<language> A compiler's internal representation of a program will typically be specified by an abstract syntax in terms of categories such as "statement", "expression" and "identifier". The syntax is abstract in two senses: it is independent of machine-oriented structures and encodings and also independent of the source syntax (concrete syntax) of the language being compiled (though it will often be very similar). A parse tree is similar to an abstract syntax tree but it will typically also contain features such as parentheses which are syntactically significant but which are implicit in the structure of the abstract syntax tree.
(08 Nov 1994)