Name

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XIASTREC

Purpose

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  XIASTREC Is A Structure Tag Recursive Existence Checker

Category

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Structures, utility, recursion

Calling Sequence

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  result = XIASTREC( struct, tag_list )

Inputs

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  Struct: A structure

Optional Inputs

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  tag_list: A string array that contains the tags, subtags,
            subsubtags, etc. whos existence you wish to verify

Keyword Parameters

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  DEBUG: Print some debug info

Outputs

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  This function returns 1 if the struct, or struct.tag, or
  struct.tag.tag.tag... exists, and 0 if it does not. It returns -1
  if called incorrectly.

Procedure

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  1. Check if the struct is valid
  2. Check if tags were passed in. If so, does tag[0] exist in struct?
  3. Recurse, checking if tag[1] exist in the struct that is tag[0].

Example

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  PRINT, XIASTREC( foo ) ; 0, foo not defined
  PRINT, XIASTREC( !P, 'thick' ) ; 1, !P.THICK exists
  x = { foo:{bar:42}, baz:'Goodbye Crue World' }
  PRINT, XIASTREC( x, 'bar' ) ; 1, x.bar exists
  PRINT, XIASTREC( x, ['foo', 'baz'] ) ; 0, x.foo.baz does not exist
  PRINT, XIASTREC( x, ['foo', 'bar' ] ) ; 1, x.foo.bar exists
  PRINT, XIASTREC( x, ['foo', 'bar', '42' ] ) ; 0, bar=42, not bar.42

Modification History

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  Written by: KDM, 2007-07-15