monic part 5: writing C programs on the calculator

[Jonathan Busby]

(02-17-2021 10:48 PM)Jonathan Busby Wrote:  

Quote:There were a few aspects of the original BNF grammar I found confusing:

1) expression_stmt -> expression ; | ;

I couldn't figure out what the ; on its own is for, so I changed the production to

expression_stmt -> expression ;

This is to allow empty expressions. You need this in cases such as :

Code:

while(x != somevalue) ;

Which could be used for busy waiting ( eg. a "spinlock" )

The above was just a random example. If you google for eg. "C empty expression uses" then you'll get many examples of different uses of "null" or empty expressions other than my simple ( and somewhat contrived ) example.

Regards,

Jonathan