @@ func (x *Rational) Format(h fmt.State, c int) {
// RatFromString returns the rational number corresponding to the
// longest possible prefix of s representing a rational number in a
// given conversion base, the actual conversion base used, and the
// prefix length.
// prefix length. The syntax of a rational number is:
//
// rational = mantissa [exponent] .
// mantissa = integer ('/' natural | '.' natural) .
// exponent = ('e'|'E') integer .
//
// If the base argument is 0, the string prefix determines the actual
// conversion base. A prefix of ``0x'' or ``0X'' selects base 16; the
// ``0'' prefix selects base 8. Otherwise the selected base is 10.
// conversion base for the mantissa. A prefix of ``0x'' or ``0X'' selects
// base 16; the ``0'' prefix selects base 8. Otherwise the selected base is 10.
// If the mantissa is represented via a division, both the numerator and
// denominator may have different base prefixes; in that case the base of
// of the numerator is returned. If the mantissa contains a decimal point,
// the base for the fractional part is the same as for the part before the
// decimal point and the fractional part does not accept a base prefix.
// The base for the exponent is always 10.
//
func RatFromString(s string, base uint) (*Rational, uint, int) {
// read nominator
// read numerator
a, abase, alen := IntFromString(s, base);
b := Nat(1);
@ -1528,15 +1540,13 @@ func RatFromString(s string, base uint) (*Rational, uint, int) {
}
// read exponent, if any
var elen int;
mlen := alen + blen;
if mlen < len(s) {
ch := s[mlen];
rlen := alen + blen;
if rlen < len(s) {
ch := s[rlen];
if ch == 'e' || ch == 'E' {
var e *Integer;
e, base, elen = IntFromString(s[mlen + 1 : len(s)], abase);
elen++;
assert(base == abase);
rlen++;
e, _, elen := IntFromString(s[rlen : len(s)], 10);
rlen += elen;
m := Nat(10).Pow(uint(e.mant.Value()));
if e.sign {
b = b.Mul(m);
@ -1546,5 +1556,5 @@ func RatFromString(s string, base uint) (*Rational, uint, int) {
}
}
return MakeRat(a, b), base, alen + blen + elen;
return MakeRat(a, b), base, rlen;
}