CODEWITHSUNDEEP
parsingantlrantlr3
MK.
MK.

Reputation: 34597

antlr: how to [sometimes] parse things in quotes?

I have a situation where my language allows quotes strings but sometimes I want to interpret the contents of the quoted string as language constructs. Think of it as, say, eval function.

So to support quoted strings i need a lexer rule and it overrides my attempts to have a grammar rule evaluating things in quotes if prefixed with 'eval'. Is there any way to deal with this in the grammar?

Upvotes: 0

Views: 135

Answers (2)

Scott Stanchfield
Scott Stanchfield

Reputation: 30652

If you want to implement an eval function, you're really looking for a runtime interpreter.

The only time you need an "eval" function is when you want to build up the content to compile at runtime. If you have the content available at compile-time, you can parse it without it being a string...

So... keep it as a string, and then use the same parser at runtime to parse/compile its contents.

Upvotes: 1

greydet
greydet

Reputation: 5539

IMO you should not try to handle this case directly through the lexer.
I think I would leave the string as it in the lexer and add some code in the eval rule of the parser that calls a sub-parser on the string content.

Upvotes: 1

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