Debugger: debug.inlineValues support for case insensitive variable names

[chrisdp]

Hey, I am working on a debugger for a case insensitive language. When looking into the source I didn't see any way to define the expressions as case insensitive.

vscode/src/vs/workbench/contrib/debug/browser/debugEditorContribution.ts

Line 79 in 1934836

function createInlineValueDecorationsInsideRange(expressions: ReadonlyArray<IExpression>, range: Range, model: ITextModel, wordToLineNumbersMap: Map<string, number[]>): IDecorationOptions[] {

With debug.inlineValues set to true I can’t get camel case vars to work. In the below example you can see we have the value for postdata but it won’t match postData in the code even though they are the same reference.

As an extension maintainer and/or author we would like to be able to define ether the language as a whole as case insensitive or the scope/variables themselves.

[weinand]

Yes, this is a valid feature request.

[isidorn]

A debug adapter could for example specify this using a capability. Or alternativly we could change the debug.inlineValues to be a string setting so the user or an extension could change it to be case insensitive. I prefer the capability approach.

[weinand]

IMO the debug adapter is not in a good position to know about case sensitivity because it has no syntax knowledge of the source language because it doesn't take transpilation into account (e.g. CoffeeScript, TypeScript -> JavaScript).

Whether a language is case sensitive or not should be knowledge that is kept close to VS Code's notion of a "word definition". @jrieken does such a concept exist?

I'm currently looking into this problem in a broader way: similar to what we did for debug hovers with the EvaluatableExpressionProvider, I'm trying to do design an InlineValueProvider that can be contributed by a language extension.

[isidorn]

@weinand that sounds like a great approach. However why do we need a separate thing for the Inline values, can we just reuse what you already did for the debug hovers with the EvaluatableExpressionProvider?

[weinand]

@isidorn yes, that's exactly what my protoyping tries to find out: do we need a new abstraction or could we just use a variant for the EvaluatableExpressionProvider. Since the EvaluatableExpressionProvider uses the mouse position, it is not a very efficient way to find all inline expressions by probing for each character position in a line of source. In addition there is no way to figure out whether an evaluatable expression for one position is the same as for the next position...
My current thinking is to have a new method that returns all evaluatable expressions for a source line.

[isidorn]

@weinand yeah that feels like a way to go here. Just a new method provideEvaluatableExpressionForLine on the EvaluatableExpressionProvider

[weinand]

Since it is a bigger effort to provide extension API for the debugger's "inline values" feature, I've created a new feature request #105690.

[weinand]

@chrisdp I've released a first cut of the "inline values provider" implementation which should make it possible to address this issue.

What you need to do:
implement an InlineValueProvider for your language that locates variables in the given lines of a document and return them from the provider as an array of InlineValueVariableLookup objects. VS Code will match them against the variables in the VARIABLE view to find their values. When creating the InlineValueVariableLookup object you can use the constructor argument caseSensitiveLookup to control how the lookup should be done.

[chrisdp]

@weinand Thanks! Thats great I'll take a look over the next few days.

[weinand]

@chrisdp I will provide more infos and a sample when preparing the release notes next week.

[chrisdp]

@chrisdp I will provide more infos and a sample when preparing the release notes next week.

That is perfect. I'll wait for that to drop then. Thanks!

[weinand]

@chrisdp a sample that shows a case sensitive variable name lookup appears in the release notes of the upcoming 1.54 release. In order to make it case-insensitive you just need to pass the value false as a third argument to the InlineValueVariableLookup constructor.
In addition you will need a regular expression that finds the variables in your language.

[chrisdp]

@weinand Thanks. I saw that and let the other maintainer of the extension we are working on know. Hopefully we will be able to take a look soon ™️ and give some feedback 👍

[weinand]

I'm closing this because we have addressed the problem by introduction of the Inline Values Provider API.