Block scope is the context just inside the braces associated with a block definition.

BlockDefinition ::= OrganizedBlockDefinition | UnorganizedBlockDefinition | RegExpBlockDefinition

There are three different subsets of block definition, based on whether the block is organized or unorganized.  A special definition subtype of unorganized block is a regular expression block, defined to conform to a pattern defined by a regular expression.

MemberFunctionDeclaration ::= FunctionDeclaration
FunctionDeclaration ::= (DataStructureType | ‘void’) S (‘*’)? S? IdentifierName S? ‘(‘ S? ParameterList S? ‘)’ S? ‘{‘ S? FunctionBodyDefinition S? ‘}’ S? ‘;’

For member function declarations in block definitions, the function name uniquely identifies the function. The name is an identifier that has not appeared earlier in the definition as a construct name, an enumerated constant block name, an enumerated constant name, or a member function name.

Member functions can be declared in both organized block definitions  and  unorganized block definitions.  There are no member functions for regular expression block definitions.

It should be noted that member functions, as they exist in most programming languages, require that an actual structure be used to serve as the scope.  In BAR, this is not necessarily the case.  Member functions for structures have the same principles as those found for structures in other languages, but block-based member functions do not have other-language equivalents.

From a programming standpoint, the biggest uncertainty regarding member functions of blocks is how the 'this' pointer is implemented.  If there are no structured members, the 'this' pointer must take on a different meaning.

For organized blocks, the 'this' pointer is treated as a pointer to a node handle.  Many operators, such as getnext or getsize, can use this pointer to locate other nodes and query information.

For unorganized blocks, the 'this' pointer is treated as either a pointer to a node handle (if block is empty) or a pointer to the first byte of data in the block (if block is not empty).

  See also:  [Organized block definitions] [Unorganized block definitions] [Regular Expression block definitions]