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Misc improvements to pretty-printing follow-up #5713

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ea4d1d5
Fix CLI: qualify two Tui.Text references that didn't resolve
OceanOak Aug 19, 2026
8a3e143
Fix unresolved Colors references in CLI
OceanOak Aug 19, 2026
31a6c3d
Fix three small correctness bugs: NO_COLOR, rootless items, LSP multi…
OceanOak Aug 19, 2026
3a9e636
Fix capped listings in deps and show
OceanOak Aug 19, 2026
6fbb7a1
Pretty: fix a group breaking because of a line break after it
OceanOak Aug 19, 2026
6332131
Fix two printer bugs that changed meaning on re-parse
OceanOak Aug 19, 2026
e4728ac
Only drop the owner from names where the resolver implies it
OceanOak Aug 19, 2026
41c58a4
Pretty: build output as chunks, join once
OceanOak Aug 19, 2026
7412660
Say why pretty-printing failed, not just that it did
OceanOak Aug 19, 2026
ed76a67
view: use the terminal's width instead of fixed 80
OceanOak Aug 19, 2026
f8b6e1d
Fix the Wasm REPL
OceanOak Aug 20, 2026
c2c9dec
Pretty: finish the Doc migration and enforce semantic round trips
OceanOak Aug 20, 2026
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244 changes: 6 additions & 238 deletions backend/src/Builtins/Builtins.Cli/Libs/Terminal.fs
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Original file line number Diff line number Diff line change
Expand Up @@ -57,223 +57,9 @@ module TerminalRestoreGuard =
System.Console.CancelKeyPress.Add(fun _ -> restoreToTerminal ())


/// Measure plain text in terminal columns using Unicode width data and
/// extended grapheme clusters.
module DisplayWidth =
let private isRegionalIndicator (value : int) : bool =
value >= 0x1F1E6 && value <= 0x1F1FF

let private clusterWidth (cluster : string) : int =
// Fast path: a lone printable ASCII character is always one column. The Wcwidth table lookup below is
// comparatively expensive, and this is the overwhelmingly common case: measuring a full-screen frame the
// slow way costs hundreds of milliseconds per frame, which is the difference between a TUI that keeps up
// with your keyboard and one that doesn't.
if cluster.Length = 1 && cluster[0] >= ' ' && cluster[0] <= '~' then
1
else

let mutable runes = cluster.EnumerateRunes()
let mutable widestScalar = 0
let mutable regionalIndicators = 0
let mutable hasEmojiVariationSelector = false

while runes.MoveNext() do
let rune = runes.Current
let value = rune.Value

if isRegionalIndicator value then
regionalIndicators <- regionalIndicators + 1

if value = 0xFE0F then hasEmojiVariationSelector <- true

let scalarWidth =
Wcwidth.UnicodeCalculator.GetWidth(
rune,
System.Nullable Wcwidth.Unicode.Version_17_0_0
)
|> max 0

widestScalar <- max widestScalar scalarWidth

if regionalIndicators >= 2 then
// Regional indicators are individually narrow but flag pairs occupy one
// wide terminal glyph.
2
elif hasEmojiVariationSelector && widestScalar = 1 then
// VS16 requests emoji presentation for otherwise narrow characters such
// as U+2764 HEAVY BLACK HEART.
2
else
widestScalar

/// Return the number of terminal columns occupied by plain, single-line text.
///
/// ANSI control sequences must be removed before calling this function.
/// Control characters have width zero.
let ofString (text : string) : int =
text |> String.toEgcSeq |> Seq.sumBy clusterWidth
module DisplayWidth = LibExecution.DisplayWidth

/// Return whether text contains an ASCII/Unicode control character.
let containsControl (text : string) : bool =
text |> Seq.exists System.Char.IsControl

/// Skip one escape sequence or control character starting at `i`, returning the next index.
///
/// `keep` receives an SGR sequence that should be preserved. Everything else is dropped: a non-SGR CSI
/// whole, and a non-CSI escape just its ESC byte, so ordinary text after it stays visible.
let private skipEscape (text : string) (i : int) (keep : string -> unit) : int =
let len = text.Length
let isFinal (c : char) = c >= '@' && c <= '~'

if i + 1 < len && text[i + 1] = '[' then
let mutable j = i + 2
let mutable validParams = true
let mutable ended = false
while j < len && not ended do
let c = text[j]
if isFinal c then
ended <- true
else
if not (System.Char.IsDigit c || c = ';' || c = ':') then
validParams <- false
j <- j + 1
if ended && text[j] = 'm' && validParams then
keep (text.Substring(i, j - i + 1))
if ended then j + 1 else len
else
i + 1

/// Terminal columns occupied by text that may carry SGR styling.
///
/// `ofString` is only meaningful for control-free text; this skips escapes and control characters and sums
/// the rest, so a styled row can be measured in one call.
let styledWidth (text : string) : int =
let mutable total = 0
let mutable i = 0

while i < text.Length do
if text[i] = '\u001b' then
i <- skipEscape text i (fun _ -> ())
elif System.Char.IsControl text[i] then
i <- i + 1
else
let cluster = System.Globalization.StringInfo.GetNextTextElement(text, i)
total <- total + clusterWidth cluster
i <- i + cluster.Length

total

/// Clip styled text to `maxWidth` terminal columns, keeping ANSI styling and dropping everything else.
///
/// Colour/style escapes (`ESC[...m`) are retained and cost no columns. Every other escape and control
/// character is dropped, so dynamic content can't move the cursor or change modes, and a double-width
/// cluster is never split in half.
///
/// Native because this needs a display-width lookup per character, and a full-screen frame is hundreds
/// of clipped spans.
let clipToWidth (text : string) (maxWidth : int) : string =
if maxWidth <= 0 then
""
else
let out = System.Text.StringBuilder()
let append (v : string) = out.Append(v) |> ignore<System.Text.StringBuilder>
let mutable remaining = maxWidth
let mutable i = 0

while i < text.Length && remaining > 0 do
if text[i] = '\u001b' then
i <- skipEscape text i append
elif System.Char.IsControl text[i] then
i <- i + 1
else
let cluster = System.Globalization.StringInfo.GetNextTextElement(text, i)
let width = clusterWidth cluster
if width > remaining then
remaining <- 0
else
append cluster
remaining <- remaining - width
i <- i + cluster.Length

out.ToString()


/// Wrap text into explicit terminal-width rows, preserving any ANSI styling it carries.
///
/// "SGR" is the ANSI escape that sets colour and style (`ESC[1;31m` and friends). Those are kept and
/// cost zero columns; every other escape and control character is dropped. A grapheme cluster is never
/// split, styling active at a wrap is reapplied at the start of the next row (the frame renderer resets
/// styling after each row), and an empty input yields one empty row.
///
/// Native rather than Dark because it runs on the interactive prompt on *every keystroke*, once per
/// character, and each character needs a display-width lookup.
let wrapStyled (text : string) (maxWidth : int) : string list =
let width = max 1 maxWidth
let completed = ResizeArray<string>()
let current = System.Text.StringBuilder()
let mutable activeStyle = ""
let mutable currentWidth = 0
let mutable wrapPending = false
let mutable i = 0

while i < text.Length do
if text[i] = '\u001b' then
let mutable kept = ""
let next = skipEscape text i (fun s -> kept <- s)
// Mirrors Dark's `nextActiveStyle`: a full reset clears accumulated styling, any other retained
// SGR appends to it, and a dropped (non-SGR) escape leaves it alone.
if kept = "\u001b[0m" then activeStyle <- ""
elif kept <> "" then activeStyle <- activeStyle + kept
current.Append(kept) |> ignore<System.Text.StringBuilder>
i <- next
elif System.Char.IsControl text[i] then
i <- i + 1
else
let cluster = System.Globalization.StringInfo.GetNextTextElement(text, i)
let charWidth = clusterWidth cluster
let shouldWrap =
wrapPending || (currentWidth > 0 && currentWidth + charWidth > width)

if shouldWrap then
completed.Add(current.ToString())
current.Clear() |> ignore<System.Text.StringBuilder>
current.Append(activeStyle) |> ignore<System.Text.StringBuilder>

current.Append(cluster) |> ignore<System.Text.StringBuilder>
currentWidth <- if shouldWrap then charWidth else currentWidth + charWidth
wrapPending <- currentWidth >= width
i <- i + cluster.Length

completed.Add(current.ToString())
List.ofSeq completed

/// Zero-based cursor position immediately after plain text.
///
/// A cursor exactly after the final column is reported at column zero of the following row, matching
/// terminal wrap behaviour. Plain text only: callers pass an already-stripped prompt prefix, so there
/// is no escape handling here.
let positionAfter (text : string) (maxWidth : int) : int * int =
let width = max 1 maxWidth
let mutable row = 0
let mutable column = 0
let mutable wrapPending = false
let mutable i = 0

while i < text.Length do
let cluster = System.Globalization.StringInfo.GetNextTextElement(text, i)
let charWidth = clusterWidth cluster
let startRow = if wrapPending then row + 1 else row
let startColumn = if wrapPending then 0 else column
let shouldWrap = startColumn > 0 && startColumn + charWidth > width
row <- if shouldWrap then startRow + 1 else startRow
column <- if shouldWrap then charWidth else startColumn + charWidth
wrapPending <- column >= width
i <- i + cluster.Length

if wrapPending then (row + 1, 0) else (row, column)


/// Report raw terminal facts used by Dark's TUI availability policy.
module TerminalCapabilities =
let isInputTerminal () : bool = not System.Console.IsInputRedirected

Expand Down Expand Up @@ -350,8 +136,12 @@ let fns () : List<BuiltInFn> =
fn =
(function
| _, _, _, [| DUnit |] ->
// Per no-color.org, only a non-empty value counts: `NO_COLOR=` is how a
// wrapper re-enables color without having to unset the variable.
let noColor =
System.Environment.GetEnvironmentVariable "NO_COLOR" |> isNull |> not
System.Environment.GetEnvironmentVariable "NO_COLOR"
|> System.String.IsNullOrEmpty
|> not
DBool(not noColor && TerminalCapabilities.isOutputTerminal ()) |> Ply
| _ -> incorrectArgs ())
sqlSpec = NotQueryable
Expand Down Expand Up @@ -493,28 +283,6 @@ let fns () : List<BuiltInFn> =
deprecated = NotDeprecated }


{ name = fn "cliTerminalInspectText" 0
typeParams = []
parameters = [ Param.make "text" TString "One candidate logical terminal row" ]
returnType = TTuple(TInt, TBool, [])
description =
"Return (display width when control-free, contains control characters)"
fn =
(function
| _, _, _, [| DString text |] ->
DTuple(
text |> DisplayWidth.ofString |> bigint |> Dval.int,
text |> DisplayWidth.containsControl |> DBool,
[]
)
|> Ply
| _ -> incorrectArgs ())
sqlSpec = NotQueryable
previewable = Pure
capabilities = LibExecution.Capabilities.noCaps
deprecated = NotDeprecated }


{ name = fn "cliTerminalSessionInfo" 0
typeParams = []
parameters = [ Param.make "unit" TUnit "A unit" ]
Expand Down
23 changes: 22 additions & 1 deletion backend/src/Builtins/Builtins.Pure/Libs/String.fs
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Original file line number Diff line number Diff line change
Expand Up @@ -15,7 +15,28 @@ module Interpreter = LibExecution.Interpreter
module Blob = LibExecution.Blob

let fns () : List<BuiltInFn> =
[ { name = fn "stringToList" 0
[ { name = fn "stringInspectText" 0
typeParams = []
parameters = [ Param.make "text" TString "One candidate logical terminal row" ]
returnType = TTuple(TInt, TBool, [])
description =
"Return (display width in terminal columns when control-free, contains control characters)"
fn =
(function
| _, _, _, [| DString text |] ->
DTuple(
text |> LibExecution.DisplayWidth.ofString |> bigint |> Dval.int,
text |> LibExecution.DisplayWidth.containsControl |> DBool,
[]
)
|> Ply
| _ -> incorrectArgs ())
sqlSpec = NotQueryable
previewable = Pure
capabilities = LibExecution.Capabilities.noCaps
deprecated = NotDeprecated }

{ name = fn "stringToList" 0
typeParams = []
parameters = [ Param.make "s" TString "" ]
returnType = TList TChar
Expand Down
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