Schema: Generic_expression_arm
SCHEMA Generic_expression_arm;
ENTITY Binary_generic_expression
ABSTRACT SUPERTYPE
SUBTYPE OF (Generic_expression);
operands : LIST[2:2] OF Generic_expression;
END_ENTITY;
ENTITY Environment;
syntactic_representation : Generic_variable;
semantics : Variable_semantics;
END_ENTITY;
ENTITY Generic_expression
ABSTRACT SUPERTYPE
OF (ONEOF (Simple_generic_expression,
Unary_generic_expression,
Binary_generic_expression,
Multiple_arity_generic_expression));
WHERE
WR1: Is_Acyclic(SELF);
END_ENTITY;
ENTITY Generic_literal
ABSTRACT SUPERTYPE
SUBTYPE OF (Simple_generic_expression);
END_ENTITY;
ENTITY Generic_variable
ABSTRACT SUPERTYPE
OF (Variable)
SUBTYPE OF (Simple_generic_expression);
INVERSE
interpretation : Environment FOR syntactic_representation;
END_ENTITY;
ENTITY Multiple_arity_generic_expression
ABSTRACT SUPERTYPE
SUBTYPE OF (Generic_expression);
operands : LIST[2:?] OF Generic_expression;
END_ENTITY;
ENTITY Simple_generic_expression
ABSTRACT SUPERTYPE
OF (ONEOF (Generic_literal,
Generic_variable))
SUBTYPE OF (Generic_expression);
END_ENTITY;
ENTITY Unary_generic_expression
ABSTRACT SUPERTYPE
SUBTYPE OF (Generic_expression);
operand : Generic_expression;
END_ENTITY;
ENTITY Variable
ABSTRACT SUPERTYPE
SUBTYPE OF (Generic_variable);
END_ENTITY;
ENTITY Variable_semantics
ABSTRACT SUPERTYPE
;
END_ENTITY;
FUNCTION Acyclic
(arg1 : Generic_expression; arg2 : SET OF Generic_expression) : BOOLEAN;
LOCAL
result: BOOLEAN;
END_LOCAL;
IF ('GENERIC_EXPRESSION_ARM.SIMPLE_GENERIC_EXPRESSION'
IN TYPEOF (arg1))
THEN
RETURN (TRUE);
END_IF;
IF arg1 IN arg2
THEN
RETURN (FALSE);
END_IF;
IF 'GENERIC_EXPRESSION_ARM.UNARY_GENERIC_EXPRESSION'
IN TYPEOF (arg1)
THEN
RETURN
(Acyclic(arg1\Unary_generic_expression.operand,arg2+[arg1]));
END_IF;
IF 'GENERIC_EXPRESSION_ARM.BINARY_GENERIC_EXPRESSION'
IN TYPEOF (arg1)
THEN
RETURN
(Acyclic(arg1\Binary_generic_expression.operands[1],arg2+[arg1])
AND
Acyclic(arg1\Binary_generic_expression.operands[2],arg2+[arg1]));
END_IF;
IF
'GENERIC_EXPRESSION_ARM.MULTIPLE_ARITY_GENERIC_EXPRESSION'
IN TYPEOF (arg1)
THEN
result := TRUE;
REPEAT i := 1 TO
SIZEOF (arg1\Multiple_arity_generic_expression.operands);
result := result AND
Acyclic(arg1\Multiple_arity_generic_expression.operands[i], arg2+[arg1]);
END_REPEAT;
RETURN (result);
END_IF;
END_FUNCTION;
FUNCTION Is_Acyclic
(arg : Generic_expression) : BOOLEAN;
RETURN (Acyclic (arg, []));
END_FUNCTION;
FUNCTION Used_variables
(arg : Generic_expression) : SET OF Generic_variable;
LOCAL
result : SET OF Generic_variable := [];
END_LOCAL;
IF 'GENERIC_EXPRESSION_ARM.GENERIC_VARIABLE'
IN TYPEOF (arg)
THEN
RETURN ([arg]);
END_IF;
IF 'GENERIC_EXPRESSION_ARM.UNARY_GENERIC_EXPRESSION'
IN TYPEOF (arg)
THEN
RETURN (Used_variables (arg\Unary_generic_expression.operand));
END_IF;
IF 'GENERIC_EXPRESSION_ARM.BINARY_GENERIC_EXPRESSION'
IN TYPEOF (arg)
THEN
RETURN(Used_variables(arg\Binary_generic_expression.operands[1])
+ Used_variables (arg\Binary_generic_expression.operands[2]));
END_IF;
IF
'GENERIC_EXPRESSION_ARM.MULTIPLE_ARITY_GENERIC_EXPRESSION'
IN TYPEOF (arg)
THEN
REPEAT i := 1 TO
SIZEOF(arg\Multiple_arity_generic_expression.operands);
result := result + Used_variables(
arg\Multiple_arity_generic_expression.operands[i]);
END_REPEAT;
RETURN (result);
END_IF;
RETURN ([ ]);
END_FUNCTION;
END_SCHEMA; -- Generic_expression_arm