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[英]Is it possible to use a with grako generated parser without grako?
[英]Basic Grako example gives IndexError
我想開始使用Grako(3.6.6),作為解析器的初體驗,我想從自定義語法生成HTML表。 以下基本測試
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)
導致錯誤
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
碰巧是partial_match = (token[0].isalpha() and token.isalnum() and self.is_name_char(self.current()) )
盡管我是解析器的新手,並且缺少文檔,但我還是要堅持使用Grako。
您能幫我建立一個輸出表格HTML的基本示例嗎?
Grako不能正確看到語法中的"\\n"
,因為令牌中不允許換行,並且在外部三重引號( """
)字符串的上下文中對\\n
進行了評估。您使用/\\n/
代替。
還要注意,如果\\n
將成為語言的一部分,那么您可能應該編寫一個@@whitespace
子句,以便解析器不會跳過該字符:
@@whitespace :: /[\t ]+/
這是您所用語言的正確語法:
grammar = """
@@whitespace :: /[\t ]+/
table = { row }+ ;
row = (cell1:cell "|" cell2:cell) "\\n";
cell = /[a-z]+/ ;
"""
我目前正在修補Grako,以檢測並報告語法中的錯誤。 更改已在Bitbucket存儲庫中。 完成測試后,我將發布一個版本。
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