Module Cf_scan_parser

module Cf_scan_parser: sig .. end

Lexical analysis with functional composition using Scanf scanners.

Overview

This module implements and extension to the Cf_parser module for mixing calls to the standard library Scanf functions with functional parsers.

Classes and Types

exception No_match

An exception provided so that the cscanf function (below) can be signaled to transform its answer with the effect that the parser stack is unwound until an alternative production can be matched.

class virtual ['i] scanner : 'i Cf_seq.t -> object .. end

A virtual base class used in the cscanf function (below) for constructing a scanning buffer from an input sequence.

Functions

val cscanf : ('i Cf_seq.t -> ('i #scanner as 's)) ->
       ('s -> exn -> 'o) ->
       ('f, Scanf.Scanning.scanbuf, 'u, 'f -> 'o, 'f -> 'o, 'o) format6 ->
       'f -> ('i, 'o) Cf_parser.t

This is the primitive function in the module. Use cscanf cf ef fmt rf to construct a parser that applies cf to the input sequence to acquire a scanner object s, invokes the s#init method to obtain a scanning buffer with which to apply Scanf.kscanf, using the exception function ef, the scanning format fmt and the return continuation rf. If the exception function raises No_match then the resulting parser unwinds to the next production alternative, otherwise the parser answers with the result of the return continuation.

val scanf : ('f, Scanf.Scanning.scanbuf, 'u, 'f -> 'o, 'f -> 'o, 'o) format6 ->
       'f -> (char, 'o) Cf_parser.t

Use scanf fmt rf to construct a lexical parser that scans the input text according to the scanning format fmt and produces the value returned by the return continuation. If the scanner raises an exception, then the parser unwinds to the next production alternative.

val scanfx : ('f, Scanf.Scanning.scanbuf, 'u, 'f -> 'o, 'f -> 'o, 'o) format6 ->
       'f -> (char #Cf_parser.cursor, char, 'o) Cf_parser.X.t

Use scanfx in place of scanf to construct a parser with a cursor weaved into the input stream.