Run the Evaluator

To run the project:

• open the Xcode project ExpressionEvaluator.xcodeproj.
• Press the run button (CMD+SHIFT+R)
• Enter input in the [Xcode] console.

That should be all you will need to know. Keep reading if issues arise.

Errors

The project runs a script during the build process that generates the ANTLR boilerplate for the grammar file.

If this fails, a nice error should show up in Xcode.

ANTLR Location

The script expects the jar file for ANTLR to be located at /usr/local/lib/antlr-4.8-complete.jar. If this is not the case for your system, change that value in build-phases/antlr-generate.sh

If this doesn't resolve it, I've included the generated files, so you could just disable the build phase titled: Generate ANTLER Parser accessible through ExpressionEvaluator(project file)->Build Phases.

Reproduction Notes

The project took some configuration to work with Swift. The project will work as-is through the Xcode project. I've added the following as notes for myself or to reproduce my setup if there is an issue.

ANTLR - Swift reference

ANTLER_JAR=/usr/local/lib/antlr-4.8-complete.jar
export CLASSPATH=".:$ANTLER_JAR:$CLASSPATH"
alias antlr4='java -Xmx500M -cp "$ANTLER_JAR:$CLASSPATH" org.antlr.v4.Tool'
alias grun='java -Xmx500M -cp "$ANTLER_JAR:$CLASSPATH" org.antlr.v4.gui.TestRig'

Install Maven

download page

Decompress that, put it at /opt/apache-maven-3.6.3

export PATH=/opt/apache-maven-3.6.3/bin:$PATH
export JAVA_HOME=$(/usr/libexec/java_home)

Configure ANTLR Runtime

git clone https://github.com/antlr/antlr4
cd antlr4
mvn install

This seems to run the tests too. Once the tests were running, I just killed the process. There is probably options to not run tests.

This generates the runtime support Xcode project.

cd antlr4/runtime/Swift
python boot.py --gen-xcodeproj

Then drag the project file into the App project and add it as a dependency.