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1 point by sjs 6165 days ago | link | parent

There is force/delay as demonstrated in SICP and On Lisp, or lazy call-by-name thunks. These are pretty rudimentary but they work.

http://swiss.csail.mit.edu/classes/6.001/abelson-sussman-lec... (iirc, streams & the metacircular evaluator)

http://mitpress.mit.edu/sicp/full-text/book/book-Z-H-27.html...

http://www.bookshelf.jp/texi/onlisp/onlisp_16.html#SEC107