let x = stmtpart1 { exp } stmtpart2 more stuff x other things
that doesn't make sense stmts can only occure in a do not in a let stmt -> exp ; | pat <- exp ; | let decls ; | ;
But what about lambdas:
stmtpart1 (\x -> {exp}) stmtpart2
And what about nested braces:
stmtpart1 { something { more } whatever } stmtpart2
There are lots of other cases to consider :)
Ok now we have finally come to implementation. I don't know a lot of compiler internals but it could work something along those lines. make "{ exp }" an expression. if you are parsing a statement there needs to be some context so an an expression can make use of the fact that it's in a do block. the expression "{ exp }" tells the statement to do "newvarname <- exp" and returns newvarname. Of course the order in which these "newvarname <- exp" will get executed is the order in which the expression results are returned, in other of the closing brackets. This should cover the lambda question and the nested question. silvio