[WIP] Chordpro format

patacrep/chordpro/ast.py

@@ -0,0 +1,71 @@
+# -*- coding: utf-8 -*-
+"""Abstract Syntax Tree for ChordPro code."""
+
+class AST:
+    """Base class for the tree."""
+    # pylint: disable=no-init
+    metadata = None
+
+    @classmethod
+    def init_metadata(cls):
+        """Clear metadata
+
+        As this attribute is a class attribute, it as to be reset at each new
+        parsing.
+        """
+        cls.metadata = {
+                '@languages': set(),
+                }
+
+class Expression(AST):
+    """ChordPro expression"""
+
+    def __init__(self, value):
+        super().__init__()
+        self.content = [value]
+
+    def prepend(self, value):
+        """Add a value at the beginning of the content list."""
+        if value is not None:
+            self.content.insert(0, value)
+        return self
+
+    def __str__(self):
+        return "".join([str(item) for item in self.content])
+
+class SongPart(AST):
+    """ChordPro start_of/end_of command
+
+    {start_of_chorus}, {end_of_tab}, {eov} ...
+    """
+
+    class Type:
+        CHORUS = ("chorus",
+                  "start_of_chorus", "end_of_chorus",
+                  "soc", "eoc")
+        VERSE = ("verse",
+                 "start_of_verse", "end_of_verse",
+                 "sov", "eov")
+        BRIDGE = ("bridge",
+                  "start_of_bridge", "end_of_bridge",
+                  "sob", "eob")
+        TAB = ("tab",
+               "start_of_tab", "end_of_tab",
+               "sot", "eot")
+
+    def __init__(self, name):
+        if "_" in name:
+            self.init_long_form(name)
+        else:
+            self.init_short_form(name)
+
+    def __str__(self):
+        return self.name
+
+    def init_short_form(self, name):
+        self.type = ""
+
+    def init_long_form(self, name):
+        self.type = ""
+
+

patacrep/chordpro/lexer.py

@@ -29,7 +29,6 @@ class ChordProLexer:
     t_RBRACE = r'}'
     t_SPACE = r'[ \t]+'
     t_COLON = r':'
-    t_WORD = r'[a-zA-Z_]+'  #TODO: handle unicode
 
     def __init__(self):
         self.__class__.lexer = lex.lex(module=self)
@@ -46,6 +45,11 @@ class ChordProLexer:
         r'\#.*'
         pass
 
+    @staticmethod
+    def t_WORD(token):
+        r'[a-zA-Z_]+[.,;:!?]?'
+        return token
+
     @staticmethod
     def t_NUMBER(token):
         r'[0-9]+'

patacrep/chordpro/parser.py

@@ -0,0 +1,88 @@
+# -*- coding: utf-8 -*-
+"""ChordPro parser"""
+
+import logging
+import ply.yacc as yacc
+
+from patacrep.chordpro.lexer import tokens, ChordProLexer
+from patacrep.chordpro import ast
+from patacrep.errors import SongbookError
+
+LOGGER = logging.getLogger()
+
+class ParsingError(SongbookError):
+    """Parsing error."""
+
+    def __init__(self, message):
+        super().__init__(self)
+        self.message = message
+
+    def __str__(self):
+        return self.message
+
+
+class Parser:
+    """ChordPro parser class"""
+
+    def __init__(self, filename=None):
+        self.tokens = tokens
+        self.filename = filename
+
+    @staticmethod
+    def __find_column(token):
+        """Return the column of ``token``."""
+        last_cr = token.lexer.lexdata.rfind('\n', 0, token.lexpos)
+        if last_cr < 0:
+            last_cr = 0
+        column = (token.lexpos - last_cr) + 1
+        return column
+
+    def p_error(self, token):
+        """Manage parsing errors."""
+        LOGGER.error("Error in file {}, line {}:{}.".format(
+            str(self.filename),
+            token.lineno,
+            self.__find_column(token),
+            )
+            )
+
+    @staticmethod
+    def p_expression(symbols):
+        """expression : brackets expression
+                      | braces expression
+                      | command expression
+                      | NEWLINE expression
+                      | word expression
+                      | SPACE expression
+                      | empty
+        """
+        if len(symbols) == 3:
+            if symbols[2] is None:
+                symbols[0] = ast.Expression(symbols[1])
+            else:
+                symbols[0] = symbols[2].prepend(symbols[1])
+        else:
+            symbols[0] = None
+
+    @staticmethod
+    def p_empty(__symbols):
+        """empty :"""
+        return None
+
+    @staticmethod
+    def p_brackets(symbols):
+        """brackets : LBRACKET expression RBRACKET"""
+        symbols[0] = symbols[2]
+
+    @staticmethod
+    def p_braces(symbols):
+        """braces : LBRACE expression COLON expression RBRACE"""
+        symbols[0] = symbols[2]
+
+
+def parsesong(string, filename=None):
+    """Parse song and return its metadata."""
+    return yacc.yacc(module=Parser(filename)).parse(
+                     string,
+                     lexer=ChordProLexer().lexer,
+                     )