src/Pure/General/source.ML
changeset 6116 8ba2f25610f7
child 6118 caa439435666
     1.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
     1.2 +++ b/src/Pure/General/source.ML	Wed Jan 13 12:44:33 1999 +0100
     1.3 @@ -0,0 +1,150 @@
     1.4 +(*  Title:      Pure/Syntax/source.ML
     1.5 +    ID:         $Id$
     1.6 +    Author:     Markus Wenzel, TU Muenchen
     1.7 +
     1.8 +Co-algebraic data sources.
     1.9 +*)
    1.10 +
    1.11 +signature SOURCE =
    1.12 +sig
    1.13 +  type ('a, 'b) source
    1.14 +  val set_prompt: string -> ('a, 'b) source -> ('a, 'b) source
    1.15 +  val get: ('a, 'b) source -> 'a list * ('a, 'b) source
    1.16 +  val unget: 'a list * ('a, 'b) source -> ('a, 'b) source
    1.17 +  val get_single: ('a, 'b) source -> ('a * ('a, 'b) source) option
    1.18 +  val exhaust: ('a, 'b) source -> 'a list
    1.19 +  val mapfilter: ('a -> 'b option) -> ('a, 'c) source -> ('b, ('a, 'c) source) source
    1.20 +  val filter: ('a -> bool) -> ('a, 'b) source -> ('a, ('a, 'b) source) source
    1.21 +  val of_list: 'a list -> ('a, 'a list) source
    1.22 +  val of_string: string -> (string, string list) source
    1.23 +  val of_file: string -> (string, string list) source
    1.24 +  val decorate_prompt_fn: (string -> string) ref
    1.25 +  val of_stream: TextIO.instream -> TextIO.outstream -> (string, unit) source
    1.26 +  val tty: (string, unit) source
    1.27 +  val source': 'a -> 'b * ('b -> bool) -> ('a * 'b list -> 'c list * ('a * 'b list)) ->
    1.28 +    ('a * 'b list -> 'd * ('a * 'b list)) option ->
    1.29 +    ('b, 'e) source -> ('c, 'a * ('b, 'e) source) source
    1.30 +  val source: 'a * ('a -> bool) -> ('a list -> 'b list * 'a list) ->
    1.31 +    ('a list -> 'c * 'a list) option ->
    1.32 +    ('a, 'd) source -> ('b, ('a, 'd) source) source
    1.33 +end;
    1.34 +
    1.35 +structure Source: SOURCE =
    1.36 +struct
    1.37 +
    1.38 +
    1.39 +(** datatype source **)
    1.40 +
    1.41 +datatype ('a, 'b) source =
    1.42 +  Source of
    1.43 +   {buffer: 'a list,
    1.44 +    info: 'b,
    1.45 +    prompt: string,
    1.46 +    drain: string -> 'b -> 'a list * 'b};
    1.47 +
    1.48 +fun make_source buffer info prompt drain =
    1.49 +  Source {buffer = buffer, info = info, prompt = prompt, drain = drain};
    1.50 +
    1.51 +
    1.52 +(* prompt *)
    1.53 +
    1.54 +val default_prompt = "> ";
    1.55 +
    1.56 +fun set_prompt prompt (Source {buffer, info, prompt = _, drain}) =
    1.57 +  make_source buffer info prompt drain;
    1.58 +
    1.59 +
    1.60 +(* get / unget *)
    1.61 +
    1.62 +fun get (Source {buffer = [], info, prompt, drain}) =
    1.63 +      let val (xs, info') = drain prompt info
    1.64 +      in (xs, make_source [] info' prompt drain) end
    1.65 +  | get (Source {buffer, info, prompt, drain}) =
    1.66 +      (buffer, make_source [] info prompt drain);
    1.67 +
    1.68 +fun unget (xs, Source {buffer, info, prompt, drain}) =
    1.69 +  make_source (xs @ buffer) info prompt drain;
    1.70 +
    1.71 +
    1.72 +(* variations on get *)
    1.73 +
    1.74 +fun get_prompt prompt src = get (set_prompt prompt src);
    1.75 +
    1.76 +fun get_single src =
    1.77 +  (case get src of
    1.78 +    ([], _) => None
    1.79 +  | (x :: xs, src') => Some (x, unget (xs, src')));
    1.80 +
    1.81 +fun exhaust src =
    1.82 +  (case get src of
    1.83 +    ([], _) => []
    1.84 +  | (xs, src') => xs @ exhaust src');
    1.85 +
    1.86 +
    1.87 +(* (map)filter *)
    1.88 +
    1.89 +fun drain_mapfilter f prompt src =
    1.90 +  let
    1.91 +    val (xs, src') = get_prompt prompt src;
    1.92 +    val xs' = Library.mapfilter f xs;
    1.93 +  in
    1.94 +    if null xs orelse not (null xs') then (xs', src')
    1.95 +    else drain_mapfilter f prompt src'
    1.96 +  end;
    1.97 +
    1.98 +fun mapfilter f src = make_source [] src default_prompt (drain_mapfilter f);
    1.99 +fun filter pred = mapfilter (fn x => if pred x then Some x else None);
   1.100 +
   1.101 +
   1.102 +
   1.103 +(** build sources **)
   1.104 +
   1.105 +(* list source *)
   1.106 +
   1.107 +(*limiting the input buffer considerably improves performance*)
   1.108 +val limit = 4000;
   1.109 +
   1.110 +fun drain_list _ xs = (take (limit, xs), drop (limit, xs));
   1.111 +
   1.112 +fun of_list xs = make_source [] xs default_prompt drain_list;
   1.113 +val of_string = of_list o explode;
   1.114 +val of_file = of_string o File.read;
   1.115 +
   1.116 +
   1.117 +(* stream source *)
   1.118 +
   1.119 +val decorate_prompt_fn = ref (fn s:string => s);
   1.120 +
   1.121 +fun drain_stream instream outstream prompt () =
   1.122 +  (TextIO.output (outstream, ! decorate_prompt_fn prompt);
   1.123 +    TextIO.flushOut outstream;
   1.124 +    (explode (TextIO.inputLine instream), ()));
   1.125 +
   1.126 +fun of_stream instream outstream =
   1.127 +  make_source [] () default_prompt (drain_stream instream outstream);
   1.128 +
   1.129 +val tty = of_stream TextIO.stdIn TextIO.stdOut;
   1.130 +
   1.131 +
   1.132 +
   1.133 +(** compose sources **)
   1.134 +
   1.135 +fun drain_source source stopper scan recover prompt src =
   1.136 +  source prompt get_prompt unget stopper scan recover src;
   1.137 +
   1.138 +
   1.139 +(* state-based *)
   1.140 +
   1.141 +fun source' init_state stopper scan recover src =
   1.142 +  make_source [] (init_state, src) default_prompt
   1.143 +    (drain_source Scan.source' stopper scan recover);
   1.144 +
   1.145 +
   1.146 +(* non state-based *)
   1.147 +
   1.148 +fun source stopper scan recover src =
   1.149 +  make_source [] src default_prompt
   1.150 +    (drain_source Scan.source stopper scan recover);
   1.151 +
   1.152 +
   1.153 +end;