CODEWITHSUNDEEP
antlr
user6879072
user6879072

Reputation: 441

ANTLR4 error: Can't load Hello as lexer or parser

So on macOS I have ANTLR4.7 installed and in the directory that antler is installed in I defined my own grammar like so:

$ cd cd /usr/local/lib
$ mkdir HelloDir
$ cd HelloDir
$ nano Hello.g4

I paste this code in the file:

// Define a grammar called Hello
grammar Hello;
r  : 'hello' ID ;         // match keyword hello followed by an identifier
ID : [a-z]+ ;             // match lower-case identifiers
WS : [ \t\r\n]+ -> skip ; // skip spaces, tabs, newlines

And than I saved the file

Then I create the classes:

$ antlr4 -Dlanguage=Swift Hello.g4 //the files are generated successfully

After this I try to see what I created:

$ grun Hello r -tree

And this is the point when the error message ruins my day:

Can't load Hello as lexer or parser

The problem might be obvious but I'm new to ANTLR. So what is the problem what am I missing?

Upvotes: 0

Views: 1569

Answers (2)

david.pfx
david.pfx

Reputation: 10863

Make sure you have a "." in your CLASSPATH. Usually it will be something like this:

.;C:\etc\etc\javalib\antlr-xxx.jar

Upvotes: 1

TomServo
TomServo

Reputation: 7409

Your syntax is correct so it suggests that you don't have something installed correctly. You're likely missing dependencies and in nano there's no convenient way to set them up. I don't use the swift target, but there are detailed instructions here on using XCode to do your setup, dependencies, and project files. I'd recommend you try that github resource; it also contains several caveats and tips to get better performance through optimization settings in release mode.

Upvotes: 0

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