Re^2: Clarifying the Comma Operator (bareword)

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Re^3: Clarifying the Comma Operator (should) by tye (Sage) on Jun 07, 2009 at 07:47 UTC
Hmm. You'll have to try much harder to explain your point. I'm fully aware of the facts you repeat above, but I'm completely lost as to why you felt it an appropriate response to my node. I also disagree with your use of "wrongly" and "should". You also appear to disagree with your own uses of "wrongly" and "should" in other replies in these threads. The rest of that (complex) sentence that you partially quoted includes: if it's a bareword that would be a legal simple identifier And 08 isn't a legal simple indentifier (and thus there is no "problem"). Nor is 08 a bareword (by either definition). And I know you know this because elsewhere you noted this (though your inclusion of "hyphen" in your explanation was erroneous). - tye	[reply]
Re^4: Clarifying the Comma Operator (should) by CountZero (Bishop) on Jun 07, 2009 at 14:42 UTC
It is indeed confusing. Unless you read (and remember all) what is in separate parts of the docs, the statement I quoted looks as if the `=>` operator will stringify its left hand argument, which it does ... sometimes and under strict conditions only. I find it surprising and having been bitten by it before, I always quote the left hand part of `=>`. It would be better --IMO-- if the docs would make a less broad statement in that respect. CountZero A program should be light and agile, its subroutines connected like a string of pearls. The spirit and intent of the program should be retained throughout. There should be neither too little or too much, neither needless loops nor useless variables, neither lack of structure nor overwhelming rigidity." - The Tao of Programming, 4.1 - Geoffrey James	[reply] [d/l] [select]
Re^3: Clarifying the Comma Operator (bareword) by JavaFan (Canon) on Jun 07, 2009 at 12:28 UTC
Actually, that's where the problem lies: 08 is not seen as a string but (wrongly) as an octal number. Perl tries to numify this "word" whereas it should be stringified. But how should perl know? perl is tokenizing when it encounters the leading 0. Considering that it know it's now expecting a TERM, the leading 0 must mean it's going to encounter an octal number. It doesn't know about the following arrow yet, but it has to decide how to tokenize the next thing. And that's why all "bare words" look like identifiers. When encountering `foo::bar => baz` [download] perl is expecting a TERM. Barewords can start terms (infix operators like the `x` tye mentions cannot - that's why infix operators can consist of letters, but prefix operators cannot), and that's why all barewords look like identifiers. Because only after tokenizing the bareword and looking at the next token, perl decides whether the bareword is an identifier (subroutine, filehandle), or a string.	[reply] [d/l]
Re^4: Clarifying the Comma Operator (bareword) by CountZero (Bishop) on Jun 07, 2009 at 17:22 UTC
Perl doesn't know for the very good reasons you quote. But the (partial) sentence I quoted from the docs, gives the impression that the `=>` operator somehow makes a string out of its left-hand argument, which it cannot do anymore as the "octal" error already occurred. CountZero A program should be light and agile, its subroutines connected like a string of pearls. The spirit and intent of the program should be retained throughout. There should be neither too little or too much, neither needless loops nor useless variables, neither lack of structure nor overwhelming rigidity." - The Tao of Programming, 4.1 - Geoffrey James	[reply] [d/l]