implement an interactive "chooser"

config.nims

@@ -12,7 +12,8 @@ task docs, "Deploy doc html + search index to public/ directory":
     deployDir = getCurrentDir() / "public"
     pkgName = "hwylterm"
     gitUrl = fmt"https://github.com/daylinmorgan/{pkgName}"
-  selfExec fmt"doc --docRoot:{getCurrentDir()}/src/ --index:on --outdir:{deployDir} src/hwylterm/cli"
+  for module in ["cli", "chooser"]:
+    selfExec fmt"doc --docRoot:{getCurrentDir()}/src/ --index:on --outdir:{deployDir} src/hwylterm/{module}"
   selfExec fmt"doc --project --index:on --git.url:{gitUrl} --git.commit:main --outdir:{deployDir} --project src/{pkgName}.nim"
   withDir deployDir:
     mvFile(pkgName & ".html", "index.html")
@@ -24,3 +25,4 @@ task docs, "Deploy doc html + search index to public/ directory":
 
 when withDir(thisDir(), system.dirExists("nimbledeps")):
   --path:"./nimbledeps/pkgs2/cligen-1.7.5-f3ffe7329c8db755677d3ca377d02ff176cec8b1"
+  --path:"./nimbledeps/pkgs2/illwill-0.4.1-9c58351502f89a16caf031cbd1992ad3fdfd3c67"

src/hwylterm.nim

@@ -1,8 +1,10 @@
 ##[
   # Hwylterm
 
-  [see bbansi](./hwylterm/bbansi.html)
-  [see cli](./hwylterm/cli.html)
+  see also these utility modules:
+
+  - [cli](./hwylterm/cli.html), requires [cligen](https://github.com/c-blake/cligen)
+  - [chooser](./hwylterm/chooser.html), requires [illwill](https://github.com/johnnovak/illwill)
 ]##
 
 import hwylterm/[spin, bbansi]

src/hwylterm/chooser.nim

@@ -0,0 +1,139 @@
+##[
+  # Hwylterm Chooser
+
+  ```nim
+  import hwylterm/chooser
+
+  let items = ["a","b","c"]
+  let item = choose(items)
+  ```
+]##
+
+
+import std/[enumerate, os, strutils, sequtils, sets, terminal]
+
+template canImport(x): bool = compiles: import x
+when not canImport(illwill): {.fatal: "hwylterm/choose requires illwill >= 0.4.1".}
+import illwill
+
+
+proc exitProc() {.noconv.} =
+  illwillDeInit()
+  showCursor()
+
+proc quitProc() {.noconv.} =
+  exitProc()
+  quit(0)
+
+type
+  State = object
+    lastKey: Key
+    buffer: string
+    selections: HashSet[Natural]
+    height, max, pos, low, high: Natural
+
+func newState[T](things: openArray[T], height: Natural): State =
+  result.max = len(things) - 1
+  result.height = height
+  result.high = height
+
+func up(s: var State) =
+  if s.pos > 0: dec s.pos
+  if (s.pos < s.low):
+      dec s.low
+      dec s.high
+
+func down(s: var State) =
+  if s.pos < s.max:
+    inc s.pos
+  if ((s.pos - s.low) > s.height) and
+     (s.pos > s.high) and
+     (s.high < s.max):
+      inc s.low
+      inc s.high
+
+func pressed(s: var State, k: Key) = s.lastKey = k
+
+func select(s: var State ) =
+  s.selections =
+    symmetricDifference(s.selections, toHashSet([s.pos]))
+
+proc clip(s: string, length: int): string =
+  if s.len > length: s[0..length]
+  else: s
+
+# proc addHelp(s: var screen) =
+
+func addThingsWindow[T](state: var State, things: openArray[T]) =
+  var window: string
+  for i, t in enumerate(things[state.low..state.high]):
+    window.add (
+      if (i + state.low) == state.pos: ">"
+      else: " "
+    )
+    window.add (
+      if (i + state.low) in state.selections: ">"
+      else: " "
+    )
+    window.add $t
+    window.add "\n"
+  state.buffer.add window
+
+
+proc draw(s: var State) =
+  let maxWidth = terminalWidth()
+  var lines= (
+    s.buffer.splitLines().mapIt(("  " & it).clip(maxWidth).alignLeft(maxWidth))
+  )
+  when defined(debugChoose):
+    lines = @[$s] & lines
+
+  for l in lines:
+    stdout.writeLine l
+
+  cursorUp lines.len
+  flushFile stdout
+  s.buffer = ""
+
+proc getSelections[T](state: State, things: openArray[T]): seq[T] =
+  if state.selections.len == 0:
+    result.add things[state.pos]
+  for i in state.selections:
+    result.add things[i]
+
+
+proc choose*[T](things: openArray[T], height: Natural = 6): seq[T] =
+  illwillInit(fullscreen = false)
+  setControlCHook(quitProc)
+  hideCursor()
+
+  var state = newState(things, height)
+
+  while true:
+    var key = getKey()
+    pressed(state, key)
+    case key:
+    of Key.None: discard
+    of Key.Down, Key.J:
+      down state
+    of Key.Up, Key.K:
+      up state
+    of Key.Tab:
+      select state
+    of Key.Enter:
+      exitProc()
+      return getSelections(state, things)
+    else: discard
+
+    addThingsWindow(state, things)
+    draw state
+    sleep 20
+
+
+when isMainModule:
+  let items = LowercaseLetters.toSeq()
+  let item = choose(items)
+  echo "selected: ", item
+
+
+

src/hwylterm/cli.nim

@@ -4,8 +4,10 @@
   Adapter to add hwylterm colors to cligen output.
 ]##
 import std/[tables]
-import cligen
 import ./bbansi
+template canImport(x): bool = compiles: import x
+when not canImport(cligen): {.fatal: "hwylterm/cli requires cligen>= 1.7.5".}
+import cligen
 
 
 type

tools/tools.nimble

@@ -5,7 +5,10 @@ author        = "Daylin Morgan"
 description   = "bringing some fun (hwyl) to the terminal"
 license       = "MIT"
 srcDir        = "../src"
-namedBin      = {"hwylterm/bbansi":"bbansi"}.toTable
+namedBin      = {
+  "hwylterm/bbansi" :"bbansi",
+  "hwylterm/chooser":"hwylchoose"
+}.toTable
 
 
 requires "nim >= 2.0.8"