Support string interpolation

zend_ast_dynamic_ast returns new node

AST stage 2.4

Support yield without parens

for now => is lowest-prec right-assoc

AST stage 1.9

Expressions (mostly) use the AST

AST-based compiler: Stage 1

Accept static member fetch in new variable (BC)

Allow only simple variables with global keyword

Merge and rename to member_name

Remove duplication

Forbid writing to temporary expressions

Support directly calling closure

Fix previous commit

Introduce dereferencable_scalar to simplify future additions

Generalize static access syntax

Allow arrays + object access for new expressions

Integrate combined scalar as dereferencable

Generalize expression dereferencing

Minor cleanup

Cleanup old grammar rules

Reintroduce new expression dereferencing

Remove reference_variable indirection

Make function calls directly callable

Recursive definition for object proprety fetches

LTR static member access