Stumped by an initial very simple grammar

[The-Futurist]

I'm reading through Terence Parr's book and experimenting as I go, I'm a Windows user.

The tools seem to work, everything it setup and I'm generating Java for now (will do C# later when I'm more accustomed to all this).

Anyway, I'm stumped, a tiny grammar (literally a tweak from what's in the book) causes me issues, look, here's the grammar and a sample input file:

This is the output from the grun command:

I cannot understand why the simplest input a=1 causes a problem! Surely a single digit 1 meets the definition of INT in that grammar?

Here is the file itself as a raw data dump:

If I change the definition of INT to be simply INT: '1' ; then it parses that file fine.

Resolved

Ok its Unicode again, here is what's actually in the g4 file:

Note, that's actually a 'EN DASH' character with code E28093 - see here.

[kaby76]

Some suggestions:

• Pitch the Java target and just use the C# target using Antlr4BuildTasks with Antlr4.Runtime.Standard. Here is a sample project set up for you.
  Generated-CSharp.zip
  After unpacking, type "dotnet run whatever-your-file-is" and the program will parse the input file.
• If you need a tree, go to lab.antlr.org and paste in your grammar and input. The output tree can be saved as .svg.
• Use the "-tokens" option to output a list of tokens so you know what the heck is going on with a parse. The prereq for a parse is a lex--make sure the tokens are right.
• Set your editor to use "utf8 no bom" or just encode the files as ASCII.