Routine Name:	substring

Description:	Returns part of original string as new substring.

Usage:		new-string = {substring string startindex [endindex]}

		new-string	returned as new string created

		string		original string
	
		startindex	integer indicating position of first character
				in string to include in new string

		endindex	integer indicating position of final character
				in string to include in new string (default:
				final character in string)

Example:	genesis >  echo { substring "0123456789" 3 7 }
		34567
		genesis >  echo { substring "0123456789" 3 }
		3456789

Notes:		The substring routine can be useful in conjunction with other
		routines (e.g., getpath) for constructing names based on part
		of an element path name.

See also:	strcat, strcmp, strncmp, strlen, findchar

