Grammar rules for regexps.

Hi, awkers,

I'm getting a bit  about the rules for what is a regexp and what
isn't (inspired by the confusion that the vim syntax highlighter suffers
from).

I'm assuming it's something to do with precedence, but can anyone
enlighten me further?

Take this:

awk -va=1 -vb=1 -vc=1 '{print a /(b+1)/ c, /(b+1)/, a (/b+1/) c}'

The first expression had the thing between the /s evaulated numerically,
the second has it evaluated as a regexp (in gawk, at any rate). The third
(fairly obviously because of the brackest) has it as a regexp (the space
is necessary to prevent a(...) looking like a functions).

Why? What are the rules?

Thanks

-Ed

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