Piq as a configuration file format

config.ml

let read_file filename =
  let ch = open_in_bin filename in
  let len = in_channel_length ch in
  let buf = Buffer.create len in
  Buffer.add_channel buf ch len;
  close_in ch;
  Buffer.contents buf


let read_config filename =
  let contents = read_file filename in
  try
    Config_piqi_ext.parse_config contents `piq
  with
    Piqi_common.Error ((file, col, line), error) ->
      failwith (Printf.sprintf "error at %s:%d:%d: %s" file col line error)


(* test *)
let _ =
  let config = read_config "config.piq" in
  Config_piqi_ext.print_config config

config.piq

:config/config [

    % the shortest form
    [ "foo" .make ]

    % explicit field name
    [ .path "foo" .make ]

    % more explicit field names
    [ .path "foo" .generator.make ]

    % alternative notation for representing enums (variants)
    [ .path "foo" .generator (.make) ]

    % the longest form
    [
        .path "foo"
        .generator.make
    ]

    % testing other enum values
    [ "bar" .latexmk ]
    [ "fum" .org ]
    [ "baz" .tensile ]
]

config.piqi

.module config

.enum [
    .name generator
    .option [ .name make ]
    .option [ .name latexmk ]
    .option [ .name org ]
    .option [ .name tensile ]
]

.record [
    .name entry
    .field [
        .name path
        .type string
    ]
    .field [
        .type generator
    ]
]

.list [
    .name config
    .type entry
]

Makefile

# this build relies on OCamlMakefile build script, it can be found here:
#
#       http://www.ocaml.info/home/ocaml_sources.html#ocaml-make
#

RESULT = config

SOURCES = \
        $(PIQI_ML_FILES) \
        config.ml


PACKS = piqi.lib


PIQI_FILES = config.piqi
PIQI_ML_FILES = config_piqi.ml config_piqi_ext.ml


PRE_TARGETS = $(PIQI_ML_FILES)


PIQIC = piqic
PIQIC_FLAGS = --pp --leave-tmp-files


all: native-code #byte-code debug-code


$(PIQI_ML_FILES): $(PIQI_FILES)
        set -e; \
        for i in $^; do \
                $(PIQIC) ocaml-ext $(PIQIC_FLAGS) $$i ; \
        done


clean::
        rm -f *.tmp.ml


include OCamlMakefile