| ANTLR(1) | General Commands Manual | ANTLR(1) |
ANTLR - ANother Tool for Language Recognition, version 4
antlr4 [options] file.g4 [ file2.g4 file3.g4 ...]
ANTLR (ANother Tool for Language Recognition) is a parser generator for reading, processing, executing, or translating structured text or binary files. It's widely used to build languages, tools, and frameworks. From a grammar, ANTLR generates a parser that can build and walk parse trees.
ANTLR generates output files in the current directory by default. This option specifies the output directory where ANTLR should generate parsers, listeners, visitors, and tokens files.
When looking for tokens files and imported grammars, ANTLR normally looks in the current directory. This option specifies which directory to look in instead. It is only used for resolving grammar references for the import statement and the tokenVocab option. The path to the primary grammar must always be fully specified.
This option generates DOT graph files that represent the internal ATN (augmented transition network) data structures that ANTLR uses to represent grammars. The files come out as Grammar.rule .dot. If the grammar is a combined grammar, the lexer rules are named Grammar Lexer.rule .dot.
By default ANTLR loads grammar files using the UTF-8 encoding, which is a very common character file encoding that degenerates to ASCII for characters that fit in one byte. If that grammar file is not the default encoding for your locale, you need this option so that ANTLR can properly interpret grammar files. This does not affect the input to the generated parsers, just the encoding of the grammars themselves.
ANTLR generates warning and error messages using templates from directory tool/resources/org/antlr/v4/tool/templates/messages/formats. By default, ANTLR uses the antlr.stg (StringTemplate group) file. You can change this to 'gnu' or 'vs2005' to have ANTLR generate messages appropriate for Emacs or Visual Studio. To make your own called X, create resource org/antlr/v4/tool/templates/messages/formats/X and place it in the CLASSPATH.
ANTLR can generate both parse tree listeners and visitors; this option and -listener aren’t mutually exclusive.
Use this option to specify a package or namespace for ANTLR-generated files. Alternatively, you can add a @header {...} action but that ties the grammar to a specific language. If you use this option and @header, make sure that the header action does not contain a package specification otherwise the generated code will have two of them.
Instead of generating a parser and/or lexer, generate a list of file dependencies, one per line. The output shows what each grammar depends on and what it generates. This is useful for build tools that need to know ANTLR grammar dependencies.
If you use -lib libdir with -depend and grammar option tokenVocab=A, then the dependencies include the library path as well.
-Xforce-atn use the ATN simulator for all predictions
-Xlog dump lots of logging info to antlr-timestamp.log
This option is useful for generating parsers in different languages without altering the grammar itself (with --Dlanguage=CSharp for example).
As part of a large build, ANTLR warning messages could go unnoticed. Turn on this option to have warnings treated as errors, causing the ANTLR tool to report failure back to the invoking commandline shell.
For those building a code generation target, this option brings up a window showing the generated code and the templates used to generate that code. It invokes the StringTemplate inspector window.
ANTLR normally builds traditional “switch on token type” decisions where possible (one token of lookahead is sufficient to distinguish between all alternatives in a decision). To force even these simple decisions into the adaptive LL(*) mechanism, use this option.
This option creates a log file containing lots of information messages from ANTLR as it processes your grammar. If you would like to see how ANTLR translates your left-recursive rules, turn on this option and look in the resulting log file.
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