fndefn_new(ast, op, lbkt, pars, rbkt, body)
fndefn_type(ast, node)
fndefn_op_get(ast, node)
fndefn_op_rep(ast, node, op)
fndefn_op_set(ast, node, op)
fndefn_lbkt_get(ast, node)
fndefn_lbkt_rep(ast, node, lbkt)
fndefn_lbkt_set(ast, node, lbkt)
fndefn_pars_get(ast, node)
fndefn_pars_rep(ast, node, pars)
fndefn_pars_set(ast, node, pars)
fndefn_rbkt_get(ast, node)
fndefn_rbkt_rep(ast, node, rbkt)
fndefn_rbkt_set(ast, node, rbkt)
fndefn_body_get(ast, node)
fndefn_body_rep(ast, node, body)
fndefn_body_set(ast, node, body)