Notes on The Standard ML Basis Library

structure General

The General structure

unit

The type unit should be an alias for {}, not an opaque type.

signature REAL

The REAL signature

min / max

The document does not specify the handling of the signed zeroes. LunarML tries to honor the sign of zero. i.e.

min (0.0, ~0.0) = min (~0.0, 0.0) = ~0.0
max (0.0, ~0.0) = max (~0.0, 0.0) = 0.0

toManExp

The condition on man should be "1.0 <= |man| * radix < radix".

realRound

The document does not explicitly say what realRound should do in the case of a tie. LunarML breaks tie by choosing the nearest even integer (like round does).

fromInt / fromLargeInt

The document says

If the absolute value of i is larger than maxFinite, then the appropriate infinity is returned.

but it should be something like "If the absolute value of i is equal to or larger than maxFinite + 0.5 ulp (in the case of the current rounding mode is TO_NEAREST), then ...".

I mean, the program

val maxFinite = IntInf.<< (0x1fffffffffffff, 0w1023 - 0w52);
print (Real.fmt (StringCvt.SCI (SOME 17)) (Real.fromLargeInt (maxFinite + 1)) ^ "\n");

should print a finite value.

fmt (SCI _)

The negative sign on the exponent part should be allowed:

[~]?[0-9].[0-9]+?E[~]?[0-9]+
                  ^^^^

signature CHAR

The CHAR signature

toString

The documentation does not say if the hexadecimal characters in \uxxxx should be uppercase or lowercase. LunarML chooses uppercase.

toString does not say what to do if the character code cannot be expressed by four hexadecimal digits (i.e. ord x >= 0x10000). LunarML plans use \U<eight hex digits> format.

scan / fromString

Should accept \U<eight hex digits>.

toCString

toString does not say what to do if the character code cannot be expressed by three octal digits (i.e. ord x >= 512). LunarML plans to use \u<four hex digits> or \U<eight hex digits> format.

fromCString

Should accept \u<four hex digits> and \U<eight hex digits> if the value satisfies the condition (x >= 0xA0 andalso not (x >= 0xD800 andalso x <= 0xDFFF)) orelse x = 0x24 orelse x = 0x40 orelse x = 0x60 (see C's spec).

signature STRING

The STRING signature

scan

The type of scan should be

val scan : (Char.char, 'a) StringCvt.reader -> (string, 'a) StringCvt.reader
         (* ^^^^^^^^^ *)

rather than

val scan : (char, 'a) StringCvt.reader -> (string, 'a) StringCvt.reader
         (* ^^^^ *)

structure Text / structure WideText

The TEXT signature

The type realisations

structure Text :> TEXT
  ...
  where type CharVector.vector = CharVector.vector
  ...

structure WideText :> TEXT
  ...
  where type CharVector.vector = WideCharVector.vector
  ...

are redundant because CharVector.vector = String.string.

structure WideTextIO

It is not clear how WideTextIO is different than TextIO.

structure OS.Path

OS.Path should support UNC paths (like \\foo\bar\baz) on Windows.