Breaks float range with step-size when trailing 0 is omitted

[peterhirn]

Issue created from fantomas-online

Code

let foo = [1. .. 0.1 .. 2.]

Result

let foo = [ 1...0.1..2. ]

Workaround

let foo = [ 1.0..0.1..2.0 ]

Extra information

• The formatted result breaks by code.
• The formatted result gives compiler warnings.
• I or my company would be willing to help fix this.

Options

Fantomas master branch at 2022-03-29T09:12:14Z - 8f2ab14

Default Fantomas configuration

[nojaf]

Hello, thank you for reporting this issue.

The fix will probably need to be somewhere around:

fantomas/src/Fantomas/CodePrinter.fs

Lines 2632 to 2659 in 8f2ab14

	| IndexRangeExpr (None, None) -> !- "*"
	| IndexRangeExpr (Some (IndexRangeExpr (Some (ConstNumberExpr e1), Some (ConstNumberExpr e2))),
	Some (ConstNumberExpr e3)) ->
	genExpr astContext e1
	+> !- ".."
	+> genExpr astContext e2
	+> !- ".."
	+> genExpr astContext e3
	| IndexRangeExpr (e1, e2) ->
	let hasSpaces =
	let rec (|AtomicExpr|_|) e =
	match e with
	| NegativeNumber _ -> None
	| SynExpr.Ident _
	| SynExpr.Const (SynConst.Int32 _, _)
	| IndexRangeExpr (Some (AtomicExpr _), Some (AtomicExpr _))
	| IndexFromEndExpr (AtomicExpr _) -> Some e
	| _ -> None
	match e1, e2 with
	| Some (AtomicExpr _), None
	| None, Some (AtomicExpr _)
	| Some (AtomicExpr _), Some (AtomicExpr _) -> false
	| _ -> true
	optSingle (fun e -> genExpr astContext e +> onlyIf hasSpaces sepSpace) e1
	+> !- ".."
	+> optSingle (fun e -> onlyIf hasSpaces sepSpace +> genExpr astContext e) e2

Are you interested in submitting a PR?