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Re: attribution of ++ to the wrong variable in "a ++b"


From: Ed Morton
Subject: Re: attribution of ++ to the wrong variable in "a ++b"
Date: Tue, 13 Sep 2022 06:40:47 -0500
User-agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:102.0) Gecko/20100101 Thunderbird/102.2.2

On 9/13/2022 5:42 AM, Pascal Maugis wrote:
Hi, as promised here is the strange, unexpected behavior of ++ that looks like an error to me, because in "a ++b", a is incremented instead of b. "a b++" and "a++ b" produce the correct results however :

   touch a.awk
   gawk -D -f ./a.awk
   eval "a=1 ; b=2"
   eval "print a ++b"   ; output = 12 : (variables will be incremented
   after the operation, ok with me as documented)
   eval "print a b"     ; output = 22 : a has been incremented instead of b
   eval "print a++b"    ; output = 22 :
   eval "print a b"     ; output = 32 : a has been incremented

The operation seems to be interpreted as "a++b", the space been uninterpreted as a separator

Pascal - with a few exceptions, white space generally doesn't matter to awk. If you want to ensure that `a ++b` gets interpreted as `a (++b)` then that latter is the code you need to write since once you remove/ignore white space `a++ b` and `a ++b` are both `a++b` which visually could be interpreted either way.

    Ed.


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