Support for number charts, transposition when generating charts.

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
@@ -26,7 +26,7 @@ type
   ChordChartPitch* = enum Af, A, Bf, B, C, Df, D, Ef, E, F, Fs, G
 
   ChordChartChord* = object
-    original*: string
+    original*: Option[string]
     rootPitch*: ChordChartPitch
     flavor*: Option[string]
     bassPitch*: Option[ChordChartPitch]
@@ -133,13 +133,15 @@ 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
@@ -185,8 +187,9 @@ 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
@@ -199,6 +202,13 @@ func parsePitch*(ctx: ParserContext, keyValue: string): ChordChartPitch =
   of "es", "eis", "e#", "f", "g𝄫": return ChordChartPitch.F
   of "e𝄪", "fs", "fis", "f#", "gf", "gb", "ges": return ChordChartPitch.Fs
   of "f𝄪", "g", "a𝄫": return ChordChartPitch.G
+  of "1": return ctx.curKeyCenter
+  of "2": return ctx.curKeyCenter + 2
+  of "3": return ctx.curKeyCenter + 4
+  of "4": return ctx.curKeyCenter + 5
+  of "5": return ctx.curKeyCenter + 7
+  of "6": return ctx.curKeyCenter + 9
+  of "7": return ctx.curKeyCenter + 11
   else: raise ctx.makeError(keyValue.strip & " is not a recognized key.")
 
 # see regexr.com/70nv1
@@ -226,7 +236,7 @@ proc parseChord*(
       else: none[ChordChartPitch]()
 
     return some(ChordChartChord(
-      original: chordValue,
+      original: some(chordValue),
       rootPitch: ctx.parsePitch(m.get.captures[0]),
       flavor: flavor,
       bassPitch: bassPitch))
@@ -236,8 +246,8 @@ 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
@@ -252,18 +262,21 @@ 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 = [
@@ -447,7 +460,7 @@ proc parseChordChart*(s: string): ChordChart =
     unparsedLineParts: @[])
 
   let metadata = parseMetadata(parserCtx)
-  parserCtx.curKeyCenter = metadata.key
+  parserCtx.curKeyCenter = metadata.key.rootPitch
 
   result = ChordChart(
     rawContent: s,