minor improevment in interpreter and fixed bug in grammar

3 jobs for master in 1 minute and 16 seconds (queued for 2 seconds)
Status Job ID Name Coverage
  Test
failed build #13541

00:00:34

failed deploy #13543

00:00:17

failed test #13542

00:00:25

 
Name Stage Failure
failed
deploy Test There is an unknown failure, please try again
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal org.antlr:antlr4-maven-plugin:4.7:antlr4 (antlr) on project proofscriptparser: ANTLR 4 caught 1 build errors. -> [Help 1]
[ERROR]
[ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.
[ERROR] Re-run Maven using the -X switch to enable full debug logging.
[ERROR]
[ERROR] For more information about the errors and possible solutions, please read the following articles:
[ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/MojoExecutionException
ERROR: Job failed: exit code 1
failed
test Test There is an unknown failure, please try again
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal org.antlr:antlr4-maven-plugin:4.7:antlr4 (antlr) on project proofscriptparser: ANTLR 4 caught 1 build errors. -> [Help 1]
[ERROR]
[ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.
[ERROR] Re-run Maven using the -X switch to enable full debug logging.
[ERROR]
[ERROR] For more information about the errors and possible solutions, please read the following articles:
[ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/MojoExecutionException
ERROR: Job failed: exit code 1
failed
build Test There is an unknown failure, please try again
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal org.antlr:antlr4-maven-plugin:4.7:antlr4 (antlr) on project proofscriptparser: ANTLR 4 caught 1 build errors. -> [Help 1]
[ERROR]
[ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.
[ERROR] Re-run Maven using the -X switch to enable full debug logging.
[ERROR]
[ERROR] For more information about the errors and possible solutions, please read the following articles:
[ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/MojoExecutionException
ERROR: Job failed: exit code 1