如何忽略pyparsing的ParseException并继续进行？

Question

我想忽略文件中与所有预定义解析器都不匹配的行，然后继续。我想忽略的行的范围很广，我无法为它们中的每一行检查和定义解析器。你知道吗

我使用try..except和pass，一旦捕获到ParseException。但是，解析立即停止。你知道吗

try:
    return parser.parseFile(filename, parse_all)

except ParseException, err:
    msg = 'Error during parsing of {}, line {}'.format(filename, err.lineno)
    msg += '\n' + '-'*70 + '\n'
    msg += err.line + '\n'
    msg += ' '*(err.col-1) + '^\n'
    msg += '-'*70 + '\n' + err.msg
    err.msg = msg

    print(err.msg)
    pass

即使出现异常，我也希望继续。你知道吗

Answer 1

Pyparsing实际上没有“continueonerror”选项，因此您需要调整解析器，以便它不会首先引发ParseException。您可以尝试将| SkipTo(LineEnd())('errors*')之类的内容添加到解析器中，作为最后一招。然后，您可以查看errors results名称来查看哪些行出错了（或者向该表达式添加一个解析操作来捕获更多的行）。你知道吗

import pyparsing as pp

era = "The" + pp.oneOf("Age Years") + "of" + pp.Word(pp.alphas)

era.runTests("""
    The Age of Enlightenment
    The Years of Darkness
    The Spanish Inquisition
    """)

印刷品：

The Age of Enlightenment
['The', 'Age', 'of', 'Enlightenment']

The Years of Darkness
['The', 'Years', 'of', 'Darkness']

The Spanish Inquisition
    ^
FAIL: Expected Age | Years (at char 4), (line:1, col:5)

添加这些行并再次调用runTests：

# added to handle lines that don't match
unexpected = pp.SkipTo(pp.LineEnd(), include=True)("no_one_expects")
era = era | unexpected

印刷品：

The Age of Enlightenment
['The', 'Age', 'of', 'Enlightenment']

The Years of Darkness
['The', 'Years', 'of', 'Darkness']

The Spanish Inquisition
['The Spanish Inquisition']
 - no_one_expects: 'The Spanish Inquisition'