Re: how to make a macro work as a single line if stmt without braces

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Sujet : Re: how to make a macro work as a single line if stmt without braces
De : bc (at) *nospam* freeuk.com (Bart)
Groupes : comp.lang.c
Date : 24. Sep 2024, 21:12:28
Autres entêtes
Organisation : A noiseless patient Spider
Message-ID : <vcv6fa$3aom3$2@dont-email.me>
References : 1 2 3 4 5 6 7 8 9 10
User-Agent : Mozilla Thunderbird
On 24/09/2024 20:59, Kaz Kylheku wrote:
On 2024-09-24, Bart <bc@freeuk.com> wrote:
(Maybe the language needs a construct like 'elif', as is used in
 The language doesn't need such a construct in order for a compiler
to implement it internally.
 You just have to treat the token sequence   else if  as a supertoken.
 Doing it at the grammar level may require two symbols of lookahead,
which is a a problem for off-the-shelf parser generation tooling based
on LALR(1) and whatnot.
That sounds as much of a hack as making a special case for 'else if' so that it doesn't need 'else {if' (and a matching } later on) when enforcing compound statements for such blocks.
One consequence of how it works now is that if I write:
     if (a) {}
     else if (b) {}
     else if (c) {}
     else {}
then use a tool I have to visualise C code in my syntax, it generates:
     if a then
     else
         if b then
         else
             if c then
             else
             fi
         fi
     fi
The nested nature is revealed. If there were 50 'else if' links, the output would disappear off to the right.
With elif, elsif etc, the compiler has the option to keep the internal structure linear (which also means it will not put pressure on the stack if somebody decides to write a million of them).

Date Sujet#  Auteur
21 Sep 24 * how to make a macro work as a single line if stmt without braces61Mark Summerfield
21 Sep 24 +- Re: how to make a macro work as a single line if stmt without braces1Lawrence D'Oliveiro
21 Sep 24 +* Re: how to make a macro work as a single line if stmt without braces50David Brown
21 Sep 24 i`* Re: how to make a macro work as a single line if stmt without braces49Andrey Tarasevich
21 Sep 24 i +- Re: how to make a macro work as a single line if stmt without braces1Bart
21 Sep 24 i +- Re: how to make a macro work as a single line if stmt without braces1Opus
21 Sep 24 i +* Re: how to make a macro work as a single line if stmt without braces5Keith Thompson
22 Sep 24 i i`* Re: how to make a macro work as a single line if stmt without braces4Andrey Tarasevich
22 Sep 24 i i +- Re: how to make a macro work as a single line if stmt without braces1Keith Thompson
22 Sep 24 i i +- Re: how to make a macro work as a single line if stmt without braces1David Brown
27 Sep 24 i i `- Re: how to make a macro work as a single line if stmt without braces1Tim Rentsch
22 Sep 24 i +* Re: how to make a macro work as a single line if stmt without braces25David Brown
22 Sep 24 i i`* Re: how to make a macro work as a single line if stmt without braces24Kaz Kylheku
22 Sep 24 i i +* Re: how to make a macro work as a single line if stmt without braces21Bart
22 Sep 24 i i i+* Re: how to make a macro work as a single line if stmt without braces14Michael S
22 Sep 24 i i ii+- Re: how to make a macro work as a single line if stmt without braces1Bart
24 Sep 24 i i ii`* Re: how to make a macro work as a single line if stmt without braces12Tim Rentsch
24 Sep 24 i i ii +* Re: how to make a macro work as a single line if stmt without braces5Andrey Tarasevich
24 Sep 24 i i ii i+- Re: how to make a macro work as a single line if stmt without braces1David Brown
24 Sep 24 i i ii i+* Re: how to make a macro work as a single line if stmt without braces2Bart
24 Sep 24 i i ii ii`- Re: how to make a macro work as a single line if stmt without braces1Keith Thompson
27 Sep 24 i i ii i`- Re: how to make a macro work as a single line if stmt without braces1Tim Rentsch
24 Sep 24 i i ii `* Re: how to make a macro work as a single line if stmt without braces6Bart
24 Sep 24 i i ii  +* Re: how to make a macro work as a single line if stmt without braces2Keith Thompson
24 Sep 24 i i ii  i`- Re: how to make a macro work as a single line if stmt without braces1Bart
24 Sep 24 i i ii  `* Re: how to make a macro work as a single line if stmt without braces3Kaz Kylheku
24 Sep 24 i i ii   `* Re: how to make a macro work as a single line if stmt without braces2Bart
25 Sep 24 i i ii    `- Re: how to make a macro work as a single line if stmt without braces1Kaz Kylheku
22 Sep 24 i i i`* Re: how to make a macro work as a single line if stmt without braces6Keith Thompson
23 Sep 24 i i i `* Re: how to make a macro work as a single line if stmt without braces5David Brown
23 Sep 24 i i i  `* Re: how to make a macro work as a single line if stmt without braces4Richard Harnden
23 Sep 24 i i i   `* Re: how to make a macro work as a single line if stmt without braces3David Brown
23 Sep 24 i i i    `* Re: how to make a macro work as a single line if stmt without braces2Richard Harnden
23 Sep 24 i i i     `- Re: how to make a macro work as a single line if stmt without braces1David Brown
22 Sep 24 i i +- Modern text editor - 'bout time someone paid attention to keeping the thread title relevant!!! (Was: how to make a macro work as a single line if stmt without braces)1Kenny McCormack
22 Sep 24 i i `- Re: how to make a macro work as a single line if stmt without braces1David Brown
28 Sep 24 i `* Re: how to make a macro work as a single line if stmt without braces16Tim Rentsch
28 Sep 24 i  +* Re: how to make a macro work as a single line if stmt without braces5Michael S
29 Sep 24 i  i`* Re: how to make a macro work as a single line if stmt without braces4Tim Rentsch
29 Sep 24 i  i `* Re: how to make a macro work as a single line if stmt without braces3Michael S
30 Sep 24 i  i  +- Re: how to make a macro work as a single line if stmt without braces1Tim Rentsch
30 Sep 24 i  i  `- Re: how to make a macro work as a single line if stmt without braces1Alan Mackenzie
29 Sep 24 i  `* Re: how to make a macro work as a single line if stmt without braces10Andrey Tarasevich
29 Sep 24 i   `* Re: how to make a macro work as a single line if stmt without braces9Tim Rentsch
29 Sep 24 i    `* Re: how to make a macro work as a single line if stmt without braces8Andrey Tarasevich
29 Sep 24 i     +- Re: how to make a macro work as a single line if stmt without braces1Michael S
30 Sep 24 i     +* Re: how to make a macro work as a single line if stmt without braces3Keith Thompson
30 Sep 24 i     i`* Re: how to make a macro work as a single line if stmt without braces2Kaz Kylheku
30 Sep 24 i     i `- Re: how to make a macro work as a single line if stmt without braces1Janis Papanagnou
30 Sep 24 i     +- Re: how to make a macro work as a single line if stmt without braces1Tim Rentsch
30 Sep 24 i     +- Re: how to make a macro work as a single line if stmt without braces1Kaz Kylheku
30 Sep 24 i     `- Re: how to make a macro work as a single line if stmt without braces1David Brown
21 Sep 24 +* Re: how to make a macro work as a single line if stmt without braces2Bart
21 Sep 24 i`- Re: how to make a macro work as a single line if stmt without braces1Mark Summerfield
21 Sep 24 +* Re: how to make a macro work as a single line if stmt without braces2Ike Naar
21 Sep 24 i`- Re: how to make a macro work as a single line if stmt without braces1Keith Thompson
21 Sep 24 +* Re: how to make a macro work as a single line if stmt without braces2Tim Rentsch
22 Sep 24 i`- Re: how to make a macro work as a single line if stmt without braces1Keith Thompson
21 Sep 24 +- Re: how to make a macro work as a single line if stmt without braces1Andrey Tarasevich
21 Sep 24 `* Re: how to make a macro work as a single line if stmt without braces2Blue-Maned_Hawk
24 Sep 24  `- Re: how to make a macro work as a single line if stmt without braces1Tim Rentsch

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