support multiline CoffeeScript comments

lib/doctest.js

@@ -144,12 +144,12 @@ const rewriteJs = sourceType => ({
       if (type === 'Line') {
         maybePushLine (value, start, loc.start.line);
       } else {
-        let offset = start;
-        let number = loc.start.line;
-        for (const text of value.split ('\n')) {
-          maybePushLine (text.replace (/^\s*[*]/, ''), offset, number);
-          offset += '\n'.length;
-          number += 1;
+        for (let from = 0, number = loc.start.line; ; number += 1) {
+          const to = value.indexOf ('\n', from);
+          const text = to < 0 ? value.slice (from) : value.slice (from, to);
+          maybePushLine (text.replace (/^\s*[*]/, ''), start + from, number);
+          if (to < 0) break;
+          from = to + '\n'.length;
         }
       }
     }
@@ -198,41 +198,61 @@ const rewriteJs = sourceType => ({
 };
 
 const rewriteCoffee = ({
-  prefix: _prefix,
+  prefix,
   openingDelimiter,
   closingDelimiter,
 }) => input => {
-  // 1a: Extract prefixed comment lines
-  const lines = [];
-  // 1b: Preserve other lines
+  // 1: Lex source text to extract comments
+  const tokens = CoffeeScript.tokens (input);
+  const comments = CoffeeScript.helpers.extractAllCommentTokens (tokens);
+
+  // 2: Preserve source text between comments
   const chunks = [];
   {
-    const prefix = '#' + _prefix;
-    let number = 0;
-    for (const [text, indent, rest] of input.matchAll (/^([ \t]*)(.*)\n?/gm)) {
-      number += 1;
-      if (rest.startsWith (prefix)) {
-        const unprefixed = (rest.slice (prefix.length)).trimStart ();
-        const line = Line (number) (unprefixed);
-        lines.push ([indent, line]);
-      } else {
-        chunks.push ([number, text]);
+    let offset = 0;
+    for (const {locationData: {range: [start, end]}} of comments) {
+      chunks.push ([offset, input.slice (offset, start)]);
+      offset = end;
+    }
+    chunks.push ([offset, input.slice (offset)]);
+  }
+
+  // 3: Extract prefixed comment lines
+  const lines = [];
+  for (const {content, locationData} of comments) {
+    const indent = ' '.repeat (locationData.first_column);
+    const offset = locationData.range[0];
+    let number = locationData.first_line + 1;
+    if (locationData.last_line > locationData.first_line) {
+      for (let from = 0; ; number += 1) {
+        const to = content.indexOf ('\n', from);
+        const text = to < 0 ? content.slice (from) : content.slice (from, to);
+        const line = Line (number) (text.trimStart ());
+        lines.push ([offset + from, indent, line]);
+        if (to < 0) break;
+        from = to + '\n'.length;
+      }
+    } else {
+      const text = content.trimStart ();
+      if (text.startsWith (prefix)) {
+        const unprefixed = (text.slice (prefix.length)).trimStart ();
+        lines.push ([offset, indent, Line (number) (unprefixed)]);
       }
     }
   }
 
-  // 2: Coalesce related input and output lines
+  // 4: Coalesce related input and output lines
   const tests = [];
   {
     let test;
     let state = openingDelimiter == null ? 'open' : 'closed';
-    for (const [indent, line] of lines) {
+    for (const [offset, indent, line] of lines) {
       if (state === 'closed') {
         if (line.text === openingDelimiter) state = 'open';
       } else if (line.text === closingDelimiter) {
         state = 'closed';
       } else if (line.text.startsWith ('>')) {
-        tests.push ([line.number, test = {indent, input: {lines: [line]}}]);
+        tests.push ([offset, test = {indent, input: {lines: [line]}}]);
         state = 'input';
       } else if (line.text.startsWith ('.')) {
         test[state].lines.push (line);
@@ -249,15 +269,15 @@ const rewriteCoffee = ({
     }
   }
 
-  // 3: Convert doctests to source text
-  for (const [number, test] of tests) {
-    chunks.push ([number, wrapCoffee (test)]);
+  // 5: Convert doctests to source text
+  for (const [offset, test] of tests) {
+    chunks.push ([offset, wrapCoffee (test)]);
   }
 
-  // 4: Sort verbatim and generated source text by original line numbers
+  // 6: Sort verbatim and generated source text by original offsets
   chunks.sort (([a], [b]) => a - b);
 
-  // 5: Concatenate source text
+  // 7: Concatenate source text
   let sourceText = '';
   for (const [, text] of chunks) sourceText += text;
   return CoffeeScript.compile (sourceText);

test/shared/index.coffee

@@ -104,20 +104,20 @@ do ->
   # ..... .5
   # 1234.5
 
-  23: 'TODO: multiline comment'
-  #
-  # > 3 ** 3 - 2 ** 2
-  # 23
-  #
-
-  24: 'TODO: multiline comment with wrapped input'
-  #
-  # > (["foo", "bar", "baz"]
-  # .  .slice(0, -1)
-  # .  .join(" ")
-  # .  .toUpperCase())
-  # "FOO BAR"
-  #
+  23: 'multiline comment'
+  ###
+    > 3 ** 3 - 2 ** 2
+    23
+  ###
+
+  24: 'multiline comment with wrapped input'
+  ###
+    > (["foo", "bar", "baz"]
+    .  .slice(0, -1)
+    .  .join(" ")
+    .  .toUpperCase())
+    "FOO BAR"
+  ###