This unifies `dump-tokens` and `dump-parse-tree` so that we don't keep writing basically the same code repeatedly.
I'll need to modify the output of SemanticsIR::Print more, and may soon unify printing multiple IRs this way (particularly including the builtins SemanticsIR) but this is intended to offer a starting point.
I may eventually try to unify lit.cfg.py files, but I was thinking about whether that works in various contexts we may run in and eventually decided copying the driver/testdata/lit.cfg.py file would be the easiest solution.
This is how I'm interpreting discussion:
- Basic elements are getting set to an ID.
- SetName exists to assign a name (which can then be referred to later with an identifier expression) to an ID.
- Expressions are broken down into a series of operations which operate on IDs.
So with something like the last test:
```
fn Main() { return 12 + 34; }
```
This becomes:
```
Function(%0,
{IntegerLiteral(%3, 12),
IntegerLiteral(%2, 34),
BinaryOperator(%1, +, %3, %2),
Return(%1),
})
SetName(`Main`, %0)
```
Note I'm treating blocks as fairly equal to the top of a file now, and basically eliminating boundaries between things. That's because we have discussed also supporting code like:
```
fn Foo() {
fn Bar() {}
Bar();
}
```
Here a declaration of a function is occurring inside a code block, so it felt like eliminating the difference was the best choice.
I know you'd commented on the separation of nodes to individual files before; I still think we're going to have a lot of different types of nodes, and so separating them out into individual files makes them easier to browse.
Working on toolchain semantics:
- SemanticsIR is set up as a container for the semantic tree.
- SemanticsIRFactory builds the tree, with separate transformations for each ParseNodeKind.
- ParseSubtreeConsumer is a helper for transforming a ParseTree::Node's children, managing size/nodes to prevent errors.
- The nodes subdirectory contains SemanticIR nodes.
- MetaNode is used to represent nodes which have "sub-classes": Statements, Declarations, and Expressions.
- MetaNodeBlock is used to represent nodes which exist together in a block with name lookup: Statements and Declarations (not Expressions).
This is traversing children first in order to address the RPO format of ParseTree. This means that when lists are formed, they're reversed to be in code-order (`FixReverseOrdering`).
This is still very much incomplete -- the main intent at present is to demonstrate structure.
Jon Ross-Perkins