Parse text literals. See: https://www.pivotaltracker.com/story/show/182496940
# Important Notes
- The left-trimming algorithm (https://github.com/enso-org/design/blob/wip/wd/enso-spec/epics/enso-spec-1.0/04.%20Expressions.md#inline-and-block-text-literals) requires two passes over the sequence of text segments. This implementation performs one pass while parsing (identifying the correct amount of trim). The other pass (applying the trim) can be done when building the value of the quoted string: Trim the amount of whitespace identified by the `trim` field off of the whitespace of each `TextSection` (the value will not exceed the amount of whitespace found in the tokens' offsets, except for tokens with 0 offset, in which case no trimming is necessary/possible).
Implements:
- UUIDs: https://www.pivotaltracker.com/story/show/182931137
- Comments: https://www.pivotaltracker.com/story/show/182981779
- Type annotations and signatures: https://www.pivotaltracker.com/story/show/182497454
- Fix getter names (https://github.com/enso-org/enso/pull/3627#discussion_r940887460).
# Important Notes
- I can't fully test UUIDs; I have tested that the data obtained in Rust matches my understanding of how the format is supposed to work. What remains to be tested is that the data in Java matches the way the old parser handles the format. So @JaroslavTulach, let me know if you see any cases where I'm not returning the same values.
- This implementation of type annotations and signatures accepts any expression in type context. It would probably be nice to narrow this down at some point, but for now I have no design info on what specifically should be allowed in type expressions; this implementation should be at least an incremental improvement.
Based on usage; I believe this handles every case in current `.enso` files.
# Important Notes
- `import` is a built-in macro, so an import statement parses as a `MultiSegmentApp`.
- Every `import` syntax will have a segment whose leading keyword is `import`; however `import` macros can be identified more efficiently by looking at only the first keyword. A `MultiSegmentApp` is an import if and only if its first keyword is in the set { "polyglot", "from", "import" }.
Provide a JNI dynamic-library interface to `enso_parser`.
# Important Notes
- The library can be built with: `cargo build -p enso-parser-jni`.
- A new `org.enso.syntax2.Parser` API is implemented on top of the JNI interface provided by `enso-parser-jni`.
- We are using the `jni` crate, since apparently Java cannot just call C-ABI functions. The crate is not well-maintained. I came across an obviously-unsound `safe` function, and found it was reported over a year ago, with a PR to fix: jni-rs/jni-rs#303. However our needs are simple. We can't trust any safety guarantees they imply, but I think we are unlikely to encounter any logic bugs using the basic bindings.
implement simple variable assignments and function definitions.
This implements:
- https://www.pivotaltracker.com/story/show/182497122
- https://www.pivotaltracker.com/story/show/182497144 (the code blocks are not created yet, but the function declaration is recognized.)
# Important Notes
- Introduced S-expression-based tests, and pretty-printing-roundtrip testing.
- Started writing tests for TypeDef based on the examples in the issue. None of them parse successfully.
- Fixed Number tokenizing.
- Moved most contents of parser's `main.rs` to `lib.rs` (fixes a warning).
