Start development of a new pretty printer for Cadence programs #1024
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turbolent
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## master #1024 +/- ##
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- Coverage 77.31% 77.22% -0.09%
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Files 274 278 +4
Lines 35347 35814 +467
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+ Hits 27327 27659 +332
- Misses 6941 7069 +128
- Partials 1079 1086 +7
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Cadence Benchstat comparisonThis branch with compared with the base branch onflow:master commit 0e7825d Results
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| "github.com/turbolent/prettier" |
| @@ -34,6 +35,7 @@ type Expression interface { | |||
| IfStatementTest | |||
| isExpression() | |||
| AcceptExp(ExpressionVisitor) Repr | |||
| Doc() prettier.Doc | |||
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I guess this returns the 'textual' representation of the expression. Would it make sense to rename it to something that reflects it? People might confuse it with 'documentation/doc-comments' (happened to me: I was wondering for a moment, can there be any doc-comments for expressions 😄 )
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It didn't occur to me, bad that's a good point! Would PrettyPrintDocument() be a better name? Any other suggestions? Naming is hard, haha
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Yea PrettyPrintDocument() sounds a better option. Some other names I could think of are PrettyPrint(), Format().
Alternatively, if we can move this to a separate visitor, then we wouldn't have this method anyway.
One general question I had was, would it make sense to move the formatting/prettying codes to a separate visitor?
That might be a big refactor though.
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Ah, I had missed that comment! Good idea, I might refactor the existing code to a separate visitor once the existing PRs are in
| separatorDoc = memberExpressionSeparatorDoc | ||
| } | ||
| return prettier.Concat{ | ||
| // TODO: potentially parenthesize |
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Probably a good solution is to introduce a ParenthesizedExpression to the AST at the parser level, so we don't have to specially handle parentheses everywhere. Expression.Doc() would delegate to ParenthesizedExpression.Doc() which would then add the parentheses.
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of-course we don't have to do it here; just a suggestion for future improvements.
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That's an interesting idea! 👌 I'd love to understand it better, let's have a sync next week
| prettier.Group{ | ||
| Doc: leftDoc, | ||
| }, | ||
| prettier.Line{}, |
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is this going to be a newline always?
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prettier.Line is rendered as ae space if there is space, or a newline if there is not.
The idea here is to break before the symbol, so that e.g. let a = 1 + 2 * 3 is rendered like this if it does not fit:
let a = 1
+ 2
* 3
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@turbolent This is amazing. Is it any how feasible to port parser to javascript? Can be useful for fcl and js-testing probably. It is for a long time in my ideas list. If there is no obvious road blocks, I would like to work on this. |
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@bluesign Parser is already available as an npm-package: https://github.com/onflow/cadence/tree/master/npm-packages/cadence-parser |
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@bluesign Yeah, like @SupunS pointed out, it should be very little work to compile to expose this to e.g. JavaScript via WebAssembly, by adding functions to the parser NPM package. I don't know what the current status is for TinyGo, but it might be able to compile the parser to a smaller binary than the reference Go compiler. |
Work towards #209
Description
Start the development of a new pretty-printer for Cadence.
Implement pretty-printing functions for the following AST nodes:
ArrayExpressionBoolExpressionDestroyExpressionDictionaryExpressionForceExpressionIdentifierExpressionIndexExpressionMemberExpressionNilExpressionPathExpressionStringExpressionUnaryExpressionInvocationExpressionIntegerExpressionCreateExpressionFixedPointExpressionConditionalExpressionBinaryExpressionCastingExpressionReferenceExpressionFunctionExpressionVariableDeclarationReturnStatementStill missing for expressions:
String()functions with pretty-print results (assume a default max line width)Also, implement a small web-based tool that helps with the development: It parses code into the AST and pretty-prints it, given a maximum line width.
masterbranchFiles changedin the Github PR explorer