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Function prototype: Difference between revisions
→{{header|ALGOL 68}}
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N := Pull;
end Main;</lang>
=={{header|ALGOL 68}}==
{{works with|ALGOL 68|Revision 1.}}
{{works with|ALGOL 68G|Any - tested with release [http://sourceforge.net/projects/algol68/files/algol68g/algol68g-2.8 algol68g-2.8].}}
{{works with|ELLA ALGOL 68|Any (with appropriate job cards) - tested with release [http://sourceforge.net/projects/algol68/files/algol68toc/algol68toc-1.8.8d/algol68toc-1.8-8d.fc9.i386.rpm/download 1.8-8d]}}
'''File: Function_prototype.a68'''<lang algol68>#!/usr/bin/a68g --script #
# -*- coding: utf-8 -*- #
# An explanation of any placement restrictions for prototype declarations #
PROC VOID no args; # Declare a function with no argument that returns an INTeger #
PROC (INT #a#,INT #b#)VOID two args; # Declare a function with two arguments that returns an INTeger #
MODE VARARGS = UNION(INT,REAL,COMPL);
PROC ([]VARARGS)VOID var args; # An empty parameter list can be used to declare a function that accepts varargs #
PROC (INT, []VARARGS)VOID at least one args; # One mandatory INTeger argument followed by varargs #
MODE OPTINT = UNION(VOID,INT), OPTSTRING=UNION(VOID,STRING); # a function that utilizes optional arguments #
PROC (OPTINT, OPTSTRING)VOID optional arguments;
# A prototype declaration for a function that utilizes named parameters #
MODE KWNAME = STRUCT(STRING name),
KWSPECIES = STRUCT(STRING species),
KWBREED = STRUCT(STRING breed),
OWNER=STRUCT(STRING first name, middle name, last name);
# due to the "Yoneda ambiguity" simple arguments must have an unique operator defined #
OP NAME = (STRING name)KWNAME: (KWNAME opt; name OF opt := name; opt),
SPECIES = (STRING species)KWSPECIES: (KWSPECIES opt; species OF opt := species; opt),
BREED = (STRING breed)KWBREED: (KWBREED opt; breed OF opt := breed; opt);
PROC ([]UNION(KWNAME,KWSPECIES,KWBREED,OWNER) #options#)VOID print pet;
# subroutines, and fuctions are procedures, so have the same prototype declarations #
# An explanation and example of any special forms of prototyping not covered by the above: #
COMMENT
If a function has no arguments, eg f,
then it is not requied to pass it a "vacuum()" to call it, eg "f()" not correct!
Rather is can be called without the () vacuum. eg "f"
A GOTO "label" is equivalent to "PROC VOID label".
END COMMENT
SKIP</lang>
=={{header|Aime}}==
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