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new_settings_in_javacc_21 [2020/09/27 00:20] – revusky | new_settings_in_javacc_21 [2022/02/15 01:49] – chamberlain | ||
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Here is a list of settings that exist in JavaCC 21 but are not (and never were) present in the legacy JavaCC tool: | Here is a list of settings that exist in JavaCC 21 but are not (and never were) present in the legacy JavaCC tool: | ||
+ | * **BASE_NAME** This option is used to set the name of the parser, lexer, constants, and NFA data files instead of using the default naming convention that prefixes these files with the name of the grammar file. If this option is set to an empty string (BASE_NAME=""; | ||
* **BASE_SRC_DIR** This supersedes the older OUTPUT_DIRECTORY setting. Files are generated // | * **BASE_SRC_DIR** This supersedes the older OUTPUT_DIRECTORY setting. Files are generated // | ||
+ | * **CONSTANTS_CLASS** This option is used to set the name of the generated constants file instead of using the default file name based on the grammar filename. | ||
+ | * **DEACTIVATE_TOKENS** This setting allows you to indicate that certain token types are de-activated by default when you instantiate the parser. Something like: '' | ||
+ | * **ENSURE_FINAL_EOL** With this setting turned on (it is off by default) the generated parser ensures that the input file ends with a newline character. (It tacks one on if it is not present.) This is a nitpicking detail but it is surprisingly difficult to write certain grammars (ones that are very line-oriented) if you cannot be sure that every line (including the last one!) ends with a newline. | ||
+ | * **EXTRA_TOKENS** This setting allows you to indicate some additional token types that are not defined with regular expressions in the lexical grammar. This can be useful particularly in token hook routines. | ||
* **FAULT_TOLERANT** This turns on the experimental support for building a [[fault tolerant]] parser. It is off by default. | * **FAULT_TOLERANT** This turns on the experimental support for building a [[fault tolerant]] parser. It is off by default. | ||
- | * **HUGE_FILE_SUPPORT** Since we believe that the normal usage of the tool is simply to build a tree, it makes little sense to have any qualms about reading in the entire input into memory. So this is the default. This option | + | * **LEXER_CLASS** This option sets the name of the generated lexer file instead of using the default file name based on the grammar filename. This option |
- | * **LEGACY_API** If you turn on this setting, the tool generates code that is more compatible with legacy JavaCC. One example is that JavaCC 21 removes publicly visible fields like Token.kind and Token.image and replaces them with getter/ | + | * **PARSER_CLASS** This option |
- | * **PRESERVE_LINE_ENDINGS** This is true by default | + | * **PRESERVE_LINE_ENDINGS** This is now off by default. |
* **SMART_NODE_CREATION** This is the default behavior, so you would have to explicitly turn it off. It means that if no JJTree-style tree-building annotation is used, then a new Node will be created if there are more than one Nodes on the stack. So, a production like '' | * **SMART_NODE_CREATION** This is the default behavior, so you would have to explicitly turn it off. It means that if no JJTree-style tree-building annotation is used, then a new Node will be created if there are more than one Nodes on the stack. So, a production like '' | ||
* **SPECIAL_TOKENS_ARE_NODES** This sets whether to add so-called " | * **SPECIAL_TOKENS_ARE_NODES** This sets whether to add so-called " | ||
- | * **TABS_TO_SPACES** This is an integer (typically from 1 to 8, in practice) that defines how many spaces a tab stop is. This is off by default, | + | * **TABS_TO_SPACES** This is an integer (typically from 1 to 8, in practice) that defines how many spaces a tab stop is. This is now set to 8 by default. (Until very recently, the default was that the option was off.) This means that all TAB characters (\t) are converted to spaces when the file is read in. Note that, if you turn this off, all reported error locations simply treat a tab character as one horizontal offset. If you want JavaCC to report errors as if a TAB stop is 4 spaces, say, you need to set TAB_SPACES=4 in your settings. |
* **TOKENS_ARE_NODES** This sets whether we add Tokens as terminal nodes to the AST. By default, it is true. | * **TOKENS_ARE_NODES** This sets whether we add Tokens as terminal nodes to the AST. By default, it is true. | ||
See [[deprecated settings]] for a list of legacy JavaCC options that no longer exist in JavaCC 21. | See [[deprecated settings]] for a list of legacy JavaCC options that no longer exist in JavaCC 21. |