pub fn expand_block(blk: P<Block>, fld: &mut MacroExpander) -> P<Block> {
    // see note below about treatment of exts table
    with_exts_frame!(fld.cx.syntax_env,false,
                     expand_block_elts(blk, fld))
}
// expand a block. pushes a new exts_frame, then calls expand_block_elts
expand a block. pushes a new exts_frame, then calls expand_block_elts
expand a block . pushes a new exts_frame then calls expand_block_elts
pub fn expand_block(blk: P<Block>, fld: &mut MacroExpander) -> P<Block> {
    // see note below about treatment of exts table
    with_exts_frame!(fld.cx.syntax_env,false,
                     expand_block_elts(blk, fld))
}
pub fn expand_block ( blk : P < Block > , fld : & mut MacroExpander ) -> P < Block > { // see note below about treatment of exts table with_exts_frame ! ( fld cx syntax_env false expand_block_elts ( blk fld ) ) }
expand a block.
expand a block .
blk
P<Block>
fld
&mut MacroExpander
blk
P<Block>
fld
&mut MacroExpander