lexical | building parsers using the Go programming language | Parser library

The regular expression you copied is for (f)lex, which uses a slightly different syntax for regular expressions. In particular, (f)lex treats " as an ordinary character inside bracketed classes, so [^"\\] is a character class matching anything other than (^) a quotation mark (") or a backslash (\\).

However, in JFlex, the " is a quoting character, whether outside or inside brackets. So the " in the character class is unterminated. Hence the error message.

So you need to backslash-escape it:

This is a bug. Have made an issue for it: https://github.com/rakudo/rakudo/issues/4403

I suggest using the workaround in the meantime.

No this meta syntax does not exist in Rascal. We did not add it.

You could write an over-estimation like this and have a post-parse filter reject more than 5 items:

In your rules, {UNKNOWN_TOKEN} appears very early. Since it matches any token of any length not containing whitespace, it will match the same tokens as any following rule (and possibly more characters as well). Since (f)lex always choses the first rule if more than one rule is possible, none of the rules after {UNKNOWN_TOKEN} will ever match.

I suggest you use fewer macros. (Or no macros at all.) They are not contributing anything to your code. They only make it unnecessarily long, and they are confusing you (I think) because macro definitions are not rules and the order of macro definitions does not affect the match, only the order of the rules themselves.

There are some other errors as well. For example, [\+\+] does not match ++. It is a character class, so it matches precisely one character. The only character it can match is + because repeated characters in a set don't change the set. (There is no need to backslash-escape + in a character class either. Inside brackets most characters lose their special meaning.) What you meant was "++".

Your code is incomplete:

When implementing such circular dependencies, make sure that the file you're using in other code doesn't contain top-level export declarations that require the other file. In your case:

• If you import Sub in some other file, its top-level export requires Parent which requires Sub, then it's impossible to resolve: the snake bites its own tail
• If you import Parent in some other file, its top-level export doesn't need Sub immediately (only when createSomething is being called). In that case, the Parent export fully resolves, then the Sub file is able to resolve its own export as well.

Assuming the full error message is ReferenceError: can't access lexical declaration`X' before initialization.

Function declarations are hoisted.

Assignments to variables are not.

You can't read addTodo before you assign a value to it.

Change the order of your source code.

Not at present, however it should be possible in a future Raku language version. Work is taking place to define a standard AST for the Raku language (currently known as "RakuAST"), and to rewrite the compiler frontend to work in terms of it. Once that is done, it will be exposed in a number of places. Macros are the most obvious consumers, however it's also planned:

• To make the AST of a block or routine available from traits, in order that traits can inspect and perhaps even modify the AST
• To introduce custom compiler passes, which will be modules that are given access to the entire AST of the scope that they are imported into

The first of these would seem to satisfy your use case. Going on current proposed API it could look something like this: