The IDL_VALIDNAME function determines whether a string may be used as a valid IDL variable name or structure tag name. Optionally, the routine can convert non-valid characters into underscores, returning a valid name string.

Examples

The following table provides IDL_VALIDNAME examples and their results.

IDL_VALIDNAME('abc')

'abc'

IDL_VALIDNAME(' a b c ')

''

IDL_VALIDNAME(' a b c ', /CONVERT_SPACES)

'_a_b_c_'

IDL_VALIDNAME('$var')

''

IDL_VALIDNAME('$var', /CONVERT_ALL)

'_$VAR'

IDL_VALIDNAME('and')

''

IDL_VALIDNAME('and', /CONVERT_ALL)

'_AND'

IDL_VALIDNAME(['and', 'or'], /CONVERT_ALL)

['_AND', '_OR']

Syntax

Result = IDL_VALIDNAME(String [, /CONVERT_ALL] [, /CONVERT_SPACES])

Return Value

Returns the input string or strings, optionally converting all spaces or non-alphanumeric characters to underscores. If an input string cannot be used as a valid variable or structure tag name, an empty string is returned.

Arguments

String

A scalar string or string array or representing the IDL variable or structure tag names to be checked.

Keywords

CONVERT_ALL

If this keyword is set, then each element of String is converted into a valid IDL variable name using the following rules:

• All non-alphanumeric characters (except “_”, “!” and “$”) are converted to underscores
• If the first character is a number or a “$”, then an underscore is prepended to the string
• If the first character is not a valid character (“_”, “!”, “A”…“Z”) then that character is converted to an underscore
• If the element of String is an empty string or a reserved word (such as “AND”) then an underscore is prepended to the string

Tip: The CONVERT_ALL keyword guarantees that a valid variable name is returned. It is useful in converting user-supplied strings into valid IDL variable names.

CONVERT_SPACES

If this keyword is set, then all spaces within each element of String are converted to underscores. If an element of String contains any other non-alphanumeric characters, then an empty string is returned, indicating that the string cannot be used as a valid variable name.

Note: CONVERT_SPACES behaves the same as CREATE_STRUCT when checking structure tag names.

Version History

See Also

CREATE_STRUCT