num: Separate public API from internal implementations

Currently we have a single `core::num` module that contains both thin
wrapper API and higher-complexity numeric routines. Restructure this by
moving implementation details to a new `imp` module.

This results in a more clean separation of what is actually user-facing
compared to items that have a stability attribute because they are
public for testing.

Author: tgross35

library/core/src/fmt/float.rs

@@ -1,6 +1,6 @@
 use crate::fmt::{Debug, Display, Formatter, LowerExp, Result, UpperExp};
 use crate::mem::MaybeUninit;
-use crate::num::{flt2dec, fmt as numfmt};
+use crate::num::imp::{flt2dec, fmt as numfmt};
 
 #[doc(hidden)]
 trait GeneralFormat: PartialOrd {

library/core/src/fmt/mod.rs

@@ -6,7 +6,7 @@ use crate::cell::{Cell, Ref, RefCell, RefMut, SyncUnsafeCell, UnsafeCell};
 use crate::char::EscapeDebugExtArgs;
 use crate::hint::assert_unchecked;
 use crate::marker::{PhantomData, PointeeSized};
-use crate::num::fmt as numfmt;
+use crate::num::imp::fmt as numfmt;
 use crate::ops::Deref;
 use crate::ptr::NonNull;
 use crate::{iter, mem, result, str};

library/core/src/fmt/num.rs

@@ -2,7 +2,7 @@
 
 use crate::fmt::NumBuffer;
 use crate::mem::MaybeUninit;
-use crate::num::fmt as numfmt;
+use crate::num::imp::fmt as numfmt;
 use crate::{fmt, str};
 
 /// Formatting of integers with a non-decimal radix.

library/core/src/num/f16.rs

@@ -14,7 +14,7 @@
 use crate::convert::FloatToInt;
 use crate::num::FpCategory;
 #[cfg(not(test))]
-use crate::num::libm;
+use crate::num::imp::libm;
 use crate::panic::const_assert;
 use crate::{intrinsics, mem};
 

library/core/src/num/f32.rs

@@ -1621,7 +1621,7 @@ impl f32 {
 #[unstable(feature = "core_float_math", issue = "137578")]
 pub mod math {
     use crate::intrinsics;
-    use crate::num::libm;
+    use crate::num::imp::libm;
 
     /// Experimental version of `floor` in `core`. See [`f32::floor`] for details.
     ///

library/core/src/num/f64.rs

@@ -1619,7 +1619,7 @@ impl f64 {
 /// They will be stabilized as inherent methods._
 pub mod math {
     use crate::intrinsics;
-    use crate::num::libm;
+    use crate::num::imp::libm;
 
     /// Experimental version of `floor` in `core`. See [`f64::floor`] for details.
     ///

library/core/src/num/bignum.rs library/core/src/num/imp/bignum.rslibrary/core/src/num/bignum.rs renamed to library/core/src/num/imp/bignum.rs

@@ -251,7 +251,7 @@ macro_rules! define_bignum {
 
             /// Multiplies itself by `5^e` and returns its own mutable reference.
             pub fn mul_pow5(&mut self, mut e: usize) -> &mut $name {
-                use crate::num::bignum::SMALL_POW5;
+                use crate::num::imp::bignum::SMALL_POW5;
 
                 // There are exactly n trailing zeros on 2^n, and the only relevant digit sizes
                 // are consecutive powers of two, so this is well suited index for the table.
@@ -281,7 +281,7 @@ macro_rules! define_bignum {
             pub fn mul_digits<'a>(&'a mut self, other: &[$ty]) -> &'a mut $name {
                 // the internal routine. works best when aa.len() <= bb.len().
                 fn mul_inner(ret: &mut [$ty; $n], aa: &[$ty], bb: &[$ty]) -> usize {
-                    use crate::num::bignum::FullOps;
+                    use crate::num::imp::bignum::FullOps;
 
                     let mut retsz = 0;
                     for (i, &a) in aa.iter().enumerate() {
@@ -320,7 +320,7 @@ macro_rules! define_bignum {
             /// Divides itself by a digit-sized `other` and returns its own
             /// mutable reference *and* the remainder.
             pub fn div_rem_small(&mut self, other: $ty) -> (&mut $name, $ty) {
-                use crate::num::bignum::FullOps;
+                use crate::num::imp::bignum::FullOps;
 
                 assert!(other > 0);
 

library/core/src/num/dec2flt/common.rs …brary/core/src/num/imp/dec2flt/common.rslibrary/core/src/num/dec2flt/common.rs renamed to library/core/src/num/imp/dec2flt/common.rs library/core/src/num/dec2flt/common.rs renamed to library/core/src/num/imp/dec2flt/common.rs

@@ -1,7 +1,9 @@
 //! Representation of a float as the significant digits and exponent.
 
-use crate::num::dec2flt::float::RawFloat;
-use crate::num::dec2flt::fpu::set_precision;
+use dec2flt::float::RawFloat;
+use dec2flt::fpu::set_precision;
+
+use crate::num::imp::dec2flt;
 
 const INT_POW10: [u64; 16] = [
     1,

library/core/src/num/dec2flt/decimal.rs …rary/core/src/num/imp/dec2flt/decimal.rslibrary/core/src/num/dec2flt/decimal.rs renamed to library/core/src/num/imp/dec2flt/decimal.rs library/core/src/num/dec2flt/decimal.rs renamed to library/core/src/num/imp/dec2flt/decimal.rs

@@ -9,7 +9,9 @@
 //! algorithm can be found in "ParseNumberF64 by Simple Decimal Conversion",
 //! available online: <https://nigeltao.github.io/blog/2020/parse-number-f64-simple.html>.
 
-use crate::num::dec2flt::common::{ByteSlice, is_8digits};
+use dec2flt::common::{ByteSlice, is_8digits};
+
+use crate::num::imp::dec2flt;
 
 /// A decimal floating-point number, represented as a sequence of decimal digits.
 #[derive(Clone, Debug, PartialEq)]