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Context.fs
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Context.fs
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module internal Fantomas.Core.Context
open System
open FSharp.Compiler.Text
open FSharp.Compiler.Syntax
open Fantomas.Core
open Fantomas.Core.ISourceTextExtensions
open Fantomas.Core.FormatConfig
open Fantomas.Core.TriviaTypes
open Fantomas.Core.SourceTransformer
type WriterEvent =
| Write of string
| WriteLine
| WriteLineInsideStringConst
| WriteBeforeNewline of string
| WriteLineBecauseOfTrivia
| WriteLineInsideTrivia
| IndentBy of int
| UnIndentBy of int
| SetIndent of int
| RestoreIndent of int
| SetAtColumn of int
| RestoreAtColumn of int
let private (|CommentOrDefineEvent|_|) we =
match we with
| Write w when (String.startsWithOrdinal "//" w) -> Some we
| Write w when (String.startsWithOrdinal "#if" w) -> Some we
| Write w when (String.startsWithOrdinal "#else" w) -> Some we
| Write w when (String.startsWithOrdinal "#endif" w) -> Some we
| Write w when (String.startsWithOrdinal "(*" w) -> Some we
| _ -> None
type ShortExpressionInfo =
{ MaxWidth: int
StartColumn: int
ConfirmedMultiline: bool }
member x.IsTooLong maxPageWidth currentColumn =
currentColumn - x.StartColumn > x.MaxWidth // expression is not too long according to MaxWidth
|| (currentColumn > maxPageWidth) // expression at current position is not going over the page width
type Size =
| CharacterWidth of maxWidth: Num
| NumberOfItems of items: Num * maxItems: Num
type WriteModelMode =
| Standard
| Dummy
| ShortExpression of ShortExpressionInfo list
type WriterModel =
{
/// lines of resulting text, in reverse order (to allow more efficient adding line to end)
Lines: string list
/// current indentation
Indent: int
/// helper indentation information, if AtColumn > Indent after NewLine, Indent will be set to AtColumn
AtColumn: int
/// text to be written before next newline
WriteBeforeNewline: string
/// dummy = "fake" writer used in `autoNln`, `autoNlnByFuture`
Mode: WriteModelMode
/// current length of last line of output
Column: int
}
member __.IsDummy =
match __.Mode with
| Dummy -> true
| _ -> false
module WriterModel =
let init =
{ Lines = [ "" ]
Indent = 0
AtColumn = 0
WriteBeforeNewline = ""
Mode = Standard
Column = 0 }
let update maxPageWidth cmd m =
let doNewline m =
let m = { m with Indent = max m.Indent m.AtColumn }
let nextLine = String.replicate m.Indent " "
let currentLine = String.Concat(List.head m.Lines, m.WriteBeforeNewline).TrimEnd()
let otherLines = List.tail m.Lines
{ m with
Lines = nextLine :: currentLine :: otherLines
WriteBeforeNewline = ""
Column = m.Indent }
let updateCmd cmd =
match cmd with
| WriteLine
| WriteLineBecauseOfTrivia -> doNewline m
| WriteLineInsideStringConst ->
{ m with
Lines = String.empty :: m.Lines
Column = 0 }
| WriteLineInsideTrivia ->
let lines =
match m.Lines with
| [] -> [ String.empty ]
| h :: tail -> String.empty :: h :: tail
{ m with Lines = lines; Column = 0 }
| Write s ->
{ m with
Lines = (List.head m.Lines + s) :: (List.tail m.Lines)
Column = m.Column + (String.length s) }
| WriteBeforeNewline s -> { m with WriteBeforeNewline = s }
| IndentBy x ->
{ m with
Indent =
if m.AtColumn >= m.Indent + x then
m.AtColumn + x
else
m.Indent + x }
| UnIndentBy x -> { m with Indent = max m.AtColumn <| m.Indent - x }
| SetAtColumn c -> { m with AtColumn = c }
| RestoreAtColumn c -> { m with AtColumn = c }
| SetIndent c -> { m with Indent = c }
| RestoreIndent c -> { m with Indent = c }
match m.Mode with
| Dummy
| Standard -> updateCmd cmd
| ShortExpression infos when (List.exists (fun info -> info.ConfirmedMultiline) infos) -> m
| ShortExpression infos ->
let nextCmdCausesMultiline =
match cmd with
| WriteLine
| WriteLineBecauseOfTrivia -> true
| WriteLineInsideStringConst -> true
| Write _ when (String.isNotNullOrEmpty m.WriteBeforeNewline) -> true
| _ -> false
let updatedInfos =
infos
|> List.map (fun info ->
let tooLong = info.IsTooLong maxPageWidth m.Column
{ info with ConfirmedMultiline = tooLong || nextCmdCausesMultiline })
if List.exists (fun i -> i.ConfirmedMultiline) updatedInfos then
{ m with Mode = ShortExpression(updatedInfos) }
else
updateCmd cmd
module WriterEvents =
let normalize ev =
match ev with
| Write s when s.Contains("\n") ->
let writeLine =
match ev with
| CommentOrDefineEvent _ -> WriteLineInsideTrivia
| _ -> WriteLineInsideStringConst
// Trustworthy multiline string in the original AST can contain \r
// Internally we process everything with \n and at the end we respect the .editorconfig end_of_line setting.
s.Replace("\r", "").Split('\n')
|> Seq.map (fun x -> [ Write x ])
|> Seq.reduce (fun x y -> x @ [ writeLine ] @ y)
|> Seq.toList
| _ -> [ ev ]
let isMultiline evs =
evs
|> Queue.toSeq
|> Seq.exists (function
| WriteLine
| WriteLineBecauseOfTrivia -> true
| _ -> false)
[<System.Diagnostics.DebuggerDisplay("\"{Dump()}\"")>]
type internal Context =
{ Config: FormatConfig
WriterModel: WriterModel
WriterEvents: Queue<WriterEvent>
TriviaBefore: Map<FsAstType, TriviaInstruction list>
TriviaAfter: Map<FsAstType, TriviaInstruction list>
SourceText: ISourceText option }
/// Initialize with a string writer and use space as delimiter
static member Default =
{ Config = FormatConfig.Default
WriterModel = WriterModel.init
WriterEvents = Queue.empty
TriviaBefore = Map.empty
TriviaAfter = Map.empty
SourceText = None }
static member Create
config
(source: ISourceText option)
(ast: ParsedInput)
(selection: TriviaForSelection option)
: Context =
let triviaInstructions, sourceText =
match source with
| Some source when not config.StrictMode -> Trivia.collectTrivia config source ast selection, Some source
| _ -> [], None
let triviaBefore, triviaAfter =
let triviaInstructionsBefore, triviaInstructionsAfter =
List.partition (fun ti -> ti.AddBefore) triviaInstructions
let createMapByType = List.groupBy (fun t -> t.Type) >> Map.ofList
createMapByType triviaInstructionsBefore, createMapByType triviaInstructionsAfter
{ Context.Default with
Config = config
SourceText = sourceText
TriviaBefore = triviaBefore
TriviaAfter = triviaAfter }
member x.WithDummy(writerCommands, ?keepPageWidth) =
let keepPageWidth = keepPageWidth |> Option.defaultValue false
let mkModel m =
{ m with
Mode = Dummy
Lines = [ String.replicate x.WriterModel.Column " " ]
WriteBeforeNewline = "" }
// Use infinite column width to encounter worst-case scenario
let config =
{ x.Config with
MaxLineLength =
if keepPageWidth then
x.Config.MaxLineLength
else
Int32.MaxValue }
{ x with
WriterModel = mkModel x.WriterModel
WriterEvents = writerCommands
Config = config }
member x.WithShortExpression(maxWidth, ?startColumn) =
let info =
{ MaxWidth = maxWidth
StartColumn = Option.defaultValue x.WriterModel.Column startColumn
ConfirmedMultiline = false }
match x.WriterModel.Mode with
| ShortExpression infos ->
if List.exists (fun i -> i = info) infos then
x
else
{ x with WriterModel = { x.WriterModel with Mode = ShortExpression(info :: infos) } }
| _ -> { x with WriterModel = { x.WriterModel with Mode = ShortExpression([ info ]) } }
member x.FromSourceText(range: range) : string option =
Option.map (fun (sourceText: ISourceText) -> sourceText.GetContentAt range) x.SourceText
member x.HasContentAfter(``type``: FsAstType, range: range) : bool =
match Map.tryFindOrEmptyList ``type`` x.TriviaAfter with
| [] -> false
| triviaInstructions -> List.exists (fun ti -> RangeHelpers.rangeEq ti.Range range) triviaInstructions
member x.HasContentBefore(``type``: FsAstType, range: range) : bool =
match Map.tryFindOrEmptyList ``type`` x.TriviaBefore with
| [] -> false
| triviaInstructions -> List.exists (fun ti -> RangeHelpers.rangeEq ti.Range range) triviaInstructions
/// This adds a WriterEvent to the Context.
/// One event could potentially be split up into multiple events.
/// The event is also being processed in the WriterModel of the Context.
let writerEvent (e: WriterEvent) (ctx: Context) : Context =
// One event could contain a multiline string or code comments.
// These need to be split up in multiple events.
let evs = WriterEvents.normalize e
let ctx' =
{ ctx with
WriterEvents = Queue.append ctx.WriterEvents evs
WriterModel =
(ctx.WriterModel, evs)
||> Seq.fold (fun m e -> WriterModel.update ctx.Config.MaxLineLength e m) }
ctx'
let hasWriteBeforeNewlineContent ctx =
String.isNotNullOrEmpty ctx.WriterModel.WriteBeforeNewline
let finalizeWriterModel (ctx: Context) =
if hasWriteBeforeNewlineContent ctx then
writerEvent (Write ctx.WriterModel.WriteBeforeNewline) ctx
else
ctx
let dump (isSelection: bool) (ctx: Context) =
let ctx = finalizeWriterModel ctx
match ctx.WriterModel.Lines with
| [] -> []
| h :: tail ->
// Always trim the last line
h.TrimEnd() :: tail
|> List.rev
|> fun lines ->
// Don't skip leading newlines when formatting a selection.
if isSelection then lines else List.skipWhile ((=) "") lines
|> String.concat ctx.Config.EndOfLine.NewLineString
let dumpAndContinue (ctx: Context) =
#if DEBUG
let m = finalizeWriterModel ctx
let lines = m.WriterModel.Lines |> List.rev
let code = String.concat ctx.Config.EndOfLine.NewLineString lines
printfn "%s" code
#endif
ctx
type Context with
member x.Column = x.WriterModel.Column
member x.FinalizeModel = finalizeWriterModel x
member x.Dump() =
let m = finalizeWriterModel x
let lines = m.WriterModel.Lines |> List.rev
String.concat x.Config.EndOfLine.NewLineString lines
let writeEventsOnLastLine ctx =
ctx.WriterEvents
|> Queue.rev
|> Seq.takeWhile (function
| WriteLine
| WriteLineBecauseOfTrivia
| WriteLineInsideStringConst -> false
| _ -> true)
|> Seq.choose (function
| Write w when (String.length w > 0) -> Some w
| _ -> None)
let lastWriteEventIsNewline ctx =
ctx.WriterEvents
|> Queue.rev
|> Seq.skipWhile (function
| RestoreIndent _
| RestoreAtColumn _
| UnIndentBy _
| Write "" -> true
| _ -> false)
|> Seq.tryHead
|> Option.map (function
| WriteLineBecauseOfTrivia
| WriteLine -> true
| _ -> false)
|> Option.defaultValue false
let private (|EmptyHashDefineBlock|_|) (events: WriterEvent array) =
match Array.tryHead events, Array.tryLast events with
| Some (CommentOrDefineEvent _), Some (CommentOrDefineEvent _) ->
// Check if there is an empty block between hash defines
// Example:
// #if FOO
//
// #endif
let emptyLinesInBetween =
Array.forall
(function
| WriteLineInsideStringConst
| Write "" -> true
| _ -> false)
events.[1 .. (events.Length - 2)]
if emptyLinesInBetween then Some events else None
| _ -> None
/// Validate if there is a complete blank line between the last write event and the last event
let newlineBetweenLastWriteEvent ctx =
ctx.WriterEvents
|> Queue.rev
|> Seq.takeWhile (function
| Write ""
| WriteLine
| IndentBy _
| UnIndentBy _
| SetIndent _
| RestoreIndent _
| SetAtColumn _
| RestoreAtColumn _ -> true
| _ -> false)
|> Seq.filter (function
| WriteLine _ -> true
| _ -> false)
|> Seq.length
|> fun writeLines -> writeLines > 1
let lastWriteEventOnLastLine ctx =
writeEventsOnLastLine ctx |> Seq.tryHead
let forallCharsOnLastLine f ctx =
writeEventsOnLastLine ctx |> Seq.collect id |> Seq.forall f
// A few utility functions from https://github.com/fsharp/powerpack/blob/master/src/FSharp.Compiler.CodeDom/generator.fs
/// Indent one more level based on configuration
let indent (ctx: Context) =
// if atColumn is bigger then after indent, then we use atColumn as base for indent
writerEvent (IndentBy ctx.Config.IndentSize) ctx
/// Unindent one more level based on configuration
let unindent (ctx: Context) =
writerEvent (UnIndentBy ctx.Config.IndentSize) ctx
/// Increase indent by i spaces
let incrIndent i (ctx: Context) = writerEvent (IndentBy i) ctx
/// Decrease indent by i spaces
let decrIndent i (ctx: Context) = writerEvent (UnIndentBy i) ctx
/// Apply function f at an absolute indent level (use with care)
let atIndentLevel alsoSetIndent level (f: Context -> Context) (ctx: Context) =
if level < 0 then
invalidArg "level" "The indent level cannot be negative."
let m = ctx.WriterModel
let oldIndent = m.Indent
let oldColumn = m.AtColumn
(writerEvent (SetAtColumn level)
>> if alsoSetIndent then writerEvent (SetIndent level) else id
>> f
>> writerEvent (RestoreAtColumn oldColumn)
>> writerEvent (RestoreIndent oldIndent))
ctx
/// Set minimal indentation (`atColumn`) at current column position - next newline will be indented on `max indent atColumn`
/// Example:
/// { X = // indent=0, atColumn=2
/// "some long string" // indent=4, atColumn=2
/// Y = 1 // indent=0, atColumn=2
/// }
/// `atCurrentColumn` was called on `X`, then `indent` was called, but "some long string" have indent only 4, because it is bigger than `atColumn` (2).
let atCurrentColumn (f: _ -> Context) (ctx: Context) = atIndentLevel false ctx.Column f ctx
/// Like atCurrentColumn, but use current column after applying prependF
let atCurrentColumnWithPrepend (prependF: _ -> Context) (f: _ -> Context) (ctx: Context) =
let col = ctx.Column
(prependF >> atIndentLevel false col f) ctx
/// Write everything at current column indentation, set `indent` and `atColumn` on current column position
/// /// Example (same as above):
/// { X = // indent=2, atColumn=2
/// "some long string" // indent=6, atColumn=2
/// Y = 1 // indent=2, atColumn=2
/// }
/// `atCurrentColumn` was called on `X`, then `indent` was called, "some long string" have indent 6, because it is indented from `atCurrentColumn` pos (2).
let atCurrentColumnIndent (f: _ -> Context) (ctx: Context) = atIndentLevel true ctx.Column f ctx
/// Function composition operator
let (+>) (ctx: Context -> Context) (f: _ -> Context) x =
let y = ctx x
match y.WriterModel.Mode with
| ShortExpression infos when infos |> Seq.exists (fun x -> x.ConfirmedMultiline) -> y
| _ -> f y
let (!-) (str: string) = writerEvent (Write str)
let (!+~) (str: string) c =
let addNewline ctx =
not (forallCharsOnLastLine Char.IsWhiteSpace ctx)
let c = if addNewline c then writerEvent WriteLine c else c
writerEvent (Write str) c
/// Print object converted to string
let str (o: 'T) (ctx: Context) =
ctx |> writerEvent (Write(o.ToString()))
/// Similar to col, and supply index as well
let coli f' (c: seq<'T>) f (ctx: Context) =
let mutable tryPick = true
let mutable st = ctx
let mutable i = 0
let e = c.GetEnumerator()
while (e.MoveNext()) do
if tryPick then tryPick <- false else st <- f' st
st <- f i e.Current st
i <- i + 1
st
/// Similar to coli, and supply index as well to f'
let colii f' (c: seq<'T>) f (ctx: Context) =
let mutable tryPick = true
let mutable st = ctx
let mutable i = 0
let e = c.GetEnumerator()
while (e.MoveNext()) do
if tryPick then tryPick <- false else st <- f' i st
st <- f i e.Current st
i <- i + 1
st
/// Process collection - keeps context through the whole processing
/// calls f for every element in sequence and f' between every two elements
/// as a separator. This is a variant that works on typed collections.
let col f' (c: seq<'T>) f (ctx: Context) =
let mutable tryPick = true
let mutable st = ctx
let e = c.GetEnumerator()
while (e.MoveNext()) do
if tryPick then tryPick <- false else st <- f' st
st <- f e.Current st
st
// Similar to col but pass the item of 'T to f' as well
let colEx f' (c: seq<'T>) f (ctx: Context) =
let mutable tryPick = true
let mutable st = ctx
let e = c.GetEnumerator()
while (e.MoveNext()) do
if tryPick then tryPick <- false else st <- f' e.Current st
st <- f e.Current st
st
/// Similar to col, apply one more function f2 at the end if the input sequence is not empty
let colPost f2 f1 (c: seq<'T>) f (ctx: Context) =
if Seq.isEmpty c then ctx else f2 (col f1 c f ctx)
/// Similar to col, apply one more function f2 at the beginning if the input sequence is not empty
let colPre f2 f1 (c: seq<'T>) f (ctx: Context) =
if Seq.isEmpty c then ctx else col f1 c f (f2 ctx)
let colPreEx f2 f1 (c: seq<'T>) f (ctx: Context) =
if Seq.isEmpty c then ctx else colEx f1 c f (f2 ctx)
/// If there is a value, apply f and f' accordingly, otherwise do nothing
let opt (f': Context -> _) o f (ctx: Context) =
match o with
| Some x -> f' (f x ctx)
| None -> ctx
/// similar to opt, only takes a single function f to apply when there is a value
let optSingle f o ctx =
match o with
| Some x -> f x ctx
| None -> ctx
/// Similar to opt, but apply f2 at the beginning if there is a value
let optPre (f2: _ -> Context) (f1: Context -> _) o f (ctx: Context) =
match o with
| Some x -> f1 (f x (f2 ctx))
| None -> ctx
let getListOrArrayExprSize ctx maxWidth xs =
match ctx.Config.ArrayOrListMultilineFormatter with
| MultilineFormatterType.CharacterWidth -> Size.CharacterWidth maxWidth
| MultilineFormatterType.NumberOfItems -> Size.NumberOfItems(List.length xs, ctx.Config.MaxArrayOrListNumberOfItems)
let getRecordSize ctx fields =
match ctx.Config.RecordMultilineFormatter with
| MultilineFormatterType.CharacterWidth -> Size.CharacterWidth ctx.Config.MaxRecordWidth
| MultilineFormatterType.NumberOfItems -> Size.NumberOfItems(List.length fields, ctx.Config.MaxRecordNumberOfItems)
/// b is true, apply f1 otherwise apply f2
let ifElse b (f1: Context -> Context) f2 (ctx: Context) = if b then f1 ctx else f2 ctx
let ifElseCtx cond (f1: Context -> Context) f2 (ctx: Context) = if cond ctx then f1 ctx else f2 ctx
let ifStroustrupElse = ifElseCtx (fun ctx -> ctx.Config.ExperimentalStroustrupStyle)
let ifStroustrup (f1: Context -> Context) =
ifElseCtx (fun ctx -> ctx.Config.ExperimentalStroustrupStyle) f1 id
/// apply f only when cond is true
let onlyIf cond f ctx = if cond then f ctx else ctx
let onlyIfCtx cond f ctx = if cond ctx then f ctx else ctx
let onlyIfNot cond f ctx = if cond then ctx else f ctx
let whenShortIndent f ctx =
onlyIf (ctx.Config.IndentSize < 3) f ctx
/// Repeat application of a function n times
let rep n (f: Context -> Context) (ctx: Context) =
[ 1..n ] |> List.fold (fun c _ -> f c) ctx
// Separator functions
let sepNone = id
let sepDot = !- "."
let sepSpace (ctx: Context) =
if ctx.WriterModel.IsDummy then
(!- " ") ctx
else
match lastWriteEventOnLastLine ctx with
| Some w when (w.EndsWith(" ") || w.EndsWith Environment.NewLine) -> ctx
| None -> ctx
| _ -> (!- " ") ctx
// add actual spaces until the target column is reached, regardless of previous content
// use with care
let addFixedSpaces (targetColumn: int) (ctx: Context) : Context =
let delta = targetColumn - ctx.Column
onlyIf (delta > 0) (rep delta (!- " ")) ctx
let sepNln = writerEvent WriteLine
// Use a different WriteLine event to indicate that the newline was introduces due to trivia
// This is later useful when checking if an expression was multiline when checking for ColMultilineItem
let sepNlnForTrivia = writerEvent WriteLineBecauseOfTrivia
let sepNlnUnlessLastEventIsNewline (ctx: Context) =
if lastWriteEventIsNewline ctx then ctx else sepNln ctx
let sepNlnUnlessLastEventIsNewlineOrStroustrup (ctx: Context) =
if lastWriteEventIsNewline ctx || ctx.Config.ExperimentalStroustrupStyle then
ctx
else
sepNln ctx
let sepStar = sepSpace +> !- "* "
let sepStarFixed = !- "* "
let sepEq = !- " ="
let sepEqFixed = !- "="
let sepArrow = !- " -> "
let sepArrowFixed = !- "->"
let sepArrowRev = !- " <- "
let sepWild = !- "_"
let sepBar = !- "| "
/// opening token of list
let sepOpenL (ctx: Context) =
if ctx.Config.SpaceAroundDelimiter then
str "[ " ctx
else
str "[" ctx
/// closing token of list
let sepCloseL (ctx: Context) =
if ctx.Config.SpaceAroundDelimiter then
str " ]" ctx
else
str "]" ctx
/// opening token of list
let sepOpenLFixed = !- "["
/// closing token of list
let sepCloseLFixed = !- "]"
/// opening token of array
let sepOpenA (ctx: Context) =
if ctx.Config.SpaceAroundDelimiter then
str "[| " ctx
else
str "[|" ctx
/// closing token of array
let sepCloseA (ctx: Context) =
if ctx.Config.SpaceAroundDelimiter then
str " |]" ctx
else
str "|]" ctx
/// opening token of list
let sepOpenAFixed = !- "[|"
/// closing token of list
let sepCloseAFixed = !- "|]"
/// opening token of sequence or record
let sepOpenS (ctx: Context) =
if ctx.Config.SpaceAroundDelimiter then
str "{ " ctx
else
str "{" ctx
/// closing token of sequence or record
let sepCloseS (ctx: Context) =
if ctx.Config.SpaceAroundDelimiter then
str " }" ctx
else
str "}" ctx
/// opening token of anon record
let sepOpenAnonRecd (ctx: Context) =
if ctx.Config.SpaceAroundDelimiter then
str "{| " ctx
else
str "{|" ctx
/// closing token of anon record
let sepCloseAnonRecd (ctx: Context) =
if ctx.Config.SpaceAroundDelimiter then
str " |}" ctx
else
str "|}" ctx
/// opening token of anon record
let sepOpenAnonRecdFixed = !- "{|"
/// closing token of anon record
let sepCloseAnonRecdFixed = !- "|}"
/// opening token of sequence
let sepOpenSFixed = !- "{"
/// closing token of sequence
let sepCloseSFixed = !- "}"
/// opening token of tuple
let sepOpenT = !- "("
/// closing token of tuple
let sepCloseT = !- ")"
let wordAnd = sepSpace +> !- "and "
let wordAndFixed = !- "and"
let wordOr = sepSpace +> !- "or "
let wordOf = sepSpace +> !- "of "
let indentSepNlnUnindent f = indent +> sepNln +> f +> unindent
// we need to make sure each expression in the function application has offset at least greater than
// indentation of the function expression itself
// we replace sepSpace in such case
// remarks: https://github.com/fsprojects/fantomas/issues/1611
let indentIfNeeded f (ctx: Context) =
let savedColumn = ctx.WriterModel.AtColumn
if savedColumn >= ctx.Column then
// missingSpaces needs to be at least one more than the column
// of function expression being applied upon, otherwise (as known up to F# 4.7)
// this would lead to a compile error for the function application
let missingSpaces = (savedColumn - ctx.FinalizeModel.Column) + ctx.Config.IndentSize
atIndentLevel true savedColumn (!-(String.replicate missingSpaces " ")) ctx
else
f ctx
let eventsWithoutMultilineWrite ctx =
{ ctx with
WriterEvents =
ctx.WriterEvents
|> Queue.toSeq
|> Seq.filter (function
| Write s when s.Contains("\n") -> false
| _ -> true)
|> Queue.ofSeq }
let private shortExpressionWithFallback
(shortExpression: Context -> Context)
fallbackExpression
maxWidth
startColumn
(ctx: Context)
=
// if the context is already inside a ShortExpression mode and tries to figure out if the expression will go over the page width,
// we should try the shortExpression in this case.
match ctx.WriterModel.Mode with
| ShortExpression infos when
(List.exists (fun info -> info.ConfirmedMultiline || info.IsTooLong ctx.Config.MaxLineLength ctx.Column) infos)
->
ctx
| _ ->
// create special context that will process the writer events slightly different
let shortExpressionContext =
match startColumn with
| Some sc -> ctx.WithShortExpression(maxWidth, sc)
| None -> ctx.WithShortExpression(maxWidth)
let resultContext = shortExpression shortExpressionContext
match resultContext.WriterModel.Mode with
| ShortExpression infos ->
// verify the expression is not longer than allowed
if
List.exists
(fun info ->
info.ConfirmedMultiline
|| info.IsTooLong ctx.Config.MaxLineLength resultContext.Column)
infos
then
fallbackExpression ctx
else
{ resultContext with WriterModel = { resultContext.WriterModel with Mode = ctx.WriterModel.Mode } }
| _ ->
// you should never hit this branch
fallbackExpression ctx
let isShortExpression maxWidth (shortExpression: Context -> Context) fallbackExpression (ctx: Context) =
shortExpressionWithFallback shortExpression fallbackExpression maxWidth None ctx
let isShortExpressionOrAddIndentAndNewline maxWidth expr (ctx: Context) =
shortExpressionWithFallback expr (indentSepNlnUnindent expr) maxWidth None ctx
let sepSpaceIfShortExpressionOrAddIndentAndNewline maxWidth expr (ctx: Context) =
shortExpressionWithFallback (sepSpace +> expr) (indentSepNlnUnindent expr) maxWidth None ctx
let expressionFitsOnRestOfLine expression fallbackExpression (ctx: Context) =
shortExpressionWithFallback expression fallbackExpression ctx.Config.MaxLineLength (Some 0) ctx
let isSmallExpression size (smallExpression: Context -> Context) fallbackExpression (ctx: Context) =
match size with
| CharacterWidth maxWidth -> isShortExpression maxWidth smallExpression fallbackExpression ctx
| NumberOfItems (items, maxItems) ->
if items > maxItems then
fallbackExpression ctx
else
expressionFitsOnRestOfLine smallExpression fallbackExpression ctx
/// provide the line and column before and after the leadingExpression to to the continuation expression
let leadingExpressionResult leadingExpression continuationExpression (ctx: Context) =
let lineCountBefore, columnBefore =
List.length ctx.WriterModel.Lines, ctx.WriterModel.Column
let contextAfterLeading = leadingExpression ctx
let lineCountAfter, columnAfter =
List.length contextAfterLeading.WriterModel.Lines, contextAfterLeading.WriterModel.Column
continuationExpression ((lineCountBefore, columnBefore), (lineCountAfter, columnAfter)) contextAfterLeading
/// combines two expression and let the second expression know if the first expression was longer than a given threshold.
let leadingExpressionLong threshold leadingExpression continuationExpression (ctx: Context) =
let lineCountBefore, columnBefore =
List.length ctx.WriterModel.Lines, ctx.WriterModel.Column
let contextAfterLeading = leadingExpression ctx
let lineCountAfter, columnAfter =
List.length contextAfterLeading.WriterModel.Lines, contextAfterLeading.WriterModel.Column
continuationExpression
(lineCountAfter > lineCountBefore || (columnAfter - columnBefore > threshold))
contextAfterLeading
/// A leading expression is not consider multiline if it has a comment before it.
/// For example
/// let a = 7
/// // foo
/// let b = 8
/// let c = 9
/// The second binding b is not consider multiline.
let leadingExpressionIsMultiline leadingExpression continuationExpression (ctx: Context) =
let eventCountBeforeExpression = Queue.length ctx.WriterEvents
let contextAfterLeading = leadingExpression ctx
let hasWriteLineEventsAfterExpression =
contextAfterLeading.WriterEvents
|> Queue.skipExists
eventCountBeforeExpression
(function
| WriteLine _ -> true
| _ -> false)
(fun e ->
match e with
| [| CommentOrDefineEvent _ |]
| [| WriteLine |]
| [| Write "" |]
| EmptyHashDefineBlock _ -> true
| _ -> false)
continuationExpression hasWriteLineEventsAfterExpression contextAfterLeading
let private expressionExceedsPageWidth beforeShort afterShort beforeLong afterLong expr (ctx: Context) =
// if the context is already inside a ShortExpression mode, we should try the shortExpression in this case.
match ctx.WriterModel.Mode with
| ShortExpression infos when
(List.exists (fun info -> info.ConfirmedMultiline || info.IsTooLong ctx.Config.MaxLineLength ctx.Column) infos)
->
ctx
| ShortExpression _ ->
// if the context is already inside a ShortExpression mode, we should try the shortExpression in this case.
(beforeShort +> expr +> afterShort) ctx
| _ ->
let shortExpressionContext = ctx.WithShortExpression(ctx.Config.MaxLineLength, 0)
let resultContext = (beforeShort +> expr +> afterShort) shortExpressionContext
let fallbackExpression = beforeLong +> expr +> afterLong
match resultContext.WriterModel.Mode with
| ShortExpression infos ->
// verify the expression is not longer than allowed
if
List.exists
(fun info ->
info.ConfirmedMultiline
|| info.IsTooLong ctx.Config.MaxLineLength resultContext.Column)
infos
then
fallbackExpression ctx
else
{ resultContext with WriterModel = { resultContext.WriterModel with Mode = ctx.WriterModel.Mode } }
| _ ->
// you should never hit this branch
fallbackExpression ctx
/// try and write the expression on the remainder of the current line
/// add an indent and newline if the expression is longer
let autoIndentAndNlnIfExpressionExceedsPageWidth expr (ctx: Context) =
expressionExceedsPageWidth
sepNone
sepNone // before and after for short expressions
(indent +> sepNln)
unindent // before and after for long expressions
expr
ctx
let sepSpaceOrIndentAndNlnIfExpressionExceedsPageWidth expr (ctx: Context) =
expressionExceedsPageWidth
sepSpace
sepNone // before and after for short expressions
(indent +> sepNln)
unindent // before and after for long expressions
expr
ctx
let sepSpaceOrDoubleIndentAndNlnIfExpressionExceedsPageWidth expr (ctx: Context) =
expressionExceedsPageWidth
sepSpace
sepNone // before and after for short expressions
(indent +> indent +> sepNln)
(unindent +> unindent) // before and after for long expressions
expr
ctx
let sepSpaceWhenOrIndentAndNlnIfExpressionExceedsPageWidth (addSpace: Context -> bool) expr (ctx: Context) =
expressionExceedsPageWidth
(ifElseCtx addSpace sepSpace sepNone)
sepNone // before and after for short expressions
(indent +> sepNln)
unindent // before and after for long expressions
expr
ctx
let autoNlnIfExpressionExceedsPageWidth expr (ctx: Context) =
expressionExceedsPageWidth
sepNone
sepNone // before and after for short expressions
sepNln
sepNone // before and after for long expressions
expr
ctx
let autoParenthesisIfExpressionExceedsPageWidth expr (ctx: Context) =
expressionFitsOnRestOfLine expr (sepOpenT +> expr +> sepCloseT) ctx
let futureNlnCheckMem (f, ctx) =
if ctx.WriterModel.IsDummy then
(false, false)
else
// Create a dummy context to evaluate length of current operation
let dummyCtx: Context = ctx.WithDummy(Queue.empty, keepPageWidth = true) |> f
WriterEvents.isMultiline dummyCtx.WriterEvents, dummyCtx.Column > ctx.Config.MaxLineLength
let futureNlnCheck f (ctx: Context) =
let isMultiLine, isLong = futureNlnCheckMem (f, ctx)
isMultiLine || isLong
/// similar to futureNlnCheck but validates whether the expression is going over the max page width
/// This functions is does not use any caching
let exceedsWidth maxWidth f (ctx: Context) =
let dummyCtx: Context = ctx.WithDummy(Queue.empty, keepPageWidth = true)
let currentLines = dummyCtx.WriterModel.Lines.Length
let currentColumn = dummyCtx.Column
let ctxAfter: Context = f dummyCtx
let linesAfter = ctxAfter.WriterModel.Lines.Length
let columnAfter = ctxAfter.Column
linesAfter > currentLines
|| (columnAfter - currentColumn) > maxWidth
|| currentColumn > ctx.Config.MaxLineLength
/// Similar to col, skip auto newline for index 0
let colAutoNlnSkip0i f' (c: seq<'T>) f (ctx: Context) =
coli
f'
c
(fun i c ->
if i = 0 then
f i c
else
autoNlnIfExpressionExceedsPageWidth (f i c))
ctx