In order to help write more concise and compact code when defining REST services, we use our own RQL-like parser to generate the queries for endpoints (using interceptors).
You'll need VS Code to efficiently edit, compile and test the ANTLR Lexer and Parser.
There is a .vscode directory in the antlr4 folder containing the proper settings for VS Code.
The settings.json contains settings for the ANTLR-plugin (ANTLR4 grammar syntax support) which we use.
The launch.json contains a debug-launch setting ready to be opened with VS Code -> launch/debug -> open file. Both contains variables you'll probably want to change:
outputDir is the directory (absolute) you want the parser-generator to copy the java-files into.
package is the Java fully-qualified-package-name the files it generates should bear.
input the filename of the file that is used as input-file when debugging.
grammar the grammar-file to start when hitting the debug-key.
startRule the main-rule (root) of your grammar.
Start up VS Code and open the folder.
You may edit the grammar.
When pressing F5 a new tab should pop up with the title Parse Tree: Rql.g4 showing the resulting parse-tree after parsing your grammar (see settings in launch.json).
You may also go to your grammar file, right click and select either:
- Show Railroad Diagram for Rule
- Show Railroad Diagram for all Rules
- Show ATN Graph for Rule
- Show Grammar Call Graph
Which will open in a new tab and are, depending on which point you chose, depending on the rule your cursor currently is located in.
After pressing F5 your grammar is generated and the files are copied.
Change to your Eclipse and refresh the folder the classes are located in, for Eclipse to detect and process the changes.
You may use the visitor now and run some tests.