[WIP, FS-1001] string interpolation #3593

realvictorprm · 2017-09-15T21:12:40Z

Signed-off-by: realvictorprm mueller.vpr@gmail.com

Signed-off-by: realvictorprm <mueller.vpr@gmail.com>

@forki

Most of the added code is from the old PR of @forki. I copied it partly because I tried to better understand how it should work roughly. However I think it's better to move a part of the parsing to the parser and lexer. But that's for later. Do not try to interpolate integers, this WILL result in an Fatal-Execution-Engine-Error. I'm afraid. Signed-off-by: realvictorprm <mueller.vpr@gmail.com>

realvictorprm

should be done later

realvictorprm · 2017-09-16T07:41:27Z

src/fsharp/FSStrings.resx

@@ -886,7 +886,7 @@
    <value>This expression is a function value, i.e. is missing arguments. Its type is {0}.</value>
  </data>
  <data name="UnitTypeExpected" xml:space="preserve">
-    <value>The result of this expression is implicitly ignored. Consider using 'ignore' to discard this value explicitly, e.g. 'expr |> ignore', or 'let' to bind the result to a name, e.g. 'let result = expr'.</value>


realvictorprm · 2017-09-16T07:41:29Z

src/fsharp/FSStrings.resx

  </resheader>
  <resheader name="writer">
-    <value>System.Resources.ResXResourceWriter, System.Windows.Forms, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>


realvictorprm · 2017-09-16T07:41:30Z

src/fsharp/FSStrings.resx

@@ -112,10 +112,10 @@
    <value>2.0</value>
  </resheader>
  <resheader name="reader">
-    <value>System.Resources.ResXResourceReader, System.Windows.Forms, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>


realvictorprm · 2017-09-16T14:40:15Z

Stuff like this is already possible:

I love it <3 this is exactly my use case!

realvictorprm · 2017-09-16T14:41:15Z

src/fsharp/TypeChecker.fs

+         else
+            mkString cenv.g m s, tpenv
+    else failwith "not supported yet"
+    //if (AddCxTypeEqualsTypeUndoIfFailed env.DisplayEnv cenv.css m overallTy cenv.g.string_ty) then 


I forgot to remove this, darn!

realvictorprm · 2017-09-16T14:42:10Z

src/fsharp/TypeChecker.fs

+                    )
+
+                // BuildFSharpMethodApp cenv.g m cenv.stringFormatEnv.Value.StringConcatMethod
+                let coersed = 


Here lies the problem, I must change the string conversion, it doesn't work for non string types and produces failing IL code.

Solved with the last commit. It's now converting all types to a string representation with the famous ToString method.

Added first real-working string-interpolation. Okay now the string interpolation should work for all types. I try to explain with this example what the compiler should produce if a string is interpolated: Example code: ```fsharp let value = 10 let interpolatedResult = $"Value as string: {value}" ``` The compiler should produce: ```fsharp let value = 10 let interpolatedResult = "Value as string: " + value.ToString() ``` Signed-off-by: realvictorprm <mueller.vpr@gmail.com>

However the lexer must be improved to respect nested interpolated strings. Currently it fails to parse them correctly. The parsing of the nested interpolated strings in CheckFormatStrings.fs needs improvement too. Removed commented code, corrected error reports. Signed-off-by: realvictorprm <mueller.vpr@gmail.com>

baronfel · 2017-09-16T20:07:59Z

src/fsharp/TypeChecker.fs

+                            | _ -> false
+                        | _ -> false
+                        )
+                let tostring =


per @vasily-kirichenko's comment on the RFC discussion thread, would it be possible here to detect if the type of the current expression is an F# type and use the equivalent of the %A format string instead of the ToString method for the type?

If it produces better results I'll definitely do so. I know thanks to you already the details why it should be different treated. To implement it I would need to know from someone which is familiar with the compiler whether I can just check if a type is an F# type.

Specifically only do this if ToString hasn't been overriden by the user.

I don't like the current casting code too. I would like to change it as soon as I found out how to inject format functions into the casting.

realvictorprm · 2017-09-18T12:59:41Z

There shouldn't be any fails, what's wrong with the CI :( ?

cartermp · 2017-09-18T17:45:05Z

@realvictorprm If you click on Details and view the Console Output, you can see why. In this case, it's a timeout.

@dotnet-bot test Windows_NT Release_ci_part2 Build

realvictorprm · 2017-09-18T17:48:30Z

Ah yes sorry. Thanks @cartermp

dsyme · 2017-09-20T12:00:01Z

@realvictorprm I went to do a review and I was going to start by looking at the tests, to understand the proposal from that perspective, rather just the implementation. Could you add a set of tests that capture both the basics and the nuances in the design? Perhaps look at the Roslyn tests for the corresponding C# feature?

thanks!

dsyme · 2017-09-20T12:00:37Z

src/fsharp/CompileOps.fs

@@ -5415,7 +5427,7 @@ let TypeCheckOneInputEventually

                // Typecheck the signature file 
                let! (tcEnv, sigFileType, createsGeneratedProvidedTypes) = 
-                    TypeCheckOneSigFile (tcGlobals, tcState.tcsNiceNameGen, amap, tcState.tcsCcu, checkForErrors, tcConfig.conditionalCompilationDefines, tcSink) tcState.tcsTcSigEnv file
+                    TypeCheckOneSigFile (tcGlobals, tcState.tcsNiceNameGen, amap, tcState.tcsCcu, checkForErrors, tcConfig.conditionalCompilationDefines, tcSink) tcState.tcsTcSigEnv (GetExpressionParser(tcConfig, new Lexhelp.LexResourceManager())) file


Bind (GetExpressionParser(tcConfig, new Lexhelp.LexResourceManager())) as a let please

dsyme · 2017-09-20T12:02:23Z

src/fsharp/pars.fsy

@@ -2672,6 +2674,7 @@ rawConstant:
  | BIGNUM { SynConst.UserNum $1 } 
  | stringOrKeywordString { SynConst.String ($1,lhs parseState) } 
  | BYTEARRAY { SynConst.Bytes ($1,lhs parseState) }
+  | STRING_INTERPOLATED { SynConst.InterpolatedString ($1,lhs parseState) }


What happens if interpolated strings are used in patterns - i.e. do we get a good error saying this is not supported?

dsyme

It's looking nice, though as I mentioned above I'd like to see test cases to understand better

realvictorprm · 2017-09-20T12:04:24Z

I understand @dsyme, I'm going to provide some tests. There are plenty of cases which needs to be caught.

Can you or someone else give me a tip on how to change the lexer / parser so that nested interpolated string expressions would be allowed?

KevinRansom · 2018-09-12T19:22:27Z

@realvictorprm, @dsyme

This PR hasn't been actively looked at in a year … do you have plans to revisit it?

Thanks

Kevin

dsyme · 2018-09-19T14:07:05Z

I will close, it is linked from the RFC but and may be used as the basis for the implementation when we rework it

First attempt towards C# like string interpolation

fc85d71

Signed-off-by: realvictorprm <mueller.vpr@gmail.com>

msftclas added the cla-already-signed label Sep 15, 2017

realvictorprm mentioned this pull request Sep 15, 2017

[RFC FS-1001 Discussion] String Interpolation fsharp/fslang-design#6

Closed

realvictorprm commented Sep 16, 2017

View reviewed changes

realvictorprm added 2 commits September 16, 2017 17:50

baronfel reviewed Sep 16, 2017

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dsyme reviewed Sep 20, 2017

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dsyme changed the title ~~[WIP] First attempt towards C# like string interpolation~~ [WIP, F# 4.2 ] First attempt towards C# like string interpolation Sep 20, 2017

dsyme added the Candidate for F# 4.2 label Sep 20, 2017

msftgits removed the cla-already-signed label Sep 26, 2017

Merge branch 'master' into stringinterpolation

0293fc3

dsyme changed the title ~~[WIP, F# 4.2 ] First attempt towards C# like string interpolation~~ [WIP, F# 4.2 ] string interpolation Dec 1, 2017

dsyme changed the title ~~[WIP, F# 4.2 ] string interpolation~~ [WIP, RFC FS-1001 ] string interpolation Dec 1, 2017

dsyme changed the title ~~[WIP, RFC FS-1001 ] string interpolation~~ [WIP, FS-1001] string interpolation Dec 1, 2017

KevinRansom removed the Candidate for F# 4.3 label Dec 7, 2017

dsyme added the Candidate for F# 4.2 label Dec 8, 2017

cartermp added Candidate for F# vNext and removed Candidate for F# 4.5 labels May 19, 2018

dsyme closed this Sep 19, 2018

cartermp removed the Candidate for F# vNext label Nov 12, 2018

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[WIP, FS-1001] string interpolation #3593

[WIP, FS-1001] string interpolation #3593

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[WIP, FS-1001] string interpolation #3593

[WIP, FS-1001] string interpolation #3593

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realvictorprm commented Sep 18, 2017

cartermp commented Sep 18, 2017 • edited

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edited