Add terminalutils

src/fusion/terminalutils.nim

@@ -0,0 +1,99 @@
+## * Utilities and convenience procs built on top of `terminal` module.
+##
+## License
+## =======
+##
+## `promptInteractive` code is based and adapted from
+## `Nimble source code <https://github.com/nim-lang/nimble/blob/master/src/nimblepkg/cli.nim>`_
+## to Nim stdlib, Nimble is distributed with Nim, Nimble itself is under the following license:
+##
+## Copyright (c) 2015, Dominik Picheta
+## All rights reserved.
+##
+## Redistribution and use in source and binary forms, with or without
+## modification, are permitted provided that the following conditions are met:
+## 1. Redistributions of source code must retain the above copyright
+##    notice, this list of conditions and the following disclaimer.
+## 2. Redistributions in binary form must reproduce the above copyright
+##    notice, this list of conditions and the following disclaimer in the
+##    documentation and/or other materials provided with the distribution.
+## 3. Neither the name of Nimble nor the
+##    names of its contributors may be used to endorse or promote products
+##    derived from this software without specific prior written permission.
+##
+## THIS SOFTWARE IS PROVIDED BY DOMINIK PICHETA ''AS IS'' AND ANY
+## EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+## WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+## DISCLAIMED. IN NO EVENT SHALL DOMINIK PICHETA BE LIABLE FOR ANY
+## DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+## (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+## LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+## ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+## (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+## SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+##
+##
+## See also:
+## * `terminal <terminal.html>`_
+import terminal
+
+
+proc promptInteractive*(question: string; answers: openArray[string]; width: Positive; indicators = ['>', '<']): string =
+  ## Terminal prompt that asks a `question` and returns only one of the answers from possible `answers`.
+  ##
+  ## .. code-block:: Nim
+  ##   echo promptInteractive("Is Schrödinger's Cat alive?", ["yes", "no", "maybe"], 40, ['>', '-'])
+  ##
+  writeStyled(question, {styleBright})
+  var
+    current = 0
+    selected = false
+  # Incase the cursor is at the bottom of the terminal
+  for arg in answers: stdout.write "\n"
+  # Reset the cursor to the start of the selection prompt
+  cursorUp(stdout, answers.len)
+  cursorForward(stdout, width)
+  hideCursor(stdout)
+
+  # The selection loop
+  while not selected:
+    setForegroundColor(fgDefault)
+    # Loop through the options
+    for i, arg in answers:
+      # Check if the option is the current
+      if i == current:
+        writeStyled($indicators[0] & " " & arg & " " & $indicators[1], {styleBright, styleUnderscore})
+      else:
+        writeStyled("  " & arg & "  ", {styleDim})
+      # Move the cursor back to the start
+      stdout.cursorBackward(arg.len + 4)
+      # Move down for the next item
+      cursorDown(stdout)
+    # Move the cursor back up to the start of the selection prompt
+    stdout.cursorUp(answers.len)
+    resetAttributes(stdout)
+
+    # Ensure that the screen is updated before input
+    flushFile(stdout)
+    # Begin key input
+    while true:
+      case getch():
+      of '\t', '\x1B':
+        current = (current + 1) mod answers.len
+        break
+      of '\r', ' ':
+        selected = true
+        break
+      of '\3':
+        showCursor(stdout)
+        raise newException(OSError, "Keyboard interrupt")
+      else: discard
+
+  # Erase all lines of the selection
+  for i in 0 ..< answers.len:
+    eraseLine(stdout)
+    cursorDown(stdout)
+  # Move the cursor back up to the initial selection line
+  stdout.cursorUp(answers.len)
+  showCursor(stdout)
+  result = answers[current]