A full-fledged Haskell implementation of the Jsonnet spec. For an introduction to the language itself, see the tutorial or language reference. We are using the same test suite used in the offical C++ and Go implementation (which is fairly comprehensive).
Here is the implementation status of the main language features:
- array and object comprehension
- array slices
- Python-style string formatting
- text blocks
- verbatim strings
- computed field names
- object-level locals
- object-level asserts (by Berk Özkütük)
- keyword parameters
- default arguments
- top-level arguments (#24)
- external variables (by Berk Özkütük)
- hidden fields (by Cristhian Motoche)
- tailstrict annotation
- outermost object reference
$ - mixin inheritence and open recursion (operator
+withselfandsuper) - field composition (operator
+:) - multiple file output (by Berk Özkütük)
- verbatim imports (by Berk Özkütük)
Using the stack build tool:
% git clone github.com/moleike/haskell-jsonnet.git
% cd haskell-jsonnet
% stack build% stack install # to install% hs-jsonnet --help
Usage: hs-jsonnet [-v|--version] [-e|--exec] [<filename>]
[(-o|--output-file <filename>) | (-m|--multi <dir>)]
[--compact] [-S|--string] [-V|--ext-str VAR=VALUE]
[--ext-str-file FILE] [--ext-code VAR=EXPR]
[--ext-code-file FILE]
Available options:
-v,--version Print version of the program
-h,--help Show this help text
-e,--exec Treat filename as code
<filename> Jsonnet source file or stdin
-o,--output-file <filename>
Write to the output file rather than stdout
-m,--multi <dir> Write multiple files to the directory, list files on
stdout
--compact Produce a compact JSON output
-S,--string Expect a string, manifest as plain text
-V,--ext-str VAR=VALUE External string variable
--ext-str-file FILE External string variable as file
--ext-code VAR=EXPR External code variable
--ext-code-file FILE External code variable as fileBy default Jsonnet programs evaluate to a JSON document, serialized using aeson.
The std library provides several methods to output other formats, e.g.
to generate a Yaml stream instead:
% hs-jsonnet -S -e "std.manifestYamlStream(['a', 1, []])"
---
"a"
---
1
---
[]
...Note the we need to use the option -S to output a verbatim string, instead of default JSON.
Similarly, to output prettified JSON:
% cat pretty.jsonnet
std.manifestJsonEx(
{
x: [1, 2, 3, true, false, null,
"string\nstring"],
y: { a: 1, b: 2, c: [1, 2] },
}, " ")
% hs-jsonnet -S pretty.jsonnet
{
"x": [
1,
2,
3,
true,
false,
null,
"string\nstring"
],
"y": {
"a": 1,
"b": 2,
"c": [
1,
2
]
}
}See the Standard library documentation for more details.
Preliminary results using the benchmarks here for comparison.
See CONTRIBUTING.md.
I took inspiration from Expresso, hnix, fixplate, Disco, and numerous other libraries. Thanks to their authors.
See LICENSE.
Copyright © 2020–present Alexandre Moreno
