RE: IfExpr has a mandatory else clause

> So is grammar ambiguity the reason that IfExpr has a
> mandatory else clause ? Are there other design considerations 

Making the else clause mandatory emphasizes that this is an expression
and not a procedural statement: it always returns a result. In most
languages where I've seen a conditional expression, both branches are
mandatory.

An exception of course is <xsl:if> in XSLT, but perhaps that's because
the semantics have only recently been recast into expression form, and
the spec still talks of this as an "instruction" rather than an
"expression".

Michael Kay