**Rules detailled here are not implemented yet **

How to represent an error

• TCERR_INTRINSIC_TYPE Error are represented with the intrinsic type ErrorCode. This type is defined like this:

01 ErrorCode TYPEDEF STRONG.
   05 Code pic X(04).

Error variable

• TCERR_IMPLICIT_ERRORCODE_VAR All TypeCobol programs can access an implicit variable always named "ErrorCode". This variable is declared with a private scope (not GLOBAL or EXTERNAL). This variable is for internal use and to call other functions/procedure. This variable can't be received as a parameter (not declared in linkage section).

• TCERR_IMPLICIT_ERRORCODE_PARAM1 All functions and procedures have a special parameter named ErrorCode. If another parameter is also named "ErrorCode", there must be an error. All call to a function or procedure must pass this ErroCode variable.

• TCERR_IMPLICIT_ERRORCODE_PARAM2 After the call to a function or procedure, you can then use the syntax:

Call getCurrentDate returning xxx
If getCurrentDate::ErrorCode not = OK
    error, by default call the paragraph used to manage error.
Else
    Ok, continue
End-if

Error management for functions and procedures

• TCERR_IMPLICIT_PARAGRAPH A paragraph used to manage error must be present in all programs, functions and procedures. By default, this paragraph is implicit and is always named TC-STANDARD-ERROR-MANAGEMENT. If another paragraph have the same name, there must be an error.

• TCERR_OVERRIDE_IMPLICIT_PARAGRAPH The implicit paragraph used to manage error can be changed. The sentence error procedure is *MY-PARAGRAPH* must be declared in identification division TODO specify exactly where

• When a function is called and there is an error, the paragraph used to manage error must be called. This is the job of the codegen, TODO see page xxxxx.

Expected errors

• TCERR_DECLARE_EXPECTED_ERRORS Function and procedure can declare error codes that the caller should test. These are errors which callee know that they are likely to occur. Syntax to declare error codes is:

declare function MyFunction PUBLIC
     input 
     returning
     error ErrorCode::Code-NotFound ErrorCode::Code-DatabaseNotAvailable '7894'

end-declare

Error keyword must be followed by either:

• ErrorCode::Code 88 level values

• Literal of length 4

• TCERR_ERROR_INSIDE_CALL A call to a function or procedure can include code to manage errors.

Call myFunction input xxxx
                returning xxxx
   on error
      when ErrorCode::Code-NotFound
         xxx
      when ErrorCode::Code-DatabaseNotAvailable
         xxxx
      when ErrorCode::Code-Fatal
      when 'U748'
         xxxx
      when other
       IMPLICIT_ERROR_PARAGRAPH
End-call

Note that when clause can only contains a ErrorCode::Code 88 level values or a literal. There is no link between error declared by the function or procedure and when clause specified in the callee. Error declared by function or procedure are just a guide for the callee. An IDE can use this declarations to autocomplete the on error statement. If not specified, the following on error statement is implied:

   on error
      when other
       IMPLICIT_ERROR_PARAGRAPH

TODO: This is the job of the CodeGen, see page xxx