:guard's should be applicable to an entire file

[OlivierBBB]

Consider e.g. the hub/instruction_handling/copy files. They are split into

• generalities
• and 1 file per opcode:
  • CALLDATACOPY
  • RETURNDATACOPY
  • CODECOPY
  • EXTCODECOPY

Every constraint in these opcode sections is of the form

(defconstraint copy-instruction---OPCODE---purpose-of-the-constraint    (:guard (copy-instruction---standard-OPCODE))

i.e. we have to repeat the guard every time. However in the spec the guard is mentioned once at the start e.g.

It would be more in line with the spec if we could declare a local (to the file) guard and have a special way of declaring constraints, say (defguardedconstraint bla ...) or so.

[DavePearce]

Some options:

• This could be a "module guard", perhaps declared as part of the module declaration.
• Or, we could have a new declaration (guard xxx) which then applies the guard to all following constraints.