BGBCC BAON - cr88192/bgbtech_shxemu GitHub Wiki

New AST Node serialization to replace use of XML.

Node:

• { tag attr* }
• { tag attr* child* }

Attr:

• var=int
• var=real
• var='shortstring'
  • Shortstring is a string which may be interned.
• var="longstring"
  • Longstring is a string which may be heap-allocated.
• var=node
• var= [node*]

Example:

• x+y
  • {binary op='+' left={ref name='x'} right={ref name='y'}}
• x*2
  • {binary op='*' left={ref name='x'} right={int value=2}}

Notes:

• For binary nodes and similar, the left/right attributes are required to be nodes.
• Possibly could allow literal values in some cases, TBD.
• Many nodes may be expressed either as an attribute or as a node.
  • {binary op='*' left={ref name='x'} right={int value=2}}
  • {binary op='*' {left {ref name='x'}} {right {int value=2}}}

Expression or Statement Node Types:

• { assign left right }
  • left=right;
• { assign op left right }
  • left=(left op right);
• { unary op value}
  • (op value)
• { binary op left right }
  • (left op right)
• { funcall name args }
  • name(args)
• { defun name args body }
  • Define function.
• { preinc name } | { postinc name } | { predec name } | { postdec name }

Statement Node:

• { vars var* }
  • { var name type }
  • { var name type init }
  • { proto name type args }
• { begin body* }
  • Block of statements.

Expression Node:

• { ref name }
  • Variable referenced by name.
• { int value }
  • Integer literal (32 or 64 bit).
• { real value }
  • Floating point literal (float or double).
• { string value }
  • String literal.

Init Expression Node:

• { list expr* }
  • List of expressions (array or struct literal).

Structs Node:

• { struct name body }
  • Struct definition (exists in structs list).
• { union name body }
  • Struct definition (exists in structs list).
• { enum name body }
  • Struct definition (exists in structs list).

Topelevel:

• { module structs types body }