In P4, parsers are considered types. Those parsers are instantiated.
The instantiated parsers are values. Previously, gp4 treated a parser
type and a parser value as identical. This PR makes that difference
clear _and_ sets the stage for the future.
TODO: Make the same distinction between control and action types and
values.
Signed-off-by: Will Hawkins <hawkinsw@obs.cr>
For types, make it optional to return a default value. While default
values for some types are meaningful, they are not meaningful for all
types (e.g., Action, Control, Parser, Parser state, etc.).
Signed-off-by: Will Hawkins <hawkinsw@obs.cr>
The compilation code was written as a precursor for implementation
with macros. The updates in this commit make the switch.
There is still plenty to do:
1. Comment Walker.
2. Comment Macros.
Signed-off-by: Will Hawkins <hawkinsw@obs.cr>
When a function is called, if there is an (in)out parameter,
make sure that updated values are propogated to the calling
function.
Signed-off-by: Will Hawkins <hawkinsw@obs.cr>
The type system (and the value system) now include attributes
for each type (things like direction, const-ness).
Signed-off-by: Will Hawkins <hawkinsw@obs.cr>
Add support for directions on parameters and attributed types. The
latter is necessary to support the former, but is not limited to
the direction use case. An attributed type is a P4 type with attributes
(like its direction, whether it is read only, etc.) Other attributes
will be added in the future.
Changes necessary to support attributed types include:
1. Global instances tracked during compilation are not attributed
types and not simply types.
2. (future) Type checking will have to make sure that a types
attributes do not affect type compatibility.
Signed-off-by: Will Hawkins <hawkinsw@obs.cr>
By adding an expected type to the compilation context, it is
now possible for type checking to occur on keyset expressions
and return statements at the moment that they are being compiled.
Previously, it was necessary to tentatively compile them and then
typecheck afterward.
Signed-off-by: Will Hawkins <hawkinsw@obs.cr>
1. Add support for field access
2. Add support for proper type checking of array access
3. Add tests for nested field and array access
Signed-off-by: Will Hawkins <hawkinsw@obs.cr>
update method will allow the creation of a new compilation context
based on the current one with new types/names.
Signed-off-by: Will Hawkins <hawkinsw@obs.cr>
Compilation interface(s) now contain a compilation context.
The change will make it easier to expand on what each step
of the compilation process needs to know to complete its task
without having to make major changes to the interface.
Signed-off-by: Will Hawkins <hawkinsw@obs.cr>
Do not pass around the MutableTree -- now that we are not
using queries for walking the AST, it is unnecessary.
Signed-off-by: Will Hawkins <hawkinsw@obs.cr>
Will Hawkins