Directly reflective meta-programming

Existing meta-programming languages operate on encodings of pro-grams as data. This paper presents a new meta-programming language, based on an untyped lambda calculus, in which structurally reflective pro-gramming is supported directly, without any encoding. The language fea-tures call-by-value and call-by-name lambda abstractions, as well as novel reflective features enabling the intensional manipulation of arbitrary pro-gram terms. The language is scope safe, in the sense that variables can neither be captured nor escape their scopes. The expressiveness of the language is demonstrated by showing how to implement quotation and evaluation operations, as proposed by Wand. The language’s utility for meta-programming is further demonstrated through additional represen-tative examples. A prototype implementation is described and evaluated