Puzzling message when testing Antlr right after setup on Windows

[Korporal]

I followed this blog post to get me started on Windows.

I created the simple Expr.g4 file as instructed, when I ran antlr Expr.g4 I get:

error(50): Expr.g4:3:12: syntax error: '?' came as a complete surprise to me
error(50): Expr.g4:3:13: syntax error: '*' came as a complete surprise to me while matching alternative
error(50): Expr.g4:3:14: syntax error: '?' came as a complete surprise to me
error(50): Expr.g4:3:16: syntax error: '?' came as a complete surprise to me
error(50): Expr.g4:3:18: syntax error: '?' came as a complete surprise to me
error(50): Expr.g4:3:19: syntax error: mismatched input ')' expecting SEMI while matching alternative
error(50): Expr.g4:4:0: syntax error: '|' came as a complete surprise to me while matching rule preamble
error(50): Expr.g4:4:8: syntax error: '?' came as a complete surprise to me
error(50): Expr.g4:4:9: syntax error: '+' came as a complete surprise to me while matching alternative
error(50): Expr.g4:4:10: syntax error: '?' came as a complete surprise to me
error(50): Expr.g4:4:12: syntax error: '?' came as a complete surprise to me
error(50): Expr.g4:4:13: syntax error: '-' came as a complete surprise to me
error(50): Expr.g4:4:14: syntax error: '?' came as a complete surprise to me
error(50): Expr.g4:4:15: syntax error: mismatched input ')' expecting SEMI while matching alternative
error(50): Expr.g4:5:0: syntax error: '|' came as a complete surprise to me while matching rule preamble
error(50): Expr.g4:6:2: syntax error: '?' came as a complete surprise to me
error(50): Expr.g4:6:4: syntax error: '?' came as a complete surprise to me
error(50): Expr.g4:6:11: syntax error: '?' came as a complete surprise to me
error(50): Expr.g4:6:13: syntax error: '?' came as a complete surprise to me

I could see that the test file was UTF-8, I therefore re-saved it as simple ANSI as an experiment and get:

error(50): Expr.g4:4:13: syntax error: '-' came as a complete surprise to me

This the text from my Expr.g4

grammar Expr;
prog: (expr NEWLINE)* ;
expr: expr (‘*’|’/’) expr
| expr (‘+’|’-’) expr
| INT
| ‘(‘ expr ‘)’
;
NEWLINE : [\r\n]+ ;
INT : [0–9]+ ;

Does antlr only accept ANSI files? If so how does one incorporate Unicode characters into a grammar?

Help is greatly appreciated.

[Korporal]

I have fixed this. The character used for a quote is not an ASCII quote, the character copied from that web page is not a conventional ASCII quote.

The quote chars copied from that web page were 0x91 and 0x92.

The one expected by Antlr is it seems 0x27.

Here's the raw file, it contains some correct and incorrect quotes to show the problem:

This seems to suggest a small weakness, perhaps Antlr could, should report that it is seeing non-ASCII characters if the grammar file is pure ASCII, if it is UTF8 it could also warn that incorrect quotes are being used rather than react as it does...