Allow requesting ANSI colors in stanc.js #1569
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src/stancjs/stancjs.ml
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| , (* NB: This should really be [Js.Unsafe.Inject (Js.array ...)] as above. | ||
| The fact that it is not is a historical mistake, and leads to the | ||
| resulting list in JS having a first entry of '0', the index. | ||
| Unfortunately, many tools have been built assuming the error message is | ||
| actually in the second entry, so we're stuck with this bad behavior. | ||
| *) | ||
| Js.Unsafe.inject (Array.map ~f:Js.string [| e |]) ) |
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So we have been using Unsafe.inject incorrectly? I think it would be better to write something like
Js.Unsafe.inject (Js.array (Array.map ~f:Js.string [| "0" ; e |]) )Or maybe just duplicate the error message?
let e = Js.string e in Js.Unsafe.inject (Js.array [| e ; e |])There was a problem hiding this comment.
Yes, more or less since the beginning. I only noticed this when building Stan Playground, and only spotted the fix while doing this change, but it's too late to really do much I think. Your suggestion of hard-coding the '0' seems reasonable to me given the choices.
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To elaborate a bit more, the 0 came from the data representation used in jsoo:
array block with tag 0 (e.g.
[|1;2|] => [0,1,2])
The missing Js.array call gets compiled down to caml_js_from_array, which is a 1-liner that returns .slice(1) of its argument
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How does Js.Unsafe.inject differ from Js.Unsafe.coerce? The latter seems tiny bit more more type-safe?
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They're exactly the same runtime code (both get compiled away to nothing), the difference seems to be that coerce requires the input be a Js.t already, which would have caught this.
I'll switch to using that, nice suggestion
Submission Checklist
Release notes
stanc.js can request ANSI escape code styling in errors and warnings by passing
color-outputas an argument. These are supported in most browser consoles.Copyright and Licensing
By submitting this pull request, the copyright holder is agreeing to
license the submitted work under the BSD 3-clause license (https://opensource.org/licenses/BSD-3-Clause)