river/token/builder: add builder package to build files #1910
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The river/token/builder package exposes an API to construct a river file, inspired by github.com/hashicorp/v2/hclwrite. It builds a list of tokens and then formats them back to the user. It can also encode Go values directly into tokens.
| func = function | ||
| capsule = capsule("chan int") |
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This is kind of a weird way to represent function and capsule values, and needs some thought in the future for how we should display them to users.
Note that however they get displayed must be valid River syntax, since we need to be able to parse the tokens to format them.
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| // Package builder exposes an API to create a River configuration file by | |||
| // constructing a set of tokens. | |||
| package builder | |||
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I'm not sure about this as a package name, but I don't want it to be too long either.
This avoids a situation where the map order is randomized. We only need to make sure one key works anyway.
pkg/river/token/builder/builder.go
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| } | ||
| } | ||
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| toks = append(toks, Token{Type: token.ILLEGAL, Lit: " "}) |
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Same here and below, not sure I get the ILLEGAL part. Is it because it's just for presentation so it doesn't matter?
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See the Token docstring:
// A Token is a wrapper around token.Token which contains the token type
// alongside its literal. Use token.ILLEGAL to write literal characters such as
// whitespace.
We just unfortunately don't have a good way to say "this should be written as-is" other than re-using token.ILLEGAL.
pkg/river/token/builder/token.go
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| // river/token doesn't have the capability of representing literal strings, so | ||
| // LiteralTok uses token.ILLEGAL as a way to uniquely identify when literal | ||
| // strings should be injected. | ||
| const LiteralTok = token.ILLEGAL |
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This feels slightly weird. It represents "whitespace" commands correct? It works, would adding a whitespace token work?
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It could be any literal text. We could add token.LITERAL, but we'd have to make it clear that the scanner never emits it and it's just for the token builder package.
WDYT?
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That feels better to me than the verbiage of illegal, but if it makes more sense to you to use illegal then keep it.
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I think it's probably fine to add a token.LITERAL since there's multiple consumers of the token package anyway
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PR Description
The river/token/builder package exposes an API to construct a River file, inspired by github.com/hashicorp/v2/hclwrite. It builds a list of tokens and then formats them back to the user.
It can also encode Go values directly into tokens.
Which issue(s) this PR fixes
Related to #1839.
Notes to the Reviewer
This also fixes some new small formatting bugs found when printing out lists that contain objects.
PR Checklist