Editing Scheme (programming language) (section)

===Nomenclature and naming conventions===
In Standard Scheme, procedures that convert from one datatype to another contain the character string "->" in their name, predicates end with a "?", and procedures that change the value of already-allocated data end with a "!". These conventions are often followed by Scheme programmers.

In formal contexts such as Scheme standards, the word "procedure" is used in preference to "function" to refer to a lambda expression or primitive procedure. In normal usage, the words "procedure" and "function" are used interchangeably. Procedure application is sometimes referred to formally as ''combination''.

As in other Lisps, the term "[[thunk]]" is used in Scheme to refer to a procedure with no arguments. The term "proper tail recursion" refers to the property of all Scheme implementations, that they perform tail-call optimization so as to support an indefinite number of active [[tail call]]s.

The form of the titles of the standards documents since R3RS, "Revised<sup>n</sup> Report on the Algorithmic Language Scheme", is a reference to the title of the [[ALGOL|ALGOL 60]] standard document, "Revised Report on the Algorithmic Language Algol 60," The Summary page of R3RS is closely modeled on the Summary page of the ALGOL 60 Report.<!--
 --><ref name="algol_report">{{Cite journal |last1=J.W. Backus |last2=F.L. Bauer |last3=J.Green |last4=C. Katz |last5=J. McCarthy P. Naur |display-authors=etal |date=January–April 1960 |title=Revised Report on the Algorithmic Language Algol 60 |url=http://www.masswerk.at/algol60/report.htm |journal=Numerische Mathematik, Communications of the ACM, and Journal of the British Computer Society |access-date=2012-08-09}}</ref><ref name="r3rs">{{Cite journal |date=December 1986 |editor2-last=William Clinger |title=Revised(3) Report on the Algorithmic Language Scheme (Dedicated to the Memory of ALGOL 60) |url=http://groups.csail.mit.edu/mac/ftpdir/scheme-reports/r3rs-html/r3rs_toc.html |journal=ACM SIGPLAN Notices |volume=21 |issue=12 |pages=37–79 |citeseerx=10.1.1.29.3015 |doi=10.1145/15042.15043 |access-date=2012-08-09 |editor=Jonathan Rees |hdl=1721.1/6424 |s2cid=43884422}}</ref>