Implementing syntax analysis of "if-else" constructs

[malharjajoo]

In order to implement the syntax analysis of "if-else" construct , don't we need to check if the number of "elses" are less than or equal to ( but never more) than the number of "ifs" ?

How can we achieve this in the grammar ( without using something like a stack ? ) ?

[m8pple]

As long as you write something like:

IfStat : TIf TLParen Expr TRParen Stat TElse Stat

then the grammar itself enforces it. If it encounters an 'else'
that doesn't match an if, then it would be a syntax error.

I believe the only place that 'else' can be found is in an
if statement, so anywhere else it wouldn't match anything.

In terms of nested ifs and elses, then we have the dangling
else situation. The bison documentation has some information
on how to handle that:
http://www.gnu.org/software/bison/manual/html_node/Shift_002fReduce.html