coffeescript - 可视化 LALR 语法

Question

我想可视化一个语法文件(实际上是 CoffeeScript 的 Jison 语法)。所以输入文件是一个 Bison/Yacc 风格的语法文件。预期的输出可能是 Graphviz 点文件或类似文件。

我不一定要寻找完整的 IDE，例如 GOLD .但是能够处理 LALR 输入很重要，这就是为什么出色的 ANLTRWorks不考虑。

我还检查了 comparison of parsers on Wikipedia ，但它仅包括 IDE 支持，但不包括可视化。

这是coffeescript grammar file我实际上想形象化。

Answer 1

以下是创建语法图的说明。

grammar.coffee的内容是可执行代码，必须运行才能获得实际的 Jison 语法。我用了Try CoffeeScript在将 Jison 调用替换为 Javascript 警报后编译它的页面。然后运行生成的 Javascript 以获取语法，它
看起来像这样:

{
  "tokens":" TERMINATOR TERMINATOR TERMINATOR STATEMENT INDENT OUTDENT INDENT OUTDENT IDENTIFIER NUMBER STRING JS REGEX BOOL = = INDENT OUTDENT : : INDENT OUTDENT RETURN RETURN HERECOMMENT PARAM_START PARAM_END -> =>  ,  , ... = ... . ?. :: :: INDEX_START INDEX_END INDEX_SOAK { }  , TERMINATOR INDENT OUTDENT CLASS CLASS CLASS EXTENDS CLASS EXTENDS CLASS CLASS CLASS EXTENDS CLASS EXTENDS SUPER SUPER  FUNC_EXIST CALL_START CALL_END CALL_START CALL_END THIS @ @ [ ] [ ] .. ... [ ] , TERMINATOR INDENT OUTDENT INDENT OUTDENT , TRY TRY TRY FINALLY TRY FINALLY CATCH THROW ( ) ( INDENT OUTDENT ) WHILE WHILE WHEN UNTIL UNTIL WHEN LOOP LOOP FOR FOR FOR OWN , FORIN FOROF FORIN WHEN FOROF WHEN FORIN BY FORIN WHEN BY FORIN BY WHEN SWITCH INDENT OUTDENT SWITCH INDENT ELSE OUTDENT SWITCH INDENT OUTDENT SWITCH INDENT ELSE OUTDENT LEADING_WHEN LEADING_WHEN TERMINATOR IF ELSE IF ELSE POST_IF POST_IF UNARY - + -- ++ -- ++ ? + - MATH SHIFT COMPARE LOGIC RELATION COMPOUND_ASSIGN COMPOUND_ASSIGN INDENT OUTDENT EXTENDS",
  "bnf":
  {
    "Root":
    [
      ["","return $$ = new yy.Block;",null],
      ["Body","return $$ = $1;",null],
      ["Block TERMINATOR","return $$ = $1;",null]
    ],
    "Body":
    [
      ["Line","$$ = yy.Block.wrap([$1]);",null],
      ["Body TERMINATOR Line","$$ = $1.push($3);",null],
      ["Body TERMINATOR","$$ = $1;",null]
    ],
    "Line":
    [
      ["Expression","$$ = $1;",null],
      ["Statement","$$ = $1;",null]
    ],
    ...

以上可以喂给Jison-to-W3C grammar converter , 结果
在这样的语法中:

Root     ::= ( Body | Block TERMINATOR )?
Body     ::= Line ( TERMINATOR Line | TERMINATOR )*
Line     ::= Expression
           | Statement
...

从这里我们可以得到Railroad Diagram Generator创建语法图:



. . .

请注意，转换器仅评估语法的“bnf”部分，因此它不考虑标记定义。这可以通过对 W3C 风格的语法进行一些手动后处理来改进。