Add bison++ & flex to .travis.yml
Disable doxygen generation on travis-ci since it causes time-out.
Add one small test to expr
Add static_asserts to sexpr_funcs.h
Roll back to flatten(line) == " "
Change operators in format:
f1 + f2 = f1 <> f2
f1 ^ f2 = f1 <> " " <> f2
Change folddoc to fold_right, add static_asserts for template functions
Update format test
Add static_asserts to template funcs in expr.h & replace.h
Add scanner base class

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
Add instantiate tests

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
Rename abst_type to abst_domain

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
Add (relaxed) version of instantiate that can substitute terms containing free variables

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
Flip order of the arguments for instance and abstract. Simplify type_checker.

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
Remove dead code

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
Rename (stack) value to svalue

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
Add support for semantic attachments. Remove expr_numeral

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>