Re^3: Illegal octal digit error

Toward the end of the Comma Operator section in perlop it says:

If the argument on the left is not a word, it is first interpreted as an expression, and then the string value of that is used.

which is consistent with observed behaviour.

True laziness is hard work

Comment on Re^3: Illegal octal digit error

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Re^4: Illegal octal digit error by ig (Vicar) on Jun 06, 2009 at 12:59 UTC
In which case a word must be something other than a sequence of "word characters". Is word defined somewhere? update: I'm guessing a word must begin with an alphabetic character or an underscore so that anything beginning with a digit is not a word. update: Looking at perl source (toke.c) it appears that anything beginning with a digit is scanned as a number while anything starting with an underscore or alphabetic character other than 'v' or 'x' is scanned as... there are quite a few possibilities here, one of which is "a word before a => operator". There is some additional testing done for 'v' and 'x'. I don't follow it all, but suspect 'v' might be the start of a version string, handled somewhat differently, and 'x' followed by a digit might be a repeat operator, depending on context. Otherwise 'v' and 'x' are handled the same as all the other alphabetics. In conclusion: it appears that a word is not any sequence of word characters, but only those that begin with underscore or an alphabetic character. Anything beginning with a digit is a number, not a word, and is not forced to be a string when on the left of '=>'.	[reply]

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Re^4: Illegal octal digit error
by ig (Vicar) on Jun 06, 2009 at 12:59 UTC

In which case a word must be something other than a sequence of "word characters". Is word defined somewhere?

update: I'm guessing a word must begin with an alphabetic character or an underscore so that anything beginning with a digit is not a word.

update: Looking at perl source (toke.c) it appears that anything beginning with a digit is scanned as a number while anything starting with an underscore or alphabetic character other than 'v' or 'x' is scanned as... there are quite a few possibilities here, one of which is "a word before a => operator". There is some additional testing done for 'v' and 'x'. I don't follow it all, but suspect 'v' might be the start of a version string, handled somewhat differently, and 'x' followed by a digit might be a repeat operator, depending on context. Otherwise 'v' and 'x' are handled the same as all the other alphabetics.

In conclusion: it appears that a word is not any sequence of word characters, but only those that begin with underscore or an alphabetic character. Anything beginning with a digit is a number, not a word, and is not forced to be a string when on the left of '=>'.

[reply]