pgm_new()instantiates a newpgmnode.pgm_type()checks if the node is apgmnode.pgm_<child>_get()returns the<child>node ofpgm.pgm_<child>_set()sets the new<child>and deletes the old<child>.pgm_<child>_rep()sets the new<child>and returns the old<child>.
Usage
pgm_new(ast, beg, exprs, end)
pgm_type(ast, node)
pgm_beg_get(ast, node)
pgm_beg_rep(ast, node, beg)
pgm_beg_set(ast, node, beg)
pgm_exprs_get(ast, node)
pgm_exprs_rep(ast, node, exprs)
pgm_exprs_set(ast, node, exprs)
pgm_end_get(ast, node)
pgm_end_rep(ast, node, end)
pgm_end_set(ast, node, end)