Adds support for Measures, Tablature and Comments (#25)

* Adds support for Measures, Tablature and Comments
* Use simpler looping

Author: Brian Kelly

src/Line.js

@@ -1,5 +1,20 @@
 export class Line {
   constructor() {
     this.parts = [];
+    this.measures = null;
+    this.tablature = null;
+    this.comment = null;
+  }
+
+  hasTablature() {
+    return this.tablature != null;
+  }
+
+  hasMeasures() {
+    return this.measures != null;
+  }
+
+  hasComment() {
+    return this.comment != null;
   }
 }

src/Measure.js

@@ -0,0 +1,5 @@
+export class Measure {
+  constructor() {
+    this.chords = [];
+  }
+}

src/SongPro.js

@@ -3,6 +3,16 @@ import { Section } from "./Section";
 import { Line } from "./Line";
 import { chunk, flatten, trim } from "lodash";
 import { Part } from "./Part";
+import { Measure } from "./Measure";
+
+const SECTION_REGEX = /#\s*([^$]*)/;
+const ATTRIBUTE_REGEX = /@(\w*)=([^%]*)/;
+const CUSTOM_ATTRIBUTE_REGEX = /!(\w*)=([^%]*)/;
+const CHORDS_AND_LYRICS_REGEX = /(\[[\w#b/]+])?([\w\s',.!()_\-"]*)/gi;
+
+const MEASURES_REGEX = /([[\w#b/\]+\]\s]+)[|]*/gi;
+const CHORDS_REGEX = /\[([\w#b+/]+)]?/gi;
+const COMMENT_REGEX = />\s*([^$]*)/;
 
 export class SongPro {
   static parse(text) {
@@ -11,9 +21,7 @@ export class SongPro {
 
     const lines = text.split("\n");
 
-    for (let i = 0; i < lines.length; i++) {
-      const text = lines[i];
-
+    for (const text of lines) {
       if (text.startsWith("@")) {
         this.processAttribute(song, text);
       } else if (text.startsWith("!")) {
@@ -29,7 +37,7 @@ export class SongPro {
   }
 
   static processAttribute(song, line) {
-    const matches = /@(\w*)=([^%]*)/.exec(line);
+    const matches = ATTRIBUTE_REGEX.exec(line);
 
     if (matches == null) {
       return;
@@ -39,7 +47,7 @@ export class SongPro {
   }
 
   static processCustomAttribute(song, line) {
-    const matches = /!(\w*)=([^%]*)/.exec(line);
+    const matches = CUSTOM_ATTRIBUTE_REGEX.exec(line);
 
     if (matches == null) {
       return;
@@ -49,7 +57,7 @@ export class SongPro {
   }
 
   static processSection(song, line) {
-    const matches = /#\s*([^$]*)/.exec(line);
+    const matches = SECTION_REGEX.exec(line);
 
     if (matches == null) {
       return;
@@ -74,33 +82,60 @@ export class SongPro {
 
     const line = new Line();
 
-    let captures = this.scan(text, /(\[[\w#b/]+])?([\w\s',.!()_\-"]*)/gi);
-    captures = flatten(captures);
-    const groups = chunk(captures, 2);
+    if (text.startsWith("|-")) {
+      line.tablature = text;
+    } else if (text.startsWith("| ")) {
+      let captures = this.scan(text, MEASURES_REGEX);
+      captures = flatten(captures);
 
-    for (let i = 0; i < groups.length; i++) {
-      const group = groups[i];
-      let chord = group[0];
-      let lyric = group[1];
+      const measures = [];
 
-      const part = new Part();
+      for (const capture of captures) {
+        let chords = this.scan(capture, CHORDS_REGEX);
+        chords = flatten(chords);
 
-      if (chord) {
-        chord = chord.replace("[", "").replace("]", "");
+        const measure = new Measure();
+        measure.chords = chords;
+        measures.push(measure);
       }
 
-      if (chord === undefined) {
-        chord = "";
-      }
-      if (lyric === undefined) {
-        lyric = "";
+      line.measures = measures;
+    } else if (text.startsWith(">")) {
+      const matches = COMMENT_REGEX.exec(text);
+
+      if (matches == null) {
+        return;
       }
 
-      part.chord = trim(chord);
-      part.lyric = trim(lyric);
+      line.comment = matches[1].trim();
+    } else {
+      let captures = this.scan(text, CHORDS_AND_LYRICS_REGEX);
+      captures = flatten(captures);
+      const groups = chunk(captures, 2);
+
+      for (const group of groups) {
+        let chord = group[0];
+        let lyric = group[1];
+
+        const part = new Part();
+
+        if (chord) {
+          chord = chord.replace("[", "").replace("]", "");
+        }
+
+        if (chord === undefined) {
+          chord = "";
+        }
+        if (lyric === undefined) {
+          lyric = "";
+        }
+
+        part.chord = trim(chord);
+        part.lyric = trim(lyric);
 
-      if (!(part.chord === "" && part.lyric === "")) {
-        line.parts.push(part);
+        if (!(part.chord === "" && part.lyric === "")) {
+          line.parts.push(part);
+        }
       }
     }
 

src/SongPro.test.js

@@ -1,6 +1,6 @@
 import { SongPro } from "./SongPro";
 
-test("attribute parsing", () => {
+test("attributes", () => {
   const song = SongPro.parse(`
 @title=Bad Moon Rising
 @artist=Creedence Clearwater Revival
@@ -22,7 +22,7 @@ test("attribute parsing", () => {
   expect(song.attrs.tuning).toEqual("Eb Standard");
 });
 
-test("custom attribute parsing", () => {
+test("custom attributes", () => {
   const song = SongPro.parse(`
 !difficulty=Easy
 !spotify_url=https://open.spotify.com/track/5zADxJhJEzuOstzcUtXlXv?si=SN6U1oveQ7KNfhtD2NHf9A
@@ -103,3 +103,49 @@ test("lyrics before chords", () => {
     "bound to take your life"
   );
 });
+
+test("measures", () => {
+  const song = SongPro.parse(`
+# Instrumental
+
+| [A] [B] | [C] | [D] [E] [F] [G] |
+`);
+
+  expect(song.sections.length).toEqual(1);
+  expect(song.sections[0].lines[0].hasMeasures()).toEqual(true);
+  expect(song.sections[0].lines[0].measures.length).toEqual(3);
+  expect(song.sections[0].lines[0].measures[0].chords).toEqual(["A", "B"]);
+  expect(song.sections[0].lines[0].measures[1].chords).toEqual(["C"]);
+  expect(song.sections[0].lines[0].measures[2].chords).toEqual([
+    "D",
+    "E",
+    "F",
+    "G",
+  ]);
+});
+
+test("tablature", () => {
+  const song = SongPro.parse(`
+# Riff
+
+|-3---5-|
+|---4---|
+`);
+  expect(song.sections.length).toEqual(1);
+  expect(song.sections[0].lines[0].hasTablature()).toEqual(true);
+  expect(song.sections[0].lines[0].tablature).toEqual("|-3---5-|");
+  expect(song.sections[0].lines[1].hasTablature()).toEqual(true);
+  expect(song.sections[0].lines[1].tablature).toEqual("|---4---|");
+});
+
+test("comments", () => {
+  const song = SongPro.parse(`
+# Comment
+
+> This is a comment.
+`);
+
+  expect(song.sections.length).toEqual(1);
+  expect(song.sections[0].lines[0].hasComment()).toEqual(true);
+  expect(song.sections[0].lines[0].comment).toEqual("This is a comment.");
+});