document unicode, such as it is

R=rsc
DELTA=18  (9 added, 0 deleted, 9 changed)
OCL=25817
CL=25832

diff --git a/src/lib/unicode/letter.go b/src/lib/unicode/letter.go
index 3b1221b87bc9176277ce1a88d315cc015569a051..d7aa678c9d25e134630893ab5317a243a9a0881d 100644 (file)
--- a/src/lib/unicode/letter.go
+++ b/src/lib/unicode/letter.go
@@ -10,14 +10,19 @@
 // link in only the tables that are used by the program,
 // etc.
 
+// This package provides data and functions to test some properties of Unicode code points.
+// It is rudimentary but will improve.
 package unicode
 
+// The representation of a range of Unicode code points.  The range runs from Lo to Hi
+// inclusive and has the specified stride.
 type Range struct {
-       lo int;
-       hi int;
-       stride int;
+       Lo int;
+       Hi int;
+       Stride int;
 }
 
+// Upper is the set of Unicode upper case letters.
 var Upper = []Range{
        Range{0x0041, 0x005a, 1},
        Range{0x00c0, 0x00d6, 1},
@@ -150,6 +155,7 @@ var Upper = []Range{
        Range{0x1d7ca, 0x1d7ca, 1},
 }
 
+// Letter is the set of Unicode letters.
 var Letter = []Range {
        Range{0x0041, 0x005a, 1},
        Range{0x0061, 0x007a, 1},
@@ -525,18 +531,19 @@ var Letter = []Range {
        Range{0x2f800, 0x2fa1d, 1},
 }
 
+// Is tests whether rune is in the specified table of ranges.
 func Is(ranges []Range, rune int) bool {
        // common case: rune is ASCII or Latin-1
        if rune < 0x100 {
                for i := 0; i < len(ranges); i++ {
                        r := ranges[i];
-                       if rune > r.hi {
+                       if rune > r.Hi {
                                continue;
                        }
-                       if rune < r.lo {
+                       if rune < r.Lo {
                                return false;
                        }
-                       return (rune - r.lo) % r.stride == 0;
+                       return (rune - r.Lo) % r.Stride == 0;
                }
                return false;
        }
@@ -547,10 +554,10 @@ func Is(ranges []Range, rune int) bool {
        for lo < hi {
                m := lo + (hi - lo)/2;
                r := ranges[m];
-               if r.lo <= rune && rune <= r.hi {
-                       return (rune - r.lo) % r.stride == 0;
+               if r.Lo <= rune && rune <= r.Hi {
+                       return (rune - r.Lo) % r.Stride == 0;
                }
-               if rune < r.lo {
+               if rune < r.Lo {
                        hi = m;
                } else {
                        lo = m+1;
@@ -559,10 +566,12 @@ func Is(ranges []Range, rune int) bool {
        return false;
 }
 
+// IsLetter reports whether the rune is an upper case letter.
 func IsUpper(rune int) bool {
        return Is(Upper, rune);
 }
 
+// IsLetter reports whether the rune is a letter.
 func IsLetter(rune int) bool {
        return Is(Letter, rune);
 }