ediScmSemanticRule

The ediScmSemanticRule defines a semantic rule.  A semantic rule is a conditional statement that dynamically controls the value or setting of a semantic object based on whether the condition is true or false.  Currently only the following semantic objects can have a semantic rule:

• Data element in a transaction set.
• Composite element in a transaction set.
• Data segment in a transaction set.

Furthermore, only the following actions can be done as a result of a semantic rule being satisfied.

• Dynamically set a user requirement for the semantic object.  If the condition of the semantic rule is satisfied then the user requirement can be dynamically set to "Used", "Not Used", "Must Use", "Recommended", "Not Recommended".
• Dynamically allow the data element to reference a value list.  If the condition of the semantic rule is satisfied then the value of a data element can be constrained to a set of values called a value list.  A value list can also contain a regular expression that defines a pattern a value is suppose to follow.
• Dynamically allow the data element to reference a code set.  If the condition of the semantic rule is satisfied then the value of a data element can be constrained to a set of code values called a code set.  Multiple code sets can be defined for a data element each defining a set of values that the data element can hold.  If the code set specify a location in a transaction set/message or dictionary where the code set can only be used, it is said to be attached.  Semantic rules can only reference code sets that are not attached.
• Dynamically launch and execute an ActiveX/COM component routine.  If the condition of the semantic rule is satisfied then execute a method in an ActiveX/COM component.  The syntax of the method must follow the syntax:

  • <return value> = <interface>.<method name>([<string parameter>])
  • Where:
    • Return value is a numeric value indicating the success or failure of the operation.  The client is notified of this value in the EventNotifyInfo with event constant Event_Info_External_Operation_Result.
    • Interface is the ActiveX/COM interface identified by the program identifier.
    • Method name is the name of the method to execute.
    • String parameter is an optional parameter to pass to the method.

Semantic Rule Syntax

Currently, the conditional statement, that FREDI recognizes, takes the following form:

if <conditional statement> then <action>

Where conditional statement is a string of logical statements that if resolved to being true will execute the action.  For example,

if data element TAX02 is equal to "M" then segment CTP at 0900 is used

The conditional clause itself takes the following form:

<semantic object> <operator> <literal value>

From the example, the clause "data element TAX02" is the semantic object; the clause "is equal to" is the operator; and the literal value is "M".

Determining the value.

The semantic object is represented by an object variable referencing an object in the implementation guideline.  The object variable contains a variable name and the location of the object in the implementation guideline.  The value resolved in the object variable is determined by locating the corresponding object in the document and extracting the data.  This value is then used to compare to the literal value.  The value determined for each of the semantic object is as follows:

• Data Element - The value of the data element.
• Composite Element - The value of all sub elements separated by the composite delimiter.
• Data Segment - The value of all the data elements and composite elements separated by their delimiters.

Operators

Currently, only the following operators are recognized:

• "exists"
• "does not exists"
• "equal to"
• "not equal to"
• "greater than"
• "greater than or equal to"
• "less than"
• "less than or equal to"

Value Comparisons

When the value in the object variable is compared with the literal value, it either does a string comparison or a numeric comparison.  A string comparison compares the a character in the first value to its corresponding character in the second value in the string starting with the leftmost character.  In a string comparison, the string value "04" is greater than the string value "004".  In a numeric comparison, the numeric value of both string values are compared.  In this case, the value "04" is equal to the value "004".  The inherent nature of data retrieved from the document is always a string, and if a numeric comparison is involved then a string to numeric conversion must takes place.  For a successful numeric conversion, the string must contain only numeric values (0 to 9), but it is possible that a string containing alphabetic character can be involved in the conversion.  If this is the case, starting from the left, a string is converted to a number character by character until a non-numeric character is encountered.  For example, the string "123.1B2" is converted to 123.1; the string "12B3" to 12; the string "B123" to zero; etc.  Note how the alphabet "B" stops the conversion.

The values in the conditional clause are compared depending on the semantic object:

• Data Element.  The value determined in the object variable, that references a data element, is compared to the literal value according to the data type of the data element.  The comparison is numeric if the data type of the data element is "Nx" or "R" in ASC/X12 or "Nx" in UN/EDIFACT; it is a string comparison otherwise.
• Composite Element.  A string comparison is made on the entire composite element string, including the delimiter, to the literal value.
• Data Segment.  A string comparison is made on the entire data segment string, including the delimiter, to the literal value.

Existence and Non-Existence

The semantic rule also tests for the existence or non-existence of a semantic object.  The existence or non-existence of an object is interpreted as follows:

• Data Element
  • Exists if the length of the data is greater than zero.
  • Does not exist if it contains empty data (length of the data is zero), or if the data element is in a data segment that does not exist.
• Composite Element
  • Exists if any of the sub element contain data.
  • Does not exist if none of its sub element contain data, or the composite element is in a data segment that does not exist.
• Data Segment
  • Exists if any of its composite element or data element contain data.
  • Does not exist if data segment is not in the document, or if none of its composite element or data element contain data.  A data segment will also test as not existing if there is a forward reference to it in the semantic rule.  That is, the semantic rule is being calculated but the data segment has not yet been encountered and resolved while processing the document.  Data segments are processed sequentially in order of their occurrence in the document.

Properties

• Description - Gets the description of the semantic rule.