preserves-schemac

The preserves-schemac program reads Preserves Schema DSL input files and outputs a binary-syntax Preserves document conforming to the metaschema.

It can either output single Schema records (corresponding to a single input file), or a Bundle of Schemas (corresponding to a directory tree of files).

Installation

Install node.js v12 or newer. Then, yarn global add @preserves/schema.

Usage

Usage: preserves-schemac [options] [input...]

Compile textual Preserves schema definitions to binary format

Arguments:
  input               Input filename or glob

Options:
  --no-bundle         Emit a single Schema instead of a schema Bundle
  --base <directory>  Base directory for sources (default: common prefix)
  -h, --help          display help for command

Examples

Single file (non-bundle)

Given a file demo.prs containing:

version 1 .
JSON =
     / @string string
     / @integer int
     / @double double
     / @boolean JSONBoolean
     / @null =null
     / @array [JSON ...]
     / @object { string: JSON ...:... } .
JSONBoolean = =true / =false .

running the following:

preserves-schemac --no-bundle demo.prs

will produce the following binary file on stdout:

00000000: b4b3 0673 6368 656d 61b7 b307 7665 7273  ...schema...vers
00000010: 696f 6e91 b30b 6465 6669 6e69 7469 6f6e  ion...definition
00000020: 73b7 b304 4a53 4f4e b4b3 026f 72b5 b5b1  s...JSON...or...
00000030: 0673 7472 696e 67b4 b304 6174 6f6d b306  .string...atom..
00000040: 5374 7269 6e67 8484 b5b1 0769 6e74 6567  String.....integ
00000050: 6572 b4b3 0461 746f 6db3 0d53 6967 6e65  er...atom..Signe
00000060: 6449 6e74 6567 6572 8484 b5b1 0664 6f75  dInteger.....dou
00000070: 626c 65b4 b304 6174 6f6d b306 446f 7562  ble...atom..Doub
00000080: 6c65 8484 b5b1 0762 6f6f 6c65 616e b4b3  le.....boolean..
00000090: 0372 6566 b584 b30b 4a53 4f4e 426f 6f6c  .ref....JSONBool
000000a0: 6561 6e84 84b5 b104 6e75 6c6c b4b3 036c  ean.....null...l
000000b0: 6974 b304 6e75 6c6c 8484 b5b1 0561 7272  it..null.....arr
000000c0: 6179 b4b3 0573 6571 6f66 b4b3 0372 6566  ay...seqof...ref
000000d0: b584 b304 4a53 4f4e 8484 84b5 b106 6f62  ....JSON......ob
000000e0: 6a65 6374 b4b3 0664 6963 746f 66b4 b304  ject...dictof...
000000f0: 6174 6f6d b306 5374 7269 6e67 84b4 b303  atom..String....
00000100: 7265 66b5 84b3 044a 534f 4e84 8484 8484  ref....JSON.....
00000110: b30b 4a53 4f4e 426f 6f6c 6561 6eb4 b302  ..JSONBoolean...
00000120: 6f72 b5b5 b104 7472 7565 b4b3 036c 6974  or....true...lit
00000130: b304 7472 7565 8484 b5b1 0566 616c 7365  ..true.....false
00000140: b4b3 036c 6974 b305 6661 6c73 6584 8484  ...lit..false...
00000150: 8484 b30c 656d 6265 6464 6564 5479 7065  ....embeddedType
00000160: 8084 84                                  ...

Piping the output to preserves-tool to pretty-print it produces:

<schema {
  version: 1,
  embeddedType: #f,
  definitions: {
    JSONBoolean: <or [
      [
        "true",
        <lit true>
      ],
      [
        "false",
        <lit false>
      ]
    ]>,
    JSON: <or [
      [
        "string",
        <atom String>
      ],
      [
        "integer",
        <atom SignedInteger>
      ],
      [
        "double",
        <atom Double>
      ],
      [
        "boolean",
        <ref [] JSONBoolean>
      ],
      [
        "null",
        <lit null>
      ],
      [
        "array",
        <seqof <ref [] JSON>>
      ],
      [
        "object",
        <dictof <atom String> <ref [] JSON>>
      ]
    ]>
  }
}>

Multiple file (bundle)

Given a directory tree containing multiple *.prs files, running

preserves-schemac '**.prs'

will produce a binary Bundle on stdout containing one Schema for each input file in the tree.