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digitalmars.D - FloatLiteral 1f

reply Philip Trettner <philip trettner.de> writes:
Hello.

When I came across the lexical definition of a FloatLiteral I wondered
how '1f' gets recognized.

The definition says:
FloatLiteral:
	Float
	Float Suffix
	Integer ImaginarySuffix
	Integer FloatSuffix ImaginarySuffix
	Integer RealSuffix ImaginarySuffix

Float contains a dot or an exponent, so this cannot be.
The suffixes for integers are only imaginary, so '1f' won't be
recognized either.

But the D Compiler compiles fine (as it should be).

Am I missing something or is this a flaw in the FloatLiteral
definition?

kind regards, Philip
Jul 27 2010
parent reply Alix Pexton <alix.DOT.pexton gmail.DOT.com> writes:
On 27/07/2010 21:46, Philip Trettner wrote:
 Hello.

 When I came across the lexical definition of a FloatLiteral I wondered
 how '1f' gets recognized.

 The definition says:
 FloatLiteral:
 	Float
 	Float Suffix
 	Integer ImaginarySuffix
 	Integer FloatSuffix ImaginarySuffix
 	Integer RealSuffix ImaginarySuffix

 Float contains a dot or an exponent, so this cannot be.
 The suffixes for integers are only imaginary, so '1f' won't be
 recognized either.

 But the D Compiler compiles fine (as it should be).

 Am I missing something or is this a flaw in the FloatLiteral
 definition?

 kind regards, Philip

This is one of many discrepancies between the docs and the implementation. I'm still working on writing productions that match the code for my visual grammar project. The code isn't that hard to read if you ever get tempted to take a look, but be wary, it's a little spread out, not all cases are handled in the same place. A...
Jul 28 2010
parent Jerry Quinn <jlquinn optonline.net> writes:
 On 27/07/2010 21:46, Philip Trettner wrote:
 Hello.

 When I came across the lexical definition of a FloatLiteral I wondered
 how '1f' gets recognized.

 The definition says:
 FloatLiteral:
 	Float
 	Float Suffix
 	Integer ImaginarySuffix
 	Integer FloatSuffix ImaginarySuffix
 	Integer RealSuffix ImaginarySuffix

 Float contains a dot or an exponent, so this cannot be.
 The suffixes for integers are only imaginary, so '1f' won't be
 recognized either.

 But the D Compiler compiles fine (as it should be).

 Am I missing something or is this a flaw in the FloatLiteral
 definition?

 kind regards, Philip


This was reported in bug 949: http://d.puremagic.com/issues/show_bug.cgi?id=949
Jul 28 2010