Add an `errors` attribute to songs, compiling the song errors

First step to #121

patacrep/latex/__init__.py

@@ -8,6 +8,7 @@ will work on simple cases, but not on complex ones.
 import logging
 from collections import OrderedDict
 
+from patacrep import errors
 from patacrep.latex.syntax import tex2plain, parse_song
 
 LOGGER = logging.getLogger(__name__)
@@ -77,32 +78,57 @@ BABEL_LANGUAGES = OrderedDict((
     # ('??_??', 'welsh'),
 ))
 
-def lang2babel(lang):
+class UnknownLanguage(Exception):
-    """Return the language used by babel, corresponding to the language code"""
+    """Error: Unknown language."""
+
+    def __init__(self, *, original, fallback, message):
+        super().__init__()
+        self.original = original
+        self.fallback = fallback
+        self.message = message
+
+def checklanguage(lang):
+    """Check that `lang` is a known language.
+
+    Raise an :class:`UnknownLanguage` excetipn if not.
+    """
     # Exact match
     if lang.lower() in BABEL_LANGUAGES:
-        return BABEL_LANGUAGES[lang.lower()]
+        return lang.lower()
     # Only language code is provided (e.g. 'fr')
     for babel in BABEL_LANGUAGES:
         if babel.startswith(lang.lower()):
-            return BABEL_LANGUAGES[babel]
+            return babel
     # A non existent country code is provided (e.g. 'fr_CD').
     language = lang.lower().split("_")[0]
     for babel in BABEL_LANGUAGES:
         if babel.startswith(language):
-            LOGGER.error(
+            raise UnknownLanguage(
-                "Unknown country code '{}'. Using default '{}' instead.".format(
+                original=lang,
+                fallback=babel,
+                message="Unknown country code '{}'. Using default '{}' instead.".format(
                     lang,
                     babel
                 )
             )
-            return BABEL_LANGUAGES[babel]
     # Error: no (exact or approximate) match found
     available = ", ".join(BABEL_LANGUAGES.keys())
-    LOGGER.error(
+    raise UnknownLanguage(
-        "Unknown language code '{}' (supported: {}). Using default 'english' instead.".format(
+        original=lang,
+        fallback="en_us",
+        message=(
+            "Unknown language code '{}' (supported: {}). Using "
+            "default 'english' instead."
+            ).format(
                 lang,
                 available
             )
     )
-    return 'english'
+
+def lang2babel(lang):
+    """Return the language used by babel, corresponding to the language code"""
+    try:
+        return BABEL_LANGUAGES[checklanguage(lang)]
+    except UnknownLanguage as error:
+        LOGGER.error(str(error))
+        return BABEL_LANGUAGES[error.fallback]

patacrep/songs/__init__.py

@@ -108,6 +108,7 @@ class Song:
         self.encoding = config["encoding"]
         self.default_lang = config["lang"]
         self.config = config
+        self.errors = []
 
         if self._cache_retrieved():
             return

patacrep/songs/chordpro/__init__.py

@@ -33,6 +33,7 @@ class ChordproSong(Song):
         self.titles = song.titles
         self.lang = song.get_data_argument('language', self.default_lang)
         self.data = song.meta
+        self.errors = song.errors
         self.cached = {
             'song': song,
             }

patacrep/songs/chordpro/ast.py

@@ -223,7 +223,7 @@ class Song(AST):
         "tag": "add_cumulative",
         }
 
-    def __init__(self, filename, directives):
+    def __init__(self, filename, directives, *, errors=None):
         super().__init__()
         self.content = []
         self.meta = OrderedDict()
@@ -231,6 +231,10 @@ class Song(AST):
         self._titles = []
         self._subtitles = []
         self.filename = filename
+        if errors is None:
+            self.errors = []
+        else:
+            self.errors = errors
         for directive in directives:
             self.add(directive)
 

patacrep/songs/chordpro/syntax.py

@@ -5,6 +5,7 @@ import ply.yacc as yacc
 import re
 
 from patacrep.songs.syntax import Parser
+from patacrep.songs import errors
 from patacrep.songs.chordpro import ast
 from patacrep.songs.chordpro.lexer import tokens, ChordProLexer
 
@@ -42,7 +43,11 @@ class ChordproParser(Parser):
                 | empty
         """
         if len(symbols) == 2:
-            symbols[0] = ast.Song(self.filename, self._directives)
+            symbols[0] = ast.Song(
+                self.filename,
+                directives=self._directives,
+                errors=self._errors,
+                )
         else:
             symbols[0] = symbols[2].add(symbols[1])
 
@@ -140,24 +145,29 @@ class ChordproParser(Parser):
 
             if match is None:
                 if argument.strip():
-                    self.error(
+                    error = errors.SongSyntaxError(
                         line=symbols.lexer.lineno,
                         message="Invalid chord definition '{}'.".format(argument),
                         )
+                    self.error(line=error.line, message=error.message)
                 else:
-                    self.error(
+                    error = errors.SongSyntaxError(
                         line=symbols.lexer.lineno,
                         message="Invalid empty chord definition.",
                         )
+                    self.error(line=error.line, message=error.message)
+                self._errors.append(error)
                 symbols[0] = ast.Error()
                 return
 
             define = self._parse_define(match.groupdict())
             if define is None:
-                self.error(
+                error = errors.SongSyntaxError(
                     line=symbols.lexer.lineno,
                     message="Invalid chord definition '{}'.".format(argument),
                     )
+                self.error(line=error.line, message=error.message)
+                self._errors.append(error)
                 symbols[0] = ast.Error()
                 return
             self._directives.append(define)
@@ -186,10 +196,14 @@ class ChordproParser(Parser):
         else:
             symbols[0] = None
 
-    @staticmethod
+    def p_line_error(self, symbols):
-    def p_line_error(symbols):
         """line_error : error directive"""
-        LOGGER.error("Directive can only be preceded or followed by spaces")
+        error = errors.SongSyntaxError(
+            line=symbols.lexer.lineno,
+            message="Directive can only be preceded or followed by spaces",
+            )
+        self._errors.append(error)
+        LOGGER.error(error.message)
         symbols[0] = ast.Line()
 
     @staticmethod
@@ -321,5 +335,8 @@ def parse_song(content, filename=None):
         lexer=ChordProLexer(filename=filename).lexer,
         )
     if parsed_content is None:
+        # pylint: disable=fixme
+        # TODO: Provide a nicer error (an empty song?)
+        # TODO: Add an error to the song.errors list.
         raise SyntaxError('Fatal error during song parsing: {}'.format(filename))
     return parsed_content

patacrep/songs/errors.py

@@ -0,0 +1,33 @@
+"""Errors in song definition (syntax errors, and so on)"""
+
+class SongError:
+    """Generic song error"""
+    # pylint: disable=too-few-public-methods
+
+    type = "generic"
+
+    def __init__(self, message):
+        self.message = message
+
+    def __str__(self):
+        raise NotImplementedError()
+
+class SongSyntaxError(SongError):
+    """Syntax error"""
+    # pylint: disable=too-few-public-methods
+
+    type = "syntax"
+
+    def __init__(self, line, message):
+        super().__init__(message)
+        #: Line of error. May be `None` if irrelevant.
+        self.line = line
+
+    def __str__(self):
+        return "Line {}: {}".format(self.line, self.message)
+
+# class FileError(SongError):
+#     type = "file"
+#
+# class LanguageError(SongError):
+#     type = "language"

patacrep/songs/syntax.py

@@ -2,6 +2,8 @@
 
 import logging
 
+from patacrep.songs import errors
+
 LOGGER = logging.getLogger()
 
 class Parser:
@@ -10,6 +12,7 @@ class Parser:
 
     def __init__(self):
         self.filename = "" # Will be overloaded
+        self._errors = []
 
     @staticmethod
     def __find_column(token):
@@ -42,11 +45,17 @@ class Parser:
     def p_error(self, token):
         """Manage parsing errors."""
         if token is None:
-            self.error(
+            error = errors.SongSyntaxError(
+                line=None,
                 message="Unexpected end of file.",
                 )
+            self.error(message=error.message)
         else:
-            self.error(
+            error = errors.SongSyntaxError(
                 line=token.lineno,
+                message="Syntax error",
+                )
+            self.error(
+                line=error.line,
                 column=self.__find_column(token),
                 )