Key of C should use flats for accidentals.

- Non-diatonic pitches are supported using Nashville numbers (#5).
- When using Nashville numbers chord variants with non-diatonic roots
  are now recognized (e.g. b7)
- Pitch rendering is now aware of key centers. For example, F# is F#
  rendered as F# when in the key of G but Gb when in the key of Ab.

pco_chords.nimble

@@ -1,6 +1,6 @@
 # Package
 
-version       = "0.4.1"
+version       = "0.5.2"
 author        = "Jonathan Bernard"
 description   = "Chord chart formatter compatible with Planning Center Online"
 license       = "MIT"

src/pco_chords.nim

@@ -34,11 +34,16 @@ when isMainModule:
     $ast & "\p" &
     "-".repeat(16) & "\p"
 
-  let outputHtml = ast.toHtml()
+  let transpose =
+    if args["--transpose"]: parseInt($args["--transpose"])
+    else: 0
+
+  let outputHtml = ast.toHtml(transpose, args["--number-chart"])
+
   if args["--output"]: writeFile($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]
@@ -76,20 +77,60 @@ iterator pairs*(ccmd: ChordChartMetadata): tuple[key, value: string] =
 
 func kind*(ccn: ChordChartNode): ChordChartNodeKind = ccn.kind
 
-func `$`*(pitch: ChordChartPitch): string =
-  case pitch
-  of Af: "Ab"
-  of A: "A"
-  of Bf: "Bb"
-  of B: "B"
-  of C: "C"
-  of Df: "Db"
-  of D: "D"
-  of Ef: "Eb"
-  of E: "E"
-  of F: "F"
-  of Fs: "F#"
-  of G: "G"
+func `$`(pitch: ChordChartPitch): string =
+  ["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:
+    scaleNames = case key
+    of A, B, D, E, G:
+      ["G#", "A", "A#", "B", "C", "C#", "D", "D#", "E", "F", "F#", "G"]
+    of Af, Bf, C, Df, Ef, F:
+      ["A♭", "A", "B♭", "B", "C", "D♭", "D", "E♭", "E", "F", "G♭", "G"]
+    of Gf:
+      ["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.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 +173,15 @@ 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 +227,40 @@ 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
+  "([b#♭♮𝄫𝄪]?[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#♭♮𝄫𝄪]?))?"             # optional bass
 let CHORD_PAT = re(CHORD_REGEX)
 
 proc parseChord*(
@@ -225,7 +281,7 @@ 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 +291,8 @@ 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 +307,32 @@ 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)
 
@@ -398,7 +458,7 @@ 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
 
@@ -422,12 +482,14 @@ 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
-                     else: raise ctx.makeError("unknown error parsing section header: " & line),
+        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 +505,7 @@ 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* = "0.5.2"
 
 const USAGE* = """Usage:
   pco_chords [options]
@@ -6,12 +6,20 @@ const USAGE* = """Usage:
 
 Options:
 
-  -i, --input <in-file>     Read input from <in-file> (rather than from
+  -i, --input <in-file>       Read input from <in-file> (rather than from
                               STDIN, which is the default).
 
-  -o, --output <out-file>   Write output to <out-file> (rather than from
+  -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.

src/pco_chordspkg/html.nim

@@ -9,6 +9,8 @@ type
     currentKey: ChordChartPitch
     sourceKey: ChordChartPitch
     currentSection: ChordChartNode
+    numberChart: bool
+    transposeSteps: int
 
 const DEFAULT_STYLESHEET* = """
 <style>
@@ -40,6 +42,13 @@ h3 {
   text-decoration: underline;
 }
 
+h3 .section-text {
+  font-style: italic;
+  font-size: 1em;
+  font-weight: normal;
+  margin: 0 0.5em;
+}
+
 .line {
   display: flex;
   flex-direction: row;
@@ -62,6 +71,10 @@ h3 {
   margin-right: 0.5em;
 }
 
+.chord .flavor {
+  font-variant-position: super;
+}
+
 .song-order h3 {
   font-style: italic;
   font-weight: normal;
@@ -82,17 +95,62 @@ h3 {
 </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 +166,13 @@ 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:
@@ -130,7 +194,8 @@ proc toHtml(ctx: var FormatContext, node: ChordChartNode, indent: string): strin
     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
@@ -156,8 +221,8 @@ proc toHtml(ctx: var FormatContext, node: ChordChartNode, indent: string): strin
       result &= "</section><section>" & headingVal & "</section><section>"
 
   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:
@@ -170,14 +235,21 @@ 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>
@@ -197,11 +269,11 @@ proc toHtml*(
   result &= "  </head>\p  <body>"
 
   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"):