A Correspondence Between ALGOL 60 and Church's Lambda-Notation: Part I*
This paper describes how some of the semantics
of ALGOL 60 can be formalized by establishing 
a correspondence between expressions of ALGOL 60 and expressions
in a modified form of Church's L-notation. 
 First a model for computer languages and compute behavior
is described, based on the notions of functional 
application and functional abstraction, but also having
analogues for imperative language features.  
Then this model is used as an "abstract object language"
into which ALGOL 60 is mapped.  Many of ALGOL 
60's features emerge as particular arrangements of
a small number of structural rules, suggesting new 
classifications and generalizations.  The correspondence
is first described informally, mainly by illustrations. 
 The second part of the paper gives a formal description,
i.e. an "abstract compiler" into the "abstract 
objct language."  This is itself presented in a "purely
functional" notation, that is one using only 
application and abstraction.
CACM February, 1965
Landin, P. J.
