[/ 
  (C) Copyright Edward Diener 2011-2015
  Distributed under the Boost Software License, Version 1.0.
  (See accompanying file LICENSE_1_0.txt or copy at
  http://www.boost.org/LICENSE_1_0.txt).
]

[section:vmd_conv Version 1.7 to 1.8 conversion]

Since the current version of VMD has been drastically changed
to make it easier to use VMD functionality this section
details equivalent functionality for previous version 1.7
VMD macros.

The changes in functionality involve the parsing of sequences.
The equivalent to all the V1.7 functionality, which looks for
various data types at the beginning of a sequence, is encompassed
by the V1.8 macro BOOST_VMD_ELEM(0,sequence,...), where '0' is the first
sequence element and 'sequence' is the sequence, with its optional
parameters.

[heading Identifier]

V1.7

BOOST_VMD_IDENTIFIER(sequence,keys,...) looked for an identifier at 
the beginning of a sequence and returned a 2-element tuple, where the first
element is the matching index starting with 1, or 0 if no identifier is found, 
and the second tuple element is the rest of the sequence or emptiness if no
identifier is found.

V1.8 equivalent

BOOST_VMD_ELEM(0,sequence,(identifiers),BOOST_VMD_TYPE_IDENTIFIER,BOOST_VMD_RETURN_AFTER,BOOST_VMD_RETURN_INDEX)
returns a 3-element tuple where the identifier found is the first tuple element, 
the rest of the sequence is the second tuple element, and the matching index, starting with
0, is the 3rd tuple element. If no identifier is found all elements of the returned tuple are empty.

V1.7

BOOST_VMD_BEGIN_IDENTIFIER(sequence,keys,...) looked for an identifier at
the beginning of a sequence and returned the matching index starting with 1, or 
0 if no identifier is found.

V1.8 equivalent

BOOST_VMD_ELEM(0,sequence,(identifiers),BOOST_VMD_TYPE_IDENTIFIER,BOOST_VMD_RETURN_INDEX)
returns a 2-element tuple where the identifier found is the first tuple element 
and the matching index, starting with 0, is the 2nd tuple element. If no identifier 
is found both elements of the returned tuple are empty.

V1.7

BOOST_VMD_AFTER_IDENTIFIER(sequence,keys,...) looked for an identifier at the
beginning of a sequence and returned the rest of the sequence or emptiness if
no identifier is found.

V1.8 equivalent

BOOST_VMD_ELEM(0,sequence,(identifiers),BOOST_VMD_TYPE_IDENTIFIER,BOOST_VMD_RETURN_ONLY_AFTER)
is the exact equivalent.

V1.7

BOOST_VMD_IS_BEGIN_IDENTIFIER(sequence,keys,...) returns 1 if input 
begins with an identifier, else 0 if it does not.

V1.8 equivalent

BOOST_VMD_ELEM(0,sequence,(identifiers),BOOST_VMD_TYPE_IDENTIFIER) returns the identifier found,
otherwise emptiness if not found. You can use 
BOOST_PP_COMPL(BOOST_VMD_IS_EMPTY(BOOST_VMD_ELEM(0,sequence,identifiers,BOOST_VMD_TYPE_IDENTIFIER))) 
as the exact equivalent.

[heading Number]

V1.7

BOOST_VMD_NUMBER(sequence,...) looked for a number at 
the beginning of a sequence and returned a 2-element tuple, where the first
element is the number and the second tuple element is the rest of the sequence.
If no number is found both tuple elements are empty.

V1.8 equivalent

BOOST_VMD_ELEM(0,sequence,BOOST_VMD_TYPE_NUMBER,BOOST_VMD_RETURN_AFTER)
is the exact equivalent.

V1.7

BOOST_VMD_BEGIN_NUMBER(sequence,...) looked for a number at
the beginning of a sequence and returned the number if found or emptiness
if no number is found.

V1.8 equivalent

BOOST_VMD_ELEM(0,sequence,BOOST_VMD_TYPE_NUMBER)
is the exact equivalent.

V1.7

BOOST_VMD_AFTER_NUMBER(sequence,...) looked for a number at the
beginning of a sequence and returned the rest of the sequence or emptiness if
no number is found.

V1.8 equivalent

BOOST_VMD_ELEM(0,sequence,BOOST_VMD_TYPE_NUMBER,BOOST_VMD_RETURN_ONLY_AFTER)
is the exact equivalent.

V1.7

BOOST_VMD_IS_BEGIN_NUMBER(sequence,...) returns 1 if input 
begins with a number, else 0 if it does not.

V1.8 equivalent

BOOST_VMD_ELEM(0,sequence,BOOST_VMD_TYPE_NUMBER) returns the number found,
otherwise emptiness if not found. You can use 
BOOST_PP_COMPL(BOOST_VMD_IS_EMPTY(BOOST_VMD_ELEM(0,sequence,BOOST_VMD_TYPE_NUMBER)))
as the exact equivalent.

[heading Array]

V1.7

BOOST_VMD_ARRAY(sequence) looked for an array at 
the beginning of a sequence and returned a 2-element tuple, where the first
element is the array and the second tuple element is the rest of the sequence.
If no array is found both tuple elements are empty.

V1.8 equivalent

BOOST_VMD_ELEM(0,sequence,BOOST_VMD_TYPE_ARRAY,BOOST_VMD_RETURN_AFTER)
is the exact equivalent.

V1.7

BOOST_VMD_BEGIN_ARRAY(sequence) looked for an array at
the beginning of a sequence and returned the array if found or emptiness
if no array is found.

V1.8 equivalent

BOOST_VMD_ELEM(0,sequence,BOOST_VMD_TYPE_ARRAY)
is the exact equivalent.

V1.7

BOOST_VMD_AFTER_ARRAY(sequence) looked for an array at the
beginning of a sequence and returned the rest of the sequence or emptiness if
no array is found.

V1.8 equivalent

BOOST_VMD_ELEM(0,sequence,BOOST_VMD_TYPE_ARRAY,BOOST_VMD_RETURN_ONLY_AFTER)
is the exact equivalent.

V1.7

BOOST_VMD_IS_BEGIN_ARRAY(sequence,...) returns 1 if input 
begins with an array, else 0 if it does not.

V1.8 equivalent

BOOST_VMD_ELEM(0,sequence,BOOST_VMD_TYPE_ARRAY) returns the array found,
otherwise emptiness if not found. You can use 
BOOST_PP_COMPL(BOOST_VMD_IS_EMPTY(BOOST_VMD_ELEM(0,sequence,BOOST_VMD_TYPE_ARRAY)))
as the exact equivalent.

[heading List]

V1.7

BOOST_VMD_LIST(sequence) looked for an list at 
the beginning of a sequence and returned a 2-element tuple, where the first
element is the list and the second tuple element is the rest of the sequence.
If no list is found both tuple elements are empty.

V1.8 equivalent

BOOST_VMD_ELEM(0,sequence,BOOST_VMD_TYPE_LIST,BOOST_VMD_RETURN_AFTER)
is the exact equivalent.

V1.7

BOOST_VMD_BEGIN_LIST(sequence) looked for a list at
the beginning of a sequence and returned the list if found or emptiness
if no list is found.

V1.8 equivalent

BOOST_VMD_ELEM(0,sequence,BOOST_VMD_TYPE_LIST) is the exact equivalent.

V1.7

BOOST_VMD_AFTER_LIST(sequence) looked for an list at the
beginning of a sequence and returned the rest of the sequence or emptiness if
no list is found.

V1.8 equivalent

BOOST_VMD_ELEM(0,sequence,BOOST_VMD_TYPE_LIST,BOOST_VMD_RETURN_ONLY_AFTER)
is the exact equivalent.

V1.7

BOOST_VMD_IS_BEGIN_LIST(sequence,...) returns 1 if input 
begins with an list, else 0 if it does not.

V1.8 equivalent

BOOST_VMD_ELEM(0,sequence,BOOST_VMD_TYPE_LIST) returns the list found,
otherwise emptiness if not found. You can use 
BOOST_PP_COMPL(BOOST_VMD_IS_EMPTY(BOOST_VMD_ELEM(0,sequence,BOOST_VMD_TYPE_LIST)))
as the exact equivalent.

[heading Seq]

V1.7

BOOST_VMD_SEQ(sequence) looked for a seq at 
the beginning of a sequence and returned a 2-element tuple, where the first
element is the seq and the second tuple element is the rest of the sequence.
If no seq is found both tuple elements are empty.

V1.8 equivalent

BOOST_VMD_ELEM(0,sequence,BOOST_VMD_TYPE_SEQ,BOOST_VMD_RETURN_AFTER)
is the exact equivalent.

V1.7

BOOST_VMD_BEGIN_SEQ(sequence) looked for a seq at
the beginning of a sequence and returned the seq if found or emptiness
if no seq is found.

V1.8 equivalent

BOOST_VMD_ELEM(0,sequence,BOOST_VMD_TYPE_SEQ) is the exact equivalent.

V1.7

BOOST_VMD_AFTER_SEQ(sequence) looked for an seq at the
beginning of a sequence and returned the rest of the sequence or emptiness if
no seq is found.

V1.8 equivalent

BOOST_VMD_ELEM(0,sequence,BOOST_VMD_TYPE_SEQ,BOOST_VMD_RETURN_ONLY_AFTER)
is the exact equivalent.

V1.7

BOOST_VMD_IS_BEGIN_SEQ(sequence,...) returns 1 if input 
begins with an seq, else 0 if it does not.

V1.8 equivalent

BOOST_VMD_ELEM(0,sequence,BOOST_VMD_TYPE_SEQ) returns the seq found,
otherwise emptiness if not found. You can use 
BOOST_PP_COMPL(BOOST_VMD_IS_EMPTY(BOOST_VMD_ELEM(0,sequence,BOOST_VMD_TYPE_SEQ)))
as the exact equivalent.

[heading Tuple]

V1.7

BOOST_VMD_TUPLE(sequence) looked for an tuple at 
the beginning of a sequence and returned a 2-element tuple, where the first
element is the tuple and the second tuple element is the rest of the sequence.
If no tuple is found both tuple elements are empty.

V1.8 equivalent

BOOST_VMD_ELEM(0,sequence,BOOST_VMD_TYPE_TUPLE,BOOST_VMD_RETURN_AFTER)
is the exact equivalent.

V1.7

BOOST_VMD_BEGIN_TUPLE(sequence) looked for a tuple at
the beginning of a sequence and returned the tuple if found or emptiness
if no tuple is found.

V1.8 equivalent

BOOST_VMD_ELEM(0,sequence,BOOST_VMD_TYPE_TUPLE) is the exact equivalent.

V1.7

BOOST_VMD_AFTER_TUPLE(sequence) looked for an tuple at the
beginning of a sequence and returned the rest of the sequence or emptiness if
no tuple is found.

V1.8 equivalent

BOOST_VMD_ELEM(0,sequence,BOOST_VMD_TYPE_TUPLE,BOOST_VMD_RETURN_ONLY_AFTER)
is the exact equivalent.

V1.7

BOOST_VMD_IS_BEGIN_TUPLE(sequence,...) returns 1 if input 
begins with an tuple, else 0 if it does not.

V1.8 equivalent

BOOST_VMD_ELEM(0,sequence,BOOST_VMD_TYPE_TUPLE) returns the tuple found,
otherwise emptiness if not found. You can use 
BOOST_PP_COMPL(BOOST_VMD_IS_EMPTY(BOOST_VMD_ELEM(0,sequence,BOOST_VMD_TYPE_TUPLE)))
as the exact equivalent.

[endsect]