FWIW, syntax-parse does a pretty good job with these same examples
except for one case. Ryan, can you fix the 'bad syntax' error?
-> (syntax-parse #'1)
readline-input::199: syntax-parse: expected non-empty sequence of
clauses in: (syntax-parse (syntax 1))
-> (syntax-parse #'1 2)
readline-input::236: ?: bad syntax in: 2
-> (syntax-parse #'1 [2])
readline-input::239: syntax-parse: expected non-empty clause body at:
(2) in: (syntax-parse (syntax 1) (2))
-> (syntax-parse #'1 [2 2])
readline-input::278: ?: expected the literal 2 at: 1 in: 1
Interesting that syntax-parse also uses its own name in the error message.
On 03/29/2010 02:15 PM, Robby Findler wrote:
I think putting "syntax-case:" at the front of the error message is
the right thing (and that's a predictable thought, as I'm sure Matthew
is thinking right now since it means that macros that use syntax-case
to do their error checking will now have to do a better job). Maybe
the presence of Ryan's syntax parse library means we can go with this
nowadays, tho?
Robby
On Mon, Mar 29, 2010 at 2:06 PM, Jon Rafkind<[email protected]> wrote:
Attached is a small patch for syntax-case that makes some error messages
slightly more pleasant (at least to me).
Old:
(syntax-case #'1 ())
bad syntax in: 1
(syntax-case #'1 () 2)
bad clause in: 2
(syntax-case #'1 () [2])
bad clause in: (2)
(syntax-case #'1 () [2 2])
bad syntax in: 1
New:
(syntax-case #'1 ())
syntax-case was unable to match any patterns in: 1
(syntax-case #'1 () 2)
expected a list of clauses in: 2
(syntax-case #'1 () [2])
expected 2 or 3 expressions in a clause in: (2)
(syntax-case #'1 () [2 2])
syntax-case was unable to match any patterns in: 1
There seems to be some disagreement with adding the name 'syntax-case' into
the error message. I could live without that I guess, but it would be nice
to change 'bad syntax' to something more informative, at least.
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