Question

我想开始使用Grako（3.6.6），作为解析器的第一次体验，我想从自定义语法生成HTML表。以下基本测试

import grako

grammar = """table = { row }+ ;
row = (cell1:cell "|" cell2:cell) "\n";
cell = /[a-z]+/ ;
"""

model = grako.genmodel("model", grammar)

ast = model.parse(
"""a | b
c | d
""", "table")
print(ast)

导致错误

  File "test.py", line 13, in <module>
    """, "table")
  File "grako\grammars.py", line 790, in grako.grammars.Grammar.parse (grako\grammars.c:27773)
  File "grako\grammars.py", line 97, in grako.grammars.GrakoContext.parse (grako\grammars.c:4391)
  File "grako\contexts.py", line 180, in grako.contexts.ParseContext.parse (grako\contexts.c:4313)
  File "grako\grammars.py", line 594, in grako.grammars.Rule.parse (grako\grammars.c:22253)
  File "grako\grammars.py", line 597, in grako.grammars.Rule._parse_rhs (grako\grammars.c:22435)
  File "grako\contexts.py", line 399, in grako.contexts.ParseContext._call (grako\contexts.c:10088)
  File "grako\contexts.py", line 433, in grako.contexts.ParseContext._invoke_rule (grako\contexts.c:11135)
  File "grako\grammars.py", line 435, in grako.grammars.PositiveClosure.parse (grako\grammars.c:17285)
  File "grako\contexts.py", line 695, in grako.contexts.ParseContext._positive_closure (grako\contexts.c:19286)
  File "grako\contexts.py", line 696, in grako.contexts.ParseContext._positive_closure (grako\contexts.c:19240)
  File "grako\grammars.py", line 435, in grako.grammars.PositiveClosure.parse.lambda10 (grako\grammars.c:17195)
  File "grako\grammars.py", line 547, in grako.grammars.RuleRef.parse (grako\grammars.c:20774)
  File "grako\grammars.py", line 594, in grako.grammars.Rule.parse (grako\grammars.c:22253)
  File "grako\grammars.py", line 597, in grako.grammars.Rule._parse_rhs (grako\grammars.c:22435)
  File "grako\contexts.py", line 399, in grako.contexts.ParseContext._call (grako\contexts.c:10088)
  File "grako\contexts.py", line 433, in grako.contexts.ParseContext._invoke_rule (grako\contexts.c:11135)
  File "grako\grammars.py", line 326, in grako.grammars.Sequence.parse (grako\grammars.c:11582)
  File "grako\grammars.py", line 268, in grako.grammars.Token.parse (grako\grammars.c:9463)
  File "grako\contexts.py", line 543, in grako.contexts.ParseContext._token (grako\contexts.c:13772)
  File "grako\buffering.py", line 301, in grako.buffering.Buffer.match (grako\buffering.c:9168)
IndexError: string index out of range

恰好是partial_match = (token[0].isalpha() and token.isalnum() and self.is_name_char(self.current()) )

尽管我不熟悉解析器并且缺少文档，但我还是想坚持Grako。

您能帮我设置一个输出表格HTML的基本示例吗？

Answer 1

Grako 没有正确地看到语法中的"\n"，因为令牌中不允许使用换行符，并且在外部上下文中评估\n -quote（"""），string。如果您使用/\n/，事情就可以了。

另请注意，如果\n将成为该语言的一部分，那么您应该编写一个@@whitespace子句，以便解析器不会跳过该字符：

@@whitespace :: /[\t ]+/

这是您语言的正确语法：

grammar = """
@@whitespace :: /[\t ]+/
table = { row }+ ;
row = (cell1:cell "|" cell2:cell) "\\n";
cell = /[a-z]+/ ;
"""

我目前正在修补 Grako 来检测和报告语法中的错误。更改已在Bitbucket存储库中。我完成测试后会发布。

Basic Grako示例给出了IndexError

1 个答案: