support qualified names for invoking a quasiquoter

[nfrisby]

Consider

module M

import qualified A (qq)
import qualified B (qq)

In 7.0.3, the quasiquotation syntax [A.qq|...|] is rejected with parse error on input `A.qq'.

Because of the stage-restriction, the only option is to create an auxiliary module

module AB where

import qualified A; import qualified B

qqA = A.qq
qqB = B.qq

and import that into M. This is a pretty heavy-weight workaround.

Is there a reason qualified names are disallowed for invoking a quasiquoter?

[pcapriotti]

The attached patch adds a "qualified quasi quote" token to the lexer, and the corresponding production to the parser.

[p.capriotti@…]

commit dc2f65f6e7c1763d848557708a980df35b755954

Author: Paolo Capriotti <p.capriotti@gmail.com>
Date:   Mon Apr 2 13:09:10 2012 +0100

    Support qualified identifiers in quasi-quotes (#5555).

 compiler/parser/Lexer.x     |   25 ++++++++++++++++++++++++-
 compiler/parser/Parser.y.pp |    5 +++++
 2 files changed, 29 insertions(+), 1 deletions(-)