FUNCTION free_variables_of

(* SCHEMA FUNCTIONAL_DATA_AND_SCHEMATIC_REPRESENTATION_MIM_LF; *)

 
FUNCTION free_variables_of(expr : generic_expression) : SET OF generic_variable
  ;
LOCAL
  typenames : SET OF STRING := stripped_typeof(expr);
  result : SET OF generic_variable := [];
  exprs : LIST OF generic_expression := [];
END_LOCAL;
  IF 'GENERIC_LITERAL' IN typenames THEN
    RETURN (result);
  END_IF;
  IF 'GENERIC_VARIABLE' IN typenames THEN
    result := result + expr;
    RETURN (result);
  END_IF;
  IF 'QUANTIFIER_EXPRESSION' IN typenames THEN
    exprs := QUERY(ge <* expr\multiple_arity_generic_expression.operands | NOT 
    (ge IN expr\quantifier_expression.variables));
    REPEAT i := 1 TO SIZEOF(exprs);
      result := result + free_variables_of(exprs[i]);
    END_REPEAT;
    REPEAT i := 1 TO SIZEOF(expr\quantifier_expression.variables);
      result := result - expr\quantifier_expression.variables[i];
    END_REPEAT;
    RETURN (result);
  END_IF;
  IF 'UNARY_GENERIC_EXPRESSION' IN typenames THEN
    RETURN (free_variables_of(expr\unary_generic_expression.operand));
  END_IF;
  IF 'BINARY_GENERIC_EXPRESSION' IN typenames THEN
    result := free_variables_of(expr\binary_generic_expression.operands[1]);
    RETURN (result + free_variables_of(expr\binary_generic_expression.operands[
    2]));
  END_IF;
  IF 'MULTIPLE_ARITY_GENERIC_EXPRESSION' IN typenames THEN
    REPEAT i := 1 TO SIZEOF(expr\multiple_arity_generic_expression.operands);
      result := result + free_variables_of(expr\
      multiple_arity_generic_expression.operands[i]);
    END_REPEAT;
    RETURN (result);
  END_IF;
  RETURN (result);
END_FUNCTION;

Referenced By

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2012-03-27T17:17:33-04:00