找不到别名的词法分析器

Posted 2023-03-30

【中文标题】找不到别名的词法分析器

【英文标题】：No Lexer For Alias Found

【发布时间】：2012-05-24 10:19:49

【问题描述】：

我正在尝试使用 Pygments 和 Beautiful Soup 作为我为 Google App Engine 构建的博客软件的代码突出显示解决方案。

它的工作原理是我的 html 帖子将使用 pre 标记来识别代码。像这样：

<p>Check out this cool code example<p>    
<pre class="python">
        import this
        def demo():
            pass</pre>

BeautifulSoup 捕获pre 标签之间的部分并将其传递给 Pygments。 Pygments 应该检查类值并应用正确的 lexar。 Pygments 然后应用格式并用格式化的文本替换原始文本。解决方案在SaltyCrane's Blog 有更详细的解释。

错误

ClassNotFound: no lexer for alias [u'python'] found

也许我只是没有正确导入模块？

代码

from google.appengine.ext import db
import fix_path
import bs4
import pygments
from bs4 import BeautifulSoup
from pygments import highlight
from pygments.lexers import get_lexer_by_name
from pygments.formatters import HtmlFormatter


    def formatter(p):
        soup = BeautifulSoup(p.otext)
        preblocks = soup.findAll('pre')
        for pre in preblocks:
            if pre.has_key('class'):
                code = ''.join([unicode(item) for item in pre.contents])
                code = unescape_html(code)
                lexer = lexers.get_lexer_by_name(pre['class'])
                formatter = formatters.HtmlFormatter()
                code_hl = highlight(code, lexer, formatter)
                pre.replaceWith(BeautifulSoup(code_hl))
            else:
                print "No Go"
        return unicode(soup)

回溯

Traceback (most recent call last):
  File "C:\Users\john\webdev\google\lib\webapp2\webapp2.py", line 1536, in __call__
    rv = self.handle_exception(request, response, e)
  File "C:\Users\john\webdev\google\lib\webapp2\webapp2.py", line 1530, in __call__
    rv = self.router.dispatch(request, response)
  File "C:\Users\john\webdev\google\lib\webapp2\webapp2.py", line 1278, in default_dispatcher
    return route.handler_adapter(request, response)
  File "C:\Users\john\webdev\google\lib\webapp2\webapp2.py", line 1102, in __call__
    return handler.dispatch()
  File "C:\Users\john\webdev\google\lib\webapp2\webapp2.py", line 572, in dispatch
    return self.handle_exception(e, self.app.debug)
  File "C:\Users\john\webdev\google\lib\webapp2\webapp2.py", line 570, in dispatch
    return method(*args, **kwargs)
  File "C:\Users\john\webdev\workspace\bsby\views.py", line 45, in post
    p.ftext = utils.formatter(p)
  File "C:\Users\john\webdev\workspace\bsby\utils.py", line 18, in formatter
    lexer = lexers.get_lexer_by_name(pre['class'])
  File "C:\Users\john\webdev\workspace\bsby\lib\pygments\lexers\__init__.py", line 80, in get_lexer_by_name
    raise ClassNotFound('no lexer for alias %r found' % _alias)
ClassNotFound: no lexer for alias [u'python'] found

【参考方案1】：

是的，这就是问题所在。我没有导入脚本运行所需的库。这是正确的代码。

import fix_path
import bs4
import pygments
from bs4 import BeautifulSoup
from pygments import highlight
from pygments import lexers
from pygments import formatters


    def formatter(p):
        soup = BeautifulSoup(p.otext)
        preblocks = soup.findAll('pre')
        for pre in preblocks:
            if pre.has_key('class'):
                code = ''.join([unicode(item) for item in pre.contents])
                lexer = lexers.get_lexer_by_name("python")
                formatter = formatters.HtmlFormatter()
                code_hl = highlight(code, lexer, formatter)
                pre.replaceWith(BeautifulSoup(code_hl))
                return unicode(soup)
            else:
                return null

这是另一个问题....

我想像这样动态提取词法名称...

lexer = lexers.get_lexer_by_name(pre['class'])

但是，当我这样做时，我收到以下错误。

ClassNotFound: no lexer for alias [u'python'] found

如果我这样做了

lexer = lexers.get_lexer_by_name("python")

它有效，但仅适用于 python。