AdvanceAndCopy is like NextToken; advance to next token that is not whitespace and return Note: The 'go' and EOF tokens are *not* copied.

NextTokenCopyingWhitespace is like s.NextToken(), but if whitespace is encountered it is simply copied into `target`.

ParseFileystems iterates through a list of filesystems and parses all files matching `*.sql`, determines which one are sqlcode files from the contents, and returns the combination of all of them.

we don't want to support double quotes, for simplicity, so that is an error and stops parsing.

PragmaToken is like SinglelineCommentToken but starting with `--sqlcode:`.

Note: A lot of stuff pass as identifiers that should really have been reserved words.

A string that has a Pos-ition in a source document.

We don't do the lexer/parser split / token stream, but simply use the Scanner directly from the recursive descent parser; it is simply a cursor in the buffer with associated utility methods.

dedicated type for reference to file, in case we need to refactor this later..