* 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>
* Fixed a couple simple crashes surfaced by running a structured fuzzer on executable_semantics parse/type-check/execute logic.
* var a: b: auto; -> var a: auto;
* Naive pointer implementation
* Bug fixes and better pointer tests
* Remove debug print statement
* Implement changes suggested by @geoffromer
Also add a failing test case that tests applying the address-of operator
to an rvalue.
* Initial implementation of block string literals following lexical_conventions/string_literals.md.
Enabled yyinput() in flex to implement parsing.
Added ParseBlockStringLiteral() helper to handler further transformations such as indenting.
Modified formar_grammar to support single-quoted strings to prevent a failure on lexer.lpp.
* Fixed _find_string_end quote parameter type int -> str.
* Update executable_semantics/syntax/BUILD
Co-authored-by: Geoff Romer <gromer@google.com>
* Addressed code review comments - split table-drived test into individual tests, renamed constants to match style guide.
* Addressed code review comments -- using EXPECT_THAT_EXPECTED() in tests, lexer comments and code cleanup.
Co-authored-by: Geoff Romer <gromer@google.com>
The `__Fn` naming is intended to mirror things like `__Continuation`.
The reason for this path is because it's not clear this is the form we'll want, and I think experimental naming will help reflect that.
Arguably missed in #769
Note, this is reminding me we have more class members to rename for `_`, but I felt it's best to use the new naming instead of adding more to clean up.
This does a mass rename of:
- `SourceLoc()` -> `source_loc()` for property naming
- `loc` -> `source_loc_` for underscore+consistency
- Generally changing function args to `source_loc` for consistency
- `Tag()` -> `kind()` for property naming and `Kind` parity
- `tag` -> `kind_` for underscore
Also renames `Pos` and `Results` on `Action`. These are a bit of an exception in that most base classes only have `Tag` and maybe `SourceLoc`, whereas `Action` has a little more. I felt okay having `source_loc()` and `kind()` on the base class where children do `Exp()` and the like, but it felt weird to me to mix it on the same class.
The reason for doing this cross-class in one PR is so that I can do it efficiently with a global replace in the codebase, rather than e.g. changing `Expression` but having to read through compiler errors to determine where it's calling `Expression`'s `Tag` versus a different `Tag`. The end result should be equivalent.
Also apply it to the list of tokens. This way there's no need for "sort order" comments.
This was a side-effect of me trying to merge in api/impl/library/package, and thinking "why am I doing this manually?"
Co-authored-by: Geoff Romer <gromer@google.com>
Doesn't add much logic, only takes advantage of parser structure for the ordering enforcement.
Note import_nonexistent tests should probably fail, but writing import tests needs a chain of functionality, and I figured I'd just start adding some to validate the syntax (not adding existent imports because that'd require multi-file structure).
This is based on discussion on #732: that we should probably parse the invalid whitespace, then reject it as part of string validation, rather than having different parses. I worry the question of "how is this parsed" may lead to subtly unexpected results if we aren't consistent, so I'm switching the logic from the lexer to the unescape library (and also adjusting the list of rejected whitespace).
Related to discussion on #738, but also trying to standardize handling of everything and make placement of token spellings (`AND "and"`) consistently in lexer.lpp.
I could have gone the other direction, removing the list of things in lexer.lpp, but this feels like it does more to use the compiler to detect skew between lexer.lpp and parser.ypp.
It was in my mind to add String in order to support libraries in `package`. `print` is added in order to have a String go to stdout. I've tried to do `print` in a way that won't be too hard to add other printable types, but it's probably also somewhat optional here -- that is, if desired, I could remove it. But it was a lot easier to doublecheck `\n` behavior with it, and I suspect it'll be helpful in other tests if it supports more value types.
On the side, this also fixes dereferencing in Pattern/Expression Print() calls, which I was noticing printing pointers instead of values. This may be another argument for moving away from passing pointers, since this seems to be a difficult-to-catch error.
Co-authored-by: Geoff Romer <gromer@google.com>
This adds a test for invalid characters (that would've failed before, because the printed char isn't escaped). Not sure if there's a good way to test the PrintDiagnostic code, as it appears to occur on bison parser errors, which I'm just not sure how to trigger.
The presence or absence of whitespace is used to determine which
operator is in use, following the rules described in #520.
Support for prefix * dereference operator follows #523.
Co-authored-by: Geoff Romer <gromer@google.com>
* AST and syntax for delimited control
* stashing for later
* a little more progress
* progress on delimited continuations
* delimit, suspend, and resume implemented (draft)
* example that generates the natural numbers
* fixes
* tinkering
* changed demo to experimental
* comments and name changes
* describe delimited continuations in the README
* renamed Snapshot to Continuation, edits to comments
* Update executable_semantics/ast/statement.h
improve comment for MakeDelimitStmt
Co-authored-by: Dave Abrahams <dabrahams@google.com>
* Update executable_semantics/interpreter/interpreter.cpp
remove snake_case
Co-authored-by: Dave Abrahams <dabrahams@google.com>
* edits to comments, change name of variable
* updates to handle review edits
* trailing whitespace
* fixes to delimited continuations, added more tests, also fixed assignment to do a copy
* improvements from Geoffrey
* new test from Geoffrey, fix for empty blocks
* more suggestions from Geoffrey
* more tests for delimited continuations, renaming some of them
* renamed test files
* improve a comment
* sketch of creating continuation
* initial implementation of shift/reset style continuations
* more documentation
* fix some camel case
* implemented deep copy of continuations, added a test case for it
* fixed a bug and got the recursive test case working
* removed __delimit, polished up __continuation
* back to shallow copy for continuations
* suggestions from Geoffrey
* removed structured binding (for now)
* Update executable_semantics/ast/expression.cpp
Co-authored-by: Geoff Romer <gromer@google.com>
* responses to Geoffrey
Co-authored-by: Dave Abrahams <dabrahams@google.com>
Co-authored-by: Geoff Romer <gromer@google.com>
We're now one step away from eliminating bare pointers in semantic actions.
There are plenty of other cleanups and modernizations that can be made in the
parser, but the elimination of bare pointers is the one that has the highest
impact for the codebase.
Slowly bringing this into line with Bison's C++ example parser
so we can use strong semantic values for symbols rather than
leaking pointers. First step is to thread a `ParseAndLexContext`
object through the whole syntactic analysis state, like the
example has. In the example, it's called `driver`.
Co-authored-by: Geoff Romer <gromer@google.com>
Distinguishes parts that come from the parser and lexer. It used to be that all
the files were called "syntax*", but lexing and parsing are distinct phases that
are easier to keep track of when distinguished. syntax.yy.cpp being the source
file generated by flex, containing the lexer was particularly confusing, because
the yy tends to indicate it is a yacc/Bison product, and the ".tab." substring,
indicating "tables" is not really useful to the developer.
These names also match up with what Bison's C++ example uses, which will make
the transition easier.
Richard Smith
Richard SmithandGeoff Romer
