cleanup

Use ZVAL_COPY until proven wrong

zend_ast_create determined child count automatically

Add zend_ast_list* variant to parser stack element

Minor cleanups in AST code

Use separate node type for lists

This saves storing the children count for normal ast nodes.

Store lineno for zval ast nodes more efficiently

Fix leaks

Must find a good way to handle constant expressions...

Use arena allocator (currently leaky!)

Fixed crash on self-referencing constant expression (part of a constant AST)

Pre-evaluate magic constants

Partial port of class declarations

Prepare zend_ast_decl for reuse with classes

Port methods

The duplicated magic method checks are ugly

Support static closures

Handle function doc comments

Fix lexer/compiler interdependency

Use dedicated func_decl ast node

Functions need a bunch of extra info, that becomes inconvenient
to handle using the normal ast structure.

Lineno corrections

Preliminary function decl support

Problem: __FUNCTION__ etc don't work anymore, due to lexer/parser
interdependency.

approx correct linenos in errors

Store (bad) estimate of lineno with ast

Currently not used yet

Support creating of ast nodes with >3 children

Rename ZEND_CONST to ZEND_AST_ZVAL

Reuse expr for static_scalar