terminal

This module contains a few procedures to control the terminal (also called console). On UNIX, the implementation simply uses ANSI escape sequences and does not depend on any other module, on Windows it uses the Windows API. Changing the style is permanent even after program termination! Use the code system.addQuitProc(resetAttributes) to restore the defaults. Similarly, if you hide the cursor, make sure to unhide it with showCursor before quitting.

Types

Style = enum
  styleBright = 1,              ## bright text
  styleDim,                   ## dim text
  styleItalic,                ## italic (or reverse on terminals not supporting)
  styleUnderscore,            ## underscored text
  styleBlink,                 ## blinking/bold text
  styleBlinkRapid,            ## rapid blinking/bold text (not widely supported)
  styleReverse,               ## reverse
  styleHidden,                ## hidden text
  styleStrikethrough          ## strikethrough
different styles for text output   Source Edit
ForegroundColor = enum
  fgBlack = 30,                 ## black
  fgRed,                      ## red
  fgGreen,                    ## green
  fgYellow,                   ## yellow
  fgBlue,                     ## blue
  fgMagenta,                  ## magenta
  fgCyan,                     ## cyan
  fgWhite,                    ## white
  fg8Bit,                     ## 256-color (not supported, see ``enableTrueColors`` instead.)
  fgDefault                   ## default terminal foreground color
terminal's foreground colors   Source Edit
BackgroundColor = enum
  bgBlack = 40,                 ## black
  bgRed,                      ## red
  bgGreen,                    ## green
  bgYellow,                   ## yellow
  bgBlue,                     ## blue
  bgMagenta,                  ## magenta
  bgCyan,                     ## cyan
  bgWhite,                    ## white
  bg8Bit,                     ## 256-color (not supported, see ``enableTrueColors`` instead.)
  bgDefault                   ## default terminal background color
terminal's background colors   Source Edit
TerminalCmd = enum
  resetStyle,                 ## reset attributes
  fgColor,                    ## set foreground's true color
  bgColor                     ## set background's true color
commands that can be expressed as arguments   Source Edit

Procs

proc terminalWidthIoctl(handles: openArray[Handle]): int {...}{.raises: [], tags: [].}
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proc terminalHeightIoctl(handles: openArray[Handle]): int {...}{.raises: [], tags: [].}
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proc terminalWidth(): int {...}{.raises: [], tags: [].}
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proc terminalHeight(): int {...}{.raises: [], tags: [].}
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proc terminalSize(): tuple[w, h: int] {...}{.raises: [], tags: [].}
Returns the terminal width and height as a tuple. Internally calls terminalWidth and terminalHeight, so the same assumptions apply.   Source Edit
proc hideCursor(f: File) {...}{.raises: [Exception, OSError], tags: [RootEffect].}
Hides the cursor.   Source Edit
proc showCursor(f: File) {...}{.raises: [Exception, OSError], tags: [RootEffect].}
Shows the cursor.   Source Edit
proc setCursorPos(f: File; x, y: int) {...}{.raises: [Exception, OSError], tags: [RootEffect].}
Sets the terminal's cursor to the (x,y) position. (0,0) is the upper left of the screen.   Source Edit
proc setCursorXPos(f: File; x: int) {...}{.raises: [Exception, OSError], tags: [RootEffect].}
Sets the terminal's cursor to the x position. The y position is not changed.   Source Edit
proc setCursorYPos(f: File; y: int) {...}{.raises: [Exception, OSError], tags: [RootEffect].}
Sets the terminal's cursor to the y position. The x position is not changed. Warning: This is not supported on UNIX!   Source Edit
proc cursorUp(f: File; count = 1) {...}{.raises: [Exception, OSError], tags: [RootEffect].}
Moves the cursor up by count rows.   Source Edit
proc cursorDown(f: File; count = 1) {...}{.raises: [Exception, OSError], tags: [RootEffect].}
Moves the cursor down by count rows.   Source Edit
proc cursorForward(f: File; count = 1) {...}{.raises: [Exception, OSError], tags: [RootEffect].}
Moves the cursor forward by count columns.   Source Edit
proc cursorBackward(f: File; count = 1) {...}{.raises: [Exception, OSError],
                                    tags: [RootEffect].}
Moves the cursor backward by count columns.   Source Edit
proc eraseLine(f: File) {...}{.raises: [Exception, OSError], tags: [RootEffect].}
Erases the entire current line.   Source Edit
proc eraseScreen(f: File) {...}{.raises: [Exception, OSError], tags: [RootEffect].}
Erases the screen with the background colour and moves the cursor to home.   Source Edit
proc resetAttributes(f: File) {...}{.raises: [Exception], tags: [RootEffect].}
Resets all attributes.   Source Edit
proc ansiStyleCode(style: int): string {...}{.raises: [ValueError], tags: [].}
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proc setStyle(f: File; style: set[Style]) {...}{.raises: [Exception], tags: [RootEffect].}
Sets the terminal style.   Source Edit
proc writeStyled(txt: string; style: set[Style] = {styleBright}) {...}{.
    raises: [Exception, IOError], tags: [RootEffect, WriteIOEffect].}
Writes the text txt in a given style to stdout.   Source Edit
proc setForegroundColor(f: File; fg: ForegroundColor; bright = false) {...}{.
    raises: [Exception], tags: [RootEffect].}
Sets the terminal's foreground color.   Source Edit
proc setBackgroundColor(f: File; bg: BackgroundColor; bright = false) {...}{.
    raises: [Exception], tags: [RootEffect].}
Sets the terminal's background color.   Source Edit
proc ansiForegroundColorCode(fg: ForegroundColor; bright = false): string {...}{.
    raises: [ValueError], tags: [].}
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proc ansiForegroundColorCode(color: Color): string {...}{.raises: [ValueError], tags: [].}
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proc ansiBackgroundColorCode(color: Color): string {...}{.raises: [ValueError], tags: [].}
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proc setForegroundColor(f: File; color: Color) {...}{.
    raises: [Exception, IOError, ValueError], tags: [RootEffect, WriteIOEffect].}
Sets the terminal's foreground true color.   Source Edit
proc setBackgroundColor(f: File; color: Color) {...}{.
    raises: [Exception, IOError, ValueError], tags: [RootEffect, WriteIOEffect].}
Sets the terminal's background true color.   Source Edit
proc isatty(f: File): bool {...}{.raises: [], tags: [].}
Returns true if f is associated with a terminal device.   Source Edit
proc getch(): char {...}{.raises: [], tags: [].}
Read a single character from the terminal, blocking until it is entered. The character is not printed to the terminal.   Source Edit
proc readPasswordFromStdin(prompt: string; password: var TaintedString): bool {...}{.
    tags: [ReadIOEffect, WriteIOEffect], raises: [IOError].}
Reads a password from stdin without printing it. password must not be nil! Returns false if the end of the file has been reached, true otherwise.   Source Edit
proc readPasswordFromStdin(prompt = "password: "): TaintedString {...}{.raises: [IOError],
    tags: [ReadIOEffect, WriteIOEffect].}
Reads a password from stdin without printing it.   Source Edit
proc resetAttributes() {...}{.noconv, raises: [Exception], tags: [RootEffect].}
Resets all attributes on stdout. It is advisable to register this as a quit proc with system.addQuitProc(resetAttributes).   Source Edit
proc isTrueColorSupported(): bool {...}{.raises: [Exception], tags: [RootEffect].}
Returns true if a terminal supports true color.   Source Edit
proc enableTrueColors() {...}{.raises: [Exception], tags: [RootEffect, ReadEnvEffect].}
Enable true color.   Source Edit
proc disableTrueColors() {...}{.raises: [Exception], tags: [RootEffect, ReadEnvEffect].}
Disable true color.   Source Edit

Macros

macro styledWrite(f: File; m: varargs[typed]): untyped

Similar to write, but treating terminal style arguments specially. When some argument is Style, set[Style], ForegroundColor, BackgroundColor or TerminalCmd then it is not sent directly to f, but instead corresponding terminal style proc is called.

Example:

stdout.styledWrite(fgRed, "red text ")
stdout.styledWrite(fgGreen, "green text")
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Templates

template ansiStyleCode(style: Style): string
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template ansiStyleCode(style: static[Style]): string
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template ansiForegroundColorCode(fg: static[ForegroundColor];
                                bright: static[bool] = false): string
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template ansiForegroundColorCode(color: static[Color]): string
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template ansiBackgroundColorCode(color: static[Color]): string
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template styledWriteLine(f: File; args: varargs[untyped])

Calls styledWrite and appends a newline at the end.

Example:

proc error(msg: string) =
  styledWriteLine(stderr, fgRed, "Error: ", resetStyle, msg)
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template styledEcho(args: varargs[untyped])
Echoes styles arguments to stdout using styledWriteLine.   Source Edit
template hideCursor()
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template showCursor()
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template setCursorPos(x, y: int)
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template setCursorXPos(x: int)
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template setCursorYPos(x: int)
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template cursorUp(count = 1)
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template cursorDown(count = 1)
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template cursorForward(count = 1)
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template cursorBackward(count = 1)
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template eraseLine()
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template eraseScreen()
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template setStyle(style: set[Style])
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template setForegroundColor(fg: ForegroundColor; bright = false)
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template setBackgroundColor(bg: BackgroundColor; bright = false)
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template setForegroundColor(color: Color)
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template setBackgroundColor(color: Color)
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