Create a Lexer class for BBC Basic files.

The Lexer class for BBC Basic handles both the numbered lines, and
unnumbered lines, of the detokenised (text) format of BBC BASIC.
The tokeniser copes, in a naive manner, with the orignal versions,
and BASIC V. It does not handle other extensions at this time, nor
does it handle inline assembler. This should be sufficient for most
cases where code needs to be presented in a colourful manner.

2 files changed, 98 insertions, 2 deletions

diff --git a/pygments/lexers/_mapping.py b/pygments/lexers/_mapping.py
index f8207e70..e57124db 100644
--- a/pygments/lexers/_mapping.py
+++ b/pygments/lexers/_mapping.py
@@ -47,6 +47,7 @@ LEXERS = {
     'AutoItLexer': ('pygments.lexers.automation', 'AutoIt', ('autoit',), ('*.au3',), ('text/x-autoit',)),
     'AutohotkeyLexer': ('pygments.lexers.automation', 'autohotkey', ('ahk', 'autohotkey'), ('*.ahk', '*.ahkl'), ('text/x-autohotkey',)),
     'AwkLexer': ('pygments.lexers.textedit', 'Awk', ('awk', 'gawk', 'mawk', 'nawk'), ('*.awk',), ('application/x-awk',)),
+    'BBCBasicLexer': ('pygments.lexers.basic', 'BBC Basic', ('bbcbasic',), ('*.bbc',), ()),
     'BBCodeLexer': ('pygments.lexers.markup', 'BBCode', ('bbcode',), (), ('text/x-bbcode',)),
     'BCLexer': ('pygments.lexers.algebra', 'BC', ('bc',), ('*.bc',), ()),
     'BSTLexer': ('pygments.lexers.bibtex', 'BST', ('bst', 'bst-pybtex'), ('*.bst',), ()),
diff --git a/pygments/lexers/basic.py b/pygments/lexers/basic.py
index b0409386..4d957c2b 100644
--- a/pygments/lexers/basic.py
+++ b/pygments/lexers/basic.py
@@ -18,7 +18,8 @@ from pygments.lexers import _vbscript_builtins
 
 
 __all__ = ['BlitzBasicLexer', 'BlitzMaxLexer', 'MonkeyLexer', 'CbmBasicV2Lexer',
-           'QBasicLexer', 'VBScriptLexer']
+           'QBasicLexer', 'VBScriptLexer', 'BBCBasicLexer']
+
 
 
 class BlitzMaxLexer(RegexLexer):
@@ -561,4 +562,98 @@ class VBScriptLexer(RegexLexer):
             (r'"', String.Double, '#pop'),
             (r'\n', Error, '#pop'),  # Unterminated string
         ],
-    }
\ No newline at end of file
+    }
+
+
+class BBCBasicLexer(RegexLexer):
+    """
+    BBC Basic was supplied on the BBC Micro, and later Acorn RISC OS.
+    It is also used by BBC Basic For Windows.
+
+    .. versionadded:: 2.4????
+    """
+    base_keywords = ['OTHERWISE', 'AND', 'DIV', 'EOR', 'MOD', 'OR', 'ERROR',
+                     'LINE', 'OFF', 'STEP', 'SPC', 'TAB', 'ELSE', 'THEN',
+                     'OPENIN', 'PTR', 'PAGE', 'TIME', 'LOMEM', 'HIMEM', 'ABS',
+                     'ACS', 'ADVAL', 'ASC', 'ASN', 'ATN', 'BGET', 'COS', 'COUNT',
+                     'DEG', 'ERL', 'ERR', 'EVAL', 'EXP', 'EXT', 'FALSE', 'FN',
+                     'GET', 'INKEY', 'INSTR', 'INT', 'LEN', 'LN', 'LOG', 'NOT',
+                     'OPENUP', 'OPENOUT', 'PI', 'POINT', 'POS', 'RAD', 'RND',
+                     'SGN', 'SIN', 'SQR', 'TAN', 'TO', 'TRUE', 'USR', 'VAL',
+                     'VPOS', 'CHR$', 'GET$', 'INKEY$', 'LEFT$', 'MID$',
+                     'RIGHT$', 'STR$', 'STRING$', 'EOF', 'PTR', 'PAGE', 'TIME',
+                     'LOMEM', 'HIMEM', 'SOUND', 'BPUT', 'CALL', 'CHAIN', 'CLEAR',
+                     'CLOSE', 'CLG', 'CLS', 'DATA', 'DEF', 'DIM', 'DRAW', 'END',
+                     'ENDPROC', 'ENVELOPE', 'FOR', 'GOSUB', 'GOTO', 'GCOL', 'IF',
+                     'INPUT', 'LET', 'LOCAL', 'MODE', 'MOVE', 'NEXT', 'ON',
+                     'VDU', 'PLOT', 'PRINT', 'PROC', 'READ', 'REM', 'REPEAT',
+                     'REPORT', 'RESTORE', 'RETURN', 'RUN', 'STOP', 'COLOUR',
+                     'TRACE', 'UNTIL', 'WIDTH', 'OSCLI']
+
+    basic5_keywords = ['WHEN', 'OF', 'ENDCASE', 'ENDIF', 'ENDWHILE', 'CASE',
+                       'CIRCLE', 'FILL', 'ORIGIN', 'POINT', 'RECTANGLE', 'SWAP',
+                       'WHILE', 'WAIT', 'MOUSE', 'QUIT', 'SYS', 'INSTALL',
+                       'LIBRARY', 'TINT', 'ELLIPSE', 'BEATS', 'TEMPO', 'VOICES',
+                       'VOICE', 'STEREO', 'OVERLAY', 'APPEND', 'AUTO', 'CRUNCH',
+                       'DELETE', 'EDIT', 'HELP', 'LIST', 'LOAD', 'LVAR', 'NEW',
+                       'OLD', 'RENUMBER', 'SAVE', 'TEXTLOAD', 'TEXTSAVE',
+                       'TWIN', 'TWINO', 'INSTALL', 'SUM', 'BEAT']
+
+
+    name = 'BBC Basic'
+    aliases = ['bbcbasic']
+    filenames = ['*.bbc']
+
+    tokens = {
+        'root': [
+            (r"[0-9]+", Name.Label),
+            (r"(\*)([^\n]*)",
+             bygroups(Keyword.Pseudo, Comment.Special)),
+            (r"", Whitespace, 'code'),
+        ],
+
+        'code': [
+            (r"(REM)([^\n]*)",
+             bygroups(Keyword.Declaration, Comment.Single)),
+            (r'\n', Whitespace, 'root'),
+            (r'\s+', Whitespace),
+            (r':', Comment.Preproc),
+
+            # Some special cases to make functions come out nicer
+            (r'(DEF)(\s*)(FN|PROC)([A-Za-z_@][A-Za-z0-9_@]*)',
+             bygroups(Keyword.Declaration, Whitespace, Keyword.Declaration, Name.Function)),
+            (r'(FN|PROC)([A-Za-z_@][A-Za-z0-9_@]*)',
+             bygroups(Keyword, Name.Function)),
+
+            (r'(GOTO|GOSUB|THEN|RESTORE)(\s*)(\d+)',
+             bygroups(Keyword, Whitespace, Name.Label)),
+
+            (r'(TRUE|FALSE)', Keyword.Constant),
+            (r'(PAGE|LOMEM|HIMEM|TIME|WIDTH|ERL|ERR|REPORT\$|POS|VPOS|VOICES)', Keyword.Pseudo),
+
+            (words(base_keywords), Keyword),
+            (words(basic5_keywords), Keyword),
+
+            ('"', String.Double, 'string'),
+
+            ('%[01]{1,32}', Number.Bin),
+            ('&[0-9a-f]{1,8}', Number.Hex),
+
+            (r'[+-]?[0-9]+\.[0-9]*(E[+-]?[0-9]+)?', Number.Float),
+            (r'[+-]?\.[0-9]+(E[+-]?[0-9]+)?', Number.Float),
+            (r'[+-]?[0-9]+E[+-]?[0-9]+', Number.Float),
+            (r'[+-]?\d+', Number.Integer),
+
+            (r'([A-Za-z_@][A-Za-z0-9_@]*[%$]?)', Name.Variable),
+            (r'([+\-]=|[$!|?+\-*/%^=><();]|>=|<=|<>|<<|>>|>>>|,)', Operator),
+        ],
+        'string': [
+            (r'[^"\n]+', String.Double),
+            (r'"', String.Double, '#pop'),
+            (r'\n', Error, 'root'),  # Unterminated string
+        ],
+    }
+
+    def analyse_text(text):
+        if text.startswith('10REM >') or text.startswith('REM >'):
+            return 0.9