package angstrom
Buffered parsing interface.
Parsers run through this module perform internal buffering of input. The parser state will keep track of unconsumed input and attempt to minimize memory allocation and copying. The Buffered.state.Partial
parser state will accept newly-read, incremental input and copy it into the internal buffer. Users can feed parser states using the feed
function. As a result, the interface is much easier to use than the one exposed by the Unbuffered
module.
On success or failure, any unconsumed input will be returned to the user for additional processing. The buffer that the unconsumed input is returned in can also be reused.
type 'a state =
| Partial of [ input | `Eof ] -> 'a state
(*The parser requires more input.
*)| Done of unconsumed * 'a
(*The parser succeeded.
*)| Fail of unconsumed * string list * string
(*The parser failed.
*)
parse ?initial_buffer_size t
runs t
and awaits input if needed. parse
will allocate a buffer of size initial_buffer_size
(defaulting to 4k bytes) to do input buffering and automatically grows the buffer as needed.
feed state input
supplies the parser state with more input. If state
is Partial
, then parsing will continue where it left off. Otherwise, the parser is in a Fail
or Done
state, in which case the input
will be copied into the state's buffer for later use by the caller.
val state_to_option : 'a state -> 'a option
state_to_option state
returns Some v
if the parser is in the Done (bs, v)
state and None
otherwise. This function has no effect on the current state of the parser.
val state_to_result : 'a state -> ('a, string) Pervasives.result
state_to_result state
returns Ok v
if the parser is in the Done (bs, v)
state and Error msg
if it is in the Fail
or Partial
state.
This function has no effect on the current state of the parser.
val state_to_unconsumed : _ state -> unconsumed option
state_to_unconsumed state
returns Some bs
if state = Done(bs, _)
or state = Fail(bs, _, _)
and None
otherwise.