The Quick Interpreter gives a "null" in the message

[peterwvj]

Description

The Quick Interpreter gives a "null" in the message if you evaluate something like "1 +" (without the quotes)

Steps to Reproduce

1. Evaluate "1+" (without the quotes) in the quick interpreter

Expected behavior:

A meaningful (parse) error should be printed.

Actual behavior:

The quick interpreter reports.

Error 2034: Unexpected token in expression: null in 'DEFAULT' (console) at line 2:0

The message should be something more meaningful than "null".

Reproduces how often:

Every time.

Versions

• Overture 2.5.2
• Ubuntu 17.04 (64 bit)
• OpenJDK 1.8.0_0151 (64 bit)

[nickbattle]

This was because the VDMToken for EOF had a "null" display string - thinking that it would never be used. But when you parse "1 +", then token location of the error is EOF. So I've made the display string for EOF be "EOF". I haven't built a full tool, but this fixes the problem on the command line (which was showing the same behaviour).

Now pushed to ncb/development.

[nickbattle]

OK, I built a version with this included, and it's fine:

1+ = Error 2034: Unexpected token in expression: EOF in 'DEFAULT' (console) at line 2:0