Directives are allowed only on their own line (with nothing else on this line)

Better error handling of the parser.

patacrep/data/examples/songs/tests/newline.sgc

@@ -32,4 +32,8 @@ New lines can also
     {newline}    
 Be surrounded by spaces
 
-New lines can {newline} appear in the middle of a line
+New lines cannot have text before them {newline}
+
+{newline} New lines cannot have text after them
+
+New lines cannot be {newline} surrounded by text.

patacrep/songs/chordpro/ast.py

@@ -60,9 +60,9 @@ class Line(AST):
 
     _template = "line"
 
-    def __init__(self):
+    def __init__(self, *items):
         super().__init__()
-        self.line = []
+        self.line = list(items)
 
     def __iter__(self):
         yield from self.line
@@ -310,7 +310,7 @@ class Directive(AST):
         return self.keyword
 
     def __str__(self):
-        return self.argument
+        return str(self.argument)
 
     @property
     def inline(self):

patacrep/songs/chordpro/syntax.py

@@ -1,5 +1,6 @@
 """ChordPro parser"""
 
+import logging
 import ply.yacc as yacc
 import re
 
@@ -7,6 +8,8 @@ from patacrep.songs.syntax import Parser
 from patacrep.songs.chordpro import ast
 from patacrep.songs.chordpro.lexer import tokens, ChordProLexer
 
+LOGGER = logging.getLogger()
+
 class ChordproParser(Parser):
     """ChordPro parser class"""
     # pylint: disable=too-many-public-methods
@@ -18,6 +21,19 @@ class ChordproParser(Parser):
         self.tokens = tokens
         self.song = ast.Song(filename)
         self.filename = filename
+        self.parser = yacc.yacc(
+            module=self,
+            debug=0,
+            write_tables=0,
+            )
+
+    def parse(self, *args, **kwargs):
+        """Parse file
+
+        This is a shortcut to `yacc.yacc(...).parse()`. The arguments are
+        transmitted to this method.
+        """
+        return self.parser.parse(*args, **kwargs)
 
     def p_song(self, symbols):
         """song : block song
@@ -32,6 +48,7 @@ class ChordproParser(Parser):
     def p_block(symbols):
         """block : SPACE block
                  | line ENDOFLINE
+                 | line_error ENDOFLINE
                  | chorus ENDOFLINE
                  | tab ENDOFLINE
                  | bridge ENDOFLINE
@@ -167,20 +184,35 @@ class ChordproParser(Parser):
         else:
             symbols[0] = None
 
+    @staticmethod
+    def p_line_error(symbols):
+        """line_error : error directive"""
+        LOGGER.error("Directive can only be preceded or followed by spaces")
+        symbols[0] = ast.Line()
+
     @staticmethod
     def p_line(symbols):
         """line : word line_next
                 | chord line_next
-                | directive line_next
+                | directive maybespace
         """
+        if isinstance(symbols[2], ast.Line):
+            # Line with words, etc.
             symbols[0] = symbols[2].prepend(symbols[1])
+        else:
+            # Directive
+            if symbols[1] is None:
+                # Meta directive. Nothing to do
+                symbols[0] = ast.Line()
+            else:
+                # Inline directive
+                symbols[0] = ast.Line(symbols[1])
 
     @staticmethod
     def p_line_next(symbols):
         """line_next : word line_next
                      | space line_next
                      | chord line_next
-                     | directive line_next
                      | empty
         """
         if len(symbols) == 2:
@@ -212,6 +244,7 @@ class ChordproParser(Parser):
     @staticmethod
     def p_chorus_content(symbols):
         """chorus_content : line ENDOFLINE chorus_content
+                          | line_error ENDOFLINE chorus_content
                           | SPACE chorus_content
                           | empty
         """
@@ -231,6 +264,7 @@ class ChordproParser(Parser):
     @staticmethod
     def p_bridge_content(symbols):
         """bridge_content : line ENDOFLINE bridge_content
+                          | line_error ENDOFLINE bridge_content
                           | SPACE bridge_content
                           | empty
         """
@@ -267,13 +301,18 @@ class ChordproParser(Parser):
         """empty :"""
         symbols[0] = None
 
+    def p_error(self, token):
+        super().p_error(token)
+        while True:
+            token = self.parser.token()
+            if not token or token.type == "ENDOFLINE":
+                break
+        self.parser.errok()
+        return token
+
 def parse_song(content, filename=None):
     """Parse song and return its metadata."""
-    return yacc.yacc(
-        module=ChordproParser(filename),
-        debug=0,
-        write_tables=0,
-        ).parse(
+    return ChordproParser(filename).parse(
         content,
         lexer=ChordProLexer(filename=filename).lexer,
         )

test/test_chordpro/newline.html

@@ -45,6 +45,6 @@
 </p>
 
 <p class="verse">
-    New lines can't  appear in the middle of a line
+    New lines cannot
 </p>
 </div>

test/test_chordpro/newline.sgc

@@ -38,4 +38,4 @@ New lines can also
 Be surrounded by spaces
 
 
-New lines can {newline} appear in the middle of a line
+New lines cannot

test/test_chordpro/newline.source

@@ -29,4 +29,4 @@ New lines can also
     {newline}    
 Be surrounded by spaces
 
-New lines can {newline} appear in the middle of a line
+New lines cannot {newline} appear in the middle of a line

test/test_chordpro/newline.tex

@@ -55,7 +55,7 @@
 
 
 \begin{verse}
-    New lines can ~\\ appear in the middle of a line
+    New lines cannot
 \end{verse}
 
 \endsong