digitalmars.D.bugs - [Issue 2734] New: Ambiguity in tokenizing: _._ as a float literal
- d-bugmail puremagic.com (32/32) Mar 15 2009 http://d.puremagic.com/issues/show_bug.cgi?id=2734
- d-bugmail puremagic.com (16/16) Mar 29 2009 http://d.puremagic.com/issues/show_bug.cgi?id=2734
- d-bugmail puremagic.com (12/12) Nov 09 2010 http://d.puremagic.com/issues/show_bug.cgi?id=2734
http://d.puremagic.com/issues/show_bug.cgi?id=2734 Summary: Ambiguity in tokenizing: _._ as a float literal Product: D Version: 2.025 Platform: PC URL: http://www.digitalmars.com/d/1.0/lex.html OS/Version: Linux Status: NEW Keywords: spec Severity: normal Priority: P2 Component: DMD AssignedTo: bugzilla digitalmars.com ReportedBy: dhasenan gmail.com http://www.digitalmars.com/d/1.0/lex.html http://www.digitalmars.com/d/2.0/lex.html Under "Floating Literals", the spec says: DecimalFloat -> DecimalDigits DecimalFloat -> DecimalDigits . DecimalDigits DecimalFloat -> . DecimalDigits etc DecimalDigits is defined as: DecimalDigits -> DecimalDigit DecimalDigits -> DecimalDigit DecimalDigits DecimalDigit -> [0123456789_] From this, we can derive: DecimalFloat -> DecimalDigits . DecimalDigits -> DecimalDigit . DecimalDigit -> _ . _ To resolve the ambiguity, _ cannot be allowed as the first character in a float, and it cannot be allowed as the first character after the decimal point. --
Mar 15 2009
http://d.puremagic.com/issues/show_bug.cgi?id=2734 unknown simplemachines.org changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |unknown simplemachines.org It appears DMD 2.026 already works as you suggest; _1.0 is not recognized as a valid float. However, 1_._1 is, which doesn't seem ambiguous to me. Once you're after the . and in a FloatLiteral, any characters in [_0-9] should be eaten to finish the float literal. The spec just needs to be corrected with a new rule that defines 0, NonZeroDigit, and then a repeating of those with DecimalDigits (Decimal is almost fine except its handling of octals.) -[Unknown] --
Mar 29 2009
http://d.puremagic.com/issues/show_bug.cgi?id=2734 Walter Bright <bugzilla digitalmars.com> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|NEW |RESOLVED CC| |bugzilla digitalmars.com Resolution| |FIXED 20:12:47 PST --- http://www.dsource.org/projects/phobos/changeset/2150 -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email ------- You are receiving this mail because: -------
Nov 09 2010