Breaks `--trace` into two flags:
- `--parser_debug`, which sets the parser debug level (which I haven't dug into piping with `--trace`, but seemed likely to be troublesome)
- `--trace_file`, which now the type checker and interpreter will use for trace information (note compile errors should use a different channel)
Most of the file edits are just mechanical testdata flag updates: `sed -i 's/--trace/--parser_debug --trace_file=-/' testdata/**/*.carbon`
To explain the output paths:
- parse/compile errors: stderr
- print() calls: stdout
- parser tracing: `--parser_debug` option, stdout (formerly stdout if `--trace`)
- type check/compile tracing: `--trace_file=<file>`, giving `-` uses stdout (formerly stdout if `--trace`)
- return code of executed Carbon code: `--trace_file` if set, stdout if not (formerly stdout always)
* Modify parser and AST nodes to include let statement
* Implement let variables
* Remove redundant code in fail_match_choice test
* Add comment for has_value_category()
* Apply suggestions from code review
Co-authored-by: Jon Meow <46229924+jonmeow@users.noreply.github.com>
* clang-format changes
* Update comments for new BindingPattern methods
* Implement nested vars in patterns
* Apply suggestions from @geoffromer's code review
Co-authored-by: Geoff Romer <gromer@google.com>
* Implement changes from code review.
* Remove maybe_var_pattern grammar rule
Co-authored-by: Jon Meow <46229924+jonmeow@users.noreply.github.com>
Co-authored-by: Geoff Romer <gromer@google.com>
Jon Meow
