Trace (GenericNamedArraylist subroutine): Difference between revisions

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Trace items (FloatNamedArraylist, NamedArraylist, and UnicodeNamedArraylist classes)

Trace displays the contents of a FloatNamedArraylist, NamedArraylist, or UnicodeNamedArraylist in a readable form, useful for debugging, for example. Trace is identical to Print, except the result is sent to the selected Trace stream (like the User Language Trace statement).

Syntax

anyNal:Trace[( [itemFunction], [NumWidth= number], [Separator= string], - [Start= number], [MaxItems= number], [Label= string], - [NameWidth= number])]

Syntax terms

%anyNal A FloatNamedArraylist, NamedArraylist, or UnicodeNamedArraylist object.
itemFunction The method that is applied to anyNal items to produce the printed output. The method must take no parameters and produce an intrinsic (Float, String, Fixed, Unicode) value. It may be a system or user-written method, a class Variable or Property, a local method, or a method variable. The default value of itemFunction is ToString.
NumWidth The number of bytes in the display of each item to use for the item number. This is an optional, name required, parameter; if you specify a value, the parameter name NumWidth is required.

Item numbers are right-justified within the indicated number of bytes, and they are truncated on the left if the length of the item number exceeds the space allocated for it. The width must be a number between -1 and 10 inclusive. If you specify a value of 0, the item number is not displayed.

If NumWidth is -1, the default, the method uses the minimum number of bytes required to show the item number. For example, one byte is required for item number 5, while five bytes are required for item number 98764.

Separator A String, 15 characters or less, to be used to separate both the item number and the item name from what follows. That is, the string you specify appears twice: once after the item number and once after the item name.

This is an optional, name required, argument whose default is a colon (:). A blank always follows the separator string. If you specify a value, the parameter name Separator is required.

Start The item number of the initial item in the output display. This is an optional, name required, argument which defaults to 1. If you specify a value, the parameter name Start is required.
MaxItems The maximum number of items to display. A zero or negative value means to display all the items.

This is an optional, name required, argument which defaults to zero. If you specify a value, the parameter name MaxItems is required.

Label A literal string that gets output before each line. This is useful for "tagging" lines to make them more identifiable.

This is an optional, name required, argument whose default is a null string. If you specify a value, the parameter name Label is required.

NameWidth The number of bytes in the display of the item name. This must be a number from -1 through 255. This is an optional, name required, if you specify a value, the parameter name NameWidth is required.

Item names are left-justified within the indicated number of bytes, and they are truncated on the right if the length of the item name exceeds the space allocated for it. If you specify a value of 0, the item name is not displayed.

This is an optional argument; it defaults to -1, which directs the method to use whatever number of bytes are necessary to show the entire item name. For example, three bytes are required for item name Foo, while eight bytes are required for item name Malmberg.

Usage Notes

  • All errors in Trace result in request cancellation.

Examples

For examples of Print method calls, see "Printing a collection".

See also

  • Audit and Print are the same as Trace except they send their output to the Model 204 audit trail or to the user's standard output destination, respectively.