Passing a definition to eval may or may not work according to R5RS. Furthermore, in many Schemes, but not in R5RS, it's possible to call eval with just one argument, implying the interaction environment. I tested the suite of Schemes to determine whether and how it's possible to add definitions to the interaction environment by evaluating the following four forms at the REPL:
(eval '(define x 32) (interaction-environment))
x
(eval '(define y 55))
yThe following Schemes allow definition by eval:
Supports both interaction-environment and single-argument eval: Gambit, Chicken, Bigloo, Kawa, SISC, SCM, Chez, Larceny, NexJ, STklos, TinyScheme, Sizzle, Spark
Supports single-argument eval but not interaction-environment: Racket, RScheme, Scheme 9, S7, XLisp, Rep, Elk, UMB, VX, Llava, SXM, FemtoLisp, Inlab (SXM provides interaction-environment but calling it signals an error)
Supports interaction-environment but not single-argument eval: Gauche, Scheme48/scsh, Guile, Vicare, Ypsilon, IronScheme, SigScheme, Dream, BDC, Sagittarius
The following Schemes do not allow definition by eval:
Does not support interaction-environment or single-argument eval: MIT, Mosh, KSi, Oaklisp, Dfsch, Owl Lisp
Supports both interaction-environment and single-argument eval, but definitions aren't visible in the interaction environment: Chibi
Supports interaction-environment but not single-argument eval, but definitions aren't visible in the interaction environment: Shoe
Does not support eval at all: Scheme 9, Schemik