Use better heuristics for chord pitch naming.

Previously we used a heuristic for choosing pitch names based on the
major scale degree, minimizing radicals. So, for example, in the key of
Gb, we render the 4 as Cb rather than B because Bb is the 3 of Gb. In
other words, we want 1:Gb, 2:Ab, 3:Bb, 4:Cb instead of re-using B. This
is standard practice in western music notation.

When rendering non-diatonic notes we prefered choosing the version that
minimized the radicals. Again in the key of Gb we would choose to render
E as E (the #6) rather than considering it as Fb (the b7) and choose to
render D as D (the #5) rather than E𝄫 (the b6). This was chosen to
reduce the number of unusual radicals like 𝄫.

However, in practice this leads to unusual charts because it is more
common when writing chordal harmony to use the b6 rather than the #5.
Similarly the b7 is far more common than the #6. This is, I think, due
to the prevalence of the major scale and minor scales and the fact that
the minor scale is built from flatting the 3, 6, and 7 of the major
scale. So when thinking in a key-center agnostic manner (like numbers)
we almost always think about these altered scale degrees as being
flatted relative to the major scale, not sharped. Because of this, in
the key of Gb, we would prefer to render a b6, b7, 1 chord walkup as
E𝄫, Fb, Gb rather than D, E, Gb.

This change redefines the heuristic used to name chord pitches to follow
a heuristic that covers all pitches in the octave based on scale degree:
1, b2, 2, b3, 3, 4, b5, 5, b6, 6, b7, 7

pco_chords.nimble

@@ -1,6 +1,6 @@
 # Package
 
-version       = "0.4.1"
+version       = "0.5.6"
 author        = "Jonathan Bernard"
 description   = "Chord chart formatter compatible with Planning Center Online"
 license       = "MIT"
@@ -12,3 +12,9 @@ bin           = @["pco_chords"]
 # Dependencies
 
 requires "nim >= 1.6.6", "docopt", "zero_functional"
+
+# Dependencies from git.jdbernard.com/jdb/nim-package
+requires "update_nim_package_version"
+
+task updateVersion, "Update the version of this tool.":
+  exec "update_nim_package_version pco_chords 'src/pco_chordspkg/cliconstants.nim'"

src/pco_chords.nim

@@ -34,11 +34,21 @@ when isMainModule:
     $ast & "\p" &
     "-".repeat(16) & "\p"
 
-  let outputHtml = ast.toHtml()
+  let transpose =
+    if args["--transpose"]: parseInt($args["--transpose"])
+    else: 0
+
+  let outputHtml =
+    if args["--large-print"]:
+      ast.toHtml(transpose, args["--number-chart"],
+        stylesheets = @[LARGE_PRINT_STYLESHEET])
+    else:
+      ast.toHtml(transpose, args["--number-chart"])
+
   if args["--output"]: writeFile($args["--output"], outputHtml)
   else: stdout.write(outputHtml)
 
- except:
+ except CatchableError:
   fatal getCurrentExceptionMsg()
   debug getCurrentException().getStackTrace()
   quit(QuitFailure)

src/pco_chordspkg/ast.nim

@@ -4,7 +4,7 @@ import zero_functional
 type
   ChordChartMetadata* = object
     title*: string
-    key*: ChordChartPitch
+    key*: ChordChartChord
     optionalProps: StringTableRef
 
   ChordChart* = ref object
@@ -23,10 +23,10 @@ type
     ccnkRedefineKey,
     ccnkNone
 
-  ChordChartPitch* = enum Af, A, Bf, B, C, Df, D, Ef, E, F, Fs, G
+  ChordChartPitch* = enum Af, A, Bf, B, C, Df, D, Ef, E, F, Gf, G
 
   ChordChartChord* = object
-    original*: string
+    original*: Option[string]
     rootPitch*: ChordChartPitch
     flavor*: Option[string]
     bassPitch*: Option[ChordChartPitch]
@@ -35,6 +35,7 @@ type
     case kind: ChordChartNodeKind
     of ccnkSection:
       sectionName*: string
+      remainingSectionLine*: Option[string]
       sectionContents*: seq[ChordChartNode]
     of ccnkLine:
       line*: seq[ChordChartNode]
@@ -77,19 +78,88 @@ iterator pairs*(ccmd: ChordChartMetadata): tuple[key, value: string] =
 func kind*(ccn: ChordChartNode): ChordChartNodeKind = ccn.kind
 
 func `$`*(pitch: ChordChartPitch): string =
-  case pitch
-  of Af: "Ab"
-  of A: "A"
-  of Bf: "Bb"
-  of B: "B"
-  of C: "C"
-  of Df: "Db"
-  of D: "D"
-  of Ef: "Eb"
-  of E: "E"
-  of F: "F"
-  of Fs: "F#"
-  of G: "G"
+  ["A♭", "A", "B♭", "B", "C", "D♭", "D", "E♭", "E", "F", "G♭", "G"][ord(pitch)]
+
+func renderPitchInKey*(
+    pitch: ChordChartPitch,
+    key: ChordChartPitch,
+    useSharps: Option[bool] = none[bool]()): string =
+
+  var scaleNames: array[(ord(high(ChordChartPitch)) + 1), string]
+  if useSharps.isNone:
+    # If we aren't told to use sharps or flats, we render the diatonic pitches
+    # according to standard theory (C# in the key of D, Db in the key of Ab)
+    # but we render non-diatonic notes with flats (prefer the b6 and b7 over
+    # the #5 and #6).
+    #
+    # TODO: In the future, we should also remember the scale degree of the
+    # chord when parsing. So, for example, in the key of D we would parse Bb as
+    # the b6 and A# as the #5. The pitch would be the same, but the scale
+    # degree would differ. This would allow us to preserve intentional choices
+    # in the chart when transposing.
+    scaleNames = case key
+    of C:
+      ["A♭", "A", "B♭", "B", "C", "D♭", "D", "E♭", "E", "F", "G♭", "G"]
+    of G:
+      ["A♭", "A", "B♭", "B", "C", "D♭", "D", "E♭", "E", "F", "F#", "G"]
+    of D:
+      ["A♭", "A", "B♭", "B", "C", "C#", "D", "E♭", "E", "F", "F#", "G"]
+    of A:
+      ["G#", "A", "B♭", "B", "C", "C#", "D", "E♭", "E", "F", "F#", "G"]
+    of E:
+      ["G#", "A", "B♭", "B", "C", "C#", "D", "D#", "E", "F", "F#", "G"]
+    of B:
+      ["G#", "A", "A#", "B", "C", "C#", "D", "D#", "E", "F", "F#", "G"]
+    of Gf:
+      ["A♭", "B𝄫", "B♭", "C♭", "D𝄫", "D♭", "E𝄫", "E♭", "F♭", "F", "G♭", "A𝄫"]
+    of Df:
+      ["A♭", "B𝄫", "B♭", "C♭", "C", "D♭", "E𝄫", "E♭", "F♭", "F", "G♭", "A𝄫"]
+    of Af:
+      ["A♭", "B𝄫", "B♭", "C♭", "C", "D♭", "E𝄫", "E♭", "F♭", "F", "G♭", "G"]
+    of Ef:
+      ["A♭", "B𝄫", "B♭", "C♭", "C", "D♭", "D", "E♭", "F♭", "F", "G♭", "G"]
+    of Bf:
+      ["A♭", "A", "B♭", "C♭", "C", "D♭", "D", "E♭", "F♭", "F", "G♭", "G"]
+    of F:
+      ["A♭", "A", "B♭", "C♭", "C", "D♭", "D", "E♭", "E", "F", "G♭", "G"]
+
+
+  elif useSharps.isSome and useSharps.get:
+    scaleNames = case key
+    of A, B, C, D, E, G:
+      ["G#", "A", "A#", "B", "C", "C#", "D", "D#", "E", "F", "F#", "G"]
+    of Af:
+      ["G#", "A", "A#", "B", "B#", "C#", "D", "D#", "E", "E#", "F#", "F𝄪"]
+    of Bf:
+      ["G#", "G𝄪", "A#", "B", "B#", "C#", "C𝄪", "D#", "E", "E#", "F#", "F𝄪"]
+    of Df:
+      ["G#", "A", "A#", "B", "B#", "C#", "D", "D#", "E", "E#", "F#", "G"]
+    of Ef:
+      ["G#", "A", "A#", "B", "B#", "C#", "C𝄪", "D#", "E", "E#", "F#", "F𝄪"]
+    of Gf:
+      ["G#", "A", "A#", "B", "C", "C#", "D", "D#", "E", "E#", "F#", "G"]
+    of F:
+      ["G#", "G𝄪", "A#", "B", "B#", "C#", "C𝄪", "D#", "D𝄪", "E#", "F#", "F𝄪"]
+
+  else: # !useSharps (useSharps.isSome and not useSharps.get)
+    scaleNames = case key
+    of C, Af, Bf, Df, Ef, F:
+      ["A♭", "A", "B♭", "B", "C", "D♭", "D", "E♭", "E", "F", "G♭", "G"]
+    of A:
+      ["A♭", "B𝄫", "B♭", "C♭", "C", "D♭", "E𝄫", "E♭", "F♭", "F", "G♭", "G"]
+    of B:
+      ["A♭", "A", "B♭", "C♭", "C", "D♭", "D", "E♭", "F♭", "F", "G♭", "G"]
+    of D:
+      ["A♭", "B𝄫", "B♭", "C♭", "C", "D♭", "E𝄫", "E♭", "F♭", "F", "G♭", "A𝄫"]
+    of E:
+      ["A♭", "B𝄫", "B♭", "C♭", "C", "D♭", "D", "E♭", "F♭", "F", "G♭", "G"]
+    of G:
+      ["A♭", "B𝄫", "B♭", "C♭", "D𝄫", "D♭", "E𝄫", "E♭", "F♭", "F", "G♭", "A𝄫"]
+    of Gf:
+      ["A♭", "A", "B♭", "C♭", "C", "D♭", "D", "E♭", "E", "F", "G♭", "G"]
+
+
+  return scaleNames[ord(pitch)]
 
 func `+`*(pitch: ChordChartPitch, steps: int): ChordChartPitch =
   cast[ChordChartPitch]((ord(pitch) + steps) mod 12)
@@ -132,13 +202,15 @@ func dump*(ccn: ChordChartNode, indent = ""): string =
     if ccn.chord.isSome:
       let chord = ccn.chord.get
       result &= "["
-      if chord.flavor.isNone and chord.bassPitch.isNone:
-        result &= chord.original
+      if chord.original.isSome and chord.flavor.isNone and
+         chord.bassPitch.isNone:
+        result &= chord.original.get
       else:
+        result &= $chord.rootPitch
         if chord.flavor.isSome:
-          result &= $chord.rootPitch & "_" & chord.flavor.get
+          result &= "_" & chord.flavor.get
         if chord.bassPitch.isSome:
-          result &= $chord.rootPitch & "/" & $chord.bassPitch.get
+          result &= "/" & $chord.bassPitch.get
       result &= "]"
 
     if ccn.word.isSome: result &= ccn.word.get
@@ -184,27 +256,40 @@ template addToCurSection(n: ChordChartNode): untyped =
   if ctx.curSection.kind == ccnkSection: ctx.curSection.sectionContents.add(n)
   else: result.add(n)
 
-func parsePitch*(ctx: ParserContext, keyValue: string): ChordChartPitch =
-  case keyValue.strip.toLower
+proc parsePitch*(ctx: ParserContext, keyValue: string): ChordChartPitch =
+  let normK = keyValue.strip.toLower
+  case normK
   of "gs", "gis", "g#", "ab", "a♭", "af", "aes": return ChordChartPitch.Af
   of "g𝄪", "a", "a♮", "b𝄫": return ChordChartPitch.A
   of "as", "ais", "a#", "bf", "bb", "b♭", "bes", "c𝄫": return ChordChartPitch.Bf
-  of "a𝄪", "b", "cb", "ces", "cf": return ChordChartPitch.B
+  of "a𝄪", "b", "c♭", "cb", "ces", "cf": return ChordChartPitch.B
   of "bs", "bis", "b#", "c", "d𝄫": return ChordChartPitch.C
-  of "b𝄪", "cs", "cis", "c#", "df", "db", "des": return ChordChartPitch.Df
+  of "b𝄪", "cs", "cis", "c#", "d♭", "df", "db", "des": return ChordChartPitch.Df
   of "c𝄪", "d", "e𝄫": return ChordChartPitch.D
-  of "ds", "dis", "d#", "ef", "eb", "ees", "f𝄫": return ChordChartPitch.Ef
-  of "d𝄪", "e", "fes", "ff": return ChordChartPitch.E
+  of "ds", "dis", "d#", "ef", "e♭", "eb", "ees", "f𝄫": return ChordChartPitch.Ef
+  of "d𝄪", "e", "f♭", "fes", "ff": return ChordChartPitch.E
   of "es", "eis", "e#", "f", "g𝄫": return ChordChartPitch.F
-  of "e𝄪", "fs", "fis", "f#", "gf", "gb", "ges": return ChordChartPitch.Fs
+  of "e𝄪", "fs", "fis", "f#", "g♭", "gf", "gb", "ges": return ChordChartPitch.Gf
   of "f𝄪", "g", "a𝄫": return ChordChartPitch.G
+  of "#7", "1", "𝄫2": return ctx.curKeyCenter
+  of "𝄪7", "#1", "b2", "♭2": return ctx.curKeyCenter + 1
+  of "𝄪1", "2", "𝄫3": return ctx.curKeyCenter + 2
+  of "#2", "b3", "♭3", "𝄫4": return ctx.curKeyCenter + 3
+  of "𝄪2", "3", "b4", "♭4": return ctx.curKeyCenter + 4
+  of "#3", "4", "𝄫5": return ctx.curKeyCenter + 5
+  of "𝄪3", "#4", "b5", "♭5": return ctx.curKeyCenter + 6
+  of "𝄪4", "5", "𝄫6": return ctx.curKeyCenter + 7
+  of "#5", "b6", "♭6": return ctx.curKeyCenter + 8
+  of "𝄪5", "6", "𝄫7": return ctx.curKeyCenter + 9
+  of "#6", "b7", "♭7", "𝄫1": return ctx.curKeyCenter + 10
+  of "7", "b1", "♭1": return ctx.curKeyCenter + 11
   else: raise ctx.makeError(keyValue.strip & " is not a recognized key.")
 
 # see regexr.com/70nv1
 let CHORD_REGEX =
-  "([A-G1-7][b#♭♮𝄫𝄪]?)" &               #      chord root
-  "(([mM1-9#b♭♮𝄫𝄪Δ+oøoø][0-9]?|min|maj|aug|dim|sus|6\\/9|\\([1-9#b♭]+\\))*)" &  # chord flavor/type
-  "(\\/([A-G1-7][b#♭♮𝄫𝄪]?))?"             # optional bass
+  "([b#♭♮𝄫𝄪]?[A-G1-7][b#♭♮𝄫𝄪]?)" &               #      chord root
+  "((min|maj|aug|dim|sus|6\\/9|[mM1-9#b♭♮𝄫𝄪Δ+oøoø°𝆩][0-9]?|\\([1-9#b♭]+\\))*)" &  # chord flavor/type
+  "(\\/([b#♭♮𝄫𝄪]?[A-G1-7][b#♭♮𝄫𝄪]?))?"             # optional bass
 let CHORD_PAT = re(CHORD_REGEX)
 
 proc parseChord*(
@@ -225,7 +310,7 @@ proc parseChord*(
       else: none[ChordChartPitch]()
 
     return some(ChordChartChord(
-      original: chordValue,
+      original: some(chordValue),
       rootPitch: ctx.parsePitch(m.get.captures[0]),
       flavor: flavor,
       bassPitch: bassPitch))
@@ -235,8 +320,8 @@ let METADATA_END_PAT = re"^-+$"
 proc parseMetadata(ctx: var ParserContext): ChordChartMetadata =
 
   var title = "MISSING"
-  var songKey = "MISSING"
   var optProps = newStringTable()
+  var songKey: Option[ChordChartChord]
 
   while ctx.curLineNum < ctx.lines.len:
     let line = ctx.nextLine
@@ -251,28 +336,32 @@ proc parseMetadata(ctx: var ParserContext): ChordChartMetadata =
     let key = m.get.captures[0].strip.tolower
     let value = m.get.captures[1].strip
     if key == "title": title = value
-    elif key == "key": songKey = value
+    elif key == "key":
+      songKey = ctx.parseChord(value)
+      if songKey.isNone:
+        raise ctx.makeError("unrecognized key: " & value)
     else: optProps[key] = value
 
   if title == "MISSING":
     raise ctx.makeError("metadata is missing the 'title' property")
 
-  if songKey == "MISSING":
+  if songKey.isNone:
     raise ctx.makeError("metadata is missing the 'key' property")
 
   result = ChordChartMetadata(
     title: title,
-    key: ctx.parsePitch(songKey),
+    key: songKey.get,
     optionalProps: optProps)
 
 const KNOWN_SECTION_NAMES = [
   "chorus", "verse", "bridge", "breakdown", "vamp", "intstrumental",
-  "interlude", "intro", "outtro", "ending", "end", "tag"
+  "interlude", "intro", "outtro", "ending", "end", "tag", "prechorus",
+  "pre-chorus", "pre chorus"
 ]
 
 let SECTION_LINE_PAT = re(
-  "^((" &                                         # case insensitive
-  "((?i)" & KNOWN_SECTION_NAMES.join("|") & ")" & # known names
+  "^((" & "((?i)" &                               # case insensitive
+  KNOWN_SECTION_NAMES.join("|") & ")" &           # known names
   "|[[:upper:]]{3,}" &                            # all upper-case words
   ") ?\\d*)" &                                    # numeric suffix (Verse 2)
 
@@ -284,13 +373,46 @@ let PAGE_BREAK_PAT = re"\s*PAGE_BREAK\s*$"
 let TRANSPOSE_PAT = re"\s*TRANSPOSE KEY ([+-]\d+)\s*$"
 let REDEFINE_KEY_PAT = re"\s*REDEFINE KEY ([+-]\d+)\s*$"
 #let NOTE_PAT = re"^(.*)({{[^}]+}}|{[^}]+})(.*)$"
-let NOTE_START_PAT = re"{{"
-let NOTE_END_PAT = re"}}"
+let NOTE_START_PAT = re"\{\{"
+let NOTE_END_PAT = re"\}\}"
 let SPACE_PAT = re"\s"
 let CHORD_IN_LYRICS_PAT = re"(\w+)(\[.+)"
-let CHORD_AND_LYRICS_PAT = re"^\[([^\]]+)\]([^\s\[]+)(.*)$"
+let CHORD_AND_LYRICS_PAT = re"^\[([^\]]*)\]([^\s\[]+)(.*)$"
 let BRACED_CHORD_PAT = re"^\[([^\]]+)\]$"
-let NAKED_CHORDS_ONLY_PAT = re("^(" & CHORD_REGEX & "\\s*\\|*\\s*)+$")
+let NAKED_CHORDS_ONLY_PAT = re("^\\s*(" & CHORD_REGEX & "\\s*\\|*\\s*)+$")
+
+proc readNote(ctx: var ParserContext, firstLine: string): tuple[pre, note, post: string] =
+  let startLineNum = ctx.curLineNum
+
+  result = ("", "", "")
+
+  let startMatch = firstLine.find(NOTE_START_PAT)
+  var endMatch = firstLine.find(NOTE_END_PAT)
+
+  if startMatch.isNone: return
+
+  if startMatch.get.matchBounds.a > 0:
+    result.pre = firstLine[0..<startMatch.get.matchBounds.a]
+
+  if endMatch.isSome:
+    result.note = firstLine[(startMatch.get.matchBounds.b + 1)..<endMatch.get.matchBounds.a]
+    result.post = firstLine[(endMatch.get.matchBounds.b + 1)..^1]
+  else:
+    # if we don't find the end of the note, then we need to read more lines
+    # until we do
+    result.note = firstLine[(startMatch.get.matchBounds.b + 1)..^1]
+
+    while ctx.lines.len > ctx.curLineNum and ctx.hasNextLine:
+      let line = ctx.nextLine
+      endMatch = line.find(NOTE_END_PAT)
+      if endMatch.isSome:
+        result.note &= line[0..<endMatch.get.matchBounds.a]
+        result.post = line[(endMatch.get.matchBounds.b + 1)..^1]
+        return
+      else: result.note &= line
+
+    raise ctx.makeError("a note section was started on line " &
+      $startLineNum & " and never closed")
 
 proc parseLineParts(ctx: ParserContext, parts: varargs[string]): seq[ChordChartNode] =
   result = @[]
@@ -334,10 +456,11 @@ proc parseLineParts(ctx: ParserContext, parts: varargs[string]): seq[ChordChartN
           chord: none[ChordChartChord](),
           word: some(p)))
 
-proc parseLine(ctx: ParserContext, line: string): ChordChartNode =
+proc parseLine(lentCtx: var ParserContext, line: string): ChordChartNode =
+  let ctx = lentCtx
   result = ChordChartNode(kind: ccnkLine)
 
-  let m = line.match(NAKED_CHORDS_ONLY_PAT)
+  var m = line.match(NAKED_CHORDS_ONLY_PAT)
   if m.isSome:
     result.line = line.splitWhitespace --> map(
       ChordChartNode(
@@ -346,49 +469,28 @@ proc parseLine(ctx: ParserContext, line: string): ChordChartNode =
         spaceBefore: false, #FIXME
         chord: ctx.parseChord(it.strip),
         word: none[string]()))
+    return
+
+  m = line.match(NOTE_START_PAT)
+  if m.isSome:
+    let (pre, note, post) = lentCtx.readNote(line)
+    result.line = ctx.parseLineParts(pre) &
+      @[ChordChartNode(
+        kind: ccnkNote,
+        inclInLyrics: true,
+        note: note)] &
+      ctx.parseLineParts(post)
+    return
 
   else: result.line = ctx.parseLineParts(line.splitWhitespace)
 
-proc readNote(ctx: var ParserContext, endPat: Regex): string =
-  let startLineNum = ctx.curLineNum
-  result = ""
-
-  while ctx.lines.len > ctx.curLineNum and ctx.hasNextLine:
-    let line = ctx.nextLine
-    let m = line.find(endPat)
-    if m.isSome:
-      result &= line[0..<m.get.matchBounds.a]
-      ctx.pushPartialsToParse(line[m.get.matchBounds.b..^1])
-      break
-    else: result &= line
-
-  if not ctx.hasNextLine:
-    raise ctx.makeError("a note section was started on line " &
-      $startLineNum & " and never closed")
 
 proc parseBody(ctx: var ParserContext): seq[ChordChartNode] =
   result = @[]
   while ctx.hasNextLine:
     var line = ctx.nextLine
 
-    var m = line.find(NOTE_START_PAT)
-    if m.isSome:
-      if m.get.matchBounds.a > 0:
-        # if this is not the first character of the line then let's split the
-        # line and continue to parse
-        ctx.pushPartialsToParse(
-          line[0..<m.get.matchBounds.a],
-          line[m.get.matchBounds.a..^1])
-        continue
-
-      else:
-        # if this is the first character of the line, then let's parse the note
-        result.add(ChordChartNode(
-          kind: ccnkNote,
-          inclInLyrics: m.get.match.len < 2,
-          note: ctx.readNote(NOTE_END_PAT)))
-
-    m = line.match(TRANSPOSE_PAT)
+    var m = line.match(TRANSPOSE_PAT)
     if m.isSome:
       addToCurSection(ChordChartNode(
         kind: ccnkTransposeKey,
@@ -398,7 +500,7 @@ proc parseBody(ctx: var ParserContext): seq[ChordChartNode] =
     m = line.match(REDEFINE_KEY_PAT)
     if m.isSome:
       let newKeyInt = (
-          cast[int](ctx.curKeyCenter) +
+          ord(ctx.curKeyCenter) +
           parseInt(m.get.captures[0])
         ) mod 12
 
@@ -415,6 +517,7 @@ proc parseBody(ctx: var ParserContext): seq[ChordChartNode] =
     m = line.match(PAGE_BREAK_PAT)
     if m.isSome:
       result.add(ChordChartNode(kind: ccnkPageBreak))
+      ctx.curSection = EMPTY_CHORD_CHART_NODE
       continue
 
     m = line.match(SECTION_LINE_PAT)
@@ -422,12 +525,14 @@ proc parseBody(ctx: var ParserContext): seq[ChordChartNode] =
       let captures = m.get.captures.toSeq
       ctx.curSection = ChordChartNode(
         kind: ccnkSection,
-        sectionName: if captures[0].isSome: captures[0].get.strip
+        sectionName:
+          if captures[0].isSome: captures[0].get.strip
           else: raise ctx.makeError("unknown error parsing section header: " & line),
+        remainingSectionLine:
+          if captures[3].isSome: some(captures[3].get.strip)
+          else: none[string](),
         sectionContents: @[])
       result.add(ctx.curSection)
-      if captures[3].isSome:
-        ctx.curSection.sectionContents &= ctx.parseLineParts(captures[3].get)
       continue
 
     else:
@@ -443,7 +548,7 @@ proc parseChordChart*(s: string): ChordChart =
     unparsedLineParts: @[])
 
   let metadata = parseMetadata(parserCtx)
-  parserCtx.curKeyCenter = metadata.key
+  parserCtx.curKeyCenter = metadata.key.rootPitch
 
   result = ChordChart(
     rawContent: s,

src/pco_chordspkg/cliconstants.nim

@@ -1,4 +1,4 @@
-const PCO_CHORDS_VERSION* = "0.4.1"
+const PCO_CHORDS_VERSION* = "0.5.6"
 
 const USAGE* = """Usage:
   pco_chords [options]
@@ -12,9 +12,18 @@ Options:
   -o, --output <out-file>     Write output to <out-file> (rather than from
                               STDOUT, which is the default).
 
+  -t, --transpose <distance>  Transpose the chart by the given number of
+                              semitones. Distance can be expressed as a
+                              positive or negative number of semitones,
+                              for example: 4, +3 or -5.
+
+  -n, --number-chart          Write out a chart using the Nashville number
+                              system rather than explicit pitches.
+
   --help                      Print this usage information
   --debug                     Enable debug logging.
   --echo-args                 Echo the input parameters.
+  --large-print               Use the large type styling.
 """
 
 const ONLINE_HELP* = """

src/pco_chordspkg/html.nim

@@ -9,6 +9,8 @@ type
     currentKey: ChordChartPitch
     sourceKey: ChordChartPitch
     currentSection: ChordChartNode
+    numberChart: bool
+    transposeSteps: int
 
 const DEFAULT_STYLESHEET* = """
 <style>
@@ -20,11 +22,102 @@ const DEFAULT_STYLESHEET* = """
 
 html { font-family: sans-serif; }
 
-.page-contents {
-  column-width: 336px;
-  column-width: 3.5in;
+.page-contents { line-height: 1.1; }
+.one-column .page-contents { column-count: 1; }
+.two-column .page-contents { column-count: 2; }
+
+.column-break { margin-bottom: auto; }
+
+h2 { font-size: 1.25em; }
+
+section {
+  break-inside: avoid;
+  padding-top: 1em;
 }
 
+h3 {
+  font-size: 1.125rem;
+  margin-bottom: 0.125em;
+  text-decoration: underline;
+}
+
+h3 .section-text {
+  font-style: italic;
+  font-size: 1em;
+  font-weight: normal;
+  margin: 0 0.5em;
+}
+
+.artist { font-style: italic; }
+
+.line {
+  display: flex;
+  flex-direction: row;
+  align-items: end;
+
+  margin-left: 0.5em;
+  margin-bottom: 0.5em;
+}
+
+.word {
+  display: flex;
+  flex-direction: column;
+  align-items: flex-start;
+}
+
+.word.space-after { margin-right: 0.5em; }
+.word.no-chord { align-self: flex-end; }
+
+.chord {
+  font-weight: 600;
+  margin-bottom: -0.25em;
+  margin-right: 0.5em;
+  white-space: nowrap;
+}
+
+.chord > * {
+  display: inline-block;
+  height: 1.2em;
+}
+
+.chord .flavor {
+  font-variant-position: super;
+}
+
+.note { margin-right: 1em; }
+
+.song-order h3 {
+  font-style: italic;
+  font-weight: normal;
+}
+
+.song-order li {
+  list-style: none;
+  margin-left: 1em;
+}
+
+@media screen {
+  body { margin: 1em; }
+}
+</style>
+"""
+
+const LARGE_PRINT_STYLESHEET* = """
+<style>
+* {
+  box-sizing: border-box;
+  margin: 0;
+  padding: 0;
+}
+
+html {
+  font-family: sans-serif;
+  font-size: 1.5em;
+}
+
+.one-column .page-contents { column-count: 1; }
+.two-column .page-contents { column-count: 2; }
+
 .column-break { margin-bottom: auto; }
 
 h2 { font-size: 1.25em; }
@@ -40,10 +133,19 @@ h3 {
   text-decoration: underline;
 }
 
+h3 .section-text {
+  font-style: italic;
+  font-size: 1em;
+  font-weight: normal;
+  margin: 0 0.5em;
+}
+
+.artist { font-style: italic; }
+
 .line {
   display: flex;
   flex-direction: row;
-  align-items: flex-end;
+  align-items: baseline;
 
   margin-left: 0.5em;
   margin-bottom: 0.5em;
@@ -56,12 +158,29 @@ h3 {
 }
 
 .word.space-after { margin-right: 0.5em; }
+.word.no-chord { align-self: flex-end; }
+
+.lyric {
+  font-weight: 600;
+}
 
 .chord {
-  font-weight: 600;
+  font-style: italic;
+  font-weight: 500;
   margin-right: 0.5em;
 }
 
+.chord > * {
+  display: inline-block;
+  height: 1.2em;
+}
+
+.chord .flavor {
+  font-variant-position: super;
+}
+
+.note { margin-right: 1em; }
+
 .song-order h3 {
   font-style: italic;
   font-weight: normal;
@@ -75,24 +194,65 @@ h3 {
 @media screen {
   body { margin: 1em; }
 }
-
-@media print {
-  .page-contents { column-count: 2; }
-}
 </style>
 """
 
-proc transpose(ctx: FormatContext, chord: ChordChartChord): string =
+func scaleDegree(root: ChordChartPitch, p: ChordChartPitch): string =
+  let distance = p - root
+  case distance:
+  of 0: "1"
+  of 1: "♭2"
+  of 2: "2"
+  of 3: "♭3"
+  of 4: "3"
+  of 5: "4"
+  of 6: "♭5"
+  of 7: "5"
+  of 8: "♭6"
+  of 9: "6"
+  of 10: "♭7"
+  of 11: "7"
+  else: raise newException(Exception, "Impossible")
+
+func format(ctx: FormatContext, chord: ChordChartChord, useNumber = false): string =
+  ##if not useNumber and chord.original.isSome: return chord.original.get
+
+  if useNumber:
+    result = "<span class=root>" &
+      ctx.currentKey.scaleDegree(chord.rootPitch) & "</span>"
+
+    if chord.flavor.isSome:
+      result &= "<span class=flavor>" & chord.flavor.get & "</span>"
+
+    if chord.bassPitch.isSome:
+      result &= "<span class=bass>/" &
+        ctx.currentKey.scaleDegree(chord.bassPitch.get) & "</span>"
+
+  else:
+    result = "<span class=root>" &
+      renderPitchInKey(chord.rootPitch, ctx.currentKey) & "</span>"
+
+    if chord.flavor.isSome:
+      result &= "<span class=flavor>" & chord.flavor.get & "</span>"
+
+    if chord.bassPitch.isSome:
+      result &= "<span class=bass>/" &
+        renderPitchInKey(chord.bassPitch.get, ctx.currentKey) & "</span>"
+
+proc transpose(ctx: FormatContext, chord: ChordChartChord): ChordChartChord =
+  result = chord
+
   let distance = ctx.currentKey - ctx.sourceKey
-
   if distance != 0:
-    result = $(chord.rootPitch + distance)
-    if chord.flavor.isSome: result &= chord.flavor.get
-    if chord.bassPitch.isSome: result &= "/" & $(chord.bassPitch.get + distance)
-    #debug "transposed " & $ctx.sourceKey & " -> " & $ctx.currentKey &
-    #  " (distance " & $distance & ")\p\tchord: " & $chord & " to " & result
-
-  else: result = chord.original
+    result = ChordChartChord(
+      original: none[string](),
+      rootPitch: chord.rootPitch + distance,
+      flavor:
+        if chord.flavor.isSome: some(chord.flavor.get)
+        else: none[string](),
+      bassPitch:
+        if chord.bassPitch.isSome: some(chord.bassPitch.get + distance)
+        else: none[ChordChartPitch]())
 
 func makeSongOrder(songOrder, indent: string): string =
   result = indent & "<section class=song-order>\p" &
@@ -108,7 +268,13 @@ proc toHtml(ctx: var FormatContext, node: ChordChartNode, indent: string): strin
   of ccnkSection:
     ctx.currentSection = node
     result &= indent & "<section>\p" &
-      indent & "  " & "<h3>" & node.sectionName & "</h3>\p"
+      indent & "  " & "<h3>" & node.sectionName
+
+    if ctx.currentSection.remainingSectionLine.isSome:
+      result &= "<span class='section-text'>" &
+        ctx.currentSection.remainingSectionLine.get & "</span>"
+
+    result &= "</h3>\p"
 
     var contents = newSeq[string]()
     for contentNode in node.sectionContents:
@@ -127,10 +293,12 @@ proc toHtml(ctx: var FormatContext, node: ChordChartNode, indent: string): strin
     result &= "<span class='word"
     #if node.spaceBefore: result&=" space-before"
     if node.spaceAfter: result&=" space-after"
+    if node.chord.isNone: result&=" no-chord"
     result &= "'>"
 
     if node.chord.isSome:
-      result &= "<span class=chord>" & ctx.transpose(node.chord.get) & "</span>"
+      result &= "<span class=chord>" &
+        ctx.format(ctx.transpose(node.chord.get), ctx.numberChart) & "</span>"
 
     result &= "<span class=lyric>"
     if node.word.isSome: result &= node.word.get
@@ -150,14 +318,11 @@ proc toHtml(ctx: var FormatContext, node: ChordChartNode, indent: string): strin
 
   of ccnkTransposeKey:
     ctx.currentKey = ctx.currentKey + node.transposeSteps
-    let headingVal = indent & "<h4 class=note>Key Change: " & $ctx.currentKey & "</h4>"
-    if ctx.currentSection.kind == ccnkNone: result &= headingVal
-    else:
-      result &= "</section><section>" & headingVal & "</section><section>"
+    result &= indent & "<h4 class=note>Key Change: " & $ctx.currentKey & "</h4>"
 
   of ccnkRedefineKey:
-    let oldKey = ctx.sourceKey
-    ctx.sourceKey = node.newKey
+    let oldKey = ctx.currentKey
+    ctx.sourceKey = node.newKey + ctx.transposeSteps
     ctx.currentKey = ctx.sourceKey
 
     if oldKey != ctx.currentKey:
@@ -170,19 +335,26 @@ proc toHtml(ctx: var FormatContext, node: ChordChartNode, indent: string): strin
 
 proc toHtml*(
     cc: ChordChart,
+    transpose = 0,
+    numberChart = false,
     stylesheets = @[DEFAULT_STYLESHEET],
     scripts: seq[string] = @[]): string =
 
   var ctx = FormatContext(
     chart: cc,
-    currentKey: cc.metadata.key,
-    sourceKey: cc.metadata.key,
-    currentSection: EMPTY_CHORD_CHART_NODE)
+    currentKey: cc.metadata.key.rootPitch + transpose,
+    sourceKey: cc.metadata.key.rootPitch,
+    currentSection: EMPTY_CHORD_CHART_NODE,
+    numberChart: numberChart,
+    transposeSteps: transpose)
+
+  debug "Formatting:\p\tsource key: " & $ctx.sourceKey & "\p\ttransposing: " &
+    $transpose & "\p\ttarget key: " & $ctx.currentKey
 
   result = """<!doctype html>
 <html>
   <head>
-    <title>""" & cc.metadata.title & "</title>\p"
+    <title>""" & cc.metadata.title & " — " & $ctx.currentKey & "</title>\p"
 
   for ss in stylesheets:
     if ss.startsWith("<style>"): result &= ss
@@ -194,14 +366,19 @@ proc toHtml*(
     elif fileExists(sc): result &= "<script>\p" & readFile(sc) & "\p</script>"
     else: warn "cannot read script file '" & sc & "'"
 
-  result &= "  </head>\p  <body>"
+  result &= "  </head>\p"
+
+  if cc.metadata.contains("columns") and cc.metadata["columns"] == "1":
+    result &= "  <body class='one-column'>"
+  else:
+    result &= "  <body class='two-column'>"
 
   var indent = "      "
-  #
+
   # Title
   result &= indent & "<h1>" & cc.metadata.title & "</h1>\p"
 
-  var metadataPieces = @["Key: " & $cc.metadata.key]
+  var metadataPieces = @["Key: " & ctx.format(ctx.transpose(cc.metadata.key))]
   if cc.metadata.contains("time signature"):
     metadataPieces.add(cc.metadata["time signature"])
   if cc.metadata.contains("bpm"):
@@ -211,6 +388,9 @@ proc toHtml*(
 
   result &= indent & "<h2>" & metadataPieces.join(" | ") & "</h2>\p"
 
+  if cc.metadata.contains("artist"):
+    result &= indent & "<div class=artist>" & cc.metadata["artist"] & "</div>\p"
+
   result &= "<div class=page-contents>"
   result &= join(cc.nodes --> map(ctx.toHtml(it, indent & "  ")), "\p")