Fixes #3 - allow multiline strings that have the first line non-empty.

lib/simple_po_parser/parser.rb

@@ -109,7 +109,7 @@ def msgctxt
           skip_whitespace
           text = message_line
           add_result(:msgctxt, text)
-          message_multiline(:msgctxt) if text.empty?
+          message_multiline(:msgctxt) if @scanner.peek(1) == '"'
         end
         msgid
       rescue PoSyntaxError => pe
@@ -127,7 +127,7 @@ def msgid
           skip_whitespace
           text = message_line
           add_result(:msgid, text)
-          message_multiline(:msgid) if text.empty?
+          message_multiline(:msgid) if @scanner.peek(1) == '"'
           if msgid_plural
             msgstr_plural
           else
@@ -155,7 +155,7 @@ def msgid_plural
           skip_whitespace
           text = message_line
           add_result(:msgid_plural, text)
-          message_multiline(:msgid_plural) if text.empty?
+          message_multiline(:msgid_plural) if @scanner.peek(1) == '"'
           true
         else
           false
@@ -174,7 +174,7 @@ def msgstr
           skip_whitespace
           text = message_line
           add_result(:msgstr, text)
-          message_multiline(:msgstr) if text.empty?
+          message_multiline(:msgstr) if @scanner.peek(1) == '"'
           skip_whitespace
           raise PoSyntaxError, "Unexpected content after expected message end #{@scanner.peek(10).inspect}" unless @scanner.eos?
         else
@@ -202,7 +202,7 @@ def msgstr_plural(num = 0)
           skip_whitespace
           text = message_line
           add_result(msgstr_key, text)
-          message_multiline(msgstr_key) if text.empty?
+          message_multiline(msgstr_key) if @scanner.peek(1) == '"'
           msgstr_plural(num+1)
         elsif num == 0 # and msgstr_key was false
           raise PoSyntaxError, "Plural message without msgstr[0] is not allowed. Line started unexpectedly with #{@scanner.peek(10).inspect}."
@@ -238,7 +238,7 @@ def previous_comments
           skip_whitespace
           text = message_line
           add_result(key, text)
-          previous_multiline(key) if text.empty?
+          previous_multiline(key) if @scanner.match?(/#\|\p{Blank}*"/)
         else
           raise PoSyntaxError, "Previous comments must start with '#| msg'. #{@scanner.peek(10).inspect} unknown."
         end
@@ -265,8 +265,10 @@ def previous_multiline(key)
 
     # parses a multiline message
     #
-    # multiline messages are indicated by an empty content as first line and the next line
-    # starting with the double quote character
+    # Multiline messages are usually indicated by an empty string as the first line,
+    # followed by more lines starting with the double quote character.
+    #
+    # However, according to the PO file standard, the first line can also contain content.
     def message_multiline(key)
       begin
         skip_whitespace

spec/simple_po_parser/fixtures/multiline.po

@@ -0,0 +1,10 @@
+#| msgid "multiline\n"
+#|"previous messageid"
+#|"with non-empty first line"
+msgid ""
+"multiline string "
+"with empty first line "
+"and trailing spaces"
+msgstr "multiline string"
+"with non-empty first line"
+"and no trailing spaces"

spec/simple_po_parser/parser_spec.rb

@@ -4,6 +4,7 @@
   let (:po_header) { File.read(File.expand_path("fixtures/header.po", __dir__))}
   let(:po_complex_message) { File.read(File.expand_path("fixtures/complex_entry.po", __dir__))}
   let(:po_simple_message) { File.read(File.expand_path("fixtures/simple_entry.po", __dir__))}
+  let(:po_multiline_message) { File.read(File.expand_path("fixtures/multiline.po", __dir__))}
 
   it "parses the PO header" do
     expected_result = {
@@ -27,6 +28,15 @@
     expect(SimplePoParser::Parser.new.parse(po_simple_message)).to eq(expected_result)
   end
 
+  it "parses the multiline entry as expected" do
+    expected_result = {
+      :msgid => ["", "multiline string ", "with empty first line ", "and trailing spaces"],
+      :msgstr => ["multiline string", "with non-empty first line", "and no trailing spaces"],
+      :previous_msgid => ["multiline\\n", "previous messageid", "with non-empty first line"],
+    }
+    expect(SimplePoParser::Parser.new.parse(po_multiline_message)).to eq(expected_result)
+  end
+
   it "parses the complex entry as expected" do
     expected_result = {
       :translator_comment => ["translator-comment", ""],