INTERFACE M3CExpsMisc;
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IMPORT M3AST_AS;
IMPORT M3Error;
PROCEDURE IsDesignator(
exp: M3AST_AS.EXP;
VAR writable: BOOLEAN)
: BOOLEAN
RAISES {};
is the given expression a designator? 'writable' is only set if 'exp' is a
designator, and indicates whether the designator is writable. If there is an
error (e.g. unset type fields, invalid expression - due to error in program
source) the result will usually be optimistic i.e. both result and 'writable'
TRUE
TYPE
Class = {Normal, Type, Interface, Method, Exception};
ClassSet = SET OF Class;
CONST
NormalOnly = ClassSet{Class.Normal};
AnyClass = ClassSet{FIRST(Class)..LAST(Class)};
PROCEDURE Classify(exp: M3AST_AS.EXP): Class RAISES {};
because types, modules, methods and exceptions have names they can appear in
expressions (though it is almost always an error). 'Classify' can be used to
spot such such bogus expressions. Usually optimistic (returns 'Normal') in the
case of errors in 'exp'
PROCEDURE IsId(
exp: M3AST_AS.EXP;
VAR defId: M3AST_AS.DEF_ID)
: BOOLEAN
RAISES {};
If 'exp' is an 'Exp_used_id' or a qualified id by an interface
masquerading a a selection 'IsId' gets the def id corresponding to this id.
Providing the def id is not unset returns TRUE and sets up 'defId'. Returns
FALSE and leaves 'defId' unchanged in all other cases
PROCEDURE WrongClass(en: M3Error.ERROR_NODE; class: Class) RAISES {};
if an expression is found to be of an unexpected class this procedure can
be used write out a wrong class message. 'class' is the unexpected class,
e.g if an expression is found to be a type when it should not be 'class' would
be 'Class.Type'
END M3CExpsMisc.