Commit graph

11 commits

Author SHA1 Message Date
Leonardo de Moura
4dd6cead83 refactor(equality): make homogeneous equality the default equality
It was not a good idea to use heterogeneous equality as the default equality in Lean.
It creates the following problems.

- Heterogeneous equality does not propagate constraints in the elaborator.
For example, suppose that l has type (List Int), then the expression
     l = nil
will not propagate the type (List Int) to nil.

- It is easy to write false. For example, suppose x has type Real, and the user
writes x = 0. This is equivalent to false, since 0 has type Nat. The elaborator cannot introduce
the coercion since x = 0 is a type correct expression.

Homogeneous equality does not suffer from the problems above.
We keep heterogeneous equality because it is useful for generating proof terms.

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
2013-10-29 16:20:06 -07:00
Leonardo de Moura
d0009d0242 feat(frontends/lean): make the first argument of if-expression implicit, add support for marking implicit arguments on builtin symbols (aka semantic attachments)
Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
2013-10-29 15:53:50 -07:00
Leonardo de Moura
7c8daf8974 fix(kernel/metavar): make sure the justification and substitution are always matching each other
Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
2013-10-29 02:39:52 -07:00
Leonardo de Moura
2c6d4d2225 fix(kernel/normalizer): do not apply substitutions in the normalizer
It is incorrect to apply substitutions during normalization.
The problem is that we do not have support for tracking justifications in the normalizer. So, substitutions were being silently applied during normalization. Thus, the correctness of the conflict resolution in the elaboration was being affected.

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
2013-10-29 02:14:48 -07:00
Leonardo de Moura
dbefc91151 fix(kernel/metavar): add normalize assignment justification
We need that when we normalize the assignment in a metavariable environment.
That is, we replace metavariable in a substitution with other assignments.

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
2013-10-27 11:02:34 -07:00
Leonardo de Moura
a5c3829d1b feat(kernel): add unexpected_metavar_occurrence exception
Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
2013-10-24 19:56:44 -07:00
Leonardo de Moura
46b9b2114a fix(tests/lean): adjust error messages in the expected output
Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
2013-10-24 19:27:26 -07:00
Leonardo de Moura
99a163f11d Simplify metavariable context. Now, we have only 'lift' and 'inst' instead of 'subst', 'lift' and 'lower'
Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
2013-09-16 19:32:28 -07:00
Leonardo de Moura
63e102055e Move metavariables to the kernel. This is the first step for implementing the new elaborator.
Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
2013-09-15 12:09:01 -07:00
Leonardo de Moura
df116f88e0 Improve pretty printer for Pi's
Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
2013-09-08 11:04:07 -07:00
Leonardo de Moura
87d3961158 Improve elaborator error messages
Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
2013-09-04 16:36:58 -07:00