[Rd] Feature Request: Allow Underscore Separated Numbers
Ivan Krylov
kry|ov@r00t @end|ng |rom gm@||@com
Sun Jul 17 08:57:22 CEST 2022
On Sat, 16 Jul 2022 11:17:17 -0400
Duncan Murdoch <murdoch.duncan using gmail.com> wrote:
> I think there's an issue with hex values. For example:
>
> > 0xa_2
> [1] 162
> > 0x2_a
> Error: unexpected input in "0x2_"
You're right, thanks! Should have checked for hex-digits when in
hex-literal mode.
One last try because I don't want to leave a bug I had introduced
myself, but as you say in your other message, this is both incomplete
without tests and documentation and effectively dead unless an R Core
member picks the whole proposal up:
--- src/main/gram.y (revision 82598)
+++ src/main/gram.y (working copy)
@@ -2091,7 +2091,9 @@
int k, c;
c = xxgetc();
- if (isdigit(c)) k = 1; else k = 2;
+ if (isdigit(c)) k = 1;
+ else if (('a' <= c && c <= 'f') || ('A' <= c && c <= 'F')) k = 2;
+ else k = 3;
xxungetc(c);
return k;
}
@@ -2526,7 +2528,7 @@
YYTEXT_PUSH(c, yyp);
/* We don't care about other than ASCII digits */
while (isdigit(c = xxgetc()) || c == '.' || c == 'e' || c == 'E'
- || c == 'x' || c == 'X' || c == 'L')
+ || c == 'x' || c == 'X' || c == 'L' || c == '_')
{
count++;
if (c == 'L') /* must be at the end. Won't allow 1Le3 (at present). */
@@ -2538,11 +2540,16 @@
if (count > 2 || last != '0') break; /* 0x must be first */
YYTEXT_PUSH(c, yyp);
while(isdigit(c = xxgetc()) || ('a' <= c && c <= 'f') ||
- ('A' <= c && c <= 'F') || c == '.') {
+ ('A' <= c && c <= 'F') || c == '.' || c == '_') {
if (c == '.') {
if (seendot) return ERROR;
seendot = 1;
}
+ if (c == '_') {
+ /* disallow underscores following 0x or followed by non-hexdigit */
+ if (nd == 0 || typeofnext() >= 3) break;
+ continue;
+ }
YYTEXT_PUSH(c, yyp);
nd++;
}
@@ -2588,6 +2595,11 @@
break;
seendot = 1;
}
+ /* underscores in significand followed by a digit must be skipped */
+ if (c == '_') {
+ if (seenexp || typeofnext() >= 2) break;
+ continue;
+ }
YYTEXT_PUSH(c, yyp);
last = c;
}
I won't be sending any more unsolicited patches for this proposal.
--
Best regards,
Ivan
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