Add truecolor and unicode support to terminal utilities.

cliutils/ansiterm.nim

@@ -1,11 +1,19 @@
-import std/[nre, sequtils]
+import std/[nre, sequtils, strutils, unicode]
+
+# See
+# - https://gist.github.com/ConnerWill/d4b6c776b509add763e17f9f113fd25b
+# - https://en.wikipedia.org/wiki/ANSI_escape_code
 
 const CSI = "\x1b["
 const RESET_FORMATTING* = "\x1b[0m"
-const ANSI_ESCAPE_CODE_ENDINGS*: seq[char] = toSeq('A'..'Z') & toSeq('a'..'z')
+const ANSI_ESCAPE_CODE_ENDINGS*: seq[Rune] =
+  toRunes(toSeq('A'..'Z') & toSeq('a'..'z'))
+
 let FORMATTING_REGEX* = re("\x1b\\[([0-9;]*)([a-zA-Z])")
 
 type
+  TrueColor* = tuple[r, g, b: int]
+
   CursorType* = enum
     ctBlockBlink = 1, ctBlock, ctUnderlineBlink, ctUnderline, ctBarBlink, ctBar
 
@@ -13,8 +21,15 @@ type
     emToEnd, emToStart, emAll
 
   TerminalColors* = enum
-    cBlack, cRed, cGreen, cYellow, cBlue, cMagenta, cCyan, cWhite
+    cBlack = 0, cRed, cGreen, cYellow, cBlue, cMagenta, cCyan, cWhite,
+    cDefault = 9
 
+    cBrightBlack = 60, cBrightRed, cBrightGreen, cBrightYellow, cBrightBlue,
+    cBrightMagenta, cBrightCyan, cBrightWhite
+
+  TerminalStyle* = enum
+    tsBold = 1, tsDim, tsItalic, tsUnderline, tsBlink, tsInverse, tsHidden,
+    tsStrikethrough
 
 proc stripFormatting*(text: string): string =
   text.replace(FORMATTING_REGEX, "")
@@ -22,47 +37,92 @@ proc stripFormatting*(text: string): string =
 proc stripAnsi*(text: string): string = stripFormatting(text)
 
 func ansiAwareSubstring*(s: string, start, length: int): string =
-  result = ""
-  var curAnsiEscCode = ""
+  var outputRunes = newSeq[Rune]()
+  var curAnsiSequences = newSeq[Rune]()
+  var runes = s.toRunes
+  var visibleRunesSeen = 0
+  var visibleOutputLen = 0
   var i = 0
-  var visibleLen = 0
 
-  while i < len(s) and visibleLen < length:
+  while i < runes.len and visibleOutputLen < length:
 
-    if len(s) > i + len(CSI) and
-      # We need to notice ANSI escape codes...
-       s[i..<i + len(CSI)] == CSI:
-      var j = i + len(CSI)
-      while j < s.len and s[j] notin ANSI_ESCAPE_CODE_ENDINGS: j += 1
+    if runes.len > i + runeLen(CSI) and
+       $runes[i..<i + len(CSI)] == CSI:
+      # Recognize ANSI escape codes...
+
+      var j = i + runeLen(CSI)
+      while j < runes.len and runes[j] notin ANSI_ESCAPE_CODE_ENDINGS: j += 1
 
       # and remember it if we're before the start of the substring
-      if i < start: curAnsiEscCode = s[i..j]
+      if visibleRunesSeen < start: curAnsiSequences.add(runes[i..j])
 
-      # or add it without increasing our substring length
-      else: result.add(s[i..j])
+      # or add it to the output without increasing our substring length
+      else: outputRunes.add(runes[i..j])
 
       # either way we want to pick up after it
       i = j
 
     else:
-      result.add(s[i])
-      visibleLen += 1
+      if visibleRunesSeen >= start:
+        outputRunes.add(runes[i])
+        inc visibleOutputLen
+      inc visibleRunesSeen
 
-    i += 1
+    inc i
 
-  result = curAnsiEscCode & result
-
-func color*(text: string, fg = cWhite, bg = cBlack): string =
-  return CSI & $int(fg) & ";" & $(int(bg) + 40) & "m" & text & RESET_FORMATTING
+    result = $(curAnsiSequences & outputRunes)
 
 
-func color*(text: string, fg: TerminalColors): string =
-  return CSI & $int(fg) & "m" & text & RESET_FORMATTING
+func ansiAwareSubstring*[T, U](s: string, r: HSlice[T,U]): string =
+  let idxStart =
+    when r.a is BackwardsIndex: s.runeLen - int(r.a)
+    else: int(r.a)
+
+  let idxEnd =
+    when r.b is BackwardsIndex: s.runeLen - int(r.b)
+    else: int(r.b)
+
+  ansiAwareSubstring(s, idxStart, idxEnd - idxStart + 1)
 
 
-func color*(text: string, bg: TerminalColors): string =
-  return CSI & $(int(bg) + 40) & "m" & text & RESET_FORMATTING
+func ansiEscSeq*(style: set[TerminalStyle]): string =
+  CSI & toSeq(style).mapIt($int(it)).join(";") & "m"
 
+func ansiEscSeq*(fg: int): string = CSI & "38;5;" & $fg & "m"
+func ansiEscSeq*(bg: int): string = CSI & "48;5;" & $bg & "m"
+
+
+func ansiEscSeq*(fg: TrueColor): string =
+  "$#38;2;$#;$#;$#m" % [CSI, $fg.r, $fg.g, $fg.b]
+
+func ansiEscSeq*(bg: TrueColor): string =
+  "$#48;2;$#;$#;$#m" % [CSI, $bg.r, $bg.g, $bg.b]
+
+
+func ansiEscSeq*(fg: TerminalColors): string = CSI & $(int(fg) + 30) & "m"
+func ansiEscSeq*(bg: TerminalColors): string = CSI & $(int(bg) + 40) & "m"
+
+
+func ansiEscSeq*(fg: TerminalColors, bg: TerminalColors, style: set[TerminalStyle]): string =
+  result = CSI
+  if style != {}: result &= toSeq(style).mapIt($int(it)).join(";") & ";"
+  result &= $(int(fg) + 30) & ";" & $(int(bg) + 40) & "m"
+
+
+func termFmt*(text: string, fg = cWhite, bg = cBlack, style: set[TerminalStyle] = {}): string =
+  return ansiEscSeq(fg, bg, style) & text & RESET_FORMATTING
+
+
+func termFmt*[C: int | TrueColor](
+    text: string,
+    fg, bg: C,
+    style: set[TerminalStyle] = {}): string =
+  return ansiEscSeq(style) & ansiEscSeq(fg = fg) & ansiEscSeq(bg = bg) &
+    text & RESET_FORMATTING
+
+
+func color*(text: string, fg = cDefault, bg = cDefault): string =
+  return termFmt(text, fg, bg, {})
 
 func invert*(text: string): string = return CSI & "7m" & text & RESET_FORMATTING
 func striketrough*(text: string): string = return CSI & "9m" & text & RESET_FORMATTING